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Effects of shading on photosynthetic capacity and growth of turfgrass species

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Johan Van Huylenbroeck at Institute for Agricultural and Fisheries Research
Johan Van Huylenbroeck
Erik Van Bockstaele at Institute for Agricultural and Fisheries Research
Erik Van Bockstaele
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Abstract

Shade affects remarkably the durability and development of turf surfaces. Species dependent differences are hereby observed. Objectives of present study were to examine effects of reduced irradiance (65% of ambient sunl~ght) on photosynthetic capacity, pigment content and growth of commercial cultivars of perennial ryegrass (Loltum. perenne L.), red fescue (Festuca rubra L.), smooth-stalked meadowgrass (Poa pratensis L.) and crested hairgrass (Koelena macrantha (Ledeb.) Schultes). For most cultivars (except 'Enjoy', 'Bartitia' and 'Limousine') leaf elonga-tion was stronger under reduced irradiance compared to full sunlight. Grass coverage decreased under shading. This reduction was highest for L.perenne. Under shade conditions chlorophyll content increased in L. perenne, decreased in P.pratensis and K. macrantha and remained unchanged in red fescue. Carotenoid content decreased in most cultivars, with only 'Olano' and 'Cindy' exhibiting a slight increase. Highest net photosynthesis rates were measured for L. perenne, lowest values for R rubra spp. trichophylla and K. macrantha. A strong reduction in maximal photosynthetic capacity was observed for P. pratensis grown under reduced irradiance. In contrast, R rubra spp. rubra reached higher net CO 2 gas exchange rates. For the other species no differences in the light response curves (expressed on dry weight basis) were observed between turf plots grown under reduced irradiance and the non-shaded control ones.
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International Turfgrass Society
Research Journal Volume 9, 2001. 353
EFFECTS OF SHADING ON PHOTOSYNTHETIC CAPACITY AND GROWTH OF
TURFGRASS SPECIES
J.M. Van Huylenbroeck* and E. Van Bockstaele
ABSTRACT
Shade affects remarkably the durability and development of turf surfaces. Species dependent differences
are hereby observed. Objectives of present study were to examine effects of reduced irradiance (65% of ambient
sunl~ght) on photosynthetic capacity, pigment content and growth of commercial cultivars of perennial ryegrass
(Loltum. perenne
L.), red fescue
(Festuca rubra
L.), smooth-stalked meadowgrass
(Poa pratensis
L.) and crested hairgrass
(Koelena macrantha
(Ledeb.) Schultes). For most cultivars (except 'Enjoy', 'Bartitia' and 'Limousine') leaf elonga-
tion was stronger under reduced irradiance compared to full sunlight. Grass coverage decreased under shading.
This reduction was highest for
L.perenne.
Under shade conditions chlorophyll content increased in
L. perenne,
decreased in
P.
pratensis
and
K.
macrantha
and remained unchanged in red fescue. Carotenoid content decreased in
most cultivars, with only 'Olano' and 'Cindy' exhibiting a slight increase. Highest net photosynthesis rates were
measured for
L. perenne,
lowest values for
R rubra
spp.
trichophylla
and
K. macrantha.
A strong reduction in maximal
photosynthetic capacity was observed for
P.
pratensis
grown under reduced irradiance. In contrast,
R rubra
spp.
rubra
reached higher net CO
2
gas exchange rates. For the other species no differences in the light response curves
(expressed on dry weight basis) were observed between turf plots grown under reduced irradiance and the non-
shaded control ones.
Keywords
Carotenoids; chlorophyll; cool-season species; light; physiology
INTRODUCTION
Shade stresses cause major problems in the
maintenance of good quality turf grasses [Beard, 1973].
In modern sport stadiums, reduction of photosynthetic
active radiation influences significantly durability and
performance of a turf surface [Baker, 1995a and bJ. As-
sociated with reduced irradiance, frequently higher rela-
tive humidity, decreased air movement, temperature
fluctuations and/or drought stress (when shade is caused
by trees) occur [Beard, 1973; Bell and Danneberger,
1999J. Together with reduced levels of irradiance these
altered micro-environmental factors influence morpho-
logical and physiological plant responses [Beard, 1997].
With increased shade, a reduction in tiller density, leaf
area index, dry weight, quantity of clipped material, and
degree of coverage was observed in different species
[Budryte-Aleksandraviciene and Schulz, 1999; Gaussoin
et aI., 1988; Wilkinson and Beard, 1974; Wu etal., 1985].
Furthermore, chlorophyll and carotenoid contents
changed and root density decreased [Bell and
Danneberger, 1999; Newell et a!., 1999; Wilkinson and
Beard, 1974; Wilkinson and Beard, 1975]. At low irradi-
ance, reduction in net photosynthesis and dark respira-
Department of Plant Genetics and Breeding (DvP), CLO-
Gent, Ministry of Small Enterprises, Trnders and Agriculture,
Caritasstraat
21, B-9090 Melle, Belgium
*Corresponding anthor: j.vanhuylenbroeck@clo.fgov.be
tion, lower light saturation levels and decreased light
compensation points are frequently observed in grasses
[Allard et aI., 1991 a,b; Kephart et a!., 1992; Wilkinson
et al., 1975; Woledge, 1971]. Recently published data on
photosynthetic characteristics of perennial ryegrass and
red fescue cultivars also demonstrated that significant
differences between species and within the same species
between cultivars existed [VanHuylenbroeck et
aI.,
1999].
In general, perennial ryegrass had a faster growth with
higher net photosynthesis and quantum efficiency and a
lower dark respiration than red fescue. These results
also showed that sufficient genetic variation in the pho-
tosynthetic parameters (dark respiration, light compen-
sation point, and quantum efficiency) was available in
both perennial ryegrass and red fescue for selection and
breeding purposes. Development of new cultivars with
superior shade adaptation is one of the challenges for
breeders in future.
Good management of a turf surface, choice of
the right grass species and polystand can pardy overcome
problems related with shade. Newly introduced grass
species such as
Deschampsia cespitosa
(L.)
Beauv. seem to
be more tolerant
to
shade compared to perennial ryegrass
and smooth-stalked meadowgrass (Schnotz, 2000].
The objective of this study was to evaluate pho-
tosynthetic capacity of turf grass species and cultivars
under shade. Therefore, photosynthetic characteristics,
354
Table 1. Summary of the perennial ryegrass (J..,oliumperenne L.), Chewings red fescue: (Festuca rubra L. spp.
commutata), slender-creeping red fescues: (Jl. r. spp. trichophylla), strong-creeping red fescue: (Jl. r. spp. ",!,bra),
crested hairgrass [Koeleria macrantha (Ledeb.) Schultes] and smooth-stalked meadowgrass (poapratenslS
L.)
cultivars used in the experiments. (Cultivars indicated with * are not yet commercially available)
Cultivar Species Company/lnstitute Country
Kelvin
Mervue
Olano*
Enjoy
Bargreen
Barlander
Barskol
Nevski
Cindy
Barkoel
Bartitia
Limousine
Lolium perenne
L.
Lolium perenne
L.
Lolium perenne
L.
Festuca rubra L. spp. commutata
Festuca rubra
L.
spp. commutata
Festuca rubra
L.
spp. trichophylla
Festuca rubra
L.
spp. trichophylla
Festuca rubra L. spp. rubra
Festuca rubra L. spp. rubra
Koeleria macrantha (Ledeb.) Schultes
Poa pratensis
L.
Poa pratensis
L.
VanderHave Grasses B.V.
DvP
DvP
Cebeco Zaden B.V.
Barenbrug Holland B.V.
Barenbrug Holland B.V.
Barenbrug Holland B.V.
DvP
Cebeco Zaden B.V.
Barenbrug Holland B.V.
Barenbrug Holland B.V.
Cebeco Zaden B.V.
The Netherlands
Belgium
Belgium
The Netherlands
The Netherlands
The Netherlands
The Netherlands
Belgium
The Netherlands
The Netherlands
The Netherlands
The Netherlands
pigment content, leaf elongation and surface cover were
measured.
MATERIALS AND METHODS
A field study was conducted that evaluated three
cuItivars of perennial ryegrass
(Lolium perenne
L.), two
cultivars of Chewings fescue:
(Festuca rubra
L.
spp.
commutata),
two cultivars of slender-creeping red fescue:
(R
r. spp.
trichophylla);
two strong-creeping red fescues:
(R r. spp. rubra), two smooth-stalked meadowgrass culti-
vars
(Paa pratensis
L.)
and one cultivar of crested hairgrass
(Koeleria macrantha
(Ledeb.) Schultes) (Table 1), grown
under two levels of irradiance. Polyethylene fabric shades
were used (Amevo, The Netherlands) to impose irradi-
ance treatments of 65% of ambient sunlight, for com-
parison with a non-shaded treatment. Midday
photosynthetic photon flux density (PPFD, 400-700 nm)
on a cloudless summer day was 993 JLmol m-zsoland 1550
JLmolm-zsolfor the 65% and 100% ambient sunlight treat-
ment, respectively. Microclimatic changes in tempera-
ture and humidity due to shading were not recorded.
Experimental design was a completely randomised block
design with two blocks. The different plots (1.5 x 1.5 m)
were sown on 14 May 1999 at the Department of Plant
Genetics and Breeding (DvP), Melle, Belgium (50
0
59'N,
3°49'E), on a sandy-loam soil with the following compo-
sition of mineral fractions: 6.7% clay (<0.002 mm), 30.3%
silt (0.050-0.002 mm) and 63%.sarid (2.0-0.05 mm). Or-
ganic mater of the soil was 2.0% and pH (HP) was 5.82.
Soil water content at field capacity was 27 volume %.
Seed sowing density was 20 g m-
2
for all species. This
resulted in differences in seedling density for the differ-
ent species, which might have had some effects on
growth, tillering and development of the plants. Three
weeks after sowing, shade cloths were placed. After es-
tablishment, the turfs were mown once or twice a week
at a height oB cm with a reel mower (Mastiff, Ransomes).
Clippings were removed each time. No irrigation was
given during the experiment. Fertilisers were applied in
equal amounts on 15
th
ofJune, 1
st
of August and 15
th
of
September. In total 75 kg ha-lN,
SO
kg ha-lPPs and 40
kg ha-lKzO was given during the experimental period.
Nitrogen was given as ammonium nitrate, phosphate as
superphosphate and potassium as potassium sulphate.
Broad-leaved weed incidence was treated with MCPA on
15 July 1999. No fungicides were used.
Growth Measurements
Plant height, measured to the nearest 0.5 cm,
was determined on 3 September 1999 after a nine day
period during which the turf was not mowed. Two sepa-
rate measurements were taken per plot.
Grass cover was visually rated as a percentage of
potential shoot density on 27 August 1999 on two 0.5 m
Z
areas per plot. To compensate for differences in seedling
density between species, percentage of full sunlight were
afterwards standardised for each cultivar to 100% and
the data for the reduced irradiance were transformed as
relative grass cover based on the grass performance in
full sunlight.
Photosynthesis Measurements
Photosynthesis at canopy level was measured
five months after establishement of the stands. An in-
fra-red gas analysis system was used, consisting of ten
glass cuvettes and operated in open differential mode as
described in detail by Lootens and Heursel [1998] and
Van Huylenbroeck et a!. [1999]. Cuvettes were placed
in a growing room which enabled computer control of
all climatic parameters. Each cuvette had a volume of
500 m1. Air flow entering each cuvette was about 0.5 1
min-ldepending on cuvette. COzconcentration of in-
coming and outgoing air was continuously monitored
by using an infra-red
gas
analyser (IRGA, MK3, Ana-
lytical Development Co., Hoddesdon, England). Air tem-
perature (20°C), COzconcentrations (380 JLl
I-I)
and
355
Relative grass cover under
reduced irradiance (performance
under
full
sunlight =100% for
each cultivar)
54
43
48
85
87
90
87
74
70
88
81
88
8.4
14.0
20.0
19.0
8.0
11.5
11.0
13.0
18.5
15.0
10.0
9.0
8.0
3.5
PPFD65%
PPFD 100%
Cultivar
Species
:rabl~ 2. Effects of reduced irradiance on average plant height (cm), and relative grass cover (%)under reduced
lrradlance compared to non-shading conditions (per cultivar, grass cover of the non-shaded plot was standardised
to=100) on different grass cultivars. Values are means (n-4).
Plant height'
L.perenne
Kelvin 10.0
Mervue 14.0
Olano 12.5
F.
r. spp.
commutata
Enjoy 7.0
Bargreen 7.5
F.
r. spp.
trichophylla
Barlander 6.0
Barskol 7.5
Nevski 13.0
Cindy 11.5
Barkoel 6.5
Bartitia 7.0
Limousine 8.0
LSD 2.9
z Plant height was determined 9 days after turf was cut to 3 cm
F.
r. spp.
rubra
K.
macrantha
P.
pratensis
relative humidity (65 %) in the cuvettes remained con-
stant during measurements, while the irradiance level
depended on the measurement. Signals from the IRGA,
thermocouples, and quantum sensor (Li-Cor, Lincoln,
USA) were fed to a datalogger (DL-2, Delta-T, Cam-
bridge, England) connected to an IBM compatible com-
puter, which enabled the program controlled logging of
these parameters. Each cuvette was sampled every 10
minutes.
For measurements, 5 cm diameter turfed cores
were taken of different cultivars, placed in plastic pots
and transferred into cuvettes. Dark respiration (Rd)and
photosynthesis at different PPFD (60, 200, 320, 550 and
700J-Lmolm.
2S'l)
were determined. Irradiation was pro-
vided by fluorescence lamps in combination with incan-
descent lamps. Before measurements were taken, plants
were allowed to adapt over a 30-min period at every
PPFD. Following this acclimation period, 3 subsequent
measurements were taken at each PPFD. Afterwards all
abovesground material (leaves and stems) was removed
and the pots were placed back in cuvettes to determine
soil respiration (soil, roots and rhizomes in the soil). Har-
vested leaves and stems were dried at 80°C for 24 h be-
fore
dry
weight (DW) was measured. For each cultivar,
four different samples were measured. Dark respiration
and net photosynthesis were calculated taking into ac-
count the corrections for soil, root and rhizome respira-
tion and expressed on a DW basis [Masarovicova, 1997J.
Pigment Determination
Leaf samples were taken on 27 August 1999 and
29 September 1999 and stored in liquid nitrogen until
analysis. Pigments (chlorophyll a, b and total caro-
tenoids) were determined spectrophotometrically
(Uvikon 930 spectrophotometer, Kontron Instruments)
after extraction in 80% aceton as described by Amon
[1949J and Lichtenthaler [1987J. During the whole pro-
cedure samples were protected from light. Results were
expressed per unit fresh weight
(FW).
Statistical Analysis
Analysis of variance was conducted on
all
data
using STATGRAFICS [STSC Inc, 1987J. When signifi-
cant differences occurred, means were separated by the
LSD (P=0.05) method. Results are presented as means
:t
standard error (s.e.)
RESULTS AND DISCUSSION
Under both full sunlight and reduced irradiance
vertical leaf extension of
L.
peT'enne
andF.
rubra
spp.
rubra
cultivars was significantly higher compared to the other
species (Table 2). These observed differences between
species and cultivars are in agreement with earlier mea-
surements under controlled growing conditions [Van
Huylenbroeck et al., 1999J. Except for 'Enjoy', 'Bartitia'
and 'Limousine', leaf elongation in the other cultivars
increased significantly under reduced irradiance com-
pared to full sunlight (Table 2). On average leaf elonga-
tion was 35% higher under reduced irradiance.
Wilkinson and Beard [1974J found that leaf length of
Paa pratensis
and
Festuca rubra
increased with decreasing
irradiance until a critical level. Below this irradiance
leve11eaflength of both species was reduced. Increased
elongation also was observed in other grasses as
bermudagrass
(Cynodon
spp) [Gaussoin et al., 1988J and
Deschampsia
[Pronczuk and Czembor, 1998J. In other
plant species often elongation of certain plant parts (stem)
is observed under moderate reduced irradiance levels.
The capacity to partition the reduced levels of available
356
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Figure
1.
Total chlorophyll (A) and carotenoid (B) content (mg
g-l
FW)
in leaves of
turfgrass
cu1tivars grown under
full
sunlight (PPFD 100%, white bars) or reduced
irradiance (PPFD 65%, hatched bars).Values are means
:t
s.e.
(n=4).
photoassimilates to certain plant parts may control this
phenomena in turfgrasses [Corre, 1983; Schnyder and
Nelson, 1988].
'furf
shoot density decreased under shading
(Table 2). The reduction in shoot density under reduced
irradiance compared to the performance in
full
sunlight
was highest for the
L.
perenne and
R
rubra spp. rubra.
cu1tiVaIS. Similar resultswere reponed earlierin differ-
ent species and itwas concluded that with increased shad~
ing the degree of coverage diminished considerably, not
due to loss of seedlings at emergence, but to a decrease
in tilleting [Budryte-Aleksandraviciene and Schulz,
1999; Wilkinson and
Beard,
1914; Wu et al.,1985].
Pigment composition ofleaves
changed
withre-
duced irradiance, but observed changes depended on
grass
species (Fig. 1). For the threeL. perenne cu1tiv.ars,
total chlorophyll content increased significantly when
grown under shade. In contrast, for 'Barkoe1'
(K.
macrantha) and
P.
pratensis 'Bartitia'and 'Limousine' a
reduction in total chlorophyll was observed (Fig. lA).
For all
R
rubra
cultivars,reduction in irradiance had no
significant effect on chlorophyll concentration. Caro-
tenoid concentration decreased in most cultivars, but
actually increased when cultivars 'Olano' and 'Cindy'
were grown in shade (Fig. lB). Changes in pigment
composition in plants grown under reduced irradiances
are observed in many plant species. In grasses both re-
ductions in pigment contents when growing under shade
conditions [Bell and Danneberger, 1999] as well as in-
creases [Allard et al,1991b] have been reponed. Shade
adapted leaves have frequently higher chlorophyll con-
tents per volume or weight compared to sun adapted
leaves
[Boardman,
1971J. Wilkinson and Beard [1915]
found that chloroplast density decreased in
P.
pratensis
357
250
200 200
150 150
100 100
100%65%
50
0,.
Kelvin 50
0,. Mervue
0
6. , ....
Olano 0
-50 -50
250 250
"'D
..-..
"
en
200 200 -
~::J
3
0
150 150
Q.
'7
(1
0> 100
",0
C\I
100
0
co
0
50 50
.:..
<5
0
E
00~
5
CIl
.
<=
-50 ~
c..
-50
-
250 250
200 200
150 150
100 100
50 100"k65% 50
0o,•
Bartitia
0
o,•
Limousine
-50 -50
0000000008°000000
0000000 00000
,....C\I('1)~LO(Or-. ,....C\I('1)~LO(o"
PPFD (I1molm-
2S-1)
PPFD (IlmoJm-
25-1)
Figure 2. Light response curves of Lolium perenne (A), Festuca rubra spp. commutata (B),
Festuca rubra spp. trichophylla
(C),
Festuea rubra spp. rubra (D),
Koeleria
macrantha (E) and
Poa pratensis
(F)
turfgrass cultivars grown under
full
sunlight (PPFD 100%, open
symbols) or reduced irradiance (PPFD 65%, closed symbols). Values are means
:t
s.e.
(n=4)
(ifnot visible,s.e.smaller than data label).
and
Erubra,
which however could not be associated with
observed differences in turf performance under shade
between the tested cultivars.
Significant differences between species in net
photosynthesis, measured at 700 }.tmolm-
2S-l,
were found
(Table 3).
L.
perenne
reached the highest net photosyn-
thetic rates, while for Er. spp. trichophylla and K.
macrantha
significantlylower values were measured. The
classificationof the species based on the photosynthetic
measurements (Table 3) agreed with those found by mea-
suring plant height (Table 2). Earlier observations un-
der controlled environmental conditions showed similar
results [Van Huylenbroeck et al, 1999]. The measure-
ments of net photosynthesis showed significant interac-
tion between turfgrass species and irradiance pretreat-
ment (Table 3). This isillustratedin the photosynthetic
light response curves (Fig.2). A strong reduction in
maximal photosynthetic capacity was observed for
E
pratensis
'Bartitia'and 'Limousine' grown under reduced
irradiance, In contrast,
E
rubra
spp
rubra
'Nevski' and
'Cindy' grown under shade reached even higher net CO
2
gas exchange rates compared to the control plants.
K.
macrantha
'Barkoel' showed no differences between both
treatments. For
L.
perenne
and
E
rubra spp.
tric/wphylla
observed differences in the light response curves (ex-
pressed on
dry
weight basis) between
turf
plots grown
under reduced irradiance and the non-shaded control
plots depended on the cultivar(Fig. 2). Wilkinson et al.
[1975] found decreased light-saturated net photosyn-
358
**
**
ACKNOWLEDGEMENTS
Po
700
164.7
162.6
194.7 C'
175.4 B
133.5 A
181.4 BC
126.0 A
170.8 B
NSY
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thesis in
Phalaenopsis
hybrids. HortSci. 33:
1183-1185.
Masarovicova, E.. 1997. Measurements of plant photo-
synthetic activity. In: M. Pessarakli (ed.) Handbook
of photosynthesis. New York, Marcel Dekker Inc.,
pp. 769-802.
Newell, A.J., J.C. Hart-Woods, and A.D. Wood. 1999.
Effects of four different levels of shade on the perfor-
mance of three grass mixtures for use in lawn tennis
courts. J. Turfgrass Sci. 75: 82-88.
Pronczuk, M. and E. Czembor. 1998. Infection of
Puccinia graminis
to
Deschampsia caespitosa
under sun
and shade conditions. In: B. Boller and F.J.
Irradiance
Turfgrass species
Irradiance x Turfgrass species
z Means followed by the same letter are not
significantly different at P= 0.01
y NS, Non-significant;
**
significant at
P=O.OI,
using analysis of variance
We thank the Department for Crop Husbandry and
&0-
physiology for use of their photosynthesis equipment.
thetic rates, lower dark respiration, and decreased light
compensation points for
R pratensis
and
E rubra
when
grown under reduced irradiance. On the other hand,
Kephart et al. [1992] reported for several C3and C4grass
species that adaptation to shade did not seem to affect
photosynthesis in full sunlight. Plants grown in 37 and
70% of ambient sunlight regimes during 55 days had net
leaf CO2gas exchange rates comparable to those grown
in full sunlight. In
Festuca arundinaceae,
shade grown
leaves never reached photosynthetic capacities of those
developed completely under full sunlight when expressed
on a leaf area basis, but they also were similar when ex-
pressed on a basis of dry matter [Allard et al., 1991b].
These results show that differences in shade tol-
erance as observed between species are related with pho-
tosynthetic features of the species. For breeding
purposes, screening at the individual plant level will be
more efficient compared to measurements at the canopy
level. Further research is therefore necessary to study
the variation between individual plants and their per-
formance under shade conditions.
Photosynthetic light response curves also show
that species
(E rubra
spp
trichophylla, E rubra
spp.
commutata,
K.
macrantha,
and
R pratensis)
performing best
under reduced irradiance (based on grass cover observa-
tions), reached their saturation level at a lower PPFD
than those species
(L.
perenne
and
E rubra
spp.
rubra)
that
were less tolerant.
Table 3. Net photosynthesis (nmol CO
2
g"lDW sol)
measured at PPFD 700 p.mol m-2solfor different
turfgrass species grown in
full
sunlight or at
reduced irradiance (data are means of all cultivars
tested in the experiment)
Source of Variation
Irradiance 100%
65%
Turfgrass species
L.
perenne
F.
r. spp. commutata
F. r. spp. trichophylla
F.
r. spp. rubra
K.
macrantha
P.
pratensis
Stadelmann (eds.), Breeding for a multifunctional
agriculture. Swiss Federal Research Station for
Agroecologyand Agriculture, Ziirich-Reckenholz,pp.
215-217.
Schnotz, G. 2000. Die Rasenschmiele (Deschampsia
cespitosa
[L.]
P.B.-eineAlternativerur die Begriining
von Problemstandorten. Rasen Turf Gazon 31: 25-
27.
Schnyder, H., and C. Nelson. 1988. Growth rates and
assimilate partitioning in the elongation zone of tall
fescue leaf blades at high and low irradiance. Plant
Physiol. 90: 1201-1206.
STSC. 1987. Statgraphics Users' Guide. Rockville:
STSC.
Van Huylenbroeck, J.M., P. Lootens, and E. Van
Bockstaele. 1999. Photosynthetic characteristics of
perennial ryegrass and red fescue turf-grass cultivars.
Grass Forage Sci. 54: 267-274.
Wilkinson, J.R, and J.B. Beard. 1974. Morphological
responses of
Poa pratensis
and
Festuca rubra
to reduced
359
light intensity. In: E.C. Roberts (ed.), Proceedings
SecondInternational TurfgrassResearchConference.
International Turfgrass Society and ASA and CSSA,
Madison, Wisconsin, USA, pp.231-240
Wilkinson, J.R, and J.B. Beard. 1975. Anatomical re-
sponses of 'Merion' Kentucky bluegrass and
'Pennlawn' red fescue at reduced light intensities.
Crop Sci. 15: 189-194.
Wilkinson,J.R,J.B. Beard,andJ.V. Krans. 1975. Pho-
tosynthetic-respiratory responses of 'Merion' Ken-
tucky bluegrass and 'Pennlawn' red fescueat reduced
light intensities. Crop Sci. 15: 165-168.
Wolledge,J. 1971. The effect of light intensity during
growth on the subsequent rate of photosynthesis of
leaves of tall fescue
(Festuca arundinaceae
Schreb.).
Ann. Bot. (London) 35: 311-322.
Wu, L., D. Huff, and W:B. Davis. 1985. Tallfescueturf
performance under a tree shade. HortSci. 20: 281-
282.
... Interestingly, the SD and SIL decreased in four bermudagrass cultivars after a prolonged period of shade stress (30 days). It is well known that shade leads to thin and elongated erect stems and tillers in many plant species (Huylenbroeck and Bockstaele, 2001). An earlier study has shown that warm-season grasses are more morphologically restricted by the shade-stress, leading to an overall decrease in turf quality (Xie et al., 2020). ...
... The asterisk ( * ) above letter indicates a significant difference (p ≤ 0.05) in one particular cultivar between normal conditions and shade stress. Huylenbroeck and Bockstaele, 2001). The maintenance of a lower ratio of Chl a/b has been found to be one of the important indicators of stress adaptability in plants (Zeng et al., 2021). ...
Adaptive Responses of Common and Hybrid Bermudagrasses to Shade Stress Associated With Changes in Morphology, Photosynthesis, and Secondary Metabolites
Article
Full-text available
  • Mar 2022
Alteration of ploidy in one particular plant species often influences their environmental adaptation. Warm-season bermudagrass is widely used as forage, turfgrass, and ground-cover plant for ecological remediation, but exhibits low shade tolerance. Adaptive responses to shade stress between triploid hybrid bermudagrass cultivars [“Tifdwarf” (TD), “Tifsport” (TS), and “Tifway” (TW)] and tetraploid common bermudagrass cultivar “Chuanxi” (CX) were studied based on changes in phenotype, photosynthesis, and secondary metabolites in leaves and stems. Shade stress (250 luminance, 30 days) significantly decreased stem diameter and stem internode length, but did not affect the leaf width of four cultivars. Leaf length of CX, TD, or TW showed no change in response to shade stress, whereas shade stress significantly elongated the leaf length of TS. The CX and the TS exhibited significantly higher total chlorophyll (Chl), Chl a, carotenoid contents, photosynthetic parameters [PSII photochemical efficiency (Fv/Fm), transpiration rate, and stomatal conductance] in leaves than the TW and the TD under shade stress. The CX also showed a significantly higher performance index on absorption basis (PIABS) in leaf and net photosynthetic rate (Pn) in leaf and stem than the other three cultivars under shade stress. In addition, the TS maintained higher proantho cyanidims content than the TW and the TD after 30 days of shade stress. Current results showed that tetraploid CX exhibited significantly higher shade tolerance than triploid TD, TS, and TW mainly by maintaining higher effective photosynthetic leaf area, photosynthetic performance of PSI and PSII (Pn and Fv/Fm), and photosynthetic pigments as well as lower Chl a/b ratio for absorption, transformation, and efficient use of light energy under shade stress. For differential responses to shade stress among three triploid cultivars, an increase in leaf length and maintenance of higher Fv/Fm, gas exchange, water use efficiency, carotenoid, and proanthocyanidin contents in leaves could be better morphological and physiological adaptations of TS to shade than other hybrid cultivars (TD and TW).
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... Shade effects on turfgrass are inevitable around trees and buildings, or in stadiums where natural turfgrasses are used for highquality playing surfaces (Bell et al. 2000, Matsubara et al. 2019). There is a large variation in the levels of shade tolerance among turfgrass species and cultivars (Gilbert andDiPaola 1985, Van Huylenbroeck andVan Bockstaele 2001). C3 cool-season grasses are generally more tolerant to shade than C4 warm-season grasses (Kephart and Buxton 1993, Awada et al. 2003, Kubásek et al. 2013. ...
... More importantly, the root system decreases faster than the shoot system, resulting in decreasing the root-to-shoot ratio, and decreases the capacity of water and nutrients uptake (Allard et al. 1991a). Ultimately, extended periods of shade conditions cause poor turfgrass quality and slow recovery from the damages by traffics and wear (Van Huylenbroeck and Van Bockstaele 2001). ...
Assessing shade stress in leaves of turf-type tall fescue (Festuca arundinacea Schreb.)
Article
Full-text available
  • Jul 2021
  • PHOTOSYNTHETICA
Shade treatment was applied to tall fescue with 30% full light. The results showed that shade increased chlorophyll (Chl) content per unit leaf mass, decreased the Chl a/b ratio in the mature leaves, and decreased effective quantum yield based on Chl fluorescence compared to the full light treatment. Shade stress did not cause increased contents of malondiadehyde at the early stages of leaf development. However, normalized vegetation indices were able to detect shade stress. Chloroplasts in the shaded leaves are arranged tightly against the periclinal cell wall and are in a spindle shape. There were no differences in the number of grana per chloroplast or grana size (thylakoids per granum) between shade and full light treatment. In conclusion, tall fescue leaves showed unique ultrastructure changes. Turfgrass managers could use vegetation indices developed from the leaf light reflection spectrum as an effective tool to assess shade stress levels and make management decisions.
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... In addition to changes in morphology, changes in leaf chlorophyll concentration and photosynthesis factors are necessary to maintain normal growth and photosynthesis and are important strategies for shade resistance in plants [28,29]. Although lower levels of light intensity can be effective in promoting the formation of Chl in the short term, long periods of low light inhibit the biosynthesis of Chl and accelerate its degradation, leading to leaf shrinkage [30,31]. After ALA treatment, we observed a remarkable rise in total Chl concentration, as well as Chl-a and Chl-b concentration, in yew seedlings under shade stress ( Figure 5). ...
Alleviation of Shade Stress in Chinese Yew (Taxus chinensis) Seedlings with 5-Aminolevulinic Acid (ALA)
Article
Full-text available
  • Jun 2023
5-aminolevulinic acid (ALA) is a novel regulator that can promote plant growth, nitrogen uptake, and abiotic stress tolerance. Its underlying mechanisms, however, have not been fully investigated. In this study, the effects of ALA on morphology, photosynthesis, antioxidant systems, and secondary metabolites in two cultivars of 5-year-old Chinese yew (Taxus chinensis) seedlings, ‘Taihang’ and ‘Fujian’, were examined under shade stress (30% light for 30 days) using different doses of ALA (0, 30, and 60 mg/L). The findings from our study show that shade stress significantly reduced plant height, stem thickness, and crown width and increased malondialdehyde (MDA) levels. However, the application of 30 mg/L ALA effectively mitigated these effects, which further induced the activity of antioxidant enzymes under shade stress, resulting in the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) being increased by 10%, 16.4%, and 42.1%, and 19.8%, 20.1%, and 42% in ‘Taihang’ and ‘Fujian’, respectively. It also promoted their role in the absorption, conversion, and efficient use of light energy. Additionally, the use of 30 mg/L ALA caused a significant increase in the concentration of secondary metabolites, including polysaccharide (PC), carotenoid (CR), and flavonoids (FA), with increases of up to 46.1%, 13.4%, and 35.6% and 33.5%, 7.5%, and 57.5% in both yew cultivars, respectively, contributing to nutrient uptake. With ALA treatment, the yew seedlings showed higher chlorophyll (total chlorophyll, chlorophyll a and b) levels and photosynthesis rates than the seedlings that received the shade treatment alone. To conclude, the application of 30 mg/L ALA alleviated shade stress in yew seedlings by maintaining redox balance, protecting the photorespiratory system, and increasing organic metabolites, thus increasing the number of new branches and shoots and significantly promoting the growth of the seedlings. Spraying with ALA may be a sustainable strategy to improve the shade-resistant defense system of yew. As these findings increase our understanding of this shade stress response, they may have considerable implications for the domestication and cultivation of yew.
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... As the amount of light and lux decreases, the starch content in the shoot and root region may decrease (Wilkinson et al., 1975). At the same time, a decrease in the amount of new shoots can be seen in turf plants grown in shaded areas (Van Huylenbroeck and Van Bockstaele, 2001). Stomatal closure response occurs due to intense starch consumption in plants grown under limited photosynthesis and constant drought and shade stress (Asghar et al., 2020). ...
Tolerance Characteristics of Turfgrasses
Chapter
Full-text available
  • Dec 2022
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... Shading reduces the total amount of radiation reaching the plants' surface. Pigments absorb more light energy, and their abundances depend on shade intensity, duration and species (Huylenbroeck & Bockstaele, 2001). Under low light intensities, most turf grasses capture more light energy by increasing the accumulation of photosynthetic pigments (Zhou et al., 2003;Wherley, Gardner & Metzger, 2005), but if pigment synthesis pathways are damaged or degraded, the contents eventually decrease (Bell & Danneberger, 1999;Zhou et al., 2010). ...
Different photosynthetic adaptation of Zoysia spp. under shading: shade avoidance and shade tolerance response
Article
Full-text available
  • Oct 2022
Reduction of ambient solar radiation is an important external challenge for plants, which affects photosynthesis and morphogenesis in agroforestry or gardening. As bottomed sessile organisms, turfgrasses have a set of sophisticated photosynthetic strategies to survive and deal with this abiotic stress. Zoysiagrass ( Zoysia spp. Willd.) is an important warm-season, perennial turfgrass that tolerates adversity, wear, trampling and extensive management. However, whole photosynthetic characteristics reaction of the zoysiagrass to shade stress have not been described because our knowledge in this area is very limited. In this study, 85% shade treatment was applied to nineteen zoysiagrass genotypes, and morphological observations and extensive determinations on plant heights, photosynthetic pigments, fluorescence dynamic curves among other parameters were made. The results showed that vegetal and photosynthetic responses of zoysiagrass were affected by shade treatment to varying degrees. Further analysis based on the principal component, subordinate function analysis and clustering methodology revealed that different shading response strategies were adopted by zoysia under shade surroundings. They were divided into four categories. The strongest shade-avoidant response strategy was adopted by ‘ZG48’ and ‘WZG59’, which had the largest comprehensive evaluation (D) values, and the stabilized shade-tolerant response was taken on by ‘ZG-3’ and ‘ZG64’, which had the lowest D values. Other varieties applied a medium strategy but with a certain tendency. These findings provide new insights into different shading response tactics of turfgrass: shade avoidance and shade tolerance response, which could be selected for further elucidation of the molecular mechanism of plant adaptation to shade environments.
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... They also noted that apparent quantum yield was unaffected by the treatments while the dark respiration rates and chlorophyll a:b ratio were greatly reduced by the shade treatment. Van Huylenbroeck et al. [8] concluded that red fescues (Festuca rubra) generally had lower LCPs than perennial ryegrasses (Lolium perenne), which corresponded to better adaptation to the lower light intensities. When multiple genotypes of four species of cool-season grasses were evaluated, Van Huylenbroeck & Van Bockstaele [9] determined that individual genotypes differed in ARTICLE their LCP within their respective species. ...
Towards estimating shade response of bermudagrass (Cynodon spp.) using field-based photosynthetic properties
Article
Full-text available
  • Apr 2022
Shade tolerance is a highly desirable trait when breeding new bermudagrass (Cynodon spp.) lines, but current screening methods can take many years to complete. There is a clear need for large-scale turfgrass breeding programs to reliably, accurately, and quickly predict shade tolerance in their germplasm. The objectives of this research were to: (i) build custom chambers to reproducibly estimate photosynthetic characteristics from turfgrass canopies at different light intensities and (ii) determine which photosynthetic characteristics are indicative of past shade performance. A custom-built chamber was constructed to determine average photosynthetic characteristics for the whole plant by studying the turfgrass canopy at natural leaf angles for light interception. Shade tolerant (11-T-56) and shade sensitive (Tifway) bermudagrass cultivars were used to examine the effectiveness of the chamber within an array of photosynthetic characteristics when the grasses were grown in full-sun and 73% shade environments. Light compensation point, chlorophyll content, quantum yield, dark respiration rate, and maximum quantum yield of photosystem II were evaluated in this trial. Based on the results of this study, the authors recommend that light compensation point or maximum quantum yield be further evaluated as an accurate indicator of shade tolerance when performed in the field on spring days with grasses grown in full sun or 73% shade environments. Lower Rd rates and ambient temperatures on spring days appear to minimize unexplained variance in the data, which would allow researchers to better detect genotypic differences during this season.
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... Subjected to high and low irradiance, the results showed that creeping bentgrass accumulates high amounts of bcarotene and lutein under high and low irradiance, which results in higher quality turfgrass surfaces than other turfgrass species when grown in shade. Huylenbroeck and Bockstaele (2001) carried out a trial on four turfgrass species under shade and found that perennial ryegrass had a faster growth with higher net photosynthesis and quantum efficiency, and a lower dark respiration than red fescue (Festuca rubra L.). Total chlorophyll content in L. ...
Investigating the exogenous application of 5-Aminlevulinic acid to improve turfgrass (Lolium perenneL.) surfaces grown in shade
Article
Full-text available
  • Dec 2021
The quality of turfgrass playing surfaces can be severely compromised when grown in the modern sports stadia environment. Shade from the large grandstands prevent direct sunlight from reaching most of the pitch and Grounds Managers are using lighting rigs to replace natural light. Other solutions are required to reduce the high energy costs of this equipment yet maintain the essential high quality of the playing surfaces. This study investigated the effect of exogenous applications of 100mg L-1e 5-Aminolevulinic acid (5-ALA) to turfgrass Lolium perenne L. grown in 100% daylight (Light) and 50% daylight (Shade). Two experiments were setup to investigate a number of parameters. Experient One consisted of turfgrass L. perenne grown in tubs containing a sand rootzone overlying gravel to replicate the modern sports pitch construction. Clippings were analysed for chlorophyll content (NDVI), % Dry Weigh and leaf nutrient content (mg kg-1). Experiment Two used the same rootzone and grass seed as in Experiment 1 but grown in 3 inch pots. Fluorescence parameters measurements concentrated on the effects of exogenous applications of 100mg L-1 on Photosystem II (PSII): Maximum Quantum Yield (Fv/Fm), Quantum Yield (ØPSII or Fq’/Fm’), and Non-Photochemical Quenching (NPQ). Exogenous applications of 100mg L-1 5-ALA resulted in significant increases in chlorophyll (NDVI) in treated plants compared the Control (non-treated) in both Light and Shade on Days 7 and 14 after treatment, and in Shade on Day 14 after treatment. % Dry Weight increased only on Day 7 after treatment in Treated Shade grown plants. There were significant differences of some nutrients due to 5-ALA treatments: Mg and Zn on Day 0 (4 hours) after treatment; Mn and Zn on Day 7 after treatment. There were some effects on fluorescence parameters, but significant differences were mainly attributed to whether the plants were grown in Light or Shade, not applications of 5-ALA.
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... Etiolation resulting in longer internode and elongated stems and leaves are primary physiological and visual responses of turfgrasses attempting to reach sunlight in reduced light environments as photosynthates and carbohydrate resources are reallocated (Schnyder & Nelson, 1989;Winstead & Ward, 1974). Other developmental responses to shade are reduction in root biomass (Baldwin, 2008) and aboveground green cover (Trappe et al., 2009) as well as reduced tillering resulting in reduced shoot density (Van Huylenbroeck & Van Bockstaele, 2001). Turfgrasses that can retain quality (a combined evaluation of color, density, texture, and uniformity) over time and have a diminished vertical leaf extension rate tend to be better adapted to reduced light environments (Wherley et al., 2013). ...
Performance of diploid and interploid hybrids of St. Augustinegrass under moderate shade
Article
Full-text available
Shadetolerance is an important factor for cultivar selection in urban areas. Diploid (2n = 2x = 18) cultivars of St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] with moderate to high shade tolerance have been popular choices for residential and commercial landscapes in the southern United States. This study evaluated 26 elite drought resistant diploid and interploid (polyploid × diploid) hybrids and four commercial cultivars under 75% continuous shade from 20 June 2017 through 30 Oct. 2018. Biweekly data were collected during the growing season for percent green cover, visual turfgrass quality, canopy color, shoot density, and daily leaf elongation rates (DER; mm d–1). Spring greenup was rated annually, and to gray leaf spot incidence was rated when naturally occurring. All genotypes lost green cover through 2017, and greenup was delayed transitioning into the summer of 2018 when most diploids struggled to recover from disease, shade, and winter injury whereas, on an average, interploid hybrids reached up to 84.0% green cover. Daily leaf elongation rates were lower for diploids than polyploids in both years. Turfgrass quality, color, and density generally declined under shade as expected. Overall, three interploid hybrids (DALSA 1329, 1404, and 1406) were the top performers demonstrating good retention of turfgrass performance traits and reduced DER under shade.
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Objektive Messverfahren zur Bestimmung von Reitbodeneigenschaften und deren Einfluss auf den Bewegungsapparat des Pferdes – Ein Überblick
Article
Full-text available
  • Dec 2023
  • WIEN TIERARZTL MONAT
Zusammenfassung In dieser Arbeit wird ein Überblick über die Methoden zur Messung von Reitbodeneigenschaften, sowie zu den bisher bekannten Einflüssen dieser Eigenschaften auf den Bewegungsapparat des Pferdes gegeben. Der Fokus liegt auf Messmethoden für mechanische Eigenschaften, welche sehr vielfältig sind und von einfachen, unidirektional messenden bis hin zu komplexen Apparaten reichen, die versuchen, den Bewegungsablauf des Pferdes möglichst genau nachzuahmen. Außerdem gibt es Geräte, die in vivo die mechanische Interaktion zwischen Gliedmaße und Boden direkt messen. Eine Kombination verschiedener Methoden, sowie das Einbeziehen anderer Bodeneigenschaften und äußerer Einflüsse ist sinnvoll, um aussagekräftigere und vergleichbarere Schlüsse über Böden und deren Auswirkung auf Pferde zu ziehen. Dazu gehören z.B. die Bodenzusammensetzung, Wetterdaten, Pflegemaßnahmen, aber auch epidemiologische Verletzungsdaten der Pferde oder Computersimulationen. Bis heute gibt es bei Pferdesportveranstaltungen kaum ein Reglement zu verwendeten Böden, jedoch werden deren Effekte auf Leistung und Sicherheit der Pferde mit fortschreitenden Untersuchungen immer offensichtlicher. Einige Faktoren wie z.B. die Bodenhärte, Scherfestigkeit oder Kraftreduktion beim Auffußen sind für ihre Relevanz diesbezüglich bekannt und in einer Vielzahl an Böden untersucht. Anhand solcher Daten gab es beispielsweise im Pferdesport bereits zahlreiche Anpassungen hin zu sichererem Bodenmaterial, eine Optimierung von Pflege und Management der Böden, sowie teilweise die Etablierung verpflichtender Bodentestungen. In jeder Reitsportdisziplin liegen andere Belastungsmuster, Risikofaktoren und Pathologien zugrunde und es besteht, insbesondere in Disziplinen abseits des Rennsportes, noch viel Raum für Forschung und weitere Optimierung der verwendeten Böden. Summary Objective Methods for Measuring Riding Surface Properties and their Influence on the Musculoskeletal System of the Horse – Review This paper presents an overview of the methods for measuring riding surface properties, as well as the known influences of these properties on the musculoskeletal system of the horse. The focus is on methods for measuring mechanical properties. They are very diverse and range from simple, unidirectional methods to complex apparatuses that aim to mimic the horse's movement as closely as possible. There are also devices that measure the mechanical interaction between the limb and the ground directly in vivo. A combination of methods, and incorporating other surface properties and external influences, is useful in drawing meaningful and comparable conclusions about surfaces and their effects on horses. These include substrate composition, weather data and maintenance practices, as well as epidemiological equine injury data and computer simulations. There are still few regulations on surfaces used in equestrian events but their effects on horse performance and safety are becoming more apparent as research progresses. Factors such as hardness, shear strength and force reduction at footing are known to be relevant in this regard and have been studied in a variety of surface types. The data have led to numerous adaptations in equestrian sports, for example towards safer soil material, an optimization of the maintenance and management of the surfaces and the establishment of obligatory soil testing, which varies from region to region. In each equestrian discipline there are different underlying loading patterns, risk factors and pathologies and there is much room for research and further optimization of the surfaces used, especially in disciplines other than racing.
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Ocena przydatności odmian życicy trwałej (Lolium perenne L.) na trawniki okresowo zacieniane
Article
Full-text available
  • Jun 2008
W latach 2000–2003 badano osiem odmian życicy trwałej (Lolium perenne L.) pochodzenia krajowego i zagranicznego oraz jedną odmianę kostrzewy czerwonej kępowej (Festuca rubra L. ssp. commutata Gaud.) i jedną śmiałka darniowego (Deschampsia caespitosa (L.) P. Beauv.) jako wzorce. Ocenę odmian przeprowadzono w dwóch doświadczeniach zlokalizowanych w pełnym słońcu i w warunkach okresowego zacienienia powodowanego przez ścianę budynku. W doświadczeniach zastosowano intensywne użytkowanie trawnikowe. Oceniano następujące cechy: ogólny aspekt estetyczny i zadarnienie w sezonach: wiosna, lato, jesień oraz nasilenie pleśni śniegowej (Microdochium nivale) po zimie. Stwierdzono, że okresowe zacienienie wpłynęło na obniżenie wartości wszystkich badanych cech odmian w porównaniu do wartości uzyskanej w pełnym słońcu. Największy spadek wartości notowano w zadarnieniu trawników. Wartość tej cechy obniżyła się średnio o 14,5% w stosunku do stanowiska nasłonecznionego, a zakres u odmian zawierał się w przedziale od 5,2% u Barcampsia — odmiany śmiałka darniowego do 22,5% u Repell — odmiany życicy trwałej. Warunki świetlne wpłynęły na ujawnienie się różnic w podatności odmian na pleśń śniegową. Większość odmian życicy trwałej była bardziej podatna na tę chorobę w cieniu w porównaniu do pełnego oświetlenia. Wyjątkiem były takie odmiany życicy jak Taya i Stoper oraz odmiany wzorcowe: Barcampsia (śmiałek darniowy) i Nimba (kostrzewa czerwona), które były mniej porażane w cieniu niż w słońcu. Generalnie odmiany życicy trwałej bardziej reagowały na zacienienie i ustępowały pod względem badanych cech odmianom wzorcowym. Spośród odmian życicy najbardziej przydatna na trawniki okresowo zacieniane okazała się odmiana Sourire. Potwierdzono wysoką tolerancje na cień odmian śmiałka darniowego.
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Response of 32 Bermudagrass Clones to Reduced Light Intensity
Article
Full-text available
  • Feb 1988
The response of bermudagrass clones ( Cynodon spp.) to reduced light intensity was determined in a greenhouse experiment. Thirty-two phenotypically diverse bermudagrass clones from broad geographic origins were subjected to two light treatments. The high-light treatment consisted of sunlight supplemented with fluorescent and incandescent light banks (160 µmol·s –1 ·m –2 ). The low-light treatment was a 90% reduction of the high-light treatment (16 µmol·s –1 ·m –2 ). Visual color, leaf length, stem internode length, stem elongation, chlorophyll concentration, and dry weight were measured. Bermudagrass clones responded to reduced light by exhibiting shorter leaves, shorter stem internodes, reduced green color, lower chlorophyll concentration and decreased dry weights. ‘Boise’, ‘No Mow’, ‘R9-P1’, ‘NM2-13’, and ‘NM3’ have been identified as being moderately insensitive to reduced light intensity, and data suggest enough variability exists to select for shade tolerance in bermudagrass.
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Irradiance, Temperature, and Carbon Dioxide Enrichment Affect Photosynthesis in Phalaenopsis Hybrids
Article
Full-text available
  • Dec 1998
The short-term effects of photosynthetic photon flux (PPF), day/night temperatures and CO2 concentration on CO2 exchange were determined for two Phalaenopsis hybrids. At 20°C, the saturating PPF for photosynthesis was 180 μmol · m-2 · s-1. At this PPF and ambient CO2 level (380 μL · L-1), a day/night temperature of 20/15°C resulted in the largest daily CO2 uptake. Higher night temperatures probably increased the respiration rate and lowered daily CO2 uptake in comparison with 20/15°C. An increase in the CO2 concentration from 380 to 950 μL · L-1 increased daily CO2 uptake by 82%.
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Chlorophylls and carotenoids: Pigments of photosynthetic biomembranes
Article
Full-text available
  • Dec 1987
Publisher Summary This chapter presents detailed information on chlorophylls and carotenoids to give practical directions toward their quantitative isolation and determination in extracts from leaves, chloroplasts, thylakoid particles, and pigment proteins. The chapter focuses on the spectral characteristics and absorption coefficients of chlorophylls, pheophytins, and carotenoids, which are the basis for establishing equations to quantitatively determine them. Therefore, the specific absorption coefficients of the pigments are re-evaluated. This is achieved by using a two-beam spectrophotometer of the new generation, which allows programmed automatic recording and printing out of the proper wavelengths and absorbancy values. Several procedures have been developed for the separation of the photosynthetic pigments, including column (CC), paper (PC), and thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC). All chloroplast carotenoids exhibit a typical absorption spectrum that is characterized by three absorption maxima (violaxanthin, neoxanthin) or two maxima with one shoulder (lutein and β-carotene) in the blue spectral region.
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Temporal Shade on Creeping Bentgrass Turf
Article
  • Jul 1999
Creeping bentgrass (Agrostis palustris Huds.) turf exposed to shade during morning hours may decline more readily than similar turf exposed to afternoon shade. This study compared the quality and physiological responses of creeping bentgrass turf exposed to morning shade with turf exposed to afternoon shade and evaluated responses of the same species exposed to varying shade densities during the same period. Semipermanent shade structures were placed on a creeping bentgrass range maintained at a 6.4-mm height. Structures provided 6 h of morning shade or 6 h of afternoon shade during the summer solstice. Each structure was covered with either 80 or 100% shade cloth and replicated three times. Control treatments of full sun and perpetual shade were also included. Treated turf was evaluated monthly for color, density, root mass, pigment concentrations, and total nonstructural carbohydrates (TNC). Regardless of response tested, no significant variation was found between plots receiving morning shade and afternoon shade or between plots in 80 and 100% shade. Canopy temperature, in comparison with air temperature, was 7% greater in morning shade than in afternoon shade, but the relationship between canopy temperatures in full sun and shade did not change during the day. Perpetual shade caused a 38% decrease in color and a 33% decline in density but treatments receiving 6 h of shade did not vary from the full sun treatment. Concentrations of chlorophyll a (46%) and b (50%), neoxanthin (31%), violaxanthin (44%), and lutein (34%) declined in perpetual shade compared with full sun. Violaxanthin concentration was influenced by photosynthetic photon flux, suggesting its potential use as a shade stress indicator.
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Growth of C3 and C4 Perennial Grasses under Reduced Irradiance
Article
  • Jul 1992
Several studies have compared C 3 and C 4 species for response to water and temperature regimes. Little comparative information exists, however, on growth responses of C 3 and C 4 species to irradiance regime. The objective of this study was to determine adaptive responses of C 3 and C 4 grasses to irradiance regime. Three C 3 and two C 4 perennial forage grasses were field—established near Ames, IA, and grown under 37, 70, and 100% of full sunlight by use of polypropylene shade cloths. Morphology and growth measurements were conducted three times at ⊄21‐d intervals each year for 2 yr. Net leaf CO 2 exchange rate (CER) was measured for one C 3 , and one C 4 grass. Specific leaf weight increased and leaf‐area ratio decreased with increasing irradiance similarly in all five species. Responses of herbage yield, shoot dry weight, and crop growth rate to irradiance were two to three times greater for C 4 grasses than for C 3 grasses. Responses of CER to irradiance were greater for the C4 grass than for the C 3 grass. Morphological adaptive responses were similar for C 3 and C 4 grasses, but responses closely related to photosynthesis (e.g., CER, growth rate, and herbage yield) were affected more in C 4 than in C 3 species.
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Shade Effects on Growth of Tall Fescue: II. Leaf Gas Exchange Characteristics
Article
  • Jan 1991
The irradiance environment during development affects the elongation rate and photosynthetic capacity of leaves. Our objective was to determine the effect of shade during development on stomatal and nonstomatal factors affecting photosynthesis. Vegetative plants of tall fescue ( Festuca arundinacea Schreb.) were grown outdoors in pots during summer of 1986 and autumn of 1987. Irradiance treatments were provided by shading the plants with neutral‐density screencloth during a 10‐wk growth period. Gas exchange characteristics of the youngest fully expanded leaf blades were measured. Irradiance required for saturation of CO 2 exchange rate (CER) at 340 µL L ‐1 ambient CO 2 was 1000 to 1200 µmol m ² s ⁻¹ of photosynthetic photon flux density when plants were grown at low irradiance (30% full sun) compared with 1500 µmol m ⁻² s ⁻¹ when grown at high irradiance (full sun). The CER per unit leaf area, measured at irradiance saturation, was 25% lower in 1986 and 14% lower in 1987 for leaves grown in low irradiance compared with leaves grown in high irradiance. Stomatal conductance to CO 2 decreased similarly, causing internal CO 2 concentration at irradiance saturation to be similar among treatments. When CER was expressed per unit dry weight or per mesophyll cell volume, no difference was observed between treatments. The adaptation to low irradiance of both leaf anatomical and physiological processes affecting photosynthesis was well coordinated; net CO 2 uptake was decreased, but relative stomatal and nonstomatal limitations were not altered.
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Shade Effects on Growth of Tall Fescue: I. Leaf Anatomy and Dry Matter Partitioning
Article
  • Jan 1991
Irradiance influences plant growth through photosynthetic activity and developmental responses. Our objectives were to determine the effect of irradiance on leaf anatomy and dry matter partitioning of tall fescue (Festuca arundinacea Schreb.). Plants were grown outdoors for 10 wk during summer 1986 and autum 1987 with or without screencloth to give irradiances of 30% (low), 60% (medium), or full (high) sun. Data were similar for both years, although daily air temperatures averaged 25°C in 1986 and 12°C in 1987
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Photosynthetic-respiratory Responses of ‘Merion’ Kentucky Bluegrass and ‘Pennlawn’ Red Fescue at Reduced Light Intensities1
Article
  • Mar 1975
The objectives were to characterize the photosynthetic‐respiratory responses of Kentucky bluegrass ( Poa pratensis L. ‘Merion’) and red fescue ( Festuca rubra L. ‘Pennlawn’) to reduced light intensities. Merion and Pennlawn were grown in separate growth chambers at light intensities of 2.7, 10.8, and 43 klux. Light quality, soil moisture, and soil temperature were standardized among chambers. Infrared CO 2 analysis was used to measure assimilation rates, light saturation levels, and light compensation points of both swards and individual plants. Both species had decreased net photosynthesis (P N ) and dark respiration (R D ), lower light saturation levels, and decreased light compensation points under reduced light intensity. Swards generally had lower P N and R D rates but higher light saturation levels and light compensation points than individual plants. Both species responded similarly to reduced light intensity in terms of P N , light saturation levels, and light compensation points. These factors could not be associated with the ability of Pennlawn to provide a more desirable turf than Merion in the shade. R D of individual plants of Pennlawn was reduced at the lowest light intensity, whereas the R D of Merion was not. This response may contribute to the positive CO 2 balance of Pennlawn at reduced light intensities and thus to its shade adaptability.
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Anatomical Responses of ‘Merion’ Kentucky Bluegrass and ‘Pennlawn’ Red Fescue at Reduced Light Intensities1
Article
  • Mar 1975
The objectives were to characterize the anatomical responses of Kentucky bluegrass and red fescue to reduced light intensities. Kentucky bluegrass ( Poa pratensis L. ‘Merion’) and red fescue ( Festuca rubra L. ‘Pennlawn’) were grown in separate growth chambers at light intensities of 2.7, 10.8. and 43 klux. Light quality, soil moisture, and soil temperature were standardized among chambers. Anatomical studies were conducted on the youngest, fully expanded leaf blade. Merion displayed a decrease in cuticle thickness and vascular and support tissues under reduced light intensities, whereas Pennlawn did not. Stomata density of both species decreased under reduced light. Stomata pore length of both species did not vary with light intensity. The number of chloroplasts/cross sectional unit area decreased with reduced light intensity for both species. Merion had increased thylakoid and grana stack development within individual chloroplasts at reduced light intensities, whereas Pennlawn chloroplast ultrastructure remained unchanged. Shade adaptation of Pennlawn may be related to more developed cuticle, vascular, and support tissue and to chloroplast ultrastructure. Stomata and chloroplast density responses of the two species to reduced light intensity were similar and could not be associated with the ability of Pennlawn to provide a more desirable turf in the shade than Merion.
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