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Confocal image of astrosclereids in the mesophyll of a longitudinally sectioned upper canopy needle from an old-growth Douglas-fir tree. Abbreviations: A = astrosclereid; E = epidermis; IS = intercellular space; M = mesophyll; T = tannin; and VC = vascular cylinder. Scale bar = 100 µm.
Source publication
Morphological differences between old-growth trees and saplings of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) may extend to differences in needle anatomy. We used microscopy with image analysis to compare and quantify anatomical parameters in cross sections of previous-year needles of old-growth Douglas-fir trees and saplings at the Wind Ri...
Context in source publication
Context 1
... cleared, whole needles of old-growth trees, astrosclereids were evenly distributed along the length of the mesophyll. Scanning electron and confocal microscopy revealed that stellate branches of astrosclereids extended into intercellular space and to points near the vascular cylinders and resin canals without attaining contact (Figures 2 and 3). Cell walls of astrosclereids fused with those of adjacent mesophyll cells. The astrosclereid lumen was connected to mesophyll cells or to intercellular space via channels in the cell walls and con- tained granular masses that stained red for ...
Citations
... Wider wall petiole vessels (W PV ) may be a leaf adaptation strategy (Gleason et al., 2018;McCulloh et al., 2009). Ternstroemia huasteca showed a higher hydraulic capacity, allowing rapid moisture adaptation, consistent with astrosclereids that may be involved in water relations, gas exchange, tannin storage, and carbon fixation (Apple et al., 2002). Given the importance of unique ecohydrological conditions in TMCF hydric relations, climate change will affect the functioning and structure of astrosclereids. ...
Tropical Mountain Cloud Forests (TMCFs) produce distinct climatic gradients that can both constrain and facilitate the presence of tree species and/or specific combinations of functional traits. Local climatic adaptation allows for maximum fitness under hydric stress, resulting in specific morphological adaptations to the TMCF tree species. In this study, we assessed the hypothesis that the functional traits of two uncommon TMCF species (Ternstroemia huasteca and T. sylvatica) would show similar morpho-anatomical adjustments to climate variation. Our research questions were: how do the Ternstroemia functional traits vary interspecifically between TMCFs? Which of these two species is the most climatically vulnerable? To answer these questions, we examined dif- ferences in wood anatomical traits and leaf vascular tissues between both species. For this, we assessed the effects of temperature, precipitation, and evapotranspiration on the functional traits of Ternstroemia in different TMCFs. Our analyses suggested that, not all climatic factors considered affected the functional traits of Ternstroemia at the same magnitude. These findings provide insights into the ecophysiological functional trait adaptation mecha- nisms in response to hydraulic deficit in TMCF understory tree species.
... The ability of pine to develop in extreme forest conditions, such as fierce competition and excessive moisture, determines its potential for survival (Egorova and Kulagin 2007). Adaptation to different environmental conditions occurs through different modifications in morphological and anatomical structure, including needle proportions (Apple et al. 2002;Grill et al. 2004;Luomala et al. 2005). The aim of the research is to study the variability of morphological and anatomical features of P.nigra needles growing in different environmental conditions. ...
In this paper the variability of morphological (needle length and needle width) and anatomical (resin ducts width, epidermis thickness, hypodermis height, number of the hypodermis layers and needle thickness) properties of Pinus nigra J.F. Arnold (black pine) needles were studied at the intra-and inter-population levels. Two mountains in Serbia, Jastrebac and Goč, were selected as experimental plots. Three Pinus nigra trees were selected from both localities (6 in total). Obtained results showed that trees on Goč had bigger dimensions of the following elements: needle length, slightly wider needle width, epidermis thickness, hypodermis height, number of hypodermis layers and needle thickness. On the other hand, resin ducts were only slightly wider by the trees from Jastrebac. The results of the analysis of variance showed that variation between studied populations, as well as variation between trees within populations was statistically significant for all needle traits except resin ducts width and hypodermis height.
... Plant rejuvenation refers to the reversal of programmed plant development whereby adult plants regain some or all of their juvenile characteristics. The initiation, progress, and termination of plant rejuvenation are regulated by complex regulatory pathways and multiple levels of cellular machinery [16] . After rejuvenation, clear phenotypic and physiological changes can usually be observed. ...
... With increasing attention being paid to plant rejuvenation, rejuvenation-associated genes (RAGs) and rejuvenation-associated small RNAs (RA-sRNAs) and their expression patterns have been studied extensively in leaves [16] . Here miR156 expression levels were significantly higher in SCs (1.46×), RCs (2.6×), RSs (3.7×), and SSs (2.17×) than in MTs (Fig. 5a), and miR172 expression showed the opposite pattern (Fig. 5b). ...
... Photosynthetic rates were lower in RSs than in other plantlets/seedlings, perhaps because their light interception was limited by the presence of the MTs [10] . In woody plants, changes in esterase and peroxidase isozymes are important markers of maturity, differentiating mature trees from juvenile [16] . Our peroxidase isozyme and sugar results were consistent with the results of other studies [20] . ...
Vegetative propagation is an important method of reproduction and rejuvenation in forestry. The growth and development of asexually propagated trees are influenced by the age and position of the propagule on the plant, effects referred to as cyclophysis and topophysis, respectively. Due to the long lifespans and large body sizes of woody trees, the selection of propagules is critically important. Here, we used three vegetative propagation methods (shoot cutting, root sprouting, and root cutting) to study the effect of different regeneration methods on juvenility of the resulting black locust plants, with seed-derived seedlings used as a control. Most characteristics of plantlets generated by root-sprouting were similar to those of seed-derived seedlings, including leaf traits and leaf anatomical structure. However, there were significant differences between the plantlets derived from shoot-cuttings and seedlings from seeds. Furthermore, the data showed that some of these age-related small RNAs and genes differed in expression among propagation methods and between plantlets/seedlings and mature trees. These age-related small RNAs, genes, and transcription factors may be used as molecular markers of juvenility and phase transitions in black locust. Our results provide useful information for the optimal propagation of woody trees and for further research into the mechanisms of root regeneration.
... Due to the considerable longevity and complex structure within the tree species, the functional traits of different individual sizes presented significant differences [38]. In this study, differences in SLA, LA and TD were not found among different plant sizes. ...
Variation in intraspecific functional traits is one of the important components of community variation, and has drawn the attention of researchers. Studying the variation of traits under different plant sizes and habitats helps to reveal the adaptation mechanism of plants. We explored intraspecific trait variations by focusing on the widespread species Quercus aliena var. acuteserrata in a 25 ha warm, temperate, deciduous broadleaved forest plot in the Qinling Mountains. We measured nine morphological and chemical traits for 90 individuals from different plant sizes and habitats. In addition, we evaluated the relative impact of plant size and environment on Q. aliena var. acuteserrata with multiple regression models. We found that plant size explained the most variance of traits. As plant size increased, the trees tended to have lower leaf nitrogen concentrations, lower leaf phosphorus concentrations, higher leaf carbon concentrations, higher leaf dry matter content (LDMC), and thinner leaves, indicating the transformation from rapid resource acquisition strategy to conservative resource-use strategy. Habitats could only explain the changes in chemical traits. Leaf carbon concentration was principally affected by topographical factors and was significant different among habitats. Leaf nitrogen concentration and LPC were significantly limited by soil N and P. In conclusion, shifts in size-dependent traits met the growth requirements of Q. aliena var. acutiserrata; the high tolerance traits associated with this tree species might elucidate important mechanisms for coping with changing environments.
... Needle age class has also been found to account for compositional variation of foliar fungal communities in both metabarcoding (Würth et al., 2019) and culture-based studies (Osono, 2008), and this is likely due to higher incidences of infection observed for older needle age classes (Sherwood and Carroll, 1974;Bernstein and Carroll, 1977;Petrini and Carroll, 1981) resulting from longer exposure to inoculum sources (Arnold and Herre, 2003). However, differences in needle physiology and morphology also accrue with increasing needle age class (Porte and Loustau, 1998;Bernier et al., 2001;Apple et al., 2002;Ishii et al., 2002;Yan et al., 2012;Eimil-Fraga et al., 2015), potentially accounting for its influence on endophyte community composition. ...
Old-growth Pseudotsuga menziesii var. menziesii forests produce complex environmental and spatial gradients along which biota assemble. Given this, it has been proposed that changes in the crown microenvironment are associated with different community assembly outcomes for needle fungi. Using high-throughput sequencing, the endophytic mycobiomes of needles were characterized for increasing ages of needles sampled along the boles of eight coastal Douglas-fir trees. Leveraging airborne light detection and ranging (LiDAR) data to create three-dimensional “point cloud” representations of tree crowns revealed that crown closure accounted for more fungal compositional variation than height in crown, and fungal richness and diversity were positively correlated with increasing crown closure. Supplementing the point clouds of each climbed tree with clouds from >5,000 randomly selected trees in the study area showed that fungal communities from closed portions of the crown were increasingly structured with needle age. These findings highlight the importance of the crown microenvironment in the development of foliar fungal communities for a foundation tree species.
... That is consistent with leaf expansion tendency in angiosperms (Euphorbiaceae), which holds that leaf support tissues are widespread in early allocation for establishing hydraulic and mechanical infrastructure and preparing for further photosynthesis [39,40]. Moreover, we supplement the follow-up leaf elongation in mature and old trees, in which leaves become shorter and wider compared with saplings and juveniles, as reported for Douglas-fir, an evergreen needle trees with dramatically morphological differences in saplings and oldgrowth [41]. Table 1 Statistical description of leaf width, maximum leaf width, leaf length and half-leaf tipping length ratio in tree age groups, using mean, standard deviation, standard error, 95% confidential intervals (lower and upper value), median, minimum and maximum value * N = sample size. ...
... The tipping ratios are small in C.lanceolata saplings and juveniles, especially smallest in 10yr-old trees, then increase to 23-yr-old in largest, finally decline in old age. Such trends are similar to the anatomical studies that reported single-vein leaves vascular cylinders area variation for Douglas-fir [41]. C.lanceolata mostly lives under conditions of abundant light and water, while they develop shaded in the understory in early stages, herein, act as activism with much consideration on efficiency. ...
Background
Leaf length and width could be a functioning relationship naturally as plant designs. Single-vein leaves have the simplest symmetrical distribution and structural design, which means that fast-growing single-vein species could interpret the scheme more efficiently. The distribution of leaf length and width can be modulated for better adaptation, providing an informative perspective on the various operational strategies in an emergency, while this mechanism is less clear. Here we selected six age groups of Cunninghamia lanceolata pure forests, including saplings, juveniles, mature, and old-growth trees. We pioneered a tapering model to describe half-leaf symmetric distribution with mathematical approximation based on every measured leaf along developmental sequence, and evaluated the ratio of leaf basal part length to total length (called tipping leaf length ratio).
Results
The tipping leaf length ratio varied among different tree ages. That means the changes of tipping leaf length ratio and leaf shape are a significant but less-noticed reflection of trees tradeoff strategies at different growth stages. For instance, there exhibited relatively low ratio during sapling and juvenile, then increased with increasing age, showing the highest value in their maturity, and finally decreased on mature to old-growth transition. The tipping leaf length ratio serves as a cost-benefit ratio, thus the subtle changes in the leaf symmetrical distribution within individuals reveal buffering strategy, indicating the selection for efficient design of growth and hydraulic in their developmental sequences.
Conclusions
Our model provides a physical explanation of varied signatures for tree operations in hydraulic buffering through growth stages, and the buffering strategy revealed from leaf distribution morphologically provides evidence on the regulation mechanism of leaf biomechanics, hydraulics and physiologies. Our insight contributes greatly to plant trait modeling, policy and management, and will be of interest to some scientists and policy makers who are involved in climate change, ecology and environment protection, as well as forest ecology and management.
... In OT, the needles were shorter than in the other ontogenetic groups. The findings that the needles were shortest in old trees corresponds with previous results obtained from intact trees of various conifer species (Apple et al. 2002;Boratyńska et al. 2008;Woodruff et al. 2008). Since needle length depends on the number of mesophyll cells in the longitudinal row (Esau 1977), a decreased needle length in OT suggests that they have the lowest activity of mesophyll cell division. ...
... These results coincide with results obtained on intact trees of Pseudotsuga menziesii (Mirb.) (Apple et al. 2002). Grafts of S had the highest needle cross-section area, which confirmed that cell division and extension in S are more active than in OT. ...
The influence of scions donor tree age on the morphological variability of needles, shoots, and branching pattern was studied in 7-year-old grafted scions of Siberian stone pine (Pinus sibirica Du Tour). We analyzed clones of four age groups: seedlings (4–7 years), young trees (38–62 years), mature trees (238–376 years), and old trees (549–700 years). The results showed that during the first 7 years after grafting, the age of the scion donor tree greatly affects branching patterns and leaf morphology of grafted trees. The age of the scion donor tree also significantly affects the growth of grafts in length, albeit to a lesser extent. Grafts derived from seedlings, young, mature, and old trees had different ratios of shoot elongation and branching: weak growth and abundant branching, strong growth and abundant branching, strong growth and medium branching, weak growth and branching, respectively. The degree of needle xeromorphy, the level of apical dominance, and the number of epicormic buds increased significantly with the age of scion donor trees. Premature (late summer and autumn) growth of dormant buds was typical only for grafts derived from seedlings and, to a lesser extent, from young trees. The closer the scion donor tree is to the ontogenetic growth peak, the more elongated and abundant the branching of the grafts derived from it.
... Leaf age is known to influence leaf surface characteristics (e.g., epicuticular wax, cutin, and pectin, number of stomata, trichomes, and glands) (Chachalis et al., 2001;England & Attiwill, 2006;Sanyal et al., 2006;Yamawo et al., 2014). Leaf cuticle thickness (England & Attiwill, 2006), leaf chemistry (e.g., aucubin, catalpol, iridoid glycosides, N, fiber, cellulose, and mineral contents) (Gomide et al., 1969a(Gomide et al., , 1969bBowers & Stamp, 1993), morphology, anatomy, and physiology (Apple et al., 2002;Day et al., 2001;Richardson et al., 2000) have been reported to change with plant age. These changes with age can influence leaf optical properties. ...
Leaf optical properties influence the red/far‐red light ratio (a signal of potential inter‐plant interaction) in plant canopies, which could alter inter‐plant interactions among species. Differences in leaf optical properties of species comprising a mixed population have significant implications for plant–plant interaction. Leaf optical properties at red (660 nm) and far‐red (730 nm) lights for the third true leaf of tomato (Solanum lycopersicon L.) and its two weeds common lamb's‐quarters (Chenopodium album L.) and redroot pigweed (Amaranthus retroflexus L.) were compared during plant development. The results showed that optical properties of the third true leaf at 660 and 730 nm changed with plant development in common lamb's‐quarters, redroot pigweed, and tomato, and the three species differed in this regard. Red/far‐red ratios of reflected (Rratio) and transmitted (Tratio) lights also changed with plant development in all species. Rratio and Tratio were greater in redroot pigweed compared to common lamb'squarters and tomato. These ratios significantly related with chlorophyll content and leaf mass per area. These differences, usually neglected, could influence growth and intra‐ and/or inter‐species interactions in plant communities comprising these species. These results provide valuable information for understanding eco‐physiology and function of vegetation cover and could help in development of effective weed management strategies.
... Indeed, leaf thickness has long been associated with the capacity of the plant to acquire resources, including water (Helmers 1943, Witkowski & Lamont 1991, and with high photosynthetic rates (Niinemets 2001). However, confounding factors that also affect leaf anatomy such the tree age, developmental level, and leaf position in the trees should be considered to ensure meaningful results (see Lin et al. 2001, Apple et al. 2002, Niinemets et al. 2007, Azuma et al. 2016, Chin & Sillet 2016. ...
Background:
Indicators of productivity could be useful to identify vulnerable species to climate change, stress and safeguarding sites, and early detection of climate change effects, but require to be developed and tested.
Species study:
Pinus patula is a tropical Mexican mountain pine on which divergent opinions are available regarding its sensitivity to global warming. Local anecdotes indicate upslope shifts.
Methods:
We use a space-for-time substitution to infer climate change sensitivity in Pinus patula, testing putative productivity indicators at different elevations: the normalized difference vegetation index (NDVI) and leaf anatomical traits, after following standardization protocols.
Results:
As elevation increases, the NDVI, leaf thickness, and the mesophyll width increased, while the xylem-to-mesophyll ratio decreased, probably as different plant manifestations to higher productivity towards the mountain tops. These results concur with other studies showing evidence of more productivity toward higher elevations on the leeward side of the southern Mexico mountains based on NDVI, small mammal abundance, soil macrofungi carpophore cover, and tree basal area. Under global warming, high elevations in south Mexico appear to become more favorable because of their less extreme cold temperatures and higher rainfall.
Conclusions:
Our results provide an explanation of previous findings suggesting that global warming could reduce the population size and the habitable area of Pinus patula, and the observed upslope shifts. After following standardization protocols, the NDVI, mesophyll width, and xylem-to-mesophyll ratio could be promising tools to assess climate change sensitivity in terrestrial plants and deserve further studies to test their validity in other situations and species.
... For instance, the amount of non-photosynthetic cell area within a needle decreased with tree age in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco; Apple et al. 2002), and thus needles in younger trees may require more water storage (i.e., higher foliar moisture content) to maintain what is presumably a higher rate of photosynthetic activity. There is greater recognition that physiological changes, possibly in association with tree age, can strongly influence patterns of foliar moisture content (Jolly and Johnson 2018), but this topic requires further investigation. ...
Background
Increasing frequency and size of wildfires over the past few decades have prompted concerns that populations of obligate seeding species may be vulnerable to repeat, short-interval fires that occur prior to these species reaching maturity. The susceptibility of populations to this risk is partially dependent on the amount and characteristics of fuel loading over time and their influence on fire behavior and effects. This study characterized fuel dynamics and modeled fire behavior across a time-since-fire chronosequence in stands of the rare, serotinous conifer, Baker cypress ( Hesperocyparis bakeri [Jeps.] Bartel), ranging in age between 3 and 147 years post fire.
Results
Litter and fine woody fuel loading (1- to 100-hour) were highest in the 10-year-old and 147-year-old stands, while coarse fuel loading (1000-hour) peaked in the 10-year-old stand and subsequently decreased with time since fire. Duff loading consistently increased with time since fire. Cone production had not occurred in the first 10 yr of stand development. Foliar moisture content in Baker cypress was inversely correlated with stand age, and older foliage had lower moisture content than younger foliage. Modeled surface fire behavior was highest in the 10-year-old and 107-year-old stands in accordance with higher litter, fine woody fuel, or shrub fuel accumulation. While foliar moisture content was higher in younger stands and influenced the critical fireline intensity, we did not observe changes in fire type.
Conclusions
Fine-fuel loading in Baker cypress stands followed a U-shaped pattern over time (first decreasing, then stable, then increasing), consistent with findings in other forests with stand-replacing fire regimes. Our results indicated that early-successional stages of Baker cypress forests have sufficient fuels to allow for the spread of wildfire and 10-year-old stands could burn with substantive fire behavior prior to cone production. Whenever possible, we recommend suppressing wildfire in stands less than 20 yr old to avoid substantial decreases or local extirpation of these rare Baker cypress populations. Our results highlight the importance of knowing the cone production patterns, fuel dynamics, and corresponding fire behavior over the development of obligate-seeder species to assess the risk of population loss due to short-interval fires.
