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Relationships of mean values for leaf traits (6SE) with mean taxon elevation for seven Hawaiian Plantago taxa. A, Percent adaxial stomatal density; B, leaf mass per area; C, leaf thickness (and density; inset); D, foliar N per mass (and per area; inset). For insets in C and D, the relationship was not significant (r s , r p , and r ic ¼ 0:18–0:53; P ¼ 0:34–0:70). Taxon symbols are as in fig. 1; open circles represent taxa from bogs, and filled circles represent taxa from woodlands. Power law relationships were fitted (see ''Material and Methods''), except for A, in which an exponential model best fit the data (all line fitting by least squares): A, %ASD ¼ e 0:00182 3 MTE , R 2 ¼ 0:93; B, LMA ¼ 0:852 3 MTE 0:635 , R ¼ 0:63; C, thickness ¼ 23:9 3 MTE 0:453 , R 2 ¼ 0:54; D, N mass ¼ 496 3 MTE À0:792 , R 2 ¼ 0:91. One asterisk, P 0:05; two asterisks, P < 0:01; three asterisks, P < 0:001; plus sign, correlation coefficients presented for the stronger relationship with maximum rather than mean taxon elevation. See text for definitions of abbreviations.
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Linkages among leaf traits and environment have most often been tested across communities but infrequently within lineages. We studied seven endemic Hawaiian Plantago taxa radiated across elevations, climates, and habitats. We grew plants of six taxa in controlled conditions for 1-2 yr and collected leaves from a seventh in the field. For all taxa,...
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Citations
... In addition, because leaf structure is the basis for leaf function, leaves can develop appropriate morphological structures to optimize functions with long-term exposure to the environment. Thus, leaf anatomical traits are also key factors in understanding plant adaptation to the environment [34,41,43]. ...
Background
With the dramatic uplift of the Qinghai–Tibet Plateau (QTP) and the increase in altitude in the Pliocene, the environment became dry and cold, thermophilous plants that originally inhabited ancient subtropical forest essentially disappeared. However, Quercus sect. Heterobalanus (QSH) have gradually become dominant or constructive species distributed on harsh sites in the Hengduan Mountains range in southeastern QTP, Southwest China. Ecological stoichiometry reveals the survival strategies plants adopt to adapt to changing environment by quantifying the proportions and relationships of elements in plants. Simultaneously, as the most sensitive organs of plants to their environment, the structure of leaves reflects of the long-term adaptability of plants to their surrounding environments. Therefore, ecological adaptation mechanisms related to ecological stoichiometry and leaf anatomical structure of QSH were explored. In this study, stoichiometric characteristics were determined by measuring leaf carbon (C), nitrogen (N), and phosphorus (P) contents, and morphological adaptations were determined by examining leaf anatomical traits with microscopy.
Results
Different QSH life forms and species had different nutrient allocation strategies. Leaves of QSH plants had higher C and P and lower N contents and higher N and lower P utilization efficiencies. According to an N: P ratio threshold, the growth of QSH species was limited by N, except that of Q. aquifolioides and Q. longispica, which was limited by both N and P. Although stoichiometric homeostasis of C, N, and P and C: N, C: P, and N: P ratios differed slightly across life forms and species, the overall degree of homeostasis was strong, with strictly homeostatic, homeostatic, and weakly homeostatic regulation. In addition, QSH leaves had compound epidermis, thick cuticle, developed palisade tissue and spongy tissue. However, leaves were relatively thin overall, possibly due to leaf leathering and lignification, which is strategy to resist stress from UV radiation, drought, and frost. Furthermore, contents of C, N, and P and stoichiometric ratios were significantly correlated with leaf anatomical traits.
Conclusions
QSH adapt to the plateau environment by adjusting the content and utilization efficiencies of C, N, and P elements. Strong stoichiometric homeostasis of QSH was likely a strategy to mitigate nutrient limitation. The unique leaf structure of the compound epidermis, thick cuticle, well-developed palisade tissue and spongy tissue is another adaptive mechanism for QSH to survive in the plateau environment. The anatomical adaptations and nutrient utilization strategies of QSH may have coevolved during long-term succession over millions of years.
... While lower light levels can be associated with higher SLA and larger leaves (Wang et al. 2020), evergreen Rhododendron have lower SLA combined with larger leaves. Plants exposed to lower light levels may also have lower midrib hydraulic conductance (Dunbar-Co et al. 2009), and we found that evergreen species had smaller xylem conduits in both their leaves and wood. This was, however, combined with a larger total midrib xylem area for evergreens, which could buffer the impact of small conduits for shade tolerant leaves (Cavender-Bares et al. 2005;Poorter et al. 2010;Choat et al. 2011). ...
... Our finding of higher proportion of airspace for evergreen leaves could be also beneficial for gas exchange in low light (Tomás et al. 2013;Earles et al. 2018). While plants exposed to lower light levels may have thinner mesophyll (Dunbar-Co et al. 2009), lower SLA can be associated with higher photosynthetic rates, owing to counter-intuitive changes in the thickness of the mesophyll (Edwards et al. 2014). ...
Plant resource strategies negotiate a trade-off between fast growth and stress resistance, characterized by specific leaf area (SLA). How SLA relates to leaf structure and function or plant climate associations remains open for debate, and leaf habit and plant architecture may alter the costs versus benefits of individual traits. We used phylogenetic canonical correspondence analysis and phylogenetic least squares to understand the relationship of anatomy and gas exchange to published data on root, wood, architectural and leaf economics traits and climate. Leaf anatomy was structured by leaf habit and carbon to nitrogen ratio was a better predictor of gas exchange than SLA. We found significant correspondence of leaf anatomy with branch architecture and wood traits, gas exchange corresponded with climate, while leaf economics corresponded with climate, architecture, wood and root traits. Species from the most seasonal climates had the highest trait–climate correspondence, and different aspects of economics and anatomy reflected leaf carbon uptake versus water use. Our study using phylogenetic comparative methods including plant architecture and leaf habit provides insight into the mechanism of whole-plant functional coordination and contextualizes individual traits in relation to climate, demonstrating the evolutionary and ecological relevance of trait–trait correlations within a genus with high biodiversity.
... Increased LA would explain lower SD values in ice hole populations than subalpine ones. Indeed, stomatal number per mm 2 is inversely proportional to LA 39,40 . Higher LPC in ice holes could depend on the location of the siliceous sites in the elevational zone of montane forests, known to be rich in soil organic matter 32 . ...
In the mountain terrain, ice holes are little depressions between rock boulders that are characterized by the exit of cold air able to cool down the rock surface even in summer. This cold air creates cold microrefugia in warmer surroundings that preserve plant species probably over thousands of years under extra-zonal climatic conditions. We hypothesized that ice hole populations of the model species Vaccinium vitis-idaea (Ericaceae) show genetic differentiation from nearby zonal subalpine populations, and high functional trait distinctiveness, in agreement with genetic patterns. We genotyped almost 30,000 single nucleotide polymorphisms using restriction site-associated DNA sequencing and measured eight functional traits indicative of individual performance and ecological strategies. Genetic results showed high differentiation among the six populations suggesting isolation. On siliceous bedrock, ice hole individuals exhibited higher levels of admixture than those from subalpine populations which could have experienced more bottlenecks during demographic fluctuations related to glacial cycles. Ice hole and subalpine calcareous populations clearly separated from siliceous populations, indicating a possible effect of bedrock in shaping genetic patterns. Trait analysis reflected the bedrock effect on populations’ differentiation. The significant correlation between trait and genetic distances suggests the genetic contribution in shaping intraspecific functional differentiation. In conclusion, extra-zonal populations reveal a prominent genetic and phenotypic differentiation determined by history and ecological contingency. Therefore, microrefugia populations can contribute to the overall variability of the species and lead to intraspecific-driven responses to upcoming environmental changes.
... The most pronounced upregulation of the foliar water-transport infrastructure and transpiration rate under experimental growth with warm to hot temperature was seen in the Polish ecotype from the site of origin with the lowest monthly precipitation over the growing season. This finding is consistent with previous reports of a positive association between foliar vein density and aridity across different species [68,69] and, most notably, between higher vein density and lower precipitation among seven species of the herbaceous genus Plantago [70]. ...
Arabidopsis thaliana ecotypes adapted to native habitats with different daylengths, temperatures, and precipitation were grown experimentally under seven combinations of light intensity and leaf temperature to assess their acclimatory phenotypic plasticity in foliar structure and function. There were no differences among ecotypes when plants developed under moderate conditions of 400 µmol photons m–2 s–1 and 25 °C. However, in response to more extreme light or temperature regimes, ecotypes that evolved in habitats with pronounced differences in either the magnitude of changes in daylength or temperature or in precipitation level exhibited pronounced adjustments in photosynthesis and transpiration, as well as anatomical traits supporting these functions. Specifically, when grown under extremes of light intensity (100 versus 1000 µmol photons m–2 s–1) or temperature (8 °C versus 35 °C), ecotypes from sites with the greatest range of daylengths and temperature over the growing season exhibited the greatest differences in functional and structural features related to photosynthesis (light- and CO2-saturated capacity of oxygen evolution, leaf dry mass per area or thickness, phloem cells per minor vein, and water-use efficiency of CO2 uptake). On the other hand, the ecotype from the habitat with the lowest precipitation showed the greatest plasticity in features related to water transport and loss (vein density, ratio of water to sugar conduits in foliar minor veins, and transpiration rate). Despite these differences, common structure–function relationships existed across all ecotypes and growth conditions, with significant positive, linear correlations (i) between photosynthetic capacity (ranging from 10 to 110 µmol O2 m−2 s−1) and leaf dry mass per area (from 10 to 75 g m−2), leaf thickness (from 170 to 500 µm), and carbohydrate-export infrastructure (from 6 to 14 sieve elements per minor vein, from 2.5 to 8 µm2 cross-sectional area per sieve element, and from 16 to 82 µm2 cross-sectional area of sieve elements per minor vein); (ii) between transpiration rate (from 1 to 17 mmol H2O m−2 s−1) and water-transport infrastructure (from 3.5 to 8 tracheary elements per minor vein, from 13.5 to 28 µm2 cross-sectional area per tracheary element, and from 55 to 200 µm2 cross-sectional area of tracheary elements per minor vein); (iii) between the ratio of transpirational water loss to CO2 fixation (from 0.2 to 0.7 mol H2O to mmol−1 CO2) and the ratio of water to sugar conduits in minor veins (from 0.4 to 1.1 tracheary to sieve elements, from 4 to 6 µm2 cross-sectional area of tracheary to sieve elements, and from 2 to 6 µm2 cross-sectional area of tracheary elements to sieve elements per minor vein); (iv) between sugar conduits and sugar-loading cells; and (v) between water conducting and sugar conducting cells. Additionally, the proportion of water conduits to sugar conduits was greater for all ecotypes grown experimentally under warm-to-hot versus cold temperature. Thus, developmental acclimation to the growth environment included ecotype-dependent foliar structural and functional adjustments resulting in multiple common structural and functional relationships.
... This axis represents the trade-off between leaf construction cost and transportation distance . Our finding that leaf economics and vein traits are decoupled (e.g., SLA and vein density) is consistent with previous studies (Sack and Frole, 2006;Dunbar-Co et al., 2009;Nardini et al., 2012;Blackman et al., 2016). One explanation for this decoupling of traits is that leaf economics and vein traits represent separate sub-systems (Li et al., 2015). ...
The variation and correlation of leaf economics and vein traits are crucial for predicting plant ecological strategies under different environmental changes. However, correlations between these two suites of traits and abiotic factors such as soil water and nitrogen content remain ambiguous. We measured leaf economics and vein traits as well as soil water and nitrogen content for two different shade-tolerant species (Betula platyphylla and Acer mono) in four mixed broadleaved-Korean pine (Pinus koraiensis) forests along a latitudinal gradient in Northeast China. We found that leaf economics traits and vein traits were decoupled in shade-intolerant species, Betula platphylla, but significantly coupled in a shade-tolerant species, A. mono. We found stronger correlations among leaf traits in the shade tolerant species than in the shade intolerant species. Furthermore, leaf economic traits were positively correlated with the soil water gradient for both species, whereas vein traits were positively correlated with soil water gradient for the shade intolerant species but negatively correlated in the shade tolerant species. Although economic traits were positively correlated with soil nitrogen gradient in shade intolerant species but not correlated in shade tolerant species, vein traits were negatively correlated with soil nitrogen gradient in shade tolerant species but not correlated in shade intolerant species. Our study provides evidence for distinct correlations between leaf economics and vein traits and local abiotic factors of species differing in light demands. We recommend that the ecological significance of shade tolerance be considered for species when evaluating ecosystem functions and predicting plant responses to environmental changes.
... GA is abundantly synthesized in growing seeds and fruits and is important in regulating physiological processes, such as seed germination, stem elongation, leaf growth, dormant bud germination, and flower and seed development (Dunbar et al., 2009;Wang, 2013;Zhou et al., 2013). Different levels of drought stress were found to significantly reduce the GA content of the leaves compared with the control. ...
Winterberry (Ilex verticillata (L.) A. Gray) is a recently introduced ornamental tree species in China that has not been closely investigated for its drought resistance. In this study, we used two-year-old cuttings from I. verticillata (L.) A. Gray and two representative varieties derived from it, I. verticillata ‘Oosterwijk’ and I. verticillata ‘Jim Dandy’, as materials to investigate how this plant responds to drought stress and whether exogenous spermidine (SPD) can alleviate the negative effects caused by drought stress. The results showed that as the degree of drought stress increased, the leaves of winterberry seedlings became chlorotic, and their edges became dry. Similarly, the relative water content, specific leaf weight, chlorophyll content, leaf nitrogen content, net photosynthetic rate, stomatal conductance and transpiration rate were significantly reduced, whereas the content of malondialdehyde continuously increased with the degree of drought stress. The activities of superoxide dismutase, peroxidase, and catalase increased under moderate drought stress and then decreased under severe drought stress. The levels of soluble sugar and abscisic acid continued to increase, while those of auxin and gibberellic acid decreased. When compared with individual drought stress, an increase in the amount of external SPD clearly alleviated the effect of drought stress on winterberry seedlings. The combined phenotypes and physiological indices of the winterberry leaves under drought stress conditions revealed that the drought resistance of the native species was significantly higher than its two varieties. This finding serves as an important theoretical foundation for the popularization and application of I. verticillata (L.) A. Gray and the two varieties.
... The study of leaf functional traits and their relationship with the environment has become a hot topic in ecological research due to the development of the leaf economic spectrum . The relationship between "trait-environment" and "trait-trait" reflects the optimal "adaptation principle" for plant growth and adaptation under natural conditions (Blonder et al., 2016;Dunbar-Co et al., 2009). Therefore, understanding the response of leaf traits and their relationships to future environmental changes is crucial for predicting vegetation distribution and ecosystem function (Kovenock and Swann, 2018). ...
Trait-based approaches have emerged as promising strategies for understanding plant adaptation mechanisms to the changing environment. At present, there are a large number of studies on the relationship between plant leaf functional traits and environment, but these studies mostly use the average value of traits instead of species, ignoring the intraspecific changes of traits. Pinus densiflora Sieb. et Zucc. is not only an urban greening tree species, but also an important afforestation tree species, which plays an important role in China's terrestrial ecosystem. In this study, the leaf nitrogen content (LN), the leaf phosphorus content (LP), nitrogen phosphorus ratio (N/P), leaf area (LA) and specific leaf area (SLA) of 16 sites (160 records) distributed in Chinese P. densiflora were measured. (1) The results showed that LN increased with the increase of mean annual precipitation (MAP) and decreased with the increase of soil organic matter (SOM). LP and SLA decreased with the increase of mean annual temperature (MAT) and increased with the increase of AN (soil available phosphorus) and AP (soil available phosphorus). N/P increased with the increase of MAT and MAP, and decreased with the increase of AN and AP. LA increased with the increase of MAT and MAP. (2) Relative importance analysis showed that MAP was the most important driver of LN and LA. The main driving factors of LP is MAT, the main driving factors of N/P is SOM, and the main influencing factors of SLA is AP. Overall, climate was the main driving factor for the variation of leaf functional traits. The variation law of leaf functional traits along environmental gradient strongly supported the temperature-plant physiological hypothesis. It enriches the understanding of leaf functional traits distribution pattern and its driving mechanism under environmental change.
... Second, we considered the relationships of growth and traits measured in a common garden with cold and aridity of the native range. Growth and trait values measured in the common garden represent differences due to genetic variation between ecotypes achieved in high-resource conditions (Cordell et al., 1998;Dunbar-Co et al., 2009;Givnish & Montgomery, 2014;Mason & Donovan, 2015), minimizing plastic changes expected for plants in the field, which may adjust to abiotic and Fig. 8 Relationships of (a) leaf nitrogen per area (N area ) and Chl per area (inset panel) with leaf mass per area, and of (b) Chl per area with N area for 15 Arabidopsis ecotypes grown in a glasshouse common garden. The r-values with significance are based on linear regressions accounting for kinship. ...
Ecophysiologists have reported a range of relationships, including intrinsic trade‐offs across and within species between plant relative growth rate in high resource conditions (RGR) vs adaptation to tolerate cold or arid climates, arising from trait‐based mechanisms. Few studies have considered ecotypes within a species, in which the lack of a trade‐off would contribute to a wide species range and resilience to climate change.
For 15 ecotypes of Arabidopsis thaliana in a common garden we tested for associations between RGR vs adaptation to cold or dry native climates and assessed hypotheses for its mediation by 15 functional traits.
Ecotypes native to warmer, drier climates had higher leaf density, leaf mass per area, root mass fraction, nitrogen per leaf area and carbon isotope ratio, and lower osmotic potential at full turgor. Relative growth rate was statistically independent of the climate of the ecotype native range and of individual functional traits.
The decoupling of RGR and cold or drought adaptation in Arabidopsis is consistent with multiple stress resistance and avoidance mechanisms for ecotypic climate adaptation and would contribute to the species’ wide geographic range and resilience as the climate changes.
... Hence, the conclusions are not consistent. Previous studies with fewer species (≤10) found a negative correlation between major vein density and leaf size, while no relationship between minor vein density and leaf size was found in most studies (Sack et al., 2008;Dunbar-Co et al., 2009;Scoffoni et al., 2011). However, Walls (2011) showed a weak relationship (R 2 = 0.11). ...
... Since total vein density was mainly determined by the minor vein length per area, which accounted for > 97% of the total vein length in this study (Supplementary Table 1), the total vein density was also not related to leaf size. This was consistent with findings from the previous globalscale dataset and small groups with no more than 10 species in previous studies (Sack et al., 2008(Sack et al., , 2012Dunbar-Co et al., 2009;Scoffoni et al., 2011). ...
Leaves are enormously diverse in their size and venation architecture, both of which are core determinants of plant adaptation to environments. Leaf size is an important determinant of leaf function and ecological strategy, while leaf venation, the main structure for support and transport, determines the growth, development, and performance of a leaf. The scaling relationship between venation architecture and leaf size has been explored, but the relationship within a community and its potential variations among species with different vein types and leaf habits have not been investigated. Here, we measured vein traits and leaf size across 39 broad-leaved woody species within a subtropical forest community in China and analyzed the scaling relationship using ordinary least squares and standard major axis method. Then, we compared our results with the global dataset. The major vein density, and the ratio of major (1° and 2°) to minor (3° and higher) vein density both geometrically declined with leaf size across different vein types and leaf habits. Further, palmate-veined species have higher major vein density and a higher ratio of major to minor vein density at the given leaf size than pinnate-veined species, while evergreen and deciduous species showed no difference. These robust trends were confirmed by reanalyzing the global dataset using the same major vein classification as ours. We also found a tradeoff between the cell wall mass per vein length of the major vein and the major vein density. These vein scaling relationships have important implications on the optimization of leaf size, niche differentiation of coexisting species, plant drought tolerance, and species distribution.
... Vein density shows a high inter-and intraspecific variation, and a very diverse responses to a combination of environmental traits (Zhu et al. 2012). For instance, higher vein density has been associated with higher sun exposure (Sack & Frole 2006) and drier soils for some species (Dunbar-Co et al. 2009). In other species, higher vein density is found under more humid conditions (Zhu et al. 2012). ...
Background:
Phenotypic and functional traits of plant populations vary with environmental conditions at local and regional scales. The analysis of these traits along environmental gradients provides information on the differential response of populations to climate changes.
Objective:
We analyzed the leaf morphological variation of an endemic oak to identify the degree of population differentiation along an environmental gradient.
Study species:
Quercus mexicana Bonpl. (Fagaceae).
Study site and dates:
Samples were collected from 39 populations in the Sierra Madre Oriental and east of the Trans-Mexican Volcanic Belt from 2014 to 2016.
Methods:
We measured eight macromorphological traits in 5,507 leaves and three micromorphological traits in 228 leaves. We performed univariate and multivariate statistical analyses to assess the morphological differentiation among populations, and the relationship between variation in leaf traits and environmental variables related to temperature and water availability.
Results:
Populations of Q. mexicana showed leaf morphological differentiation along its distribution. Significant linear correlations were found between leaf traits and environmental variables. Smaller and thicker leaves with lower density of trichomes and smaller stomata were found in populations located in more arid regions. In contrast, larger and thinner leaves with higher trichome density and larger stomata occurred in more humid places.
Conclusions:
Populations of Q. mexicana are adapted to a wide range of climatic conditions. Considering the predictive future climatic changes for the region (i.e., warmer and drier conditions), Q. mexicana populations with traits better adapted to a more humid and cooler environments could be negatively affected.
