Leaf Morphological Traits Research Articles

Response of leaf functional traits to precipitation change: A case study from tropical woody tree

Precipitation change is one of the most important forms of current global climate change, which will significantly influence the plant growth and development. Although numerous experiments have been conducted to investigate the effects of precipitation regulation on the plant growth and ecosystem process, the response of leaf functional traits of tropical woody species to the precipitation change is still poorly understood. In this study, three treatments, including delayed wet season (DW), wetter wet season (WW) and control check (CK), were established to examine the responses of leaf functional traits, including morphological traits, photosynthetic pigments, and non-structural carbohydrates (NSC) of the dominant woody tree, Symplocos chunii , to the simulated precipitation change in a secondary tropical forest of southern China. Our results showed that the specific leaf area (SLA), photosynthetic pigments, and NSC contents exhibited distinctly seasonal variations ( P < 0.05), but the simulated precipitation changes did not alter the leaf morphological traits (leaf length, width, or area) of S. chunii after six-year treatment. The leaf total chlorophyll contents increased observably by 83.9% in DW, and the chlorophyll b was increased by 181.5% compared to CK ( P < 0.05), while WW markedly reduced chlorophyll b content but remarkably increased carotenoid content ( P < 0.05). However, DW significantly reduced NSC contents in both dry and wet seasons. In contract, WW treatment significantly reduced leaf soluble sugar content only in the early stage of wet season, but after that, the WW did not alter the leaf soluble sugar and starch contents, even with the approach of dry season. These indicated that the precipitation change would alter the leaf photosynthetic rates thus influence the carbon assimilation, further regulate the allocation and transformation pattern of leaf NSC contents in tropical woody trees. The results suggest that the tropical woody trees may adapt to the frequent precipitation change via regulating the allocation and transformation of non-structural carbohydrates.

Frequency distribution and potence ratio of agronomic traits in F1 generation of intraspecific crosses of Robusta coffee.

Leaf morphological traits and internode length significantly affect the adapt-ability and production of coffee plants, respectively. Therefore, genetic studies of these two characters can support the effectiveness of Robusta coffee breeding program for obtaining superior planting materials. This study aimed to determine the diversity and frequency distribution of F1 generation on internode length and leaf size of Robusta coffee crosses. The study involved six groups of F1 progeny and their reciprocals (F1R) resulted from a cross of three parents, namely BP 961, Q 121, and BP 409. Each cross combination was planted with 41–49 progenies singly side by side in Kaliwining Experimental Station, Jember, Indonesia. The observed traits were internode length and leaf size. Analysis results of progeny variation distribution showed that most of the F1 and F1R progenies from intraspecific Robusta crosses had shorter branches than both parents in all combinations of crosses, even in BP 961 × BP 409 crosses. In addition, all F1 and F1R progenies had shorter internodes than both parents. More than 50% of the progeny of Q 121 × BP 409 and BP 961 × BP 409 crosses showed leaf length trait between parents. This indicates the absence of dominance of one parent in the progeny. Less than 20.9% of the progeny had a narrower leaf size than Q 121 parent. Most of the F1 and F1R crosses had a leaf width between both parents. The leaf length and leaf width traits were incomplete dominance or recessive, while the internodelength was overdominant.

Physiological Factors Limiting Leaf Net Photosynthetic Rate in C3 Crops like Rice and Approaches for Improving It

Improving leaf photosynthetic capacity is one of the most promising approaches to further boost crop yield. Clarifying factors limiting leaf photosynthetic capacity, especially in C3 crops, is meaningful for designing strategies to improve it. Leaf net photosynthetic rate (A) is one of the parameters describing leaf photosynthetic capacity. In the present study, physiological factors limiting A in C3 crops such as rice were discussed and different approaches for A improvement were summarized to provide theoretical guidance for increasing leaf photosynthetic capacity. A will be limited by both CO2 availability and light intensity over periods from a few hours to several days, and by one of them over shorter intervals. Under current ambient atmospheric conditions, A of C3 crops is mainly limited by Rubisco activity and the CO2 concentration in chloroplasts. Leaf nitrogen content affects A by regulating Rubisco content and leaf anatomy; leaf morphological and anatomical traits limit A by impacting stomatal and mesophyll CO2 diffusion. Further improvements of A in C3 crops can be achieved by designing or introducing high-activity Rubisco; adjusting leaf nitrogen allocation to optimize leaf anatomy and leaf chemical composition; modifying leaf morphology and anatomy for greater CO2 diffusion; improving the activity of proteins and enzymes associated with sugar transportation and utilization; introducing C4 photosynthetic mechanisms and combining high photosynthetic traits by conventional breeding.

EVALUATING THE FUNCTIONAL TRAITS OF THE PIONEERING SPECIES: INSIGHTS TO FOREST RESTORATION

The influence of plant traits on interspecific demographic rates to growth and mortality has recently received an increasing attention because it allows understanding of the underlying determinants of species success especially in open degraded areas. This study examined the trait-based approach in selecting potential species for forest restoration. Five (5) native/indigenous pioneer species were evaluated for functional traits such as plant height, branching architecture, leaf dry matter content, specific leaf area, stem density, and bark thickness. All samples were collected from healthy and well grown mature trees growing in secondary forest of Central Mindanao University. The range of values for the various functional traits as observed by Ostertag and Perez-Harguindeguy were used to evaluate. Based on the result, three species such as Phyllantus albus, Polyscias nodosa, and Buchanania arborescence showed to fit in those values hence we recommend that these species should be considered as primary restoration species in various denuded areas of the Philippines. Our result suggests that multiple functional traits (i.e. Leaf anatomical traits, leaf morphological traits and leaf stomatal traits) are still required to be measured to select appropriate plant species for restoration.

Population structure, regeneration potential and leaf morphological traits of Rhododendron campanulatum D.Don along an altitudinal gradient in Western Himalaya

The vegetation of the alpine treeline ecotone is among the most vulnerable and sensitive to global climate change. Treeline species respond to global warming through changes in their population structure, regeneration, plant functional traits and shift in their habitat. This study was carried out on Rhododendron campanulatum D.Don, a typical plant species of the Himalayan treeline ecotone, to understand the variation in population structure, regeneration potential and leaf morphological traits along the altitudinal gradient (3100–3550 m.a.s.l.) in Tungnath, Western Himalaya. We reported the higher seedling (3480 stem ha−1) and juvenile (2210 stem ha−1) density of the species above the treeline at 3400 m.a.s.l. This clearly shows a good regeneration status and indicates the upward shift of the species. Leaf morphological traits such as length, width, and the specific leaf area decreased with an increase in elevation but leaf thickness increased with an increase in elevation. SLA was higher (71.14 cm2/g; p < 0.001) at 3100 m.a.s.l. located below the treeline than 3550 m.a.s.l. (60.08 cm2/g; p < 0.001)) located above the treeline. The results indicate that the species has large flexibility in the morphological performance and its high level of plasticity in morphological traits may explain its wider niche and ability to survive in harsh alpine conditions.

A new major QTL for flag leaf thickness in barley (Hordeum vulgare L.)

BackgroundCarbohydrate accumulation of photosynthetic organs, mainly leaves, are the primary sources of grain yield in cereals. The flag leaf plays a vital role in seed development, which is probably the most neglected morphological characteristic during traditional selection processes.ResultsIn this experiment, four flag leaf morphological traits and seven yield-related traits were investigated in a DH population derived from a cross between a wild barley and an Australian malting barley cultivar. Flag leaf thickness (FLT) showed significantly positive correlations with grain size. Four QTL, located on chromosomes 1H, 2H, 3H, and 5H, respectively, were identified for FLT. Among them, a major QTL was located on chromosome 3H with a LOD value of 18.4 and determined 32% of the phenotypic variation. This QTL showed close links but not pleiotropism to the previously reported semi-dwarf gene sdw1 from the cultivated barley. This QTL was not reported before and the thick leaf allele from the wild barley could provide a useful source for improving grain yield through breeding.ConclusionsOur results also provided valuable evidence that source traits and sink traits in barley are tightly connected and suggest further improvement of barley yield potential with enhanced and balanced source and sink relationships by exploiting potentialities of the wild barley resources. Moreover, this study will provide a novel sight on understanding the evolution and development of leaf morphology in barley and improving barley production by rewilding for lost superior traits during plant evolution.

Influence of Juvenile Growth on Xylem Safety and Efficiency in Three Temperate Tree Species

The evolution of the internal water transport system was a prerequisite for high plant productivity. In times of climate change, understanding the dependency of juvenile growth on xylem hydraulic physiology is therefore of high importance. Here, we explored various wood anatomical, hydraulic, and leaf morphological traits related to hydraulic safety and efficiency in three temperate broadleaved tree species (Acer pseudoplatanus, Betula pendula, and Sorbus aucuparia). We took advantage of a severe natural heat wave that resulted in different climatic growing conditions for even-aged plants from the same seed source growing inside a greenhouse and outside. Inside the greenhouse, the daily maximum vapour pressure deficit was on average 36% higher than outside during the growing seasons. Because of the higher atmospheric moisture stress, the biomass production differed up to 5.6-fold between both groups. Except for one species, a high productivity was associated with a high hydraulic efficiency caused by large xylem vessels and a large, supported leaf area. Although no safety-efficiency trade-off was observed, productivity was significantly related to P50 in two of the tree species but without revealing any clear pattern. A considerable plasticity in given traits was observed between both groups, with safety-related traits being more static while efficiency-related traits revealed a higher intra-specific plasticity. This was associated with other wood anatomical and leaf morphological adjustments. We confirm that a high hydraulic efficiency seems to be a prerequisite for a high biomass production, while our controversial results on the growth–xylem safety relationship confirm that safety-efficiency traits are decoupled and that their relationship with juvenile growth and water regime is species-specific.

Broad‐ and small‐scale environmental gradients drive variation in chemical, but not morphological, leaf traits of vascular epiphytes

Abstract Variation in leaf functional traits along environmental gradients can reveal how vascular epiphytes respond to broad‐ and small‐scale environmental gradients. Along elevational gradients, both temperature and precipitation likely play an important role as drivers of leaf trait variation, but these traits may also respond to small‐scale changes in light, temperature and humidity along the vertical environmental gradient within forest canopies. However, the relative importance of broad‐ and small‐scale environmental gradients as drivers of variation in leaf functional traits of vascular epiphytes is poorly understood. Here, we examined variation in morphological and chemical leaf traits of 102 vascular epiphyte species spanning two environmental gradients along Cofre de Perote mountain in Mexico: (i) a broad‐scale environmental gradient approximated by elevation as well as by species' lower and upper elevational limits, and (ii) small‐scale environmental gradients using the relative height of attachment of an epiphyte on a host tree as a proxy for variation in environmental conditions within the forest canopy. We also assessed whether variation in morphological and chemical leaf traits along these gradients was consistent across photosynthetic pathways (CAM and C3). Broad‐ and small‐scale environmental gradients explained more variation in chemical traits (marginal R2: 11%–89%) than in morphological traits (marginal R2: 2%–31%). For example, leaf carbon isotope signatures (δ13C), which reflects water‐use efficiency, varied systematically across both environmental gradients, suggesting a decrease in water‐use efficiency with increasing lower and upper elevational limits and an increase in water‐use efficiency with relative height of attachment. The influence of lower and upper elevational limits on trait variation differed between photosynthetic pathways, except for leaf dry matter content and leaf nitrogen‐to‐phosphorus ratio. Contrary to our expectations, broad‐ and small‐scale environmental gradients explained minimal variation in morphological leaf traits, suggesting that environmental conditions do not constrain morphological leaf trait values of vascular epiphytes. Our findings suggest that assessing multiple drivers of leaf trait variation among photosynthetic pathways is key for disentangling the mechanisms underlying responses of vascular epiphytes to environmental conditions. Read the free Plain Language Summary for this article on the Journal blog.

Bosques monotípicos de Gonopterodendron sarmientoi: ambiente, genética y morfología de los palosantales

Gonopterodendron sarmientoi is a native tree species from Chaco region forest that grows in mixed forest or in pure dense forests (palosantales). Due to habitat destruction and high exploitation, G. sarmientoi is threatened; hence, baseline information about the forests where the species grows is needed to guide future management and conservation programs. The objective of this article is to characterize the environment, genetic diversity and morphology of G. sarmientoi’s palosantales (n=10), in relation to the species’ mixed forests (n=14). For that, along the whole range of the species distribution, we compared the palosantales and mixed forests regarding their composition of plant species and site attributes (soil type and vegetation index), genetic diversity obtained with neutral markers, and leaf and tree morphological traits. The palosantales were characterized by having fewer companion species forests (mean 8; min. 1; max. 14), predominantly with shrub species, in relation to mixed forests (mean 10; min. 8; max. 13). The soils of the palosantales showed high content of clay and low levels of organic carbon and sand. The lowest nutrients sampled sites were palosantales located in the center-west of the species range, in the triple border Argentina-Bolivia-Paraguay, and in the palosantales on Bermejo river paleochannels (Argentina). The vegetation index confirmed the low productivity of palosantales forests (NDVI palosantales 0.38; NDVI mixed forests 0.51). The palosantales were similar in genetic diversity with respect to mixed forest (nucleotide diversity 0.00103 vs. 0.00120; Shannon index 0.89 vs. 1.02, respectively). Morphologically, G. sarmientoi trees in the palosantales were shorter and shrubbier than the mixed forest trees. The forests of G. sarmientoi require focused research that considers the singularities of each type of forest, allowing conservation of the species and the derived ecosystem services.

Phylogeography and Population Genetics of Rosa chinensis var. spontanea and R. lucidissima Complex, the Important Ancestor of Modern Roses.

Rosa chinensis var. spontanea and R. lucidissima complex are the morphologically very similar key ancestors of modern roses with high importance in rose research and breeding. Although widely distributed in subtropical central and southwestern China, these two taxa are highly endangered. We sampled a total of 221 specimens and 330 DNA samples from 25 populations across the two taxa's whole range. Leaf morphological traits were compared. Two chloroplast DNA intergenic spacers (trnG-trnS, petL-psbE) and ITS were used for population genetics and phylogenetic study to delimit the boundary between the two taxa, assess the genetic variation, uncover the possible evolutionary mechanism responsible for the differentiation within the complex, and make the conservation recommendations. The complex exhibited high levels of genetic variation (hTcpDNA = 0.768, hTITS = 0.726) and high population differentiation even over small geographic distance. We suggest R. chinensis var. spontanea and R. lucidissma be treated as independent taxa, and the northern populations around and within the Sichuan Basin being R. chinensis var. spontanea, having broader leaflets and paler full-blooming flowers, while those in the middle and southern Yunnan-Guizhou Plateau and the adjacent regions being R. lucidissma, having narrower leaflets and darker full-blooming flowers. Transitional areas between the southeastern Sichuan Basin and northeastern Guizhou are the contact or the hybridization zone of the two taxa. Ancestral haplotypes of the complex (R. lucidissma) evolved at about 1.21–0.86 Mya in southeastern Yunnan-Guizhou Plateau and its adjacent regions and survived there during the Quaternary Oscillation. Ancestral haplotypes of R. chinensis var. spontanea deviated from R. lucidissma at about 0.022–0.031 Mya at the transitional areas (Daloushan and Wulingshan Mountains) between the northeastern edge of Yunnan-Guizhou Plaeteau and the southeastern border of Sichuan Basin, where they survived the LGM. The evolution of the complex included spatial isolation and inter-species hybridization. The complex's endangered status might be the result of over-exploitation for its ornamental and medical value, or due to reforestation of some originally open habitats. We provide specific recommendations for the two taxa's in situ and ex situ conservation.

Phenotypic Variation and Peel Contribution to Fruit Antioxidant Contents in European and Japanese Plums.

Herein, we studied the variation in leaf and fruit morphological traits and antioxidant contents in 43 local and foreign cultivars (cvs) grown under the same experimental conditions in the widely cultivated plum species Prunus domestica and Prunus salicina. The peel contribution of fruit bioactive compounds in a serving portion, correlations among the examined parameters, and group patterns in each plum species were also studied. The species and cvs were sufficiently separated. Compared to Japanese cvs, European cvs had less elongated leaves and smaller and sweeter fruit with less total phenol and antioxidant capacities. The Japanese cvs ‘Red ace’ and the widely grown ‘Black Amber’, together with the European ‘Tuleu Dulce’, ‘BlueFre’, and the landrace ‘Asvestochoriou’ make up groups with rich dietary sources of phytochemicals. The peel tissue contained higher total phenols and antioxidant capacities compared to the flesh, while the peel/flesh ratios varied widely among the cvs (6.6-fold). The variation in the antioxidant contents was lower among the cvs calculated per serving portion (3.7-fold); yet the peel tissue contribution was equal to that of the flesh (48.6%), signifying its high nutritive value. We observed increased sweetness in the fruit in the later-harvested cultivars, while cvs with more blue- and red-colored peel generally contained higher antioxidant contents mainly in the European plums. Moreover, larger fruit sizes were positively correlated with larger and more elliptic leaf shapes. In conclusion, the significant role of the genotype and the peel tissue as a source of bioactive compounds in plums were outlined with prospects of utilization in future breeding programs.

Leaf morpho-physiological comparison between native and non-native plant species in a Mediterranean island

Islands tend to be more prone to plant invasions than mainland regions, with the Mediterranean ones not being an exception. So far, a large number of studies on comparing leaf morphological and physiological traits between native and non-native plants in Mediterranean environments have been performed, although none of them on Mediterranean islands. To fill this gap, this study focuses on 14 plant species grown in a controlled growth chamber in the absence of stress. The goal was (1) to differentiate leaf morpho-physiological traits between native and non-native plants on a Mediterranean island and (2) to deepen in the underlying causes of the differential photosynthetic traits displayed by non-native species. Results showed that in Mediterranean islands, non-native plant species show on average larger values of net CO2 assimilation, stomatal conductance (gm), photosynthetic nitrogen-use efficiency, among others, and lower leaf mass per area (LMA) and leaf thickness, compared to the native species. Among the assessed traits, this study reports for the first time larger gm, and lower mesophyll conductance limitation in non-native species, which seems to be linked to their lower LMA. These novel traits need to be added to the ‘leaf physiological trait invasive syndrome’. It was also found that on a Mediterranean island, native and non-native species are placed on opposite sides of the leaf economics spectrum, with non-native species being placed on the ‘‘fast-return’’ end. In conclusion, this study demonstrates that non-native species inhabiting a Mediterranean island possess distinct leaf morphological and physiological traits compared to co-occurring native species, at least during the favorable growth season, which increases the chances of a successful invasion.

Two Dominant Herbaceous Species Have Different Plastic Responses to N Addition in a Desert Steppe.

Nitrogen (N) deposition rates are increasing in the temperate steppe due to human activities. Understanding the plastic responses of plant dominant species to increased N deposition through the lens of multiple traits is crucial for species selection in the process of vegetation restoration. Here, we measured leaf morphological, physiological, and anatomical traits of two dominant species (Stipa glareosa and Peganum harmala) after 3-year N addition (0, 1, 3, and 6 g N m−2 year−1, designated N0, N1, N3, and N6, respectively) in desert steppe of Inner Mongolia. We separately calculated the phenotypic plasticity index (PI) of each trait under different N treatments and the mean phenotypic plasticity index (MPI) of per species. The results showed that N addition increased the leaf N content (LNC) in both species. N6 increased the contents of soluble protein and proline, and decreased the superoxide dismutase (SOD) and the peroxidase (POD) activities of S. glareosa, while increased POD and catalase (CAT) activities of P. harmala. N6 increased the palisade tissue thickness (PT), leaf thickness (LT), and palisade-spongy tissue ratio (PT/ST) and decreased the spongy tissue–leaf thickness ratio (ST/LT) of S. glareosa. Furthermore, we found higher physiological plasticity but lower morphological and anatomical plasticity in both species, with greater anatomical plasticity and MPI in S. glareosa than P. harmala. Overall, multi-traits comparison reveals that two dominant desert-steppe species differ in their plastic responses to N addition. The higher plasticity of S. glareosa provides some insight into why S. glareosa has a broad distribution in a desert steppe.

The role of nutritional impairment in carbon‐water balance of silver fir drought‐induced dieback

Rear‐edge populations at the xeric distribution limit of tree species are particularly vulnerable to forest dieback triggered by drought. This is the case of silver fir (Abies alba) forests located in Southwestern Europe. While silver fir drought‐induced dieback patterns have been previously explored, information on the role played by nutritional impairment is lacking despite its potential interactions with tree carbon‐water balances. We performed a comparative analysis of radial growth, intrinsic water‐use efficiency (iWUE), oxygen isotopes (δ18O) and nutrient concentrations in leaves of declining (DD) and non‐declining (ND) trees in silver fir in four forests in the Spanish Pyrenees. We also evaluated the relationships among dieback predisposition, intraspecific trait variation (wood density and leaf traits) and rhizosphere soil physical–chemical properties. The onset of growth decline in DD trees occurred more than two decades ago, and they subsequently showed low growth resilience against droughts. The DD trees presented consistently lower foliar concentrations of nutrients such as P, K, Cu and Ni than ND trees. The strong effects of foliar nutrient status on growth resilience indices support the key role played by mineral nutrition in tree functioning and growth before, during and after drought. In contrast, variability in wood density and leaf morphological traits, as well as soil properties, showed weak relationships with tree nutritional status and drought performance. At the low elevation, warmer sites, DD trees showed stronger climate–growth relationships and lower δ18O than ND trees. The uncoupling between iWUE and δ18O, together with the positive correlations between P and K leaf concentrations and δ18O, point to deeper soil/bedrock water sources and vertical decoupling between nutrient and water uptake in DD trees. This study provides novel insights into the mechanisms driving silver fir dieback and highlights the need to incorporate tree nutrition into forest dieback studies.

Leaf morphological traits as adaptations to multiple climate gradients.

Leaf morphological traits vary systematically along climatic gradients. However, recent studies in plant functional ecology have mainly analysed quantitative traits, while numerical models of species distributions and vegetation function have focused on traits associated with resource acquisition; both ignore the wider functional significance of leaf morphology.A dataset comprising 22 leaf morphological traits for 662 woody species from 92 sites, representing all biomes present in China, was subjected to multivariate analysis in order to identify leading dimensions of trait covariation (correspondence analysis), quantify climatic and phylogenetic contributions (canonical correspondence analysis with variation partitioning) and characterise co‐occurring trait syndromes (k‐means clustering) and their climatic preferences.Three axes accounted for >20% of trait variation in both evergreen and deciduous species. Moisture index, precipitation seasonality and growing‐season temperature explained 8%–10% of trait variation; family 15%–32%. Microphyll or larger, mid‐ to dark green leaves with drip tips in wetter climates contrasted with nanophyll or smaller glaucous leaves without drip tips in drier climates. Thick, entire leaves in less seasonal climates contrasted with thin, marginal dissected, aromatic and involute/revolute leaves in more seasonal climates. Thick, involute, hairy leaves in colder climates contrasted with thin leaves with marked surface structures (surface patterning) in warmer climates. Distinctive trait clusters were linked to the driest and most seasonal climates, for example the clustering of picophyll, fleshy and succulent leaves in the driest climates and leptophyll, linear, dissected, revolute or involute and aromatic leaves in regions with highly seasonal rainfall. Several trait clusters co‐occurred in wetter climates, including clusters characterised by microphyll, moderately thick, patent and entire leaves or notophyll, waxy, dark green leaves. Synthesis. The plastic response of size, shape, colour and other leaf morphological traits to climate is muted, thus their apparent shift along climate gradients reflects plant adaptations to environment at a community level as determined by species replacement. Information on leaf morphological traits, widely available in floras, could be used to strengthen predictive models of species distribution and vegetation function.

Phenotypic plasticity and selection on leaf traits in response to snowmelt timing and summer precipitation

Vegetative traits of plants can respond directly to changes in the environment, such as those occurring under climate change. That phenotypic plasticity could be adaptive, maladaptive, or neutral. We manipulated the timing of spring snowmelt and amount of summer precipitation in factorial combination and examined responses of specific leaf area (SLA), trichome density, leaf water content (LWC), photosynthetic rate, stomatal conductance and intrinsic water-use efficiency (iWUE) in the subalpine herb Ipomopsis aggregata. The experiment was repeated in three years differing in natural timing of snowmelt. To examine natural selection, we used survival, relative growth rate, and flowering as fitness indices. A 50% reduction in summer precipitation reduced stomatal conductance and increased iWUE, and doubled precipitation increased LWC. Combining natural and experimental variation, earlier snowmelt reduced soil moisture, photosynthetic rate and stomatal conductance, and increased trichome density and iWUE. Precipitation reduction reversed the mortality selection favoring high stomatal conductance under normal and doubled precipitation, and higher LWC improved growth. Earlier snowmelt is a strong signal of climate change and can change expression of leaf morphology and gas exchange traits, just as reduced precipitation can. Stomatal conductance and SLA showed adaptive plasticity under some conditions.

Effect of Water Stress on Physiological and Morphological Leaf Traits: A Comparison among the Three Widely-Spread Invasive Alien Species Ailanthus altissima, Phytolacca americana, and Robinia pseudoacacia.

Invasive alien species (IAS) are a problem, especially in drought-prone environments such as the Mediterranean Basin where the exacerbation of the already severe conditions could constrain the native species acclimatation degree, creating new opportunities for IAS. Climate change may drive IAS expansions, even if different IAS can vary in their acclimatation response. Thus, it is important to obtain a broader insight of how the different IAS face abiotic stress. This research aimed to compare the effect of the imposed water stress on physiological and morphological leaf traits of Ailanthus altissima (AA), Robinia pseudoacacia (RP), and Phytolacca americana (PA), which are widely spread IAS in the Mediterranean Basin. Our results showed a species-dependent effect of the water stress at a physiological and morphological level, as well as an interaction between species and stress duration. Despite a common strategy characterized by low stomatal control of the photosynthesis, AA, PA, and RP differ in their sensitivity to water stress. In particular, even if AA was characterized by a more water-spending strategy, it was more resistant to water stress than PA and RP. In this view, the key factor was its plasticity to increase leaf mass per area (LMA) in response to water stress.

Variability in leaf morphological traits of an endemic Mexican oak ( Quercus mexicana Bonpl.) along an environmental gradient

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.&#x0D; Objective: We analyzed the leaf morphological variation of an endemic oak to identify the degree of population differentiation along an environmental gradient.&#x0D; Study species: Quercus mexicana Bonpl. (Fagaceae).&#x0D; 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.&#x0D; 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.&#x0D; 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.&#x0D; 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.

Population Variability of Almond-Leaved Willow (Salix triandra L.) Based on the Leaf Morphometry: Isolation by Distance and Environment Explain Phenotypic Diversity

Almond-leaved willow (Salix triandra L., Salicaceae) is a dioecious shrub, rarely a small tree that grows under various environmental conditions. We examined the population structure of 12 populations of almond-leaved willow using nine leaf morphological traits and specific leaf area. Populations were selected from a range of habitats, from continental to the sub-Mediterranean zone, to examine the influence of environmental conditions (climate and altitude) and geographic distance on leaf variability. Significant differences were confirmed among all populations for all traits, with significant correlations between geographic location of populations and morphological traits, and between environmental conditions and morphological traits. Large-leaved populations were found in continental and sub-Mediterranean climates, while small-leaved populations were found in higher elevations and smaller karstic rivers. In addition, populations from floodplains showed greater variability than populations from the karstic habitats, indicating a positive influence of lowland habitats and possible underlying differences in gene pool size. In conclusion, we found that environmental conditions and geographical distances in addition to genetic drift, are the main influences on the variability in almond-leaved willow, with the species showing a high level of plasticity and adaptation to local environmental conditions.

An Overview of the functioning of Temperate Forest Ecosystems with Particular Reference to Himalayan Temperate Forest

Plant functional traits (PETs) are an important indicator of structure and function of forest ecosystem. However, the succinct accounting of the linkages across the various forest types are lacking across the literature. Therefore, the objective of the study was to synthesize current knowledge about and ecosystem function and services along with their linkages to PFTs in temperate forest ecosystem. A systematic literature review with appropriate keywords and suitable inclusion and exclusion criterion was applied for generating of the information in accordance to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Forty-eight studies (31 on functional traits and 17 on linkages of PFT with various ecosystem services) reveals that aboveground biomass and wood productivity was associated with leaf morphological, chemical and stem traits, however, only a few studies dealt with leaf physiological, stoichiometry, regenerative and root traits. Litter decomposition was mostly associated with leaf chemical and morphological traits followed by leaf physiological and stoichiometry traits; however, evaluations between PFTs and ecosystem services (ESs) were categorically not accounted the association with stem, root and regenerative traits in temperate forests. Leaf morphological, chemical, stoichiometry and stem traits were important predictors of ecosystem process and functioning and facilitate for the measurements of ecosystem services. However, limited and skewed studies suggest more focus researches on physiological, regenerative and root traits in temperate forest for assessing the unexplored services. The state of the science information of temperate forest ecosystem services with traits relationship is useful for forest planning, management and maintaining multi-functionality and services of temperate forest besides identifies future priorities for forest sustainability.