Variation In Leaf Morphology Research Articles

Spatial, genetic and biotic factors shape within‐crown leaf trait variation and herbivore performance in a foundation tree species

Abstract Functional trait variation within individual plants is predicted to have important ecological consequences. However, our understanding of the sources contributing to subindividual trait heterogeneity, and the ramifications thereof, is poor. In a common garden, we sampled multiple genotypes of mature trembling aspen Populus tremuloides at different vertical crown levels and quantified the contributions of genetic, spatial and biotic (herbivory) factors to subindividual morphological and chemical leaf trait variance. Bioassays using gypsy moth Lymantria dispar L. caterpillars were conducted to study the impacts of spatial and genotypic factors on insect performance. Crown position was the primary source of subindividual variation in leaf morphology and explained more of the variance in morphological traits than tree genotype. Effects of spatial, genetic and biotic factors on within‐crown chemistry were highly compound specific. For many compounds, changes in within‐crown concentrations differed among genotypes, revealing that genotypic variation not only contributes to phytochemical diversity among individuals of the same population, but also affects subindividual chemical trait heterogeneity. For many defence‐related compounds, total within‐crown variance itself differed among genotypes and was in many cases a heritable trait. Bioassays revealed that effects of crown position on caterpillar performance varied among tree genotypes and caterpillar sexes. We demonstrate that even relatively small trees can express subtle but distinct levels of within‐crown leaf trait variation. In aspen, this variation is shaped not only by spatial factors, but also by genetics and to a lesser degree by herbivory. Within‐crown variation in defence chemistry might itself provide a defensive phenotype against herbivores and contribute to the biological diversity of canopy insect communities. A free Plain Language Summary can be found within the Supporting Information of this article.

Phenotypic plasticity of leaf shape in selected and semi-domesticated genotypes as new tool of Argania spinosa L. Skeels breeding

Leaves are part of the plant organs that are important to sustain its life. These organs are sensitive to climate changes and may present phenotypic plasticity in response to environmental conditions. However, affirmation of the leaves morphological plasticity and their regulation in different environments is still little studied up to date. In the present research, we evaluated performance of 20 different groups of Argania spinosa (L.) Skeels genotypes (half-sibling). Each group contains 3 half-sibs. Genotype × environment interactions (GxE) were evaluated as well, for shape and size leaves. To perform this, geometric morphometric principles were applied to analyze genotypes morphology in three locations (Central, North-Western and South-Western of Morocco). Univariate and multivariate analysis was used for data analysis. Results showed significant variation of symmetric and asymmetric components for genotypes, half-sibling and location with relatively high variation coefficient (ca 60%). Shape and size differences among genotypes, suggest that they were the main source in leaf morphology variation. Canonical Variate Analysis of leaf shapes reveals that the regions are clearly distinct from each other. For symmetric component analysis, Mahalanobis distances values among locations reached 35.53 between South-Western and North-Western locations, 21.88 North-Western and Central locations and 18.29 for South-Western and Central location. The differentiation between the groups using the Canonical Variations value showed a significant effect of the environment on the studied argan tree genotypes. Small leaves and narrow blades were observed in Central location compared to others. However, leaves originated from South-Western location had mainly an ovate shape. The same genotypes presented a high spectrum of shape variation varying from obovate to ovate in the other regions. This study highlights the strong correspondence between leaf morphology and genotype within different environments, and demonstrates that GxE interaction shave an impact to take into consideration in breeding programs.

Leaf Morphological Variation of Acanthus in Some Estuarine Areas of Cilacap

Acanthus is the only genus of family Acanthaceae which occupies mangroves habitat. Despite the importance of Acanthus, collection, characterization and improvement of its germplasm is limited. Hence, this will hinder its effective conservation and utilization. Therefore, the objective of this research was to identify morphological variation of Acanthus in some estuarine areas of Cilacap Central java in relation to habitat. The method used in this study was survey with stratified sampling. The variables measured included, leaf shape, size, apex, base, margin, color and spine. The results of this study indicated that the different location affect some morphological characteristics. Most of the Acanthus population observed in this study have direction of stem axial spines facing upwards, green, inflorescences spika, petals large, light violet Similar to characters Acanthus ilicifolius has variations in leaf margin, leaf shape and size.

Morphological variation of fine root systems and leaves in primary and secondary tropical forests of Hainan Island, China

In older, unlogged rainforest of Hainan Island, China, leaves of saplings were larger, and fine root systems of saplings were thicker with fewer root tips than in historically logged areas. These results were consistent among 15 Angiosperm lineages, even though families differed widely in their leaf and root traits. How plant organ morphologies vary with environment is key for inferring plant functional strategies. We were interested in quantifying any changes in fine root and leaf morphology of saplings with local-scale environmental variation in tropical forest, and if any variation in organ morphologies differed with plant lineage. We measured functional traits of fine root systems and leaves of saplings from 15 families in historically logged and unlogged Chinese tropical forest, where soil fertility and texture slightly decreased with greater forest age. Root morphological traits were more conservative, while leaf morphologies were more acquisitive in primary forest than in secondary forest. From secondary to primary forests, mean root system diameter increased 0.4 mm, mean specific root length decreased 3.5 m kg−1, and mean root system branching intensity decreased by 0.3 tips cm−1. Similarly, from secondary to primary forests, average leaf area increased 7 cm2 and specific leaf area decreased 0.8 m2 kg−1. Leaf thickness and root tissue density were not different. Among the selected plant families, root and leaf morphological differences between forest types were consistent. Within lineage (i.e., intraspecific) root and leaf morphological variation showed contrasting patterns. Local-scale variation in soil phosphorus and base saturation affected intraspecific variation in root diameter and specific root length.

Genotypic and Phenotypic Correlations between Leaf-Rust Disease and Leaf Morphology and its Ratio in Arabica Coffee


 Selection parameter in coffee breeding for leaf rust (Hemeleia vastatrix) resistance is very important. Breeders used leaf-rust severity and leaf-rust incidence as parameters of direct selection. However, scientific proof is not yet available whether leaf morphology can be used as a parameter of indirect selection. The objective of this research was to seek the possibility of leaf morphology parameter and its ratio to be used as selection criteria through analyses of genotypic and phenotypic correlations of parameter of rust disease and parameter of leaf morphology and its ratio. The result revealed that genotypes showed significant variations in leaf-rust severity (5.21–25.84%), leaf morphology, and leaf-morphology ratio. Leaf length to leaf width ratio, leaf length to leaf area ratio, and leaf width to leaf weight ratio were not affected by the environment. Leaf-rust severity performed highly significant positive genotypic and phenotypic correlations the ratio of with leaf length to leaf area. For selection criteria, leaf-rust severity could be better used rather than leaf-rust incidence and branch-rust incidence. The ratio of leaf length to leaf area could also be used as an indirect selection criterion because the ratio showed a highly significant genotypic correlation with leaf-rust severity (rGab = 0.254**). However, the ratio of leaf length to leaf area is even better chosen for selection criteria rather than leaf-rust severity because the ratio was not affected by the environment.
 
 Keywords: fungus, Hemeleia vastatrix, indirect selection

Variation of leaf morphology of hibiscus rosa-sinensis l. under various light intensities at Universitas Indonesia campus area and Citayam, Depok

Hibiscus rosa-sinensis L. is a plant that has been cultivated as an ornamental plant, especially in Indonesia. Universitas Indonesia, located in Depok, has ten variations of H. rosa-sinensis in size, shape, and color of flowers. The flower shape consists of three types, namely, single, double, and crested. In this study, it is reported the comparison of leaf morphology from several types of H. rosa-sinensis L. Twenty leaves from each variety were used for morphometric measurement, and light intensity data from each location of the plant variety was also collected. There are two locations, Universitas Indonesia (UI) Campus Area and Citayam. The results showed that two individuals Crested Peach plant in Citayam, which grown under different light intensity has significantly different in leaf surface area but no difference in stomata surface area. Big Single Red and Double Pink located in UI exposure by the same light intensity has the same leaf surface area and stomata surface area. Comparing Small Single Red Citayam and Small Single Red UI exposure by different light intensity has significantly different in leaf surface area and stomata surface area. Two Crested Peach in UI, exposured by the same light intensity, were significantly different in leaf surface area and has the same stomata surface area. This study showed that light intensity could influence the variation of leaf morphology of several Hibiscus rosa-sinensis L. flower types, but not all flower types.

Environmental pressure rather than ongoing hybridization is responsible for an altitudinal cline in the morphologies of two oaks

AbstractAimsIn a contact zone between related taxa, phenotypic variation can result from genetic and/or environmental gradients. This study aimed to clarify the cause of phenotypic variation in leaf morphology of two Quercus crispula varieties—crispula (QCC) and mongolicoides (QCM)—in their contact zone along an altitudinal gradient.MethodsWe measured 6 morphological traits of leaves and recorded genotypes of 13 nuclear microsatellite loci for 48 individuals in the contact zone and 24 individuals in each of the reference populations of QCC and QCM. We constructed a model explaining the phenotypic variation (leaf morphology) in relation to environmental (altitude) and genetic (ancestry from the reference population) gradients.Important FindingsBoth morphological and genetic markers distinguished the two varieties in the reference populations well. We were able to confirm the power of both morphological and genetic markers. Individuals within the contact zone population had intermediate ancestry that was slightly biased to QCM ancestry, and the distribution of their morphologies overlapped with those of the two varieties in the reference populations. The effect of altitude on leaf morphological traits was significant, while that of ancestry was not. Distributions of ancestry and interclass heterozygosity in the contact zone population resembled those in F2 or later generation hybrids. These results indicate that in the contact zone between QCC and QCM, there is no ongoing hybridization, but environmental pressure has created an altitudinal gradient in morphological traits through phenotypic plasticity and/or variation in functional genes.

Intraspecific trait variation across elevation predicts a widespread tree species' climate niche and range limits.

Global change is widely altering environmental conditions which makes accurately predicting species range limits across natural landscapes critical for conservation and management decisions. If climate pressures along elevation gradients influence the distribution of phenotypic and genetic variation of plant functional traits, then such trait variation may be informative of the selective mechanisms and adaptations that help define climatic niche limits. Using extensive field surveys along 16 elevation transects and a large common garden experiment, we tested whether functional trait variation could predict the climatic niche of a widespread tree species (Populus angustifolia) with a double quantile regression approach. We show that intraspecific variation in plant size, growth, and leaf morphology corresponds with the species' total climate range and certain climatic limits related to temperature and moisture extremes. Moreover, we find evidence of genetic clines and phenotypic plasticity at environmental boundaries, which we use to create geographic predictions of trait variation and maximum values due to climatic constraints across the western US. Overall, our findings show the utility of double quantile regressions for connecting species distributions and climate gradients through trait‐based mechanisms. We highlight how new approaches like ours that incorporate genetic variation in functional traits and their response to climate gradients will lead to a better understanding of plant distributions as well as identifying populations anticipated to be maladapted to future environments.

Rapid identification of the BjRCO gene associated with lobed leaves in Brassica juncea via bulked segregant RNA-seq

Leaf morphology varies significantly among Brassica juncea. However, little is known regarding the causal gene that controls lobed leaf shape in B. juncea. In our study, the BjRCO gene, which is associated with leaf morphological variation, was cloned from chromosome A10 in B. juncea via BSR-seq. Blast analysis suggested that the BjRCO encodes a HD-Zip I transcription factor, which may serve as a positive regulator of lobed leaf formation in leaf mustard. Interestingly, the lobed leaf genes reported in the related species of Brassica (B. rapa, B. napus, and B. juncea) were located in A10. Phylogenetic analysis showed that BjRCO was also homologous to the lobed leaf gene BoLl reported on chromosome 9 in B. oleracea. In addition, qRT-PCR results showed that the expression levels of the BjRCO gene were higher expressed in the inner small lobed leaves than in the little sawtooth-like leaves (LSL). These results of this study indicate that the BjRCO gene is related to lobed leaf formation in B. juncea. These findings help to establish a solid foundation for future research investigating the molecular mechanism governing lobed leaf formation in B. juncea.

Morphological differentiation among populations of Quercus elliptica Neé (Fagaceae) along an environmental gradient in Mexico and Central America

Background: Variation in leaf morphology is an important indicator of how plants respond to different environmental conditions. Leaf trait variation is associated with physiological responses of plants to gradients of humidity and temperature. 
 Objective: We analyzed the variation in the leaf morphological and functional traits of Quercus elliptica and its relationships with environmental and geographic variables across the distribution of this species to evaluate population differentiation using ecological niche models.
 Study species: Quercus elliptica Neé (Fagaceae).
 Study sites and dates: Plants were collected in diverse forest types between 350 and 2,400 m in elevation in Mexico and Central America during 2016 and 2017.
 Methods: We measured and analyzed the differentiation in morphological and functional traits of 4,017 leaves from 402 trees from 41 populations using univariate and multivariate analyses.
 Results: The leaf length and thickness and specific leaf area (SLA) of Q. elliptica were significantly correlated with the seasonality of temperature, precipitation, elevation and aridity. We identified two divergent morphological groups: (1) populations distributed along the Pacific coast with broad and thin elliptical leaves with high SLA values and inhabited humid forests at more than 1,200 m elevation, and (2) populations located along the Gulf of Mexico coast, and in southern Mexico and Central America with thicker, narrower leaves and lower SLA values and inhabited seasonal tropical forests in less than 1,200 m in elevation. 
 Conclusions: Climate and geographic barriers and the ecological niche models supported the population differentiation of Q. elliptica .

Morphological variation of leaf traits in the Ternstroemia lineata species complex (Ericales: Penthaphylacaceae) in response to geographic and climatic variation.

Variation in leaf morphology is correlated with environmental variables, such as precipitation, temperature and soil composition. Several studies have pointed out that individual plasticity can largely explain the foliar phenotypic differences observed in populations due to climatic change and have suggested that the environment plays an important role in the evolution of plant species by selecting for phenotypic variation. Thus, the study of foliar morphology in plant populations can help us identify the environmental factors that have potentially influenced the process of species diversification. In this study, we analyzed morphological variation in the leaf traits of the Ternstroemia lineata species complex (Penthaphylacaceae) and its relation to climatic variables across the species distribution area to identify the patterns of morphological differentiation within this species complex. Based on the collected leaves of 270 individuals from 32 populations, we analyzed nine foliar traits using spatial interpolation models and multivariate statistics. A principal component analysis identified three main morphological traits (leaf length and two leaf shape variables) that were used to generate interpolated surface maps to detect discrete areas delimited by zones of rapid change in the values of the morphological traits. We identified a mosaic coarse-grain pattern of geographical distribution in the variation of foliar traits. According to the interpolation maps, we could define nine morphological groups and their geographic distributions. Longer leaves, spatulate leaves and the largest foliar area were located in sites with lower precipitation and higher seasonality of precipitation following a northwest–southeast direction and following significant latitudinal and longitudinal gradients. According to the phenogram of the relationships of the nine morphological groups based on morphological similarity, the putative species and subspecies of the T. lineata species complex did not show a clear pattern of differentiation. In this study, we found a complex pattern of differentiation with some isolated populations and some other contiguous populations differentiated by different traits. Further genetic and systematic studies are needed to clarify the evolutionary relationships in this species complex.

Morphological and molecular characterization of a hybrid zone between Prosopis alba and P. nigra in the Chaco region of northwestern Argentina

Abstract The Gran Chaco is the largest dry forest in South America. One of the key taxa of this biome is the genus Prosopis (Fabaceae) which contains several economically important species. One of the characteristics of this genus is its natural capacity to exchange genetic information among congeneric species, generating zones of high morphological and genetic variability at contact points. The study and management of these contact areas can contribute to the dynamic conservation of these native genetic resources. In this study, we analysed three sites within a gradient of land aridity, where P. nigra and P. alba grow in sympatry and apparently hybridize. This is the first study performed in both, Prosopis pure sites and hybrid swarm, which includes a spatially explicit approach and simultaneously analyses fruit and leaf morphological variation, together with molecular information (microsatellites markers). We performed a multivariate morphological analysis, Bayesian genetic clustering and multivariate associations between genetic and morphological variability in the pure parental populations and in the hybrid swarm, considering possible spatial autocorrelation. Bayesian cluster analysis revealed two distinct groups corresponding to each species, differentiating the pure morphotypes from sites 1 and 2. Site 3, corresponding to the hybrid swarm, was composed of pure P. alba and P. nigra trees and hybrid individuals. We found morphological and molecular evidence of hybridization between P. alba and P. nigra, and detected novel phenotypes in the hybrid site.

Morphological variation of Chrysanthemum lavandulifolium induced by 5-azaC treatment

To explore the possible role of DNA methylation in plant development. Different concentrations of the DNA methyltransferase inhibitor 5-azacytidine were used on different components of Chrysanthemum lavandulifolium (stem and hypocotyl). The effects of 5-azaC on plantlet growth and flower development were investigated. Results showed that low concentrations of 5-azaC (20 μmol L−1–100 μmol L−1) inhibited plantlet growth (from the stem segments), and high concentrations of 5-azaC (150 μmol L−1–200 μmol L−1) promoted plantlet growth. This inhibition is similar in the regeneration of hypocotyls, except that the concentration range of 5-azaC is different. Low concentration of 5-azaC (10 μmol L−1–20 μmol L−1) inhibit generation or growth of callus-generated plantlets, high concentration of 5-azaC (150 μmol L−1–200 μmol L−1) promoted the growth of hypocotyl regeneration seedlings. In thus, the inhibitory effect of plantlet was similar in hypocotyl regeneration. Therefore, different explants have different sensitivities to methyltransferase inhibitor (5-azaC) treatment. Progeny plants treated with stems of C. lavandulifolium under the short days condition, the control plants (about 15 leaves) did not bloom, plants undergoing high concentration treatments flowered in some strains (flowering rate 80% in treatment 6), and the pitch of all unflowering plants was dwarfed. It seems that 5-azaC can break the C. lavandulifolium adolescent period limit, potentially by inducing the photoperiodic in advance or through another mechanism, after 5-azaC processing may alters key gene methylation, resulting in flowering. In the hypocotyl-treated progeny after multiple passages, all treatments had flowering and non-flowering lines under short-day conditions, and the flowering rate was between 39.29% and 78.43%. We also obtained a continuous flowering line was obtained (2-8-2), and this trait exhibited stable by asexual reproduction. In addition, abundant variation in leaf morphology, flower shape and stem color variation were observed in hypocotyl regeneration plants. All the evidence suggests that the methyltransferase inhibitor (5-azaC) may affect the DNA methylation level of many key genes regulating plant growth and development. This study provides phenotypic data and materials for further exploring the role of DNA methylation in the growth and flower induction of C. lavandulifolium.

Relative genome size variation in the African agroforestry tree Parkia biglobosa (Fabaceae: Caesalpinioideae) and its relation to geography, population genetics, and morphology.

Variation in genome size and in chromosome number can be linked to genetic, morphological, and ecological characteristics, and thus be taxonomically significant. We screened the relative genome size (RGS) and counted the number of mitotic chromosomes in the African agroforestry tree Parkia biglobosa, a widely distributed savannah species that shows conspicuous morphological clinal variation and strong genetic structure, and tested for linkage of RGS variation to geography, leaf morphology, and population genetic variation. An improved protocol for the preparation of chromosomes was developed. The study is based on 58 individuals from 15 populations covering most of the distribution range of the species. We observed differences in RGS among individuals of up to 10.2%, with some of the individuals differing statistically in RGS from the bulk of screened individuals. Most of the RGS variation was within populations, whereas variation was unrelated to any of the tested features of the species. Those chromosome numbers that could be exactly established were invariable 2n = 2x = 26. In conclusion, there was no evidence from the karyological data for structured intraspecific taxonomic heterogeneity.

Evaluating the performance of PROSPECT in the retrieval of leaf traits across canopy throughout the growing season

Leaf traits and subsequently leaf spectral properties depend on the leaf phenological stage and light conditions within a canopy. The PROSPECT radiative transfer model has been extensively and successfully used to retrieve leaf traits for mature, sunlit leaves at peak vegetation growth, i.e. summer. However, research on the quantification of leaf traits using PROSPECT across the canopy vertical profile throughout the growing season is still lacking. Therefore, this study aims at examining the effect of leaf position on the performance of the PROSPECT model in modelling leaf optical properties and retrieving leaf chlorophyll content (Cab), equivalent water thickness (EWT), and leaf mass per area (LMA) throughout the growing season. To achieve this objective, we collected 588 leaf samples from the upper and lower canopies of deciduous stands over three seasons (i.e., spring, summer and autumn) in Bavaria Forest National Park, Germany. Leaf traits including Cab, EWT and LMA, were measured for all the samples, and their reflectance spectra were obtained using an ASD FieldSpec-3 Pro FR spectroradiometer coupled with an Integrating Sphere. We initially assessed the performance of the PROSPECT model by comparing reflectance spectra generated in forward mode against reflectance spectra measured on leaf samples collected in the field. We subsequently inverted the PROSPECT model to retrieve Cab, EWT and LMA using the look-up-table (LUT) approach. Our results consistently demonstrated that the measured reflectance of leaf samples collected from the lower canopy had a stronger match with PROSPECT simulated reflectance spectra, especially in the NIR spectrum compared to leaf samples collected from the upper canopy throughout the growing season. This observation concurred with the pattern of Cab and EWT retrieval accuracies across the canopy i.e. the retrieval accuracy for the lower canopy was consistently higher (NRMSE = 0.1-0.2 for Cab; NRMSE = 0.125-0.16 for EWT) when compared to the upper canopy (NRMSE = 0.122 - 0.269 for Cab; NRMSE = 0.162 -0.0.258 for EWT) across all seasons. In contrast, LMA retrieval accuracies for the upper canopy (NRMSE = 0.146 - 0.184) were higher compared to the lower canopy (NRMSE = 0.162 - 0.239) for all seasons except for the spring season. For all the leaf traits examined in this study, the range in retrieval accuracy between the upper and lower canopy was greater in summer (compared to other seasons). We report for the first time that although the PROSPECT model provides reasonable retrieval accuracy of Cab, EWT and LMA, variations in leaf biochemistry and morphology through the vertical canopy profile affects the performance of the model over the growing season. Findings of this study have important implications on field sampling protocols and upscaling leaf traits to canopy and landscape level using multi-layered physical models coupled with PROSPECT.

A Comprehensive Comparative Study for the Authentication of the Kadsura Crude Drug.

The stems and roots of Kadsura species have been used as the folk medicine in Traditional Chinese medicine (TCM) and have good traditional efficacy and medicinal application with a long history. Among these species, K. coccinea, K. heteroclita and K. longipedunculata are the most widely distributed species in the regions of south and southwest China. Owing to their similar appearance, the crude drugs are often confusedly used by some folk doctors, even some pharmaceutical factories. To discriminate the crude drugs, haplotype analysis based on cpDNA markers and ITS was firstly employed in this study. Generic delimitation, interspecific interrelationships, and the identification of medicinal materials between K. longipedunculata and K. heteroclita remained unresolved by the existing molecular fragments. The original plant could be identified through the morphological character of flower, fruit and leaf. However, in most situation collectors have no chance to find out these characters due to lack of reproductive organs, and have no experience with the minor difference and transitional variation of leaf morphology. The chemical characterization show that the chemometric of chemical composition owned higher resolution to discriminate three herbs of Kadsura species. In conclusion, this integrative approach involving molecular phylogeny, morphology and chemical characterization could be applied for authentication of the Kadusra. Our study suggests the use of this comprehensive approach for accurate characterization of this closely related taxa as well as identifying the source plant and confused herbs of TCM.

Effect of elevation and genotype on leaf morphological variation in Pistacia atlantica subsp. mutica in southern Yazd province forest

در این پژوهش برای ارزیابی اثر ارتفاع از سطح دریا و ژنوتیپ بر صفات مورفولوژیکی برگ گونه­ی بنه ( subsp. muticaPistacia atlantica)، سه جمعیت در نقاط ارتفاعی 1850، 2050 و 2400 متر از سطح دریا در جنگل باغ­شادی استان یزد، انتخاب شد. به ترتیب از جمعیت نخست، پنج پایه و از دو جمعیت­ دیگر، 10 پایه به­صورت تصادفی گزینش و برخی صفات مورفولوژیک پایه­ها در محل ثبت شد. از هر پایه، تعدادی برگ، جمع­آوری و در هم آمیخته شد. سپس پنج برگ از هر پایه، به­طور تصادفی انتخاب و 12 صفت از قبیل ابعاد برگ، وزن تر و خشک برگ و غیره اندازه­گیری شد. سپس با استفاده از روش تجزیه و تحلیل واریانس و مقایسات میانگین به روش دانکن و همبستگی پیرسون، صفات اندازه­گیری شده، تجزیه و تحلیل شد. نتایج حاکی از وجود اختلاف معنی­دار آماری از نظر صفات مورد مطالعه در بین سه جمعیت­ بود. همچنین بین پایه­های مورد بررسی در هر جمعیت اختلاف معنی­دار آماری مشاهده شد و در آخر قوی­ترین پایه­ها در هر جمعیت براساس صفات مهم معرفی شد. بر اساس نتایج تحقیق حاضر، پایه­های 6، 7، 8 و 9 از جمعیت A، پایه­های 1، 3، 4، 8 و 9 از جمعیت B و کلیه پایه­های جمعیتC به­ویژه پایه شماره 5، به عنوان پایه­های دارای فنوتیپ مناسب­تر از نظر صفات برگ معرفی می­شوند. در ضمن، جمعیت C به عنوان جمعیت مطلوب­تر انتخاب شد. می­توان تنوع مشاهده شده را به نقش ارتفاع از سطح دریا و ساختار ژنتیکی پایه­ها مربوط دانست که در عین­حال می­تواند نوعی سازگاری و پاسخ فیزیولوژیکی درختان به شرایط محیطی قلمداد گردد.

Ploidy and hybridity effects on leaf size, cell size and related genes expression in triploids, diploids and their parents in Populus.

Cell-size enlargement plays a pivotal role in increasing the leaf size of triploid poplar, and polyploidization could change leaf shape. ABP1 was highly expressed in triploid plants and positively related to cell size. In the plant kingdom, the leaf is the most important energy production organ, and polyploidy often exhibits a "Gigas" effect on leaf size, which benefits agriculture and forestry. However, little is known regarding the cellular and molecular mechanisms underlying the leaf size superiority of polyploid woody plants. In the present study, the leaf area and abaxial epidermal cells of diploid and triploid full-sib groups and their parents were measured at three different positions. We measured the expression of several genes related to cell division and cell expansion. The results showed that the leaf area of triploids was significantly larger than that of diploids, and the triploid group showed transgressive variation compared to their full-sib diploid group. Cell size but not cell number was the main reason for leaf size variation. Cell expansion was in accordance with leaf enlargement. In addition, the leaf shape changes in triploids primarily resulted from a significant decrease in the leaf ratio of length to -width. Auxin-binding protein 1 (ABP1) was highly expressed in triploids and positively related to leaf size. These results enhanced the current understanding that giant leaf is affected by polyploidy vigor. However, significant heterosis is not exhibited in diploid offspring. Overall, polyploid breeding is an effective strategy to enhance leaf size, and Populus, as an ideal material, plays an important role in studying the leaf morphological variations of polyploid woody plants.

Geometric morphometric analyses of leaf shapes in two sympatric Chinese oaks: Quercus dentata Thunberg and Quercus aliena Blume (Fagaceae)

Geometric morphometric analyses (GMMs) of the leaf shape can distinguish two congeneric oak species Quercus dentata Thunberg and Quercus aliena Blume in sympatric areas. High genetic and morphological variation in different Quercus species hinder efforts to distinguish them. In China, Q. dentata and Q. aliena are generally sympatrically distributed in warm temperate forests, and share some leaf morphological characteristics. The aim of this study was to use the morphometric methods to discriminate these sympatric Chinese oaks preliminarily identified from molecular markers. Three hundred sixty-seven trees of seven sympatric Q. dentata and Q. aliena populations were genetically assigned to one of the two species or hybrids using Bayesian clustering analysis based on nSSR. This grouping served as a priori classification of the trees. Shapes of 1835 leaves from the 367 trees were analyzed in terms of 13 characters (landmarks) by GMMs. Correlations between environmental and leaf morphology parameters were studied using linear regression analyses. The two species were efficiently discriminated by the leaf morphology analyses (96.9 and 95.9% of sampled Q. aliena trees and Q. dentata trees were correctly identified), while putative hybrids between the two species were found to be morphologically intermediate. Moreover, we demonstrated that the leaf morphological variations of Q. aliena, Q. dentata, and their putative hybrids are correlated with environmental factors, possibly because the variation of leaf morphology is part of the response to different habitats and environmental disturbances. GMMs were able to correctly classify individuals from the two species preliminary identified as Q. dentata or Q. aliena by nSSR. The high degree of classification accuracy provided by this approach may be exploited to discriminate other problematic species and highlight its utility in plant ecology and evolution studies.

Late Oligocene Fissistigma (Annonaceae) leaves from Guangxi, low-latitude China and its paleoecological implications

Fissistigma nanningense sp. nov. (Annonaceae) is described based on well-preserved mummified leaves from the Oligocene Yongning Formation of Nanning, Guangxi, southern China. They are characterized by retuse apex, a swollen petiole, eucamptodromous to simple brochidodromous secondary veins, percurrent tertiary veins, an obvious sub-vascular bundle and abundant oil cells. The nearest living relative of F. nanningense is considered to be Fissistigma glaucescens based on both qualitative morphological comparisons and the principal component analysis. The climbing habit of this genus indicates that a multilayered structure must have existed in the Oligocene forest of Guangxi. Moreover, according to the variation of leaf morphology in F. glaucescens under different environment, analogically, the present fossil leaves possessing small size and retuse apex indicate that they might grow in a sparse forest, or/and under the nutrient-poor conditions.