Variation In Leaf Shape Research Articles

Functional and historical drivers of leaf shape evolution in palms (Arecaceae)

AbstractAimLeaves display a remarkable variety of shapes, each with potential ecological advantages in specific climates. While the relations between leaf shape and either climate or height have been relatively well studied in eudicots, the macroecological drivers of shape remain poorly known in monocots. Here, we investigated the associations between climate and plant height with the evolution of leaf shape in a clade with high species and morphological diversity.LocationGlobal.Time periodCretaceous to contemporary.Major taxa studiedPalms (Arecaceae).MethodsWe apply a Bayesian phylogenetic mixed model to test for associations between climate and leaf shape (all – entire‐leaved, pinnate‐dissected, palmate‐dissected and costapalmate). We further reconstruct the ancestral leaf shape using multistate speciation and extinction models and compare the frequency of shapes with global temperatures through time.ResultsWe find that plant height associates with dissected leaves and that annual precipitation associates with pinnate shapes. The ancestral leaf shape is unclear, but early diversification was dominated by pinnate‐dissected palms, which has remained the most species‐rich form of leaves throughout palm history.Main ConclusionsPalms that are tall and live in humid regions are more likely to have pinnate leaves. Through geological time scales, temperature did not play an obvious role in determining leaf shapes. This study contributes to our understanding of how the diversity of leaf shapes is linked to biological and climatic factors.

The role of DNA methylation in the maintenance of phenotypic variation induced by grafting chimerism in Brassica.

Grafting facilitates the interaction between heterologous cells with different genomes, resulting in abundant phenotypic variation, which provides opportunities for crop improvement. However, how grafting-induced variation occurs and is transmitted to progeny remains elusive. A graft chimera, especially a periclinal chimera, which has genetically distinct cell layers throughout the plant, is an excellent model to probe the molecular mechanisms of grafting-induced variation maintenance. Here we regenerated a plant from the T-cell layer of a periclinal chimera, TCC (where the apical meristem was artificially divided into three cell layers - from outside to inside, L1, L2, and L3; T = Tuber mustard, C = red Cabbage), named rTTT0 (r = regenerated). Compared with the control (rsTTT, s = self-grafted), rTTT0 had multiple phenotypic variations, especially leaf shape variation, which could be maintained in sexual progeny. Transcriptomes were analyzed and 58 phenotypic variation-associated genes were identified. Whole-genome bisulfite sequencing analyses revealed that the methylome of rTTT0 was changed, and the CG methylation level was significantly increased by 8.74%. In rTTT0, the coding gene bodies are hypermethylated in the CG context, while their promoter regions are hypomethylated in the non-CG context. DNA methylation changes in the leaf shape variation-associated coding genes, ARF10, IAA20, ROF1, and TPR2, were maintained for five generations of rTTT0. Interestingly, grafting chimerism also affected transcription of the microRNA gene (MIR), among which the DNA methylation levels of the promoters of three MIRs associated with leaf shape variation were changed in rTTT0, and the DNA methylation modification of MIR319 was maintained to the fifth generation of selfed progeny of rTTT0 (rTTT5). These findings demonstrate that DNA methylation of coding and non-coding genes plays an important role in heterologous cell interaction-induced variation formation and its transgenerational inheritance.

Characterization of Some Cichorium Taxa Grown under Mediterranean Climate Using Morphological Traits and Molecular Markers

The verification of taxonomic identities is of the highest significance in the field of biological study and categorization. Morpho-molecular characterization can clarify uncertainties in distinguishing between taxonomic groups. In this study, we characterized five local taxa of the genus Cichorium using morphological and molecular markers for taxonomic authentication and probably future genetic improvement. The five Cichorium taxa grown under the Mediterranean climate using morphological traits and molecular markers showed variations. The examined taxa showed a widespread range of variations in leaf characteristics, i.e., shape, type, texture, margin, and apex and cypsela characteristics i.e., shape, color, and surface pattern. The phylogenetic tree categorized the Cichorium intybus var. intybus and C. intybus var. foliosum in a single group, whereas C. endivia var. endivia was grouped separately. However, C. endivia var. crispum and C. endivia subsp. pumilum were classified as a cluster. The recorded variance between classes using the molecular markers SCoT, ISSR, and RAPD was documented at 34.43%, 36.62%, and 40.34%, respectively. Authentication using molecular tools proved the usefulness of a dichotomous indented key, as revealed by morphological identification. The integrated methodology using morphological and molecular assessment could support improved verification and authentication of the various taxa of chicory. It seems likely that the Egyptian chicory belongs to C. endivia subsp. pumilum.

Comparative Analysis of the Photosynthetic Characteristics and Active Compounds of Semiliquidambar cathayensis Chang Heteromorphic Leaves

In the present study, the variation patterns of leaf shape in different populations of individual Semiliquidambar cathayensis plants were analyzed to investigate the relationship among leaf shape variation, photosynthetic properties, and active compounds to understand the genetic characteristics of S. cathayensis and screen elite germplasms. The leaf shape of 18 offspring from three natural S. cathayensis populations was analyzed to investigate the level of diversity and variation patterns of leaf shape. Furthermore, photosynthetic pigment content, physiological parameters of photosynthesis, and the active compounds in leaves of different shapes were determined. Statistical analysis showed that the leaf shape variation in S. cathayensis indicated a high level of genetic diversity among and within the populations. Cluster analysis showed that the three natural populations formed two clusters, one whose offspring was dominated by entire leaves and another characterized by palmately trifoliate leaves. The differences in photosynthetic characteristics and active compounds of leaves of three different shapes were comprehensively evaluated using principal component analysis. Two principal components with a cumulative contribution rate of 92.768% were extracted, of which the highest comprehensive score was for asymmetrically lobed leaves. The leaf shape in different S. cathayensis germplasms exhibited distinct patterns, and there were some correlations between the photosynthetic properties and active compounds in leaves of different shapes. Thus, the leaf shape can be used to predict active compound content, and in turn, select varieties based on that purpose; it also provides a simple and effective method to classify S. cathayensis germplasms.

Enhanced genome-wide association reveals the role of YABBY11-NGATHA-LIKE1 in leaf serration development of Populus.

Leaf margins are complex plant morphological features that contribute to leaf shape diversity, which affects plant structure, yield, and adaptation. Although several leaf margin regulators have been identified to date, the genetic basis of their natural variation has not been fully elucidated. In this study, we profiled two distinct leaf morphology types (serrated and smooth) using the persistent homology mathematical framework (PHMF) in two poplar species (Populus tomentosa and Populus simonii, respectively). A combined genome-wide association study (GWAS) and expression quantitative trait nucleotide (eQTN) mapping were applied to create a leaf morphology control module using data from P. tomentosa and P. simonii populations. Natural variation in leaf margins was associated with YABBY11 (YAB11) transcript abundance in poplar. In P. tomentosa, PtoYAB11 carries a premature stop codon (PtoYAB11PSC), resulting in the loss of its positive regulation of NGATHA-LIKE1 (PtoNGAL-1) and RIBULOSE BISPHOSPHATE CARBOXYLASE LARGE SUBUNIT (PtoRBCL). Overexpression of PtoYAB11PSC promoted serrated leaf margins, enlarged leaves, enhanced photosynthesis, and increased biomass. Overexpression of PsiYAB11 in P. tomentosa promoted smooth leaf margins, higher stomatal density, and greater light damage repair ability. In poplar, YAB11-NGAL1 is sensitive to environmental conditions, acts as a positive regulator of leaf margin serration, and may also link environmental signaling to leaf morphological plasticity.

From genes to shape in leaf development and evolution

Plant leaves display tremendous variation in shape. Here, we discuss how information obtained from genetics, live imaging and computational modeling has helped conceptualize the ways in which gene activity is translated into different leaf shapes. In this framework, the action of genes on leaf form can be captured as the sum of their effects on the amount, duration, and direction of cellular growth, which together produce leaf geometry. We use three different examples to illustrate this point. First, the emergence of complex versus simple leaves in eudicots, which arises from differences in organ-wide growth duration as well as local growth repression at the leaf margin. Second, the development of strap-shaped grass leaves with a broad sheathing base versus the typical eudicot leaves with a narrow petiole, where these features of grass leaves emerged through lateral expansion of the zone of leaf progenitor cells, coupled with later remodeling of growth of early domains of the leaf blade. Third, the formation of insect traps on carnivorous plants that arose through constrained directional growth that produced a 3D deformation. In all the above examples, changes in gene expression of different classes of homeobox genes have contributed to the altered growth patterns underlying these different aspects of leaf shape diversity.

Effects of Altitude and Leaf Age on Leaf Shape in an Alpine Shrub: The Relevance for the Leaf Area Estimation Model

Nondestructive methods to estimate leaf area (LA) by leaf length (L) and/or width (W) are useful in plant physiology and ecology studies. However, both environmental and ontogenic factors may influence leaf size and/or shape, which may alter the coefficient of LA models. We carried an investigation along an altitudinal gradient in the Sergyemla Mountains, southeast Tibet. In August 2009, we selected nine sites at about every 50 m in altitude from 4,250 m to 4,640 m a.s.l. A total of 4,245 different leaf-aged Rhododendron aganniphum var. schizopeplum (a dominant overstory species) leaves were measured. Compared with the single dimensional models, the two-dimensional model encompassing both L and W (model 5) reflected higher R2 (0.98–0.99) and lower MSE (1.19–3.21) across different leaf age groups for each site, implying that such model could provide the best fit for LA estimation. Analysis of covariance further illustrated that two leaf dimensions model was irrespective of leaf age effects in eight out of the nine sites. Leaf shape (L:W ratio) varied between sites and tended to decrease at higher altitudes (4500–4640 m a.s.l.), leading to significant differences in coefficients of the two-dimension model between every two adjacent sites. For overstory species in alpine habitats, altitude rather than leaf age may affect leaf shape which alters the coefficients of LA estimation models. Since leaf shape of different species (overstory species versus understory ones) may show different responses to a certain environmental gradient, researchers must pay attention to the variation of leaf shape when estimating species-specific LA by measuring L and W, especially when leaves of the top overstory species were collected at different sites.

Morphological and molecular results from a geographical transect focusing on Quercus pubescens/Q. virgiliana ecological-altitudinal vicariance in peninsular Italy

Quercus pubescens and Q. virgiliana are the most cited taxa in the Italian deciduous oak forests floristic and phytosociological literature. According to some authors, Q. pubescens is typical of inland areas and higher altitudes whereas Q. virgiliana restricted to the coastal plain and the hilly belt. Seven pubescent oak populations distributed along an altitudinal transect in central Italy have been analysed from a coenological, morphological and molecular point of view. The vegetation sampling was carried out using the phytosociological approach. Morphological variation of tree individuals was analysed using 14 leaf traits, while leaf shape variation was investigated using the Procrustes ANOVA. Genetic analyses were carried out through twelve EST-SSRs markers. Results: only the leaf pubescence exhibited discriminating power among all the leaf morphological traits considered. Very low differences in the leaf-shape emerged from geometric morphometric analysis. Genetic analyses did not evidence statistically significant clusters. Bayesian analyses including data from genetically pure populations of Q. pubescens, Q. petraea and Q. frainetto assigned all the seven populations investigated to Q. pubescens. Neither the morphological nor the genetic results allowed to identify specimens attributable to Q. pubescens or Q. virgiliana nor to highlight a possible ecological-altitudinal vicariance between these two species.

Anatomical determinants of gas exchange and hydraulics vary with leaf shape in soybean.

Leaf shape in crops can impact light distribution and carbon capture at the whole plant and canopy level. Given similar leaf inclination, narrow leaves can allow a greater fraction of incident light to pass through to lower canopy leaves by reducing leaf area index, which can potentially increase canopy-scale photosynthesis. Soybean has natural variation in leaf shape which can be utilized to optimize canopy architecture. However, the anatomical and physiological differences underlying variation in leaf shape remain largely unexplored. In this study, we selected 28 diverse soybean lines with leaf length to width ratios (leaf ratio) ranging between 1.1 and 3.2. We made leaf cross-sectional, gas exchange, vein density and hydraulic measurements and studied their interrelationships among these lines. Our study shows that narrow leaves tend to be thicker, with an ~30 µm increase in leaf thickness for every unit increase in leaf ratio. Interestingly, thicker leaves had a greater proportion of spongy mesophyll while the proportions of palisade and paraveinal mesophyll decreased. In addition, narrow and thicker leaves had greater photosynthesis and stomatal conductance per unit area along with greater leaf hydraulic conductance. Our results suggest that selecting for narrow leaves can improve photosynthetic performance and potentially provide a yield advantage in soybean.

Comparison of Leaf Shape between a Photinia Hybrid and One of Its Parents.

Leaf shape and size can vary between hybrids and their parents. However, this has seldom been quantitatively tested. Photinia × fraseri is an important landscaping plant in East Asia as a hybrid between evergreen shrubs P. glabra and P. serratifolia. Its leaf shape looks like that of P. serratifolia. To investigate leaf shape, we used a general equation for calculating the leaf area (A) of broad-leaved plants, which assumes a proportional relationship between A and product of lamina length (L) and width (W). The proportionality coefficient (which is referred to as the Montgomery parameter) serves as a quantitative indicator of leaf shape, because it reflects the proportion of leaf area A to the area of a rectangle with L and W as its side lengths. The ratio of L to W, and the ellipticalness index were also used to quantify the complexity of leaf shape for elliptical leaves. A total of >4000 leaves from P. × fraseri and P. serratifolia (with >2000 leaves for each taxon) collected on a monthly basis was used to examine: (i) whether there is a significant difference in leaf shape between the two taxa, and (ii) whether there is a monotonic or parabolic trend in leaf shape across leaf ages. There was a significant difference in leaf shape between the two taxa (p < 0.05). Although there were significant differences in leaf shape on a monthly basis, the variation in leaf shape over time was not large, i.e., leaf shape was relatively stable over time for both taxa. However, the leaf shape of the hybrid was significantly different from its parent P. serratifolia, which has wider and more elliptical leaves than the hybrid. This work demonstrates that variations in leaf shape resulting from hybridization can be rigorously quantified and compared among species and their hybrids. In addition, this work shows that leaf shape does not changes as a function of age either before or after the full expansion of the lamina.

The cellular basis for synergy between RCO and KNOX1 homeobox genes in leaf shape diversity

Leaves of seed plants provide an attractive system to study the development and evolution of form. Leaves show varying degrees of margin complexity ranging from simple, as in Arabidopsis thaliana, to fully dissected into leaflets in the closely related species Cardamine hirsuta. Leaflet formation requires actions of Class I KNOTTED1-LIKE HOMEOBOX (KNOX1) and REDUCED COMPLEXITY (RCO) homeobox genes, which are expressed in the leaves of C.hirsuta but not A.thaliana. Evolutionary studies indicate that diversification of KNOX1 and RCO genes was repeatedly associated with increased leaf complexity. However, whether this gene combination represents a developmentally favored avenue for leaflet formation remains unknown, and the cell-level events through which the combined action of these genes drives leaflet formation are also poorly understood. Here we show, through a genetic screen, that when a C.hirsuta RCO transgene is expressed in A.thaliana, then ectopic KNOX1 expression in leaves represents a preferred developmental path for leaflet formation. Using time-lapse growth analysis, we demonstrate that KNOX1 expression in the basal domain of leaves leads to prolonged and anisotropic cell growth. This KNOX1 action, in synergy with local growth repression by RCO, is instrumental in generating rachises and petiolules, the linear geometrical elements, that bear leaflets in complex leaves. Our results show how the combination of cell-level growth analyses and genetics can help us understand how evolutionary modifications in expression of developmentally important genes are translated into diverse leaf shapes.

Perkecambahan Polen Bunga Jengger Ayam (Celosia argantea)

Celosia cristata is one of specialty cut flowers category. Celosia cristata has leaf color, leaf shape and stem color diversity. The diversity in Celosia cristata has attracted the attention of breeders to develop new varieties of this commodity by means of hybridization. Therefore, before the hybridization of Celosia cristata is being conducted, it is necessary to study the estimated time required for pollen to reach the embryo sac and fertilization occurs to ensure the probability of successful hybridization in plant breeding program. Pollen germination in this study was carried out by in vitro method using pollen germination media consisting of 12 grams of sucrose, 0.01 grams of H3BO3, 100 ml of distilled water, and 0.1 M HCl or 0.1 M NaOH (to maintain the pH of the media at pH 6.4). The germinated pollen was observed with a microscope until the germination reed reached its maximum length, then the length of the germination reed was measured. The measured growth of germination reeds was then compared with the length of the distance from the stigma to the embryo sac. After that, the estimated time required from pollination to fertilization was being predicted. Based on the results of the study, the estimated time needed by Celosia cristata from pollination (pollen fall to the stigma) to fertilization (fusion between male and female gamete cells) was 131.9 minutes.

Geometric Morphometrics use in the examination of subgenus Quercus leaf shape variation in Algeria

Abstract The latest findings on the taxonomic review of Quercus faginea Lam. complex using ‘traditional morphometrics’, demonstrating that the species is represented in Algeria by both Q. faginea and Q. canariensis Willd. Significant variations of the leaf form were also discernible among both species. In this study, the landmark-based geometric morphometrics analysis was used to assess the shape variation of the leaves found on oak stands. 2,600 leaves per 13 stands were collected and scanned, and then using Tps range and MorphoJ software, 11 landmarks—that represent the leaf morphological features—were recorded on leaf images. Shape components and non-forms variations were obtained through a full Procrustes fit followed by creating a leaf-superimposed configuration. Principal component analysis, canonical variate analysis, and discriminate analysis were used to statistically evaluate the leaf shape variability. The results revealed no clear distinction between the two species based on leaf shape. Climate change and environmental factors also appear to have possibly caused a divergent morphological evolution; a reduced leaf size with enduring indumentum—among other Q. faginea traits—could be an efficient mean of adapting to Mediterranean xeric conditions.

Burchellia R.Br. (Rubiaceae: Ixoroideae), a monotypic genus endemic to southern Africa

Burchellia R.Br. (Rubiaceae: Ixoroideae) is endemic to southern Africa. The type species, B. bubalina (L.f.) Sims, is based on Lonicera bubalina L.f., for which we designate a lectotype. We provide an account of the genus with comprehensive nomenclature and synonymy, including a taxonomic history of all names, and morphological descriptions for the genus and species, as well as distribution and ecological notes. The occurrence of hairy pocket-domatia in the species is variable. Examination of material from throughout the range of the species reveals a continuous pattern of variation in leaf size, shape and density of the vestiture, as well as in the size and colour of the corolla. We accordingly recognise a single variable species.

Tree Size Influences Leaf Shape but Does Not Affect the Proportional Relationship Between Leaf Area and the Product of Length and Width.

The Montgomery equation predicts leaf area as the product of leaf length and width multiplied by a correction factor. It has been demonstrated to apply to a variety of leaf shapes. However, it is unknown whether tree size (measured as the diameter at breast height) affects leaf shape and size, or whether such variations in leaf shape can invalidate the Montgomery equation in calculating leaf area. Here, we examined 60 individual trees of the alpine oak (Quercus pannosa) in two growth patterns (trees growing from seeds vs. growing from roots), with 30 individuals for each site. Between 100 and 110 leaves from each tree were used to measure leaf dry mass, leaf area, length, and width, and to calculate the ellipticalness index, ratio of area between the two sides of the lamina, and the lamina centroid ratio. We tested whether tree size affects leaf shape, size, and leaf dry mass per unit area, and tested whether the Montgomery equation is valid for calculating leaf area of the leaves from different tree sizes. The diameters at breast height of the trees ranged from 8.6 to 96.4 cm (tree height ranged from 3 to 32 m). The diameter at breast height significantly affected leaf shape, size, and leaf dry mass per unit area. Larger trees had larger and broader leaves with lower leaf dry mass per unit area, and the lamina centroid was closer to the leaf apex than the leaf base. However, the variation in leaf size and shape did not negate the validity of the Montgomery equation. Thus, regardless of tree size, the proportional relationship between leaf area and the product of leaf length and width can be used to calculate the area of the leaves.

Genetic Differentiation among Subspecies of Banksia nivea (Proteaceae) Associated with Expansion and Habitat Specialization

Subspecies are traditionally defined using phenotypic differences associated with different geographical areas. Yet patterns of morphological and genetic variation may not coincide and thereby fail to reflect species’ evolutionary history. The division of the shrub Banksia nivea Labill. into one widespread (B. nivea subsp. nivea) and two geographically localized subspecies (B. nivea subsp. uliginosa (A.S. George) A.R. Mast &amp; K.R. Thiele and B. nivea subsp. Morangup (M. Pieroni 94/2)) in south-west Australia has been based mainly on variation in leaf shape and pistil length, although flowering time and habitat differences are also evident, and subsp. uliginosa occurs on a different substrate. To assess the genetic divergence of B. nivea subspecies, we genotyped representatives from each subspecies for nuclear microsatellite and non-coding chloroplast sequence variation. We used distance and parsimony-based methods to assess genetic relatedness. Patterns were consistent with the existing taxonomy of subsp. nivea and uliginosa but not subsp. Morangup. Phylogenetic analyses revealed evidence for a more recent divergence of subsp. uliginosa associated with expansion from dryer sandy soils into the winter-wet ironstone soils in the southwest of Western Australia, consistent with progressive long-term climatic drying. Nuclear microsatellites showed low to moderate diversity, high population differentiation overall, and genetic structuring of subspecies in different biogeographical areas. We propose this pattern reflects the predicted impact of a patchy distribution, small populations, and restrictions to gene flow driven by both distance and biogeographic differences in subspecies’ habitats.

Eff-UNet++: A novel architecture for plant leaf segmentation and counting

Leaf segmentation learns more about leaf-level traits such as leaf area, count, stress, and development phases. In plant phenotyping, segmentation and counting of plant organs like leaves are a major challenge due to considerable overlap between leaves and varying environmental conditions, including brightness variation and shadow, blur due to wind. Further, the plant's inherent challenges, such as the leaf texture, genotype, size, shape, and density variation of leaves, make the leaf segmentation task more complex. To meet these challenges, the present work proposes a novel method for leaf segmentation and counting employing Eff-Unet++, an encoder-decoder-based architecture. This architecture uses EfficientNet-B4 as an encoder for accurate feature extraction. The redesigned skip connections and residual block in the decoder utilize encoder output and help to address the information degradation problem. In addition, the redesigned skip connections reduce the computational complexity. The lateral output layer is introduced to aggregate the low-level to high-level features from the decoder, which improves segmentation performance. The proposed method validates its performance on three datasets: KOMATSUNA dataset, Multi-Modality Plant Imagery Dataset (MSU-PID), and Computer Vision for Plant Phenotyping dataset (CVPPP). The proposed approach outperforms the existing state-of-the-art methods UNet, UNet++, Residual-UNet, InceptionResv2-UNet, and DeeplabV3 leaf segmentation results achieve best dice (BestDice): 83.44, 71.17, 78.27 and Foreground-Background Dice (FgBgDice): 97.48, 91.35, 96.38 on KOMATSUNA, MSU-PID, and CVPPP dataset respectively. In addition, for leaf counting the results are difference in count (DiffFG): 0.11, 0.03, 0.12 and Absolute Difference in count (AbsDiffFG): 0.21, 0.38, 1.27 on KOMATSUNA, MSU-PID, and CVPPP dataset respectively.

Gold nanoparticles and electromagnetic irradiation in tissue culture systems of bleeding heart: biochemical, physiological, and (cyto)genetic effects

This study aimed to analyze the effect of various mutagens on the in vitro development, physiological activity, acclimatization efficiency, and genetic integrity of Lamprocapnos spectabilis ‘Valentine’. Gold nanoparticles (AuNPs), microwaves, and X-rays were used at different doses. The profiles of primary and secondary metabolites and the enzymatic activity in the produced plants were studied. The usefulness of various genetic markers in the detection of mutations in the species was compared. The genome size of L. spectabilis was estimated for the first time. It was found that the addition of AuNPs into the culture medium had a positive impact on the in vitro development and multiplication of plants. All of the shoots regenerated adventitious roots, but plants subjected to the longest microwave irradiation (3 × 9 s) and the non-treated control had the lowest acclimatization efficiency. Application of mutagens significantly affected the activity and profile of most enzymes and phytochemicals studied, however, the final effect depended on the agent type and dose. Mutations were detected by DAMD, RAPD, and SCoT markers in 7.5% of plants, but not by ISSRs. Phenotype variation in leaf shape was found in four plants. The genome size of L. spectabilis was found to be very small; about 1281 Mbp.

Patterns of leaf morphological variation in Quercus frainetto Ten. growing on different soil types in Serbia

Leaf morphology is at a certain level defined by the ways in which plants adapt to different habitats, especially in large trees. In this study, morphological variations in leaf size and shape of the Hungarian oak (Quercus frainetto Ten.) growing on different soil types (lithic leptosol, vertisol, cambisol) were investigated in the central part of Serbia (Sumadija). The information on soil type was obtained using a digitalized soil map of the Republic of Serbia, while leaf traits were characterized by geometric morphometric methods. Landmark analysis and leaf measurements showed significant differences among the analyzed groups, with individuals growing on nutrient-poor, shallow soils having smaller leaves with greater lobation. The observed differences suggest that the levels of soil productivity influence variations in leaf patterns. More studies on a larger sample size and along a broader spatial scale are needed to fully understand the differences in the patterns of leaf morphological variation in Q. frainetto.

The Biology of Canadian Weeds. 159.Capsella bursa-pastoris(L.) Medik.

Capsella bursa-pastoris (L.) Medik, shepherd’s purse, is a cosmopolitan summer or winter annual weed species distributed throughout temperate and subtropical regions of the world and is considered one of the most common plants on earth. It is an opportunistic annual that colonizes newly disturbed, open or dry environments and is ubiquitous in cultivated lands in Canada. In annual crops in western Canada, C. bursa-pastoris has been among the 20 most abundant weeds since the first weed surveys in 1970. It is most easily distinguished by its small white four-petalled flowers and its heart-shaped seed-pods, but exhibits considerable variation in leaf shape and flowering time. It has been used for food and medicine by numerous cultures. Its golden-brown seeds are produced in large numbers predominantly through self-pollination and can form a substantial seed bank, with reported values ranging to several hundred thousand seeds m−2. While seeds usually disperse near the mother plant, long-distance dispersal by attaching to vehicles, people and other vectors may be facilitated by its mucilaginous coat. Capsella bursa-pastoris does not produce fertile hybrids with other species of economic or ecological significance. It is generally well controlled by soil-applied and foliar (post-emergence) herbicides although its presence in agricultural fields may result in substantial yield loss, as documented in cole crops in North America and grain crops in Europe. The species can host a wide range of insect, nematode, fungal, viral, and bacterial pests that may damage crop species.