Search Results (29)

Crack-templated thin films, inspired by naturally occurring patterns such as leaf venation, spider webs, and the networked structure of dried egg white, represent a paradigm shift in the design of functional materials. Traditionally, cracks in coatings are seen as defects to be avoided due to their potential to compromise mechanical integrity and performance. However, in this context, cracks are deliberately induced and meticulously controlled to serve as templates for versatile applications. This review explores the latest advances in preparation techniques, including solvent evaporation and thermal stress induction, with a focus on the interplay between material properties (e.g., polymers and ceramics) and process parameters (e.g., drying rates and temperature, layer thickness, substrate interactions) that govern crack behavior. The resulting crack patterns offer tunable features, such as density, width, shape, and orientation, which can be harnessed for applications in semitransparent electrodes, flexible sensors, and wearable and energy storage devices. Our study aims to navigate the advancements in crack engineering in the last 10 years and underscores its importance as a purposeful and versatile strategy for next-generation thin-film technologies, offering a novel and affordable approach to transforming perceived defects into assets for cutting-edge thin-film technologies. Full article

The aim of the present study was to explore heavy metal tolerance and accumulation potential in Anthyllis vulneraria subsp. maritima plants from coastal sand dunes in controlled conditions. Plants were established from seeds collected in coastal sand dunes and cultivated in substrates in greenhouse conditions. A gradual treatment with CdCl₂, PbOAc, CuSO₄, MnSO₄, and ZnSO₄ was performed until three final concentrations for each metal were reached. The number of leaves, their biomass, and biomass of roots were negatively affected by increasing concentrations of lead (Pb) and manganese (Mn) in substrate, but no negative effect was evident for cadmium (Cd), copper (Cu), and zinc (Zn). Visible effects of metal toxicity were evident for Pb-treated plants (appearance of thinner leaves, yellowing of older leaves), as well as for Mn-treated plants (reduced leaf size, curled leaves, red leaf venation). There was a significant decrease in water content in old leaves at high Pb and increasing Mn concentration, indicating accelerated leaf senescence. Increase in polyphenol oxidase activity in leaves was evident in all the plants treated with heavy metals. In contrast, an increase in peroxidase activity was evident only for plants treated with 50 and 100 mg L⁻¹ Cd, 500 mg L⁻¹ Pb, 200–1000 mg L⁻¹ Mn, and 500 mg L⁻¹ Zn. Metal accumulation potential for Cd and Cu was the highest in the roots, but for Pb, Mn, and Zn, more metal accumulated in old leaves. It can be concluded that A. vulneraria subsp. maritima plants are tolerant to high Cd, Cu, and Zn, but moderately susceptible to Pb and Mn. However, oxidative enzyme activity cannot be unequivocally used as a specific indicator of metal tolerance. In respect to phytoremediation potential, the plants have very good accumulation capacity for Pb, Mn, and Zn. Full article

Aerides rosea (Orchidaceae) boasts high ornamental value due to its pleasant aroma, foxtail spike, and elegant floral morphology. Inducing A. rosea to become tetraploid enhances horticultural traits and facilitates fertile intergeneric hybrids through crosses with other market-available tetraploid species. The experimental design involved the application of colchicine at varying concentrations—0.05%, 0.1%, and 0.2%—to a solid medium. Exposure durations were 5, 10, and 15 days, with treatments conducted under sterile conditions on 6-week-old protocorms post-germination. Results indicated that the protocorms were sensitive to colchicine concentrations exceeding 0.05%, with high concentrations leading to a mortality rate exceeding 50%. Flow cytometry (FCM) with 4′,6-diamidino-2-phenylindole (DAPI) staining confirmed a doubling of chromosome numbers in tetraploid plants (2n = 4x = 76) compared to diploid controls (2n = 2x = 38). Induction efficiency was significantly influenced by colchicine concentration and treatment duration. A 10-day treatment with 0.2% colchicine yielded a 70.00% tetraploid induction rate; however, considering protocorm survival, a 5-day treatment with 0.05% colchicine was preferable, achieving a 63.55% survival rate and a 56.67% tetraploid induction rate. Tetraploid plants exhibited distinct morphological traits, such as a more compact growth habit, thicker leaves, and increased stem and root thickness. Leaf morphology changes included larger stomata with reduced density, denser spongy mesophyll, and more pronounced venation. Tetraploids also demonstrated a 1.94-fold increase in genome size compared to diploids. The tetraploid genotypes developed in this study hold significant potential for future Aerides breeding programs. Full article

In computer vision, recognizing plant pictures has emerged as a multidisciplinary area of interest. In the last several years, much research has been conducted to determine the type of plant in each image automatically. The challenges in identifying the medicinal plants are due to the changes in the effects of image light, stance, and orientation. Further, it is difficult to identify the medicinal plants due to factors like variations in leaf shape with age and changing leaf color in response to varying weather conditions. The proposed work uses machine learning techniques and deep neural networks to choose appropriate leaf features to determine if the leaf is a medicinal or non-medicinal plant. This study presents a neural network design based on PSR-LeafNet (PSR-LN). PSR-LeafNet is a single network that combines the P-Net, S-Net, and R-Net, all intended for leaf feature extraction using the minimum redundancy maximum relevance (MRMR) approach. The PSR-LN helps obtain the shape features, color features, venation of the leaf, and textural features. A support vector machine (SVM) is applied to the output achieved from the PSR network, which helps classify the name of the plant. The model design is named PSR-LN-SVM. The advantage of the designed model is that it suits more considerable dataset processing and provides better results than traditional neural network models. The methodology utilized in the work achieves an accuracy of 97.12% for the MalayaKew dataset, 98.10% for the IMP dataset, and 95.88% for the Flavia dataset. The proposed models surpass all the existing models, having an improvement in accuracy. These outcomes demonstrate that the suggested method is successful in accurately recognizing the leaves of medicinal plants, paving the way for more advanced uses in plant taxonomy and medicine. Full article

Polar auxin transport (PAT) is a known component controlling leaf complexity and venation patterns in some model plant species. Evidence indicates that PAT generates auxin converge points (CPs) that in turn lead to local leaf formation and internally into major vein formation. However, the role of PAT in more diverse leaf arrangements and vein patterns is largely unknown. We used the pharmacological inhibition of PAT in developing pinnate tomato, trifoliate clover, palmate lupin, and bipinnate carrot leaves and observed dosage-dependent reduction to simple leaves in these eudicots. Leaf venation patterns changed from craspedodromous (clover, carrot), semi-craspedodromous (tomato), and brochidodromous (lupin) to more parallel patterning with PAT inhibition. The visualization of auxin responses in transgenic tomato plants showed that discrete and separate CPs in control plants were replaced by diffuse convergence areas near the margin. These effects indicate that PAT plays a universal role in the formation of different leaf and vein patterns in eudicot species via a mechanism that depends on the generation as well as the separation of auxin CPs. Computer simulations indicate that variations in PAT can alter the number of CPs, corresponding leaf lobe formation, and the position of major leaf veins along the leaf margin in support of experimental results. Full article

Cytokinesis in plant cells begins with the fusion of vesicles that transport cell wall materials to the center of the cell division plane, where the cell plate forms and expands radially until it fuses with the parental cell wall. Vesicle fusion is facilitated by trans-SNARE complexes, with assistance from Sec1/Munc18 (SM) proteins. The SNARE protein KNOLLE and the SM protein KEULE are required for membrane fusion at the cell plate. Due to the crucial function of KEULE, all Arabidopsis (Arabidopsis thaliana) keule mutants identified to date are seedling lethal. Here, we identified the Arabidopsis serrata4-1 (sea4-1) and sea4-2 mutants, which carry recessive, hypomorphic alleles of KEULE. Homozygous sea4-1 and sea4-2 plants are viable and fertile but have smaller rosettes and fewer leaves at bolting than the wild type. Their leaves are serrated, small, and wavy, with a complex venation pattern. The mutant leaves also develop necrotic patches and undergo premature senescence. RNA-seq revealed transcriptome changes likely leading to reduced cell wall integrity and an increase in the unfolded protein response. These findings shed light on the roles of KEULE in postembryonic development, particularly in the patterning of rosette leaves and leaf margins. Full article

Landmark-based geometric morphometrics (GM) was used to examine, for the first time, spontaneous hybridization between Alnus incana (L.) Moench and Alnus rohlenae Vít, Douda and Mandák, and to assess inter- and intrapopulation variability in leaf shape, leaf size and venation in natural populations in Serbia (Western Balkans). Two geographically distant (30 km) and two close (1.2 km) populations were selected to examine hybridization. The variability in leaf shapes was assessed by canonical variate analysis and linear discriminant analysis performed on the symmetric component of variation. Covariation between the symmetric component of shape variation and the number of pairs of secondary leaf veins was investigated with partial least squares analysis. Static allometry was examined for the first time in the genus Alnus Mill. A higher proportion of A. incana leaves was classified as A. rohlenae in geographically close populations, which is in accordance with the hypothesis about spontaneous hybridization. No single leaf of A. rohlenae was classified as A. incana, indicating that putative hybrids can only be found in grey alder populations. This study demonstrates that GM is a powerful tool for species delimitation and hybrid detection in the genus Alnus and it can be used for preliminary screening in hybrid zones. Full article

Soybeans are vulnerable to drought and temperature increases potentially induced by climate change. Hydraulic dysfunction and stomatal closure to avoid excessive transpiration are the main problems caused by drought. The vulnerability of soybeans to drought will depend on the intensity and duration of water stress. The purpose of this study was to determine if the use of cover crops (CCs) can influence the gas exchange potential of glyphosate-tolerant soybeans when the vapor pressure deficit (Vpd) increases. This two-year study was conducted in an open experimental field comprising direct seeding plots with or without CCs. Stomatal conductance (Gs) was measured five times on the same identified leaves following glyphosate-based herbicide application. These leaves were then collected in order to observe the stomata and foliar traits with a scanning electron microscope. The Vpd was calculated concomitantly to Gs measurements at the leaf surface. The results suggest that the use of CCs promotes phenotypic change in soybean leaves (more elaborate venation and a higher abaxial stomatal density), which in turn may enhance their tolerance to drier conditions. In 2019, Gs could be up to 29% higher in plots with CCs compared to those without CCs with similar Vpd values. This study shows that the benefits of using CCs can be observed via the morphological development strategies of the crop plants and their higher tolerance to drought. Full article

Hindwing venation is one of the most important morphological features for the functional and evolutionary analysis of beetles, as it is one of the key features used for the analysis of beetle flight performance and the design of beetle-like flapping wing micro aerial vehicles. However, manual landmark annotation for hindwing morphological analysis is a time-consuming process hindering the development of wing morphology research. In this paper, we present a novel approach for the detection of landmarks on the hindwings of leaf beetles (Coleoptera, Chrysomelidae) using a limited number of samples. The proposed method entails the transfer of a pre-existing model, trained on a large natural image dataset, to the specific domain of leaf beetle hindwings. This is achieved by using a deep high-resolution network as the backbone. The low-stage network parameters are frozen, while the high-stage parameters are re-trained to construct a leaf beetle hindwing landmark detection model. A leaf beetle hindwing landmark dataset was constructed, and the network was trained on varying numbers of randomly selected hindwing samples. The results demonstrate that the average detection normalized mean error for specific landmarks of leaf beetle hindwings (100 samples) remains below 0.02 and only reached 0.045 when using a mere three samples for training. Comparative analyses reveal that the proposed approach out-performs a prevalently used method (i.e., a deep residual network). This study showcases the practicability of employing natural images—specifically, those in ImageNet—for the purpose of pre-training leaf beetle hindwing landmark detection models in particular, providing a promising approach for insect wing venation digitization. Full article

The current study was designed to assess the comparative morphology of eight olive cultivars with different geographical origins and diverse genetic backgrounds, introduced to a new climatic zone. The morphological parameters of eight (five exotic and three domestic) olive cultivars (Bari Zaitoon-1, Bari Zaitoon-2, Favolosa (FS-17), Koroneiki, Balkasar, Ottobratica, Leccino, and Arbequina) were compared at the experimental area of the Department of Botany, The Islamia University of Bahawalpur, Pakistan (29°24′0″ North, 71°41′0″ East, 401–421 feet above sea level). Plant height, number of leaves/15 cm shoot, leaf size characteristics (leaf length, leaf width, leaf area, and length/width ratio), leaf shape characteristics (margin, leaf axil, base, and apex angles), leaf pigments (Chlorophyll a, Chlorophyll b, total chlorophyll contents, and carotenoids), phyllotaxy, and leaf color and venation were recorded. The highest plant height (28 cm) was obtained by Bari Zaitoon-2 followed by Bari Zaitoon-1 (24 cm), both of which are domestic cultivar of Pakistan, while the shortest height (5 cm) was obtained by Koroneiki. Leccino displayed the highest average number of leaves (17.8) on main shoot, followed by BARI-2 (16.4) and the lowest score was from Balkasar (10.4). Leaf area ranged from 5.66 cm² (Bari Zaitoon-1) to 3.08 cm² (Koroneiki). The longest leaf length (5.74 cm) was found in Bari Zaitoon-1 and the shortest (4.04 cm) in Koroneiki, while the broadest leaves were found in Leccino (1.54 cm) and the narrowest (1.12 cm) in Koroneiki. Bari Zaitoon-2 led in leaf length to width ratio (4.058) followed by Bari Zaitoon-1 (3.772) with small lanceolate leaves hardly reaching the value of 4, with the lowest value illustrated by Leccino. The total chloroplast pigments were highest in FS-17 followed by Bari Zaitoon-1 and Bari Zaitoon-2, while the lowest was in Arbequina. Chlorophyll a was highest in Bari Zaitoon-1 followed by FS-17 and Balkasar, with the lowest rate in Arbequina. Chlorophyll b content of FS-17 was the highest whereas the Chlorophyll b and total chlorophyll contents in Arbequina were the lowest of all the cultivars. The highest value of total carotenoids was found in Balkasar followed by FS-17 with the lowest value in Arbequina. The phyllotaxy was categorized into three types, i.e., alternate, opposite, and whorled. The combination of two or more types was usually observed on the same branch. The whorl of four leaves was also present in rare cases. Leaf venation was both pinnate and reticulate. The leaf base of most (four) of the olive cultivars, i.e., Arbequina, Balkasar, Leccino and FS-17, were cuneate having acute, rounded, apiculate, and cuspidate leaf tips, respectively. The findings revealed remarkable variations in olive morphology, especially in the leaves and a successful record of the preliminary data of olive cultivars from the study area was made. The present research demonstrated that local olive cultivars have unique characteristics that differentiate them from imported cultivars. Thus, local cultivars provide novel genetic resources that should be conserved. Full article

Arabidopsis thaliana ecotypes adapted to native habitats with different daylengths, temperatures, and precipitation were grown experimentally under seven combinations of light intensity and leaf temperature to assess their acclimatory phenotypic plasticity in foliar structure and function. There were no differences among ecotypes when plants developed under moderate conditions of 400 µmol photons m⁻² s⁻¹ and 25 °C. However, in response to more extreme light or temperature regimes, ecotypes that evolved in habitats with pronounced differences in either the magnitude of changes in daylength or temperature or in precipitation level exhibited pronounced adjustments in photosynthesis and transpiration, as well as anatomical traits supporting these functions. Specifically, when grown under extremes of light intensity (100 versus 1000 µmol photons m⁻² s⁻¹) or temperature (8 °C versus 35 °C), ecotypes from sites with the greatest range of daylengths and temperature over the growing season exhibited the greatest differences in functional and structural features related to photosynthesis (light- and CO₂-saturated capacity of oxygen evolution, leaf dry mass per area or thickness, phloem cells per minor vein, and water-use efficiency of CO₂ uptake). On the other hand, the ecotype from the habitat with the lowest precipitation showed the greatest plasticity in features related to water transport and loss (vein density, ratio of water to sugar conduits in foliar minor veins, and transpiration rate). Despite these differences, common structure–function relationships existed across all ecotypes and growth conditions, with significant positive, linear correlations (i) between photosynthetic capacity (ranging from 10 to 110 µmol O₂ m⁻² s⁻¹) and leaf dry mass per area (from 10 to 75 g m⁻²), leaf thickness (from 170 to 500 µm), and carbohydrate-export infrastructure (from 6 to 14 sieve elements per minor vein, from 2.5 to 8 µm² cross-sectional area per sieve element, and from 16 to 82 µm² cross-sectional area of sieve elements per minor vein); (ii) between transpiration rate (from 1 to 17 mmol H₂O m⁻² s⁻¹) and water-transport infrastructure (from 3.5 to 8 tracheary elements per minor vein, from 13.5 to 28 µm² cross-sectional area per tracheary element, and from 55 to 200 µm² cross-sectional area of tracheary elements per minor vein); (iii) between the ratio of transpirational water loss to CO₂ fixation (from 0.2 to 0.7 mol H₂O to mmol⁻¹ CO₂) and the ratio of water to sugar conduits in minor veins (from 0.4 to 1.1 tracheary to sieve elements, from 4 to 6 µm² cross-sectional area of tracheary to sieve elements, and from 2 to 6 µm² cross-sectional area of tracheary elements to sieve elements per minor vein); (iv) between sugar conduits and sugar-loading cells; and (v) between water conducting and sugar conducting cells. Additionally, the proportion of water conduits to sugar conduits was greater for all ecotypes grown experimentally under warm-to-hot versus cold temperature. Thus, developmental acclimation to the growth environment included ecotype-dependent foliar structural and functional adjustments resulting in multiple common structural and functional relationships. Full article

As organs of photosynthesis, leaves are of vital importance for plants and a source of inspiration for biomimetic developments. Leaves are composed of interconnected functional elements that evolved in concert under high selective pressure, directed toward strategies for improving productivity with limited resources. In this paper, selected basic components of the leaf are described together with biomimetic examples derived from them. The epidermis (the “skin” of leaves) protects the leaf from uncontrolled desiccation and carries functional surface structures such as wax crystals and hairs. The epidermis is pierced by micropore apparatuses, stomata, which allow for regulated gas exchange. Photosynthesis takes place in the internal leaf tissue, while the venation system supplies the leaf with water and nutrients and exports the products of photosynthesis. Identifying the selective forces as well as functional limitations of the single components requires understanding the leaf as an integrated system that was shaped by evolution to maximize carbon gain from limited resource availability. These economic aspects of leaf function manifest themselves as trade-off solutions. Biomimetics is expected to benefit from a more holistic perspective on adaptive strategies and functional contexts of leaf structures. Full article

Leaf hydraulic conductance (K_Leaf) is a measure of the efficiency of water transport through the leaf, which determines physiological parameters such as stomatal conductance, photosynthesis and transpiration rates. One key anatomical structure that supports K_Leaf is leaf venation, which could be subject to evolutionary pressure in dry environments. In this context, it is useful to assess these traits in species from arid climates such as S. peruvianum and S. chilense, in order to determine their hydraulic strategy and potential aptitude for the improvement of domestic tomato (S. lycopersicum). In this work, we measured K_Leaf, vein density, together with leaf water isotope composition (δ¹⁸O, δ²H) and leaf carbon isotope composition (δ¹³C), from which we derived proxies for outside-vein hydraulic resistance (R_ox) and intrinsic water use efficiency (WUE_i), respectively. The two wild species showed contrasting hydraulic strategies, with S. chilense performing as a water-spender, whereas S. peruvianum showed a water-saving strategy. Interestingly, S. lycopersicum was rather conservative, and showed the highest WUE_i. The low water transport capacity of S. peruvianum was not explained by vein density traits, but was related with the effective pathlength L, an isotope-derived proxy for R_ox. The low WUE_i of S. peruvianum suggest strong photosynthetic limitations. Our results show a wide diversity in water-use strategies in the genus, encouraging a detailed characterization of wild relatives. From a methodological point of view, we provide evidence supporting the use of water isotopes to assess changes in mesophyll hydraulic conductance, not attributable to vein density. Full article

Plants are exposed to various external stresses influencing physiology, anatomy, and morphology. Shape, geometry, and size of shoots and leaves are particularly affected. Among the latter, peltate leaves are not very common and so far, only few studies focused on their properties. In this case study, four Begonia species with different leaf shapes and petiole attachment points were analyzed regarding their leaf morphology, anatomy, and biomechanical properties. One to two plants per species were examined. In all four species, the petiole showed differently sized vascular bundles arranged in a peripheral ring and subepidermal collenchyma. These anatomical characteristics, low leaf dry mass, and low amount of lignified tissue in the petiole point toward turgor pressure as crucial for leaf stability. The petiole-lamina transition zone shows a different organization in leaves with a more central (peltate) and lateral petiole insertion. While in non-peltate leaves simple fiber branching is present, peltate leaves show a more complex reticulate fiber arrangement. Tensile and bending tests revealed similar structural Young’s moduli in all species for intercostal areas and venation, but differences in the petiole. The analysis of the leaves highlights the properties of petiole and the petiole-lamina transition zone that are needed to resist external stresses. Full article

Bamboo is an important component in subtropical and tropical forest communities. The plant has characteristic long lanceolate leaves with parallel venation. Prior studies have shown that the leaf shapes of this plant group can be well described by a simplified version (referred to as SGE-1) of the Gielis equation, a polar coordinate equation extended from the superellipse equation. SGE-1 with only two model parameters is less complex than the original Gielis equation with six parameters. Previous studies have seldom tested whether other simplified versions of the Gielis equation are superior to SGE-1 in fitting empirical leaf shape data. In the present study, we compared a three-parameter Gielis equation (referred to as SGE-2) with the two-parameter SGE-1 using the leaf boundary coordinate data of six bamboo species within the same genus that have representative long lanceolate leaves, with >300 leaves for each species. We sampled 2000 data points at approximately equidistant locations on the boundary of each leaf, and estimated the parameters for the two models. The root–mean–square error (RMSE) between the observed and predicted radii from the polar point to data points on the boundary of each leaf was used as a measure of the model goodness of fit, and the mean percent error between the RMSEs from fitting SGE-1 and SGE-2 was used to examine whether the introduction of an additional parameter in SGE-1 remarkably improves the model’s fitting. We found that the RMSE value of SGE-2 was always smaller than that of SGE-1. The mean percent errors among the two models ranged from 7.5% to 20% across the six species. These results indicate that SGE-2 is superior to SGE-1 and should be used in fitting leaf shapes. We argue that the results of the current study can be potentially extended to other lanceolate leaf shapes. Full article