Leaf Epidermis Research Articles

Atlas of leaf surface micromorphology in Aloe L. (Asphodelaceae) from the Horn of Africa region

The confident identification to species rank of fragmentary and sterile plant material is often challenged by the absence of diagnostic characters, which are present in intact specimens, reproductive parts, and plants in habitat. Here, we consider leaf surface micromorphology for the identification of the genus Aloe in the Horn of Africa region. Primary and secondary sculpturing of the leaf epidermis and stomata were characterised from SEM micrographs of 35 taxa representing 31 species of Aloe (Asphodelaceae subfam. Alooideae). Detailed comparison revealed that leaf surface characters are conserved between species and within-species variation is modest. Closely related taxa in the Aloe adigratana—A. camperi—A. sinana species complex could be distinguished using leaf surface micromorphology alone. These characters also guide species delimitation; in the species complex including A. schoelleri and A. steudneri, a narrow circumscription is supported, whereas with A. ankoberensis and A. pulcherrima, a wider circumscription merits consideration. The observed trait combinations are characteristic of plants in xeric environments, with the most notable feature being stomata that are most deeply sunken in species in more arid habitats. Our findings support the use of comparative study of micromorphological leaf surface characters for species identification and taxonomy in the genus Aloe.

Misregulation of MYB16 expression causes stomatal cluster formation by disrupting polarity during asymmetric cell divisions.

Stomatal pores and the leaf cuticle regulate evaporation from the plant body and balance the tradeoff between photosynthesis and water loss. MYB16, encoding a transcription factor involved in cutin biosynthesis, is expressed in stomatal lineage ground cells, suggesting a link between cutin biosynthesis and stomatal development. Here, we show that the downregulation of MYB16 in meristemoids is directly mediated by the stomatal master transcription factor SPEECHLESS (SPCH) in Arabidopsis thaliana. The suppression of MYB16 before an asymmetric division is crucial for stomatal patterning, as its overexpression or ectopic expression in meristemoids increased stomatal density and resulted in the formation of stomatal clusters, as well as affecting the outer cell wall structure. Expressing a cutinase gene in plants ectopically expressing MYB16 reduced stomatal clustering, suggesting that cutin affects stomatal signaling or the polarity setup in asymmetrically dividing cells. The clustered stomatal phenotype was rescued by overexpressing EPIDERMAL PATTERNING FACTOR2, suggesting that stomatal signaling was still functional in these plants. Growing seedlings ectopically expressing MYB16 on high-percentage agar plates to modulate tensile strength rescued the polarity and stomatal cluster defects of these seedlings. Therefore, the inhibition of MYB16 expression by SPCH in the early stomatal lineage is required to correctly place the polarity protein needed for stomatal patterning during leaf morphogenesis.

Cell biology of the leaf epidermis: Fate specification, morphogenesis, and coordination.

As the outermost layer of plants, the epidermis serves as a critical interface between plants and the environment. During leaf development, the differentiation of specialized epidermal cell types, including stomatal guard cells, pavement cells, and trichomes, occurs simultaneously, each providing unique and pivotal functions for plant growth and survival. Decades of molecular-genetic and physiological studies have unraveled key players and hormone signaling specifying epidermal differentiation. However, most studies focus on only one cell type at a time, and how these distinct cell types coordinate as a unit is far from well-comprehended. Here we provide a review on the current knowledge of regulatory mechanisms underpinning the fate specification, differentiation, morphogenesis, and positioning of these specialized cell types. Emphasis is given to their shared developmental origins, fate flexibility, as well as cell cycle and hormonal controls. Furthermore, we discuss computational modeling approaches to integrate how mechanical properties of individual epidermal cell types and entire tissue/organ properties mutually influence each other. We hope to illuminate the underlying mechanisms coordinating the cell differentiation that ultimately generate a functional leaf epidermis.

The Tea Plant Leaf Cuticle: From Plant Protection to Tea Quality.

Camellia sinensis (tea tree) is a perennial evergreen woody crop that has been planted in more than 50 countries worldwide; its leaves are harvested to make tea, which is one of the most popular nonalcoholic beverages. The cuticle is the major transpiration barrier to restrict nonstomatal water loss and it affects the drought tolerance of tea plants. The cuticle may also provide molecular cues for the interaction with herbivores and pathogens. The tea-making process almost always includes a postharvest withering treatment to reduce leaf water content, and many studies have demonstrated that withering treatment-induced metabolite transformation is essential to shape the quality of the tea made. Tea leaf cuticle is expected to affect its withering properties and the dynamics of postharvest metabolome remodeling. In addition, it has long been speculated that the cuticle may contribute to the aroma quality of tea. However, concrete experimental evidence is lacking to prove or refute this hypothesis. Even though its relevance to the abiotic and biotic stress tolerance and postharvest processing properties of tea tree, tea cuticle has long been neglected. Recently, there are several studies on the tea cuticle regarding its structure, wax composition, transpiration barrier organization, environmental stresses-induced wax modification, and structure–function relations. This review is devoted to tea cuticle, the recent research progresses were summarized and unresolved questions and future research directions were also discussed.

Effect of shading on the English oak (Quercus robur L.) seedlings water regime

Shading is a common urban stress in the city due to the light block from buildings. Oaks stands are found as part of park areas, forests and in point gardening in many large cities of the world. In this work we examined anatomical and physiological aspects of the adaptation of oak seedlings to the lack of light. To determine the intensity of transpiration, leaf hydration, and water deficiency, the weight indicators of the leaves were measured. Anatomically, the analysis of the leaf epidermis was carried out by microscopy of varnish prints. Changes were revealed in the anatomical structure of the leaf and were irreversible in the water regime undo shading. It was found the correlation between stomatal apparatus of the leaves and incoming solar radiation amount. With the optimal combination of hydrometeofactors, the evaporation rate in the heavily shaded leaves during the day did not exceed 15 ± 0.9 g/(m2h), which was 30…35% of the transpiration intensity in the well-lit control leaves. Then, shading by 80% reduced transpiration by 50…65 %. The influence of the degree of shading on the water regime of oak seedlings is shown for the first time at forest-steppe region.

First report of rust on onion caused by Puccinia allii in Korea

In August 2018, rust was observed on onions (Allium cepa) grown in Dalseong, South Korea. In the field where the rust occurred, the disease incidence exceeded 60%. The urediniospores produced on diseased leaves were globose to ellipsoid and 20‒30 × 20‒28 μm in size. They had a thick outer wall (1‒2 μm) and many spines were apparent on the surface under light microscopy. When the uredinium was mature, the epidermis of the onion leaf ruptured to expose many yellow to dark red urediniospores, appearing as a powder. DNA sequencing and phylogenetic analysis of the internal transcribed spacer (ITS) region confirmed that the isolate was Puccinia allii. Based collectively on the morphological characteristics and molecular identification, the causal fungus was identified as P. allii. This is the first report of rust caused by P. allii on onion in Korea, a disease that may constitute a serious threat to production of this crop in Korea.

Foliar water uptake of four shrub species in a semi-arid desert

Dew water plays an important role in supporting biological processes in desert ecosystems. Although some mechanisms underlying how plants survive in water-limited environments have been investigated, the water-use strategies of most desert plants remain unclear. We investigated whether foliar uptake of dew water occurs in four dominant shrub species (Artemisia ordosica, Hedysarum mongolicum, Salix psammophila, and Caragana korshinskii), in the Mu Us Desert of northern China. A fluorescent tracing experiment indicated that all four species absorbed water via leaf trichomes and cuticles, and A. ordosica also absorbed water via the stomata. A dew water exposure experiment and isotopic tracing revealed that water entered the leaves and stems of the four species, thereby enhancing their water potential. The relative contribution of dew water to the total water in the leaves of A. ordosica, H. mongolicum, S. psammophila, and C. korshinskii was 20.0 ± 7.0%, 8.4 ± 6.4%, 7.8 ± 1.9%, 3.1 ± 2.3%, respectively. The results demonstrated that all four species had the capacity to absorb water by their leaves, and the absorbed water could be transported to the stems. Our findings suggest that foliar water uptake may be one of the survival mechanisms by shrubs in the desert environment.

Water Sorption and Desorption of Isolated Cuticles From Three Woody Species With Focus on Ilex aquifolium.

The cuticle is a lipid-rich layer that protects aerial plant organs against multiple stress factors such as dehydration. In this study, cuticle composition and structure in relation to water loss are examined in a broad ecophysiological context, taking into consideration leaf age and side from Ilex aquifolium (holly) in comparison with Eucalyptus globulus (eucalypt) and Prunus laurocerasus (cherry laurel). Enzymatically isolated cuticular membranes from holly leaves were studied under three treatment conditions: natural (no chemical treatment), after dewaxing, and after methanolysis, and the rate of water loss was assessed. Structural and chemical changes were evaluated using different microscopy techniques and by Fourier transform infrared (FTIR) spectroscopy. The potential mechanisms of solute absorption by holly leaves were additionally evaluated, also testing if its prickly leaf margin may facilitate uptake. The results indicate that the treatment conditions led to structural changes, and that chemical composition was hardly affected because of the occurrence of cutan. Structural changes led to more hydrophilic adaxial surfaces, which retained more water and were more efficient than natural cuticles, while changes were not significant for abaxial surfaces. Across natural cuticles, age was a significant factor for eucalypt but not for holly. Young eucalypt cuticles were the group that absorbed more water and had the lowest water loss rate. When comparing older leaf cuticles of the three species, cherry laurel was found to absorb more water, which was, however, lost more slowly, compared with the other species. Evidence was gained that holly leaves can absorb foliar-applied solutes (traced after calcium chloride application) through the adaxial and abaxial surfaces, the adaxial mid veins, and to a lower extent, the spines. In conclusion, for the species examined, the results show variations in leaf cuticle composition and structure in relation to leaf ontogeny, and water sorption and desorption capacity.

A Deep Learning-Based Method for Automatic Assessment of Stomatal Index in Wheat Microscopic Images of Leaf Epidermis.

The stomatal index of the leaf is the ratio of the number of stomata to the total number of stomata and epidermal cells. Comparing with the stomatal density, the stomatal index is relatively constant in environmental conditions and the age of the leaf and, therefore, of diagnostic characteristics for a given genotype or species. Traditional assessment methods involve manual counting of the number of stomata and epidermal cells in microphotographs, which is labor-intensive and time-consuming. Although several automatic measurement algorithms of stomatal density have been proposed, no stomatal index pipelines are currently available. The main aim of this research is to develop an automated stomatal index measurement pipeline. The proposed method employed Faster regions with convolutional neural networks (R-CNN) and U-Net and image-processing techniques to count stomata and epidermal cells, and subsequently calculate the stomatal index. To improve the labeling speed, a semi-automatic strategy was employed for epidermal cell annotation in each micrograph. Benchmarking the pipeline on 1,000 microscopic images of leaf epidermis in the wheat dataset (Triticum aestivum L.), the average counting accuracies of 98.03 and 95.03% for stomata and epidermal cells, respectively, and the final measurement accuracy of the stomatal index of 95.35% was achieved. R2 values between automatic and manual measurement of stomata, epidermal cells, and stomatal index were 0.995, 0.983, and 0.895, respectively. The average running time (ART) for the entire pipeline could be as short as 0.32 s per microphotograph. The proposed pipeline also achieved a good transferability on the other families of the plant using transfer learning, with the mean counting accuracies of 94.36 and 91.13% for stomata and epidermal cells and the stomatal index accuracy of 89.38% in seven families of the plant. The pipeline is an automatic, rapid, and accurate tool for the stomatal index measurement, enabling high-throughput phenotyping, and facilitating further understanding of the stomatal and epidermal development for the plant physiology community. To the best of our knowledge, this is the first deep learning-based microphotograph analysis pipeline for stomatal index assessment.

Harold Wager and the photography of plants

The recent surge of interest in the sensory, cognitive and communicative strategies of plant life and the development of neurobotany and phyto-philosophy resumes a debate that briefly flourished in the early twentieth century. Francis Darwin and Gottlieb Haberland then proposed that plants possessed vision and memory, a position rapidly abandoned until its recent revival. A striking contribution to the earlier debate was botanist Harold Wager’s showing of a series of photographs purported to have been taken using lens extracted from plant leaf epidermis. The article will reflect on the status of this photographic practice, in which plants are posed as the photographing subject rather than photographed object, and consider its wider implications for non-human photographic practices.

First Report of Colletotrichum siamense causing Anthracnose on White Frangipani (Plumeria alba L.) in Malaysia.

Plumeria alba L. is a flowering plant in the family Apocynaceae and widely cultivated in Malaysia as a cosmopolitan ornamental plant. In January 2020, anthracnose lesions were observed on leaves of Plumeria alba planted in Agricultural Farm, Universiti Putra Malaysia, in Selangor state, Malaysia. The disease mainly affected the leaves with symptoms occurring with approximately a 60% disease incidence. Ten symptomatic leaves were sampled from 3 different trees in the farm. Symptoms initiated as small circular necrotic spots that rapidly enlarged into black lesions with pale brown borders. Diseased tissues (5×5 mm) were surface-sterilized with 70% ethanol for 1 min, rinsed three times with sterile distilled water, dried on sterile filter papers, plated on PDA and, incubated at 25 °C with a 12-h photoperiod. A total of seven single-spore isolates with similar colony morphologies were obtained from tissue samples. After 7 days, the colonies raised the entire margin and showed white-to-gray aerial mycelium, orange conidial masses in the center and appeared dark brown at the center of the reverse view. The conidia were 1-celled, hyaline, smooth-walled, cylindrical with narrowing at the center, averaged (13-15 μm × 3 - 4 μm) (n=40) in size. Morphological characteristics of the isolates were similar to those detailed in taxonomic description of Colletotrichum sp. (Prihastuti et al. 2009). For molecular identification, genomic DNA of two representative isolates, PL3 and PL4 was extracted from fresh mycelium using DNeasy Plant Mini Kit (Qiagen, USA). The internal transcribed spacer (ITS) region, actin (ACT) and calmodulin (CAL) genes were amplified using ITS5/ITS4 (White et al. 1990), ACT-512F/783R (Carbone and Kohn 1999) and CL1C/CL2C primer sets (Weir et al. 2012). A BLAST nucleotide search of GenBank using ITS sequences showed 100% identity to Colletotrichum siamense ex-type culture ICMP 18578 (GenBank accession no. JX010171). ACT and CAL sequences showed 100% identity with C. siamense ex-type isolate BPD-I2 (GenBank accession no. FJ907423 and FJ917505). The sequences were deposited in GenBank (ITS: accession nos. MW335128, MT912574), ACT: accession nos. MW341257, MW341256, CAL: accession nos. MW341255 and MT919260). Based on these morphological and molecular characteristics, the fungus was identified as C. siamense. Pathogenicity of PL3 and PL4 isolates was verified using four healthy detached leaves of Plumeria alba. The leaves were surface-sterilized using 70% ethanol and rinsed twice with sterile water before inoculation. The leaves (three inoculation sites/leaf) were wounded by puncturing with a sterile needle through the leaf cuticle and inoculated in the wound site with 10-μl of conidial suspension (1×106 conidia/ml) from 7-days-old culture on PDA. Four leaves were used as a control and were inoculated only with 10-μl of sterile distilled water. Inoculated leaves were kept in humid chambers for 2 weeks at 25 °C with 98% relative humidity on a 12-h fluorescent light/dark period. The experiment was repeated three times. Anthracnose symptoms were observed on all inoculated leaves after 3 days, whereas controls showed no symptoms. Fungal isolates from the diseased leaves showed the same morphological characteristics as isolates PL3 and PL4, confirming Koch's postulates. C. siamense has been reported causing anthracnose on rose (Rosa chinensis) in China (Feng et al. 2019), Coffea arabica in Thailand (Prihastuti et al. 2009) and mango leaf anthracnose in Vietnam (Li et al. 2020). To our knowledge, this is the first report of Colletrotrichum siamense causing leaf anthracnose on Plumeria alba in Malaysia. Accurate identification of this pathogen provides a foundation in controlling anthracnose disease on Plumeria alba.

Microscopy and Histochemistry of Leaves and Stems of Baccharis Subgenus Coridifoliae (Asteraceae) Through LM and SEM-EDS

This research reports for the first time the anatomical characteristics of all species belonging to Baccharis subgenus Coridifoliae (Asteraceae). The anatomy and micro-morphology of aerial vegetative organs of ten species: B. albilanosa, B. artemisioides, B. bicolor, B. coridifolia, B. erigeroides, B. napaea, B. ochracea, B. pluricapitulata, B. scabrifolia, and B. suberectifolia are investigated by light and scanning electron microscopy. The number of secretory ducts, crystal morphology, presence or absence of conical nonglandular trichomes, leaves cross-section shape, margin morphology, anticlinal epidermal cell walls shape, and cuticle structure were identified as characters with diagnostic value for species. Similarity cluster analysis allows the formation of three groups based on a percentage of similarity between 45 and 84%. Some species showed differential characteristics as the presence of up to four secretory ducts in the midrib in B. albilanosa; smooth cuticles onboth sides of the leaf epidermis in B. erigeroides; flat midrib shape on both sides of the leaves in B. napaea; and convex–flat midrib shape in B. suberectifolia. The remaining species can be differentiated by a set of anatomical features. Anatomical and histochemical characteristics of stems and leaves provided data to support species identification.

Interactive effects of tree species mixture and climate on foliar and woody trait variation in a widely distributed deciduous tree

Abstract Despite increasing reports of severe drought and heat impacts on forest ecosystems, community‐level processes, which could potentially modulate tree responses to climatic stress, are rarely accounted for. While numerous studies indicate a positive effect of species diversity on a wide range of ecosystem functions and services, little is known about how species interactions influence tree responses to climatic variability. We quantified the intraspecific variation in 16 leaf and wood physiological, morphological and anatomical traits in mature beech trees (Fagus sylvatica L.) at six sites located along a climatic gradient in the French Alps. At each site, we studied pure beech and mixed stands with silver fir (Abies alba Mill.) or downy oak (Quercus pubescens Willd.). We tested how functional traits differed between the two species mixtures (pure vs. mixed stands) within each site and along the climatic gradient. We found significant changes in many traits along the climatic gradient as conditions progressively got drier and warmer. Independent of the mixture, reduced leaf‐level CO2 assimilation, stomatal size and thicker leaf cuticles, consistent with a more conservative resource use strategy, were found. At the drier sites, higher foliar stable carbon isotopic composition (δ13C), thicker mesophyll tissues and lower specific leaf area (SLA) in pure stands suggest that beech had more acquisitive traits there compared to mixed stands. At the wetter sites, trees in beech‐silver fir mixtures had higher chlorophyll concentration, lower δ13C, larger xylem vessels and higher SLA, suggesting a more acquisitive resource use strategy in mixed stands than in pure stands. Our work revealed that species interactions are significant modulators of functional traits, and that they can be just as important drivers of intraspecific trait variation as climatic conditions. We show that downy oak mixtures lead to an adaptive drought response by common beech in dry environments. In contrast, in milder climates, interactions with silver fir seem to increase beech resource acquisition and productivity. These findings highlight a strong context dependency and imply that incorporating local interspecific interactions in research on climate impacts could improve our understanding and predictions of forest dynamics. A free Plain Language Summary can be found within the Supporting Information of this article.

Large differences in leaf cuticle conductance and its temperature response among 24 tropical tree species from across a rainfall gradient.

Summary More frequent droughts and rising temperatures pose serious threats to tropical forests. When stomata are closed under dry and hot conditions, plants lose water through leaf cuticles, but little is known about cuticle conductance (g min) of tropical trees, how it varies among species and environments, and how it is affected by temperature.We determined g min in relation to temperature for 24 tropical tree species across a steep rainfall gradient in Panama, by recording leaf drying curves at different temperatures in the laboratory.In contrast with our hypotheses, g min did not differ systematically across the rainfall gradient; species differences did not reflect phylogenetic patterns; and in most species g min did not significantly increase between 25 and 50°C. g min was higher in deciduous than in evergreen species, in species with leaf trichomes than in species without, in sun leaves than in shade leaves, and tended to decrease with increasing leaf mass per area across species. There was no relationship between stomatal and cuticle conductance.Large species differences in g min and its temperature response suggest that more frequent hot droughts may lead to differential survival among tropical tree species, regardless of species’ position on the rainfall gradient.

Variations in morphological and epidermal features of shade and sun leaves of two species: Quercus bambusifolia and Q. myrsinifolia.

Microclimatic differences between the periphery and the interior of tree crowns result in a variety of adaptive leaf macromorphological and anatomical features. Our research was designed to reveal criteria for sun/shade leaf identification in two species of evergreen oaks, applicable to both modern and fossil leaves. We compared our results with those in other species similarly studied. For both Quercus bambusifolia and Q. myrsinifolia (section Cyclobalanopsis), leaves from single mature trees with well-developed crowns were collected in the South China Botanical Garden, Guangzhou, China. We focus on leaf characters often preserved in fossil material. SVGm software was used for macromorphological measurement. Quantitative analyses were performed and box plots generated using R software with IDE Rstudio. Leaf cuticles were prepared using traditional botanical techniques. Principal characters for distinguishing shade and sun leaves in the studied oaks were identified as leaf lamina length to width ratio (L/W), and the degree of development of venation networks. For Q. myrsinifolia, shade and sun leaves differ in tooth morphology and the ratio of toothed lamina length to overall lamina length. The main epidermal characters are ordinary cell size and anticlinal wall outlines. For both species, plasticity within shade leaves exceeds that of sun leaves. Morphological responses to sun and shade in the examined oaks are similar to those in other plant genera, pointing to useful generalizations for recognizing common foliar polymorphisms that must be taken into account when determining the taxonomic position of both modern and fossil plants.

Establishing asymmetry: stomatal division and differentiation in plants.

In the leaf epidermis, stomatal pores allow gas exchange between plants and the environment. The production of stomatal guard cells requires the lineage cells to divide asymmetrically. In this Insight review, we describe an emerging picture of how intrinsic molecules drive stomatal asymmetric cell division in multidimensions, from transcriptional activities in the nucleus to the dynamic assembly of the polarity complex at the cell cortex. Given the significant roles of stomatal activity in plant responses to environmental changes, we incorporate recent advances in external cues feeding into the regulation of core molecular machinery required for stomatal development. The work we discuss here is mainly based on the dicot plant Arabidopsis thaliana with summaries of recent progress in the monocots.

Leaf Epidermis: The Ambiguous Symplastic Domain.

The ability to develop secondary (post-cytokinetic) plasmodesmata (PD) is an important evolutionary advantage that helps in creating symplastic domains within the plant body. Developmental regulation of secondary PD formation is not completely understood. In flowering plants, secondary PD occur exclusively between cells from different lineages, e.g., at the L1/L2 interface within shoot apices, or between leaf epidermis (L1-derivative), and mesophyll (L2-derivative). However, the highest numbers of secondary PD occur in the minor veins of leaf between bundle sheath cells and phloem companion cells in a group of plant species designated “symplastic” phloem loaders, as opposed to “apoplastic” loaders. This poses a question of whether secondary PD formation is upregulated in general in symplastic loaders. Distribution of PD in leaves and in shoot apices of two symplastic phloem loaders, Alonsoa meridionalis and Asarina barclaiana, was compared with that in two apoplastic loaders, Solanum tuberosum (potato) and Hordeum vulgare (barley), using immunolabeling of the PD-specific proteins and transmission electron microscopy (TEM), respectively. Single-cell sampling was performed to correlate sugar allocation between leaf epidermis and mesophyll to PD abundance. Although the distribution of PD in the leaf lamina (except within the vascular tissues) and in the meristem layers was similar in all species examined, far fewer PD were found at the epidermis/epidermis and mesophyll/epidermis boundaries in apoplastic loaders compared to symplastic loaders. In the latter, the leaf epidermis accumulated sugar, suggesting sugar import from the mesophyll via PD. Thus, leaf epidermis and mesophyll might represent a single symplastic domain in Alonsoa meridionalis and Asarina barclaiana.

Anatomical characterization of 18 commercially important varieties of Phoenix dactylifera L. by using microscopy

Date palm (Phoenix dactylifera L.) is an important traditional crop having socioeconomic values. To best of literature review and our knowledge, there is a gap of taxonomic study on the role of morpho-anatomical features of date palm for correct identification of its varieties. With the advancement in the field of microscopy, anatomical features are considered very effective taxonomical markers. The present study was aimed to analyze the taxonomic variations using leaf epidermal anatomy and to highlight the importance of leaf epidermis to resolve identification ambiguities among the different varieties of date palms. The study includes analysis of leaf epidermal anatomy of 18 different commercial varieties of date palm collected from different areas of Pakistan. A diverse range of shape and size of epidermal cells, subsidiary cells, guard cells, stomata, stomatal pore was observed on abaxial as well as adaxial among studied date palm varieties via LM and found to be very helpful tool in discrimination of varieties. The shape of epidermal cells on both abaxial and adaxial surfaces varies including elongated, irregular, polygonal, curved, and spherical or sometime mixed of these. The values of stomatal indices on both surfaces showed wide variations.

Diet preferences of common warthogs (Phacochoerus africanus) in Gassi and Haro Aba Diko controlled hunting areas, Western Ethiopia

To assess feeding ecology and diet preferences of common warthogs (Phacochoerus africanus (Gmelin, 1788), the study was conducted in Gassi Controlled Area (GCHA) and in Haro Aba Diko Controlled Hunting Area (HADCHA) from May 2017 to June 2018. Diet composition of common warthog was determined using feeding quadrat and microhistological methods. From the leaf cuticle fragments observed of feces, 41 and 45 plant species were recognized as annual dietary components of common warthog in GCHA and HADCHA, respectively. Uncertainty of epidermal fragments and fine digestion, led certain forage species consumed by warthogs to be unidentified. In Gassi Controlled Hunting Area, Cynodon nlemfuensis (75.5%), Cynodon dactylon (69%), and Cyperus fischerianus (47%) had the higher relative frequency occurrence (RFO) in the feces of the animal during the wet season. In Haro Aba Diko Controlled Hunting Area, C. nlemfuensis (76.5%), C. dactylon (73.5%) and H. rufa (57.5%) were the top three forage species with higher RFO in the feces of the warthog during the dry season. During the wet season in GCHA, C. fischerianus, D. abyssinica, C. dactylon, C. nlemfuensis, Hyparrhenia rufa, A. abyssinicus, Sesbania sesban and Diplolophium africanum were identified as the staple forage species of common warthogs. In HADCHA, C. fischerianus, D. abyssinica, C. dactylon, C. nlemfuensis, H. rufa, H. hirta, S. poiretiana, A. abyssinicus, and S. sesban were identified as the staple forage species of warthogs during the wet season. In GCHAC. dactylon, C. nlemfuensis and A. abyssinicus were the top three species which showed high acceptability during the wet and dry seasons. Hyparrhenia hirta, was high acceptability during the wet season which was less acceptability during the dry season but the difference was not significant. In HADCHA C. fischerianus, D. abyssinica, C. dactylon, and C. nlemfuensis, showed high acceptability during both seasons. Therefore, common warthogs foraged on wide range of food resources of graminoids, forbs, and shrubs in the study areas. Certain staple forage species were frequently preferred, because of their compatibility with the physiology of warthogs.

Micro morphological foliar taxonomic studies of genus Paspalum based on scanning electron microscopy.

Paspalum is one of the 10 largest genera in Poaceae and is considered as a complex and taxonomically difficult genus due to its similar morphological characters within the species which makes it difficult to delimit taxa within the same genus. The current research work establishes the distinction among species of this genus and resolves taxonomic confusions among this genus. And this distinction is done by micro morphological foliar anatomical characterization by light and scanning electron microscopy. Both the abaxial and adaxial epidermal cuticles of three different species of genus Paspalum were studied and their phytoliths were observed through elemental dispersive spectrophotometric analysis by SEM first time in Pakistan. Results showed great variation in studied anatomical features. P. dilatatum Poir. was comprised of macro-hairs in the intercostal regions only whereas no macro-hairs were found in P. distichum Linn. and P. scrobiculatum Linn. Beak-shaped prickles were found in the intercostal regions on adaxial surface only in P. distichum Linn. and P. scrobiculatum Linn. whereas in P. dilatatum Poir., knife-shaped prickles were present in intercostal regions only on both abaxial and adaxial surfaces of leaf epidermis. No papillae were seen in P. dilatatum Poir whereas in P. distichum Linn. and P. scrobiculatum Linn. papillae were found abundantly. In genus paspalum, P. dilatatum Poir. phytoliths showed lowest mass percentage of silicon as 15.13% whereas P. distichum Linn. phytoliths showed highest mass percentage of silicon as 22.00%. Based on micro morphological foliar characteristics a taxonomic key of studied species is also provided to delimit the taxa.