Micromorphologie des épidermes foliaires chez quelques espèces de Medicago

1983 ◽  
Vol 61 (12) ◽  
pp. 3461-3470 ◽  
Author(s):  
Catherine Damerval

The micromorphology of the abaxial epidermis of the first and sixth leaf has been studied in seven annual species of Medicago L. The pattern of the epidermal cells and of the stomatal complex does not allow differentiation of the taxa. Three main types of trichomes are recognized on the two foliar levels; their localization on the first leaf epidermis allows identification of five taxa out of seven. Four quantitative variables are also examined: stomatal density, trichome density, guard cell length, and stomatal index. The variable having the best discriminant value is the guard cell length on the first leaf. It is possible to identify each of the seven species by a combination of two features: the localization of the types of trichomes on the first leaf and the stomatal density on the sixth leaf.

2021 ◽  
Vol 12 ◽  
Author(s):  
Chuancheng Zhu ◽  
Yusong Hu ◽  
Hude Mao ◽  
Shumin Li ◽  
Fangfang Li ◽  
...  

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.


2020 ◽  
Vol 287 (1919) ◽  
pp. 20192876
Author(s):  
Gregory J. Jordan ◽  
Raymond J. Carpenter ◽  
Barbara R. Holland ◽  
Nicholas J. Beeton ◽  
Michael D. Woodhams ◽  
...  

The size of plant stomata (adjustable pores that determine the uptake of CO 2 and loss of water from leaves) is considered to be evolutionarily important. This study uses fossils from the major Southern Hemisphere family Proteaceae to test whether stomatal cell size responded to Cenozoic climate change. We measured the length and abundance of guard cells (the cells forming stomata), the area of epidermal pavement cells, stomatal index and maximum stomatal conductance from a comprehensive sample of fossil cuticles of Proteaceae, and extracted published estimates of past temperature and atmospheric CO 2 . We developed a novel test based on stochastic modelling of trait evolution to test correlations among traits. Guard cell length increased, and stomatal density decreased significantly with decreasing palaeotemperature. However, contrary to expectations, stomata tended to be smaller and more densely packed at higher atmospheric CO 2 . Thus, associations between stomatal traits and palaeoclimate over the last 70 million years in Proteaceae suggest that stomatal size is significantly affected by environmental factors other than atmospheric CO 2 . Guard cell length, pavement cell area, stomatal density and stomatal index covaried in ways consistent with coordinated development of leaf tissues.


2017 ◽  
Vol 52 (1) ◽  
pp. 1-6 ◽  
Author(s):  
AA Abdul Rahaman ◽  
OM Olaniran ◽  
FA Oladele

The effect of industrial effluents was studied with respect to growth and leaf anatomy of three Sesamum indicum varieties (NGB 00931, NGB 00937 and NGB 00939). Industrial effluents (25%, 50%, 75% and 100%) from two industries are used to irrigate the plants. Although, the control plants possessed larger leaves and longer stems than the effluent-treated plants, at lower concentration, the plant growth is relatively higher. Gradual decrease in the germination of seeds and seedling growth with increase in effluent concentration was observed. The best germination and seedling growth was observed at the 25% concentration. Leaf epidermal features (stomatal density, stomatal index, stomatal size, trichome density, tricome index, trichome size and number of epidermal cells) are more influenced in the effluent-treated plants than in the control plants from the Peace Standard Pharmaceutical Industry than in the effluent from the Global Soap & Detergent Industry. Thus the industrial effluents can be safely used for irrigation purposes with proper treatment and dilution at 25%.Bangladesh J. Sci. Ind. Res. 52(1), 1-6, 2017


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 999E-1000
Author(s):  
Madhulika Sagaram ◽  
Leonardo Lombardini ◽  
Larry Grauke

An assessment of anatomical traits of pecan cultivars (`Pawnee', `Mohawk', and `Starking hardy giant') collected from three locations (Tifton, Ga.; Chetopa, Kans.; and Stillwater, Okla.) was conducted at Texas A&M University. The objective of the study was to provide an understanding of patterns of geographic variation within the natural range for anatomical (stomatal density, stomatal index, and epidermal cell density) traits. Microscopy using acetate casts was used as the means to investigate the patterns of variation in the epidermal characteristics of pecan leaf. `Starking hardy giant' had the greatest number of stomates/cm2 (46,229, 47,807, and 45,990 at Tifton, Chetopa, and Stillwater, respectively) while `Mohawk' had the least (37,397, 36,217, and 35,305). `Pawnee' had the greatest number of epidermal cells/cm2 (251,806, 250,098 and 254,883 at Tifton, Chetopa, and Stillwater, respectively) while `Starking hardy giant' had the least (141,699, 138,405, and 142,155). Differences in stomatal index were observed between the three cultivars at Tifton and Stillwater. No differences in stomatal index were observed between `Pawnee' and `Mohawk' at Chetopa. The study showed that stomatal density as well as epidermal cell density of all the tested cultivars were significantly different (P < 0.05) at a particular location but no differences were observed in a given cultivar grown at different locations.


2019 ◽  
Vol 54 (2) ◽  
pp. 111-116
Author(s):  
KA Abdul Kareem ◽  
TJ Olobatoke ◽  
AA Abdul Rahaman ◽  
OT Mustapha

UV radiant seedlings of Capsicum annuum, C. Chinenese and Capsicum frutescens were studied anatomically to observe the UV effects on the leaf epidermis, stem and root ultrastructures. While there is a higher percentage of stomatal index in the UV-exposed plants compared to the controlled, unexposed plants, there is no correlation in the stomatal density and stomatal size between the exposed and unexposed plants to the ultraviolet irradiation. There was also no correlation between the stomatal size and the stomatal density in both treatments (exposed and unexposed) in all the plants. Significant differences were observed in the stomatal index on both leaf surfaces between the exposed and controlled plants of C. frutescens and C. annuum. Cell walls of the stem and root wereobserved to be thicker in the UV-exposed plants. Bangladesh J. Sci. Ind. Res.54(2), 111-116, 2019


2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Silvia Radice ◽  
Miriam E. Arena

<em>Berberis microphylla</em> G. Forst is a fruit shrub native from Patagonia, considered as a non-timber forest product. In recent years, there has been an increased demand for its fruits, both for fresh and industrialized consumption, being the establishment of commercial orchards in different sites a need to meet this demand. <em>B. microphylla</em> cloned plants have been introduced from Ushuaia, Tierra del Fuego to Buenos Aires province in order to evaluate its phenotypic plasticity and the possibility of fruit production. At the same time, a comparative study on the morphology and anatomy of the mature leaves of <em>B. microphylla</em> grown in two different environmental conditions was carried out. Moreno leaves were significantly larger than Ushuaia leaves in all the morphological parameters registered, while Ushuaia leaves were more circular than Moreno leaves with the highest roundness and elongation indexes. Nevertheless, histological sections showed that Ushuaia leaves have one more layer of palisade cells respect to Moreno leaves. Ushuaia leaves showed higher palisade cells, larger abaxial epidermal cells and thicker cuticles than Moreno leaves. The stomatal density was superior on Moreno leaves. Scanning Electron Microscope of abaxial epidermis showed a surface with numerous ridges of different forms that prevent the layout of epidermal cells on Moreno leaves. Appearance of this surface is glossy and oily. On the contrary, epidermal cells are well recognized on Ushuaia leaves. Stomata of anomocytic type were observed and surface looks waxy. Auto-fluorescence on leaf cross sections were observed on the vascular bundles and partially on the epidermis cells. <em>B.</em> <em>microphylla</em> leaves showed a high phenotypic plasticity between the two sites of cultivation. The changes in the leaf morphology and structure observed in Moreno leaves could indicate that the plants are trying to adjust its morphology to the new culture conditions <em>i.e.</em> higher temperatures and lower irradiance.


2018 ◽  
Vol 30 ◽  
pp. 28-38
Author(s):  
Baba Maiya Pradhan ◽  
Devendra M. Bajracharya

Dendrobium Swartz is one of the largest and most problematic genus of the tribe Dendrobieae of the family Orchidaceae. Nepal harbors about thirty-one species of Dendrobium. Micro morphological characters like the stomatal complex in fifteen species of DendrobiumSwartz (Orchidaceae) of Nepal were studied for understanding the taxonomic significance of stomatal complex within the genus. For the study of stomatal complex of leaf, Carpenter’smethod was followed. Stomatal index and stomatal frequency were calculated using formulagiven by Salisbury. The terminologies used for the stomatal complex type were followed those of Patel. In all species the leaf surface was found hypostamic. Tetracytic (a-tetra-monocyclic,b-tetra-monocyclic and c-tetra-monocyclic) and eupara twi-monocyclic with hexa-monocyclictypes of stomata were recorded in the genus. Tetracytic type was found in fourteen species and eupara twi-monocyclic with hexa-monocyclic was found in only one species. The elliptical shape of stomata was found in more species than the circular shape. The epidermal cells of leaf was found rectangular, square, polygonal to irregular. The distribution of stomata on leaf surface, type of stomata and shape of epidermal cells were found to be taxonomically significant. These characters could be used as distinguishing characters to delimit the species in the genus.


2009 ◽  
Vol 61 (4) ◽  
pp. 847-851 ◽  
Author(s):  
A.A. Abdulrahaman ◽  
F.O. Egbedo ◽  
F.A. Oladele

Dioscorea alata L. has three stomatal complex types, namely, paracytic, anisocytic, and tetracytic stomata, with percentage frequency values of 50, 18, and 32, respectively. Dioscorea bulbifera has paracytic and anisocytic stomata, with percentage frequency values of 87.60 and 12.40, respectively. Dioscorea cayenensis has anisocytic stomata, with a percent?age frequency value of 100. Dioscorea dumetorum has tetracytic and paractytic stomata, with percentage frequency values of 91.05 and 8.95, respectively. Both D. esculenta and D. rotundata have paracytic stomata, with a percentage frequency of 100. The range of variation of stomatal density is from 10 (lowest value) in D. alata and D. dumentorum to 27 (highest value) in D. bulbifera. The stomatal index also varies, from 24 in D. alata to 47 in D. cayenensis. The size of stomata in all species is small, varying in length from 0.74 ?m in D. alata to 1.79 ?m in D. dumentorum. An indented dichotomous key based on stomatal features was constructed to distinguish and identify the species.


2017 ◽  
Vol 10 (1) ◽  
pp. 1-9
Author(s):  
Mahipal S. Shekhawat ◽  
M. Manokari

Background:Due to non-availability or short supply of original medicinal plants the crude drugs from the plants are adulterated by similarly resembling plants. Micromorphological studies of leaves could help in the identification and authentication of the original medicinal plant from the crude drug materials.Objective:To investigate the qualitative and quantitative micromorphological parameters of the leaves ofCardiospermum halicacabum.Method:The foliar micromorphological parameters such as orientation, stomatal types and morphology; density, distribution of trichomes and stomata; stomatal index and trichome types, paradermal sections were obtained manually by the standard method. The leaves were excised and fixed primarily in formalin, acetic acid and ethyl alcohol solution; cleared in 70% ethanol, bleached with 5% NaOH and rinsed in distilled water. The cleared leaves were used for the study of venation pattern, vein-islets, veinlet terminations and arrangement of crystals.Results:The microscopic examinations revealed the presence of anomocytic and anisocytic types of stomata with the abaxial epidermis of leaves. The stomatal density was 72 and stomatal index reported as 33.1. Glandular trichomes were few with uniseriate stalk, capitate multiseriate and multicellular head. Non-glandular trichomes frequent which were unicellular, uniseriate and bristle in nature. The density of vein islets and veinlet termination was observed as 18 and 13 respectively.Conclusion:The foliar micromorphological (stomata, vein clearing etc.) findings could be used in the proper identification and authentication ofC. halicacabumfrom the crude plant materials which is essential in quality control measures.


2019 ◽  
Vol 67 (7) ◽  
pp. 463
Author(s):  
Doaa M. Hanafy ◽  
Paul D. Prenzler ◽  
Rodney A. Hill ◽  
Geoffrey E. Burrows

Mentha (mint) is a genus in the Lamiaceae with a worldwide distribution. It has a complex classification due to frequent hybridisation at the interspecific level, variation in basic chromosome number and the occurrence of polyploidy (diploid to nonaploid). Although there have been many studies of Mentha leaf micromorphology, usually only a few taxa were described. The aim of this study was to characterise the micromorphology of Mentha leaves. Nineteen Mentha taxa, covering all four sections of the genus, were grown under controlled conditions and adaxial and abaxial leaf surfaces were examined using stereo and scanning electron microscopes. This study included examination of the previously uninvestigated Australian species, M. australis and M. diemenica. The study revealed that average lamina length varied from 3 mm (M. requienii) to 34 mm (M. × niliaca) and leaves were sessile (M. spicata) to where petiole length was 50% of total leaf length (M. requienii). Peltate and capitate glandular trichomes were found on the adaxial and abaxial leaf surfaces of almost all taxa. Most taxa were hypostomatous. A few taxa had amphistomatous leaves which was interesting given that Mentha is a mesophytic genus naturally found in moist environments beside streambanks and lake shores. Average guard cell length varied from 14 µm (M. suaveolens) to 27 µm (M. × piperita f. citrata ‘Basil’) with larger guard cell length correlated with larger DNA content and chromosome number. Two species in section Pulegium (M. requienii and M. pulegium) had small laminas, relatively long petioles and high adaxial stomatal density which distinguished them from taxa in the other three sections. Larger DNA content in plants can be associated with larger cell size. Most studies of Mentha leaf micromorphology make no mention of ploidy. The present study indicates this should be considered when comparing relative cell size between species.


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