Leaf epidermal characters (e.g. stomata) are hereby indicated as an important tool in delimiting species in the genus Chlorophytum

Plate 2: Photomicrographs of folia epidermis of Chlorophytum plant
studied. ai, bi, ci and di show tetracytic stomata on the abaxial
surface while aii, bii, cii and dii show tetracytic stomata on the
adaxial surface of C. orchidastrum C. bichetii, C. stenopetalum and
C. macrophyllum respectively

Leaf epidermal studies of four species of Chlorophytum Ker- Gawl in Nigeria

Omokanye B. S., Mustapha O. T., Abdulrahaman A. A., Kolawole O. S., (2020)

1 National Open University of Nigeria, Offa Community Study Center Offa, Kwara State.

2,3 Department of Plant Biology Faculty of Life science, University of Ilorin, Ilorin, Nigeria.

4 Department of Biological Sciences Federal University Kashere, Gombe State, Nigeria.
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J. Appl. Sci. Environ. Manage 24(11): 1963-1968 – DOI: 10.4314/jasem.v24i11.17

https://www.ajol.info/index.php/jasem

file:///C:/Users/wille/Downloads/202589-Article%20Text-507174-1-10-20210111%20(1).pdf

ABSTRACT:

Studies of the foliar epidermal morphology in four species of Chlorophytum; C. orchidastrum, C. bichetii, C. stenopetalum and C. macrophyllum revealed the presence of stomata on both sides of the leaves (amphistomatic stomata distribution). In C. orchidastrum, few stomata are present on the adaxial surfaces. Stomata type has no diagnostic importance as all the species studied have tetracytic stomata. Stomata index (<10%) on the adaxial surface in C. orchidastrum easily distinguished the species from others. In C. bichetii and C. macrophyllum stomata index (<50%) was recorded while stomata index (>50%) was recorded for C. stenopetalum on the adaxial surface. Stomata index on the abaxial surface also shows that fewer stomata occur in C. macrophyllum compared with C. stenopetalum. The studies also revealed smooth leaf margin for C. orchidastrum. Papillea out growth were observed on the leaf margin of C. stenopetalum and C. macrophyllum, Papillea projections were however more pronounced in C. bichetii. Leaf epidermal character is hereby indicated as an important tool in delimiting species in the genus Chlorophytum.

These orchids have various structure of epidermis cells and an anomocytic type of stomata cells that is similar to dicotyledon plants

Struktur Sel Epidermis dan Stomata Daun Beberapa Tumbuhan Suku Orchidaceae

Rompas Y. (2011)

Yulanda Rompas,

Department of Biology
Faculty of Mathematics and Natural SciencesUniversitas Sam Ratulangi. Manado, North Sulawesi

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Jurnal Bios Logos 1(1): 13–19 – https://doi.org/10.35799/jbl.1.1.2011.371

https://ejournal.unsrat.ac.id/index.php/bioslogos/article/view/371

Abstrak

Telah dilakukan penelitian untuk menentukan struktur sel epidermis dan stomata pada beberapa tumbuhan anggota suku Orchidaceae yang merupakan anggota marga Arachnis, Phalaenopsis dan Vanilla. Metode deskriptif digunakan untuk menggambarkan struktur sel epidermis dan stomata daun anggrek kalajengking, anggrek bulan dan vanili berdasarkan pengamatan irisan memanjang sel-sel epidermis pada permukaan bawah daun dengan mikroskop cahaya. Hasil penelitian menunjukkan adanya variasi struktur sel epidermis dan stomata anomositik seperti pada tumbuhan dikotil.

Abstract

A research was conducted to determine the structure of epidermis and stomata cells on several Orchidaceae plants, such as genus Arachnis, Phalaenopsis and Vanilla. The descriptive method was used to describe the structure of epidermis and leaf stomata cells of scorpion orchids, moon orchids and vanilla by observing the epidermis of longitudinal section of lower leaf using light microscope. The research result showed that these plants had various structure of epidermis cells and had anomocytic type of stomata cells that was similar to dicotyledon plants.

Stomata morphology and distribution of Paraphalaenopsis spp (Orchidaceae) from in vitro growth and greenhouse conditions

Stomata cells studies of Paraphalaenopsis spp. From in vitro and greenhouse condition

Garvita R. V., Wawangningrum H. (2020)

R. VITRI GARVITA, HARY WAWANGNINGRUM – Research Center for Plant Conservation and Botanic Gardens, Indonesian Institute of Sciences. Jl. Ir. H. Juanda No. 13, Bogor 16123, West Java, Indonesia

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Biodiversitas 21(3): 1116–1121 – https://doi.org/10.13057/biodiv/d210335

https://smujo.id/biodiv/article/view/4706

Abstract

In vitro micropropagation is an efficient biotechnological strategy for conservation and commercial plantlet production. The ultimate success of in vitro microporapagation depends on the ability to transfer plants out of culture, known as acclimatization stage.

The morphology, anatomy and physiology of plantlets in in vitro culture conditions is different from the plants in environment condition (greenhouse), therefore they are unable to compete with soil microbes and to cope with the environmental conditions.

The aim of this research is to determine stomata morphology and distribution of Paraphalaenopsis spp (Orchidaceae) from in vitro growth and greenhouse conditions. The leaf stomata cells of Paraphalaenopsis spp. (Paraphalaenopsis serpentilingua, Paraphalaenopsis labukensis and Paraphalaenopsis laycockii) was undertaken by observing the stomata preparation of the upper leaf and lower leaf by using microscope fitted with optic visual seven. The descriptive method was used to describe the stomata morphology by observing the epidermis of longitudinal section and stomata length of upper and lower leaf by using a microscope. The results showed that these plants had anomocytic type of stomata cells. The distributions of stomata are in the upper and lower epidermis leaf in all Paraphalaenopsis spp from in vitro growth and greenhouse.

Spatial pattern of stomata in Michelia

Spatial distribution characteristics of stomata at the areole level in Michelia cavaleriei var. platypetala (Magnoliaceae)

The spatial pattern of stomata is mainly caused by small-scale epidermal competition.

Shi P., Jiao Y., Diggle P. J., Turner R., Wang R., Niinemets Ü. (2021)

Annals of Botany –  https://doi.org/10.1093/aob/mcab106

https://www.botany.one/2021/11/spatial-arrangement-of-stomata-in-michelia/

In hierarchically reticulate venation patterns, smaller orders of veins form areoles in which stomata are located. Shi et al. aimed to quantify the spatial relationship among stomata at the areole level.

Previous studies have shown that stomatal density is negatively correlated with stomatal size, so that a lower stomatal density corresponds to a larger stomatal size. On average, the number of stomata within an areole is observed to be positively related to the areole size for many plant groups. Although prior studies have shown a negative correlation between the lamina surface area occupied by vascular bundle sheaths and stomatal density, the spatial relationship between stomata has not been extensively examined.

Positions of the sections sampled for analysis of stomatal distributions (left panel) and an image of a representative chemically cleared leaf showing the venation pattern (right panel) of the warm temperate evergreen tree M. cavaleriei var. platypetala. Source Shi et al. 2021.

For each of 12 leaves of Michelia cavaleriei var. platypetala, the scientists assumed that stomatal characteristics were symmetrical on either side of the midrib, and divided the leaf surface on one side of the midrib into six layers equidistantly spaced along the apical–basal axis. They then further divided each layer into three positions equidistantly spaced from midrib to leaf margin, resulting in a total of 18 sampling locations. In addition, for 60 leaves, they sampled three positions from midrib to margin within only the widest layer of the leaf. Stomatal density and mean nearest neighbour distance (MNND) were calculated for each section. A replicated spatial point pattern approach quantified stomatal spatial relationships at different distances (0–300 μm).

The botanists observed a tendency towards regular arrangement (inhibition as opposed to attraction or clustering) between stomatal centres at distances <100 μm. Spatial inhibition might be caused by the one-cell-spacing rule, resulting in more regular arrangement of stomata, and it was found to exist at distances up to ~100 μm. This work implies that leaf hydraulic architecture, consisting of both vascular and mesophyll properties, is sufficient to prevent important spatial variability in water supply at the areole level.

Oryza barthii can be used in traditional breeding programs in enhancing the stomatal size of elite rice cultivars

Stomatal diversity in Oryza “Sativa Complex”. Files of stomata are arranged in parallel on the surface along the length of the leaf. Some of the stomatal complexes are shown by red arrows. Scale bar is 50.0 μm. The images are captured from the abaxial epidermal layers after scraping of leaf tissues, under 40x magnification with 10x eyepiece of a BX51 light microscope (Olympus). The oval shapes are the marks of trichomes on the leaf. Difference in number and size in stomata is very prominent in the species. Note the larger stomata of O. glaberrima, O. barthii and smaller stomata of O. nivara and O. meridionalis as compared to Oryza sativa. Red lined boxes are the zoomed part of the leaves showing stomatal features

Natural Diversity in Stomatal Features of Cultivated and Wild Oryza Species

Chatterjee J., Thakur V., Nepomuceno R., Coe R. A., Dionora J., Elmido-Mabilangan A., Llave A. D., Delos Reyes A. m., Monroy A. N., Canicosa I., Bandyopadhyay, Jena K. K., Brar D. S., Quick W. P. (2020)

Jolly ChatterjeeVivek ThakurRobert NepomucenoRobert A. CoeJacqueline DionoraAbigail Elmido-MabilanganAbraham Darius LlaveAnna Mae Delos ReyesApollo Neil MonroyIrma CanicosaAnindya BandyopadhyayKshirod K. JenaDarshan S. BrarWilliam Paul Quick,

Rice 13: 58 – https://doi.org/10.1186/s12284-020-00417-0

https://thericejournal.springeropen.com/articles/10.1186/s12284-020-00417-0#citeas

Abstract

Background

Stomata in rice control a number of physiological processes by regulating gas and water exchange between the atmosphere and plant tissues. The impact of the structural diversity of these micropores on its conductance level is an important area to explore before introducing stomatal traits into any breeding program in order to increase photosynthesis and crop yield. Therefore, an intensive measurement of structural components of stomatal complex (SC) of twenty three Oryza species spanning the primary, secondary and tertiary gene pools of rice has been conducted.

Results

Extensive diversity was found in stomatal number and size in different Oryza species and Oryza complexes. Interestingly, the dynamics of stomatal traits in Oryza family varies differently within different Oryza genetic complexes. Example, the Sativa complex exhibits the greatest diversity in stomatal number, while the Officinalis complex is more diverse for its stomatal size. Combining the structural information with the Oryza phylogeny revealed that speciation has tended towards increasing stomatal density rather than stomatal size in rice family. Thus, the most recent species (i.e. the domesticated rice) eventually has developed smaller yet numerous stomata. Along with this, speciation has also resulted in a steady increase in stomatal conductance (anatomical, gmax) in different Oryza species. These two results unambiguously prove that increasing stomatal number (which results in stomatal size reduction) has increased the stomatal conductance in rice. Correlations of structural traits with the anatomical conductance, leaf carbon isotope discrimination (∆13C) and major leaf morphological and anatomical traits provide strong supports to untangle the ever mysterious dependencies of these traits in rice. The result displayed an expected negative correlation in the number and size of stomata; and positive correlations among the stomatal length, width and area with guard cell length, width on both abaxial and adaxial leaf surfaces. In addition, gmax is found to be positively correlated with stomatal number and guard cell length. The ∆13C values of rice species showed a positive correlation with stomatal number, which suggest an increased water loss with increased stomatal number. Interestingly, in contrast, the ∆13C consistently shows a negative relationship with stomatal and guard cell size, which suggests that the water loss is less when the stomata are larger. Therefore, we hypothesize that increasing stomatal size, instead of numbers, is a better approach for breeding programs in order to minimize the water loss through stomata in rice.

Conclusion

Current paper generates useful data on stomatal profile of wild rice that is hitherto unknown for the rice science community. It has been proved here that the speciation has resulted in an increased stomatal number accompanied by size reduction during Oryza’s evolutionary course; this has resulted in an increased gmax but reduced water use efficiency. Although may not be the sole driver of water use efficiency in rice, our data suggests that stomata are a potential target for modifying the currently low water use efficiency in domesticated rice. It is proposed that Oryza barthii can be used in traditional breeding programs in enhancing the stomatal size of elite rice cultivars.

Stomata in Vanilla

Stomatal characterization of five species of the genus Vanilla – Caracterización estomática de cinco especies del género Vanilla

Reyes-López D., Quiroz-Valentín J., Kelso-Bucio H. A., Huerta-Lara M., Avendaño-Arrazate C. H., Lobato-Ortiz R. (2015)

Delfino Reyes-López 2, Jonathan Quiroz-Valentín 2, Henry Arturo Kelso-Bucio 3, Manuel Huerta-Lara 4, Carlos Hugo Avendaño-Arrazate 5, Ricardo Lobato-Ortiz 6,

2 Benemérita Universidad Autónoma de Puebla, Facultad de Ingeniería Agrohidráulica. Dom. Con. San Juan Acateno, Teziutlán Puebla, México. 

3 Productos Agropecuarios KEBU, S.A. San Félix, Chiriquí, Panamá. 

4 Benemérita Universidad Autónoma de Puebla, Instituto de Ciencias, Departamento Universitario para el Desarrollo Sustentable. 

5 Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias (INIFAP) – Campo Experimental Rosario Izapa. 

6 Colegio de Postgraduados, Posgrado en Recursos Genéticos y Productividad – Genética. Campus Montecillo.Km.36.5 carr. México-Texcoco.56230, Motecillo, Texcoco, Edo. México

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Agron. Mesoam. 26(2): 237-246 – ISSN 2215-3608 – http://dx.doi.org/10.15517/am.v26i2.19279

https://revistas.ucr.ac.cr/index.php/agromeso/article/view/19279/19418

ABSTRACT

The objective was to characterize the stomata of five species of vanilla. Throughout 2012, leaf samples of V. planifolia G. JacksonV. pompona SchiedeV. indora SchiedeV. insignis Ames and V. odorota Presl were taken from the vanilla germplasm bank at the Benemérita Universidad Autónoma de Puebla.

The stomata size was obtained considering their length and width, as well as the index and stomata number of the abaxial and adaxial leaf surfaces in a randomized complete block design with three replications. V. pompona Schiede and V. inodora Schiede showed the highest stomatal index with 8713 and 8246 stomata per mm2, respectively, followed by V. odorata Presl with 4412 stomata per mm2V. insignis Ames and V. planifolia G. Jackson showed the lowest stomata index with 2968 and 1378 stomata per mm2, respectively, in the abaxial leaf surface, these differences were statistically significant (P≤0.05).

According to the position of the leaf stomata, V. planifolia G. Jackson and V. inodora Schiede can be considered to be hypostomatics since they showed stomata only in the abaxial leaf surface. V. insignis AmesV. inodora Schiede and V. odorata Presl. can be considered to be anfiestomatic because they showed stomata in both the abaxial and adaxial leaf surfaces. V. inodora Schiede had smaller stomata compared with the other species.That is an important feature to be included in the genetic improvement of the genus Vanilla, because due to climate change, temperature will increase and precipitation will decrease, so Vainilla will require more efficient genotypes for water use.

RESUMEN

Caracterización estomática de cinco especies del género Vanilla. El objetivo de este estudio fue caracterizar los estomas de cinco especies de vainilla. Durante el año 2012 se tomaron muestras de hoja de Vanilla planifolia G. Jackson, V. pompona Schiede, V. inodora Schiede, V. insignis Ames y V. odorata Presl, del banco de germoplasma de vainilla de la Benemérita Universidad Autónoma de Puebla. Se obtuvo el tamaño de estomas al considerar el largo y ancho de estos, índice y número estomático de la parte abaxial y adaxial de la hoja, en un diseño de bloques completos al azar con tres repeticiones. V. pompona Schiede V. inodora Schiede presentaron mayor índice estomático con 8713 y 8246 estomas por mm2, respectivamente, seguido por V. odorata Presl con 4412 estomas por mm2V. insignis Ames y V. planifolia G. Jackson tuvieron el menor índice estomático con 2968 y 1378 estomas por mm2, respectivamente, en la superficie abaxial de la hoja, diferencias que fueron estadísticamente significativas (p≤ 0,05). Por la posición de los estomas en la hoja, V. planifolia G. Jackson y V. pompona Schiede se pueden considerar hipoestomáticas por presentar estomas solamente en la parte abaxial de la hoja. V. insignis AmesV. inodora Schiede V. odorata Presl se pueden considerar anfiestomáticas por presentar estomas en la parte abaxial y adaxial de la hoja. V. inodora Schiede presentó estomas más pequeños en comparación con las demás especies, característica importante para ser integrada en el mejoramiento genético del género Vanilla, al considerar el cambio climático, donde el aumento de temperatura y disminución de la precipitación requieren de genotipos con mayor eficiencia en el uso de agua.

Stomata in Holcoglossum (Orchidaceae)

Figure 1. Characteristics of the epidermal cells (LM). A–B. Holcoglossum amesianum. A, adaxial, tetracytic; B, abaxial, brachyparacytic and laterocytic 1+2. C–D. H. subulifolium. C, adaxial, tetracytic and brachyparacytic; D, abaxial, tetracytic. E–F. H. kimballianum. E, adaxial, tetracytic; F, abaxial, tetracytic. G–H. H. wangii. G, adaxial, tetracytic; H, abaxial, tetracytic. I. Papilionanthe biswasiana, brachyparacytic and laterocytic 1+2. B–I have the same scale bars as in A.

Systematic significance of leaf epidermal features in Holcoglossum (Orchidaceae)

Fan J., He R., Zhang Y., Jin X. (2014)

Jie Fan 1Runli He 1Yinbo Zhang 2Xiaohua Jin 3,

  • 1 College of Chinese Medicine, Shanxi University of Traditional Chinese Medicine, Taiyuan, China.
  • 2 College of Environmental Science and Resources, Shanxi University, Taiyuan, China.
  • 3 State Key Laboratory of Systematics and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Figure 2. Characteristics of the epidermal cells (LM). A–B. Ascocentrum ampullaceum. A, adaxial; B, abaxial, polarcytic 6 (2+2) and polarcytic 5 (1+2). C–D. Vanda pumila. C, adaxial; D, abaxial, brachyparacytic and polarcytic 6 (2+2). E–F. Holcoglossum flavescens. E, adaxial, tetracytic, polarcytic 5(1+2) and polarcytic 6 (2+2); F,abaxial, polarcytic 5 (1+2) and laterocytic 3+4. G–H. H. sinicum. G, adaxial, paracytic and laterocytic 1+2; H, abaxial, polarcytic 5 (1+2) and polarcytic 5 (1+2). I. H. rupestre, adaxial, polarcytic 5 (1+2). Scales are the same as in Fig 2.

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PLoS One 9(7): e101557 – doi: 10.1371/journal.pone.0101557 – eCollection 2014 –

https://pubmed.ncbi.nlm.nih.gov/24983996/

Figure 5. Characteristics of the epidermal cells (SEM). Adaxial on the left, abaxial on the right. A–B. Holcoglossum amesianum; C–D. H. subulifolium; E–F. H. wangii. A–D, F have the same scale bars as in E.

Abstract

Determining the generic delimitations within Aeridinae has been a significant issue in the taxonomy of Orchidaceae, and Holcoglossum is a typical case.

We investigated the phylogenetic utility of the morphological traits of leaf epidermis in the taxonomy of Holcoglossum s.l. by using light and scanning electron microscopy to analyze 38 samples representing 12 species of Holcoglossum, with five species from five closely related genera, such as Ascocentrum, Luisia, Papilionanthe, Rhynchostylis and Vanda.

Our results indicated that Holcoglossum can be distinguished from the related genera based on cuticular wax characteristics, and the inclusion of Holcoglossum himalaicum in Holcoglossum is supported by the epidermis characteristics found by LM and SEM.

The percentage of the tetracytic, brachyparacytic, and laterocytic stomata types as well as the stomata index and certain combinations of special wax types support infrageneric clades and phylogenetic relationships that have been inferred from molecular data.

Laterocytic and polarcytic stomata are perhaps ecological adaptations to the strong winds and ample rains in the alpine region of the Hengduanshan Mountains.

The number of stomata and microhairs of Paspalum vaginatum in relation to abiotic conditions in a breakwater

Variation in the number of stomata and microhairs of Paspalum vaginatum Sw: in relation to abiotic conditions in a breakwater in the Lagoa dos Patos estuary, RS-Brazil – (Variação do número de estômatos e micropêlos em Paspalum vaginatum Sw: em relação às condições abióticas numa marisma do estuário da Lagoa dos Patos, RS-Brasil)

Bastos E. de O., Perazzolo M., Baptista J. M. R. (1992)

Eleci de Oliveria Bastos, Mara Perazzolo, Jusseli Maria Rocha Baptista,

I Bolsista de Iniciação Científica FAPERGS (proc. 1848). Av. dos Arquipélagos, 39 96215-000 – Rio Grande – RS

II Depto de Ciências Morfo-Biológicas – URG – CP.474, 96500-900 – Rio Grande – RS

III Depto de Química (Lab. Hidroquímica) – URG – CP.474, 96500-900 – Rio Grande – RS

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Acta Bot. Bras. 6 (2) – https://doi.org/10.1590/S0102-33061992000200007 –

https://www.scielo.br/j/abb/a/tj9p65jG9cGsy73LHq5sr5N/?lang=pt

Paspalum vaginatum Sw., a perennial, stoloniferous grass with small leaves presenting stomata on both epidermises is characteristic of salt marshes, growing under stressful conditions near the west breakwater of the Rio Grande outlet, Lagoa dos Patos, Rio Grande do Sul, Brazil. Monthly counts of stomata and microhairs on the adaxial and abaxial surfaces were related to the abiotic characteristics of the enviroment. The number of microhairs of the abaxial leaf surface varied significantly and directly with interstitial water temperature close to the rhyzosphere. However, these counts did not correlate with the interstitial salinity. The results suggest that the species is a facultative halophyte. Stomata counts of the abaxial surface showed an inverse relation to precipitation. Paspalum vaginatum appears to be a species with xeromorphic characteristics.

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Resumos

Paspalum vaginatum Sw., gramínea perene, estolonífera, com folhas anfistomáticas e pequenas é característica de pântanos salgados, crescendo em condições estressantes na marisma da lagoa dos Patos, molhe oeste da Barra do Rio Grande, RS. Foram feitas contagens mensais de estômatos e micropêlos nas superfícies adaxial e abaxial das lâminas e relacionadas às características abióticas do ambiente. O número de micropêlos da superfície foliar abaxial variou significativamente e diretamente com a temperatura da água intersticial junto às rizosferas. Estes, porém, não mantiveram correlação com a salinidade intersticial. Os resultados sugerem que a espécie seja uma halófita facultativa. O número de estômatos da superfície abaxial manteve um relacionamento inverso com a pluviosidade. Paspalum vaginatum, apresenta-se como uma espécie com características xeromórficas.

The three genera can be distinguished from epidermal cell shape, stomata complex and the presence of stomata

Leaf Surface Comparison of Three Genera of Araceae in Indonesia

Erlinawati E. F. T. (2013)

Ina Erlinawati Eka Fatmawati Tihurua,

Buletin Kebun Raya – DOI: 10.14203/bkr.v16i2.36https://www.neliti.com/id/publications/54404/leaf-surface-comparison-of-three-genera-of-araceae-in-indonesia

Abstrak

Alocasia, Colocasia and Remusatia are the genera of Araceae family which have high economic value, such as for food and ornamental plants. Those three genera, previously treated as Colocasieae tribe. Later, based on Nauheimer, L. et al. study in 2012, using plastid and nuclear DNA, Alocasia is placed in different tribe.

Study on leaf anatomy of Araceae is still poor known. Comparison of three genera of Araceae, indicates a difference in the epidermis. Alocasia and Colocasia have stomata on both leaf surfaces (amphistomatic) but Remusatia has stomata only limited on the lower surface. The three genera can be distinguished from epidermal cell shape, stomata complex and the presence of stomata.

Collection “Anatomy of the pineapple” – Early stages of stomata

“Page 57 – Early stages of stomata and trichome formation,” – Fig. 50

Krauss B. H. (1940)

Krauss Beatrice H.,

UHM Library Digital Image Collections, accessed February 20, 2022 – 

https://digital.library.manoa.hawaii.edu/items/show/29816

https://digital.library.manoa.hawaii.edu/items/show/29816#?c=0&m=0&s=0&cv=0&xywh=-131%2C-1%2C2808%2C3296

Description

Fig. 50 . Early stages of stomata and trichome formation. Abaxial epidermis of the basal region of a tetraploid seedling leaf, A, and of a young, i.e., prechlorophyllaceous, leaf from the center of the leafy terminus of the stem (i.e., the so-called “crown” or “top”), B and C, to show the development of the stomata and trichomes. (Arrows indicate the direction of the main axis of the leaf), fu, furrow; lac, lateral accessory cell of etoma; mgc, mother cell from which stoma guard cells are formed; pac, polar accessory cell of stoma; ri, ridge; tac, trichome accessory cell; mtc, initial, or mother, cell of trichome; wc, wedge-shaped cell in lateral position to stoma mother cell — the presence of these wedge-shaped cells in the epidermis facilitates the location of the stomata at this early stage of development. (The cells forming the stoma and trichome structures are more heavily outlined to show their location). A, X340; B and C, X400.