Stomata in the Xerophytic Leaf of Larrea



Angiosperm Morphology: Stomata in the Xerophytic Leaf of Larrea

by Berkshire Community College Bioscience Image Library (2014)

Flickr –

The leaves of Larrea show numerous structural adaptations that extend their tolerance to drought and desiccation.

The epidermis consists of a single layer of small compact and heavily cutinized cells. Most epidermal cells contain dark staining deposits of waterproofing resins. Long epidermal hairs and stomata are present over the entire leaf surface. Stomata are roofed by epidermal cells with ledge like extension of cutin and overlay large substomatal chambers.

Two or three rows of tightly packed palisade mesophyll are present below the adaxial and abaxial epidermis. Spongy mesophyll is reduced to a narrow central band that supports the vascular bundles. In some preparations resins may be seen lining the stomatal cavities and coating the outsides of palisade cells. Idioblasts containing crystals of calcium oxalate are abundantly distributed through both mesophylls.

Small, centrally located vascular bundles span the breadth of the leaf. The bundles are collateral and closed with xylem of vessels and tracheids towards the adaxial(upper) surface and phloem of sieve tubes and companion cells towards the abaxial (bottom) surface. Cambium is not present.

Each vascular bundle is wrapped by a bundle sheath and supported towards adaxial and abaxial surfaces by small caps of supportive sclerenchyma. Abaxial caps are especially well developed.


Stomata of selected species



Stomata morphology: descriptions of selected species

by Riera S. (xxxx)

Santiago Riera


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Stomatal crypts



Stomatal crypts

Anonymous (x)

Fig. 10.3-10. Transverse section of oleander leaf (Nerium oleander). Oleander leaves are a favorite in plant anatomy laboratories because they demonstrate a placement of stomata that has ecological significance. The arrows indicate three stomatal crypts: the crypts are large chambers in the mesophyll, covered with an epidermis that contains stomata as well as trichomes (hairs) that project into the crypt. The epidermis on the exposed surface of the leaf – between crypts – lacks stomata. The narrow opening between the crypt and the atmosphere, combined with the presence of trichomes, causes the air inside the crypt to be rather immobile, even if there is a strong wind blowing over the leaf. Any water molecule that diffuses out of a stomatal pore will spend so much time that there is a high probability it will diffuse back into one of the stomata in the crypt. See following figures for higher magnifications


Abnormal stomata



On the occurrence of abnormal stomata in plants

by Parveen F., Kidwai N. (1979)

Department of Botany, The University, Allahabad, India


in Current Science 48(19): 841-849 –


A number of different types of unusual and abnormal stomata are described along with examples of taxa in which they have been reported.
As the abnormalities are more common in mature leaves it is suggested that they are due to an interaction of factors responsible for stomatal differentiation and leaf maturation and may belong to the last generation of meristemoids.


SEM Images of Stomata of Different Tomato Cultivars



Analysis of SEM Images of Stomata of Different Tomato Cultivars Based on Morphological Features

by Sanyal P., Bhattacharya U., Bandyopadhyay S. K. (2008)

Pritimoy Sanyal Ujjwal Bhattacharya Samir K. Bandyopadhyay

inModeling & Simulation, 2008. AICMS 08. Second Asia International Conference on

IEEE – DOI: 10.1109/AMS.2008.81 –


Tomato is one of the important cash crops in the world. There are several varieties of tomato cultivars. Their identifications as well as taxonomy had been studied in the literature using different laboratory methods. Both morphological and/or genetical characteristics were considered in these available studies. However, to the best of our knowledge, there does not exist any study employing an image analysis based approach.
Also, morphological features of stomata of tomato cultivars had not been studied before for the present purpose.
In this article, we report results of our recent study of morphological features of stomata of different tomato cultivars based on their Scanning Electron Microscopy (SEM) images. Interestingly, these results of the present study are supported by the protein binding pattern of the seeds of respective cultivars.

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A scanning electron microscope study of guard cells

by Dayanandan P., Kaufman P. B. (1973)

P . Dayanandan, P . B. Kaufman,
Department of Botany, University of Michigan, Ann Arbor, MI. 48104



in “3lst Ann. Proc. Electron Microscopy Soc. Amer.” New Orleans, La., t973. C. J. Arce-nbaux (ed.). –


A three dimensional appreciation of the guard ce11 morphology coupled with ultrastructural studies should lead to a better understanding of their still obscure dynamics of movement. We have found the SEM of great value not only in studies of the surface details of stomata but also in resolving the structures and relationships that exist between the guard and subsidiary cells. We now report the isolation and SEM studies of guard cells from nine genera of plants.

Guard cells were isolated from the following plants: Psilotum nudum, four species of Equisetum, Cycas revoluta, Ceratozamia sp., Pinus sylvestris, Ephedra cochuma, Welwitschia mirabilis, Euphorbia tirucalli and Allium cepa.




Stomata and Types of Stomata

Bhatia S. C. (2017)

Lesson Prepared Under MHRD project “National Mission on Education Through ICT”

Discipline: Botany

Paper: Plant Anatomy

National Coordinator: Prof. S.C. Bhatla

Lesson: Trichomes and Stomata

Lesson Developer: Dr Smriti Singh

Department/College: Acharya Narender Dev College

Lesson Reviewer: Prof.S.C.Bhatla

Department/College: Botany, University of Delhi

Language Editor: Dr Sonal Bhatnagar

Department/College: Hindu College

Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL


in Trichomes and Stomata – Virtual Learning Environment – University of Delhi, India –

It is an opening/ pore/ intercellular space in the epidermis, through which gaseous exchange takes place in plants. It is surrounded by two specific cells known as guard cells. Stomatal pores together with guard cells are known as stoma. Generally guard cells are bean or crescent shaped in dicots which have dorsiventral or bifacial leaves, and dumbell shaped in monocots which have isobilateral or unifacial leaves. Further, these guard cells are surrounded by various number of cells known as subsidiary cells. This epidermal intercellular space or pore together with guard cells and subsidiary cells is known as stomatal complex (stoma + subsidiary cells). Below the stomata there is intercellular space in mesophyll cells known as stomatal chamber. Stomata are found on young stem, leaves, flower, and fruit. Exceptionally they are also found on roots of Pea (Pisum arvense) and Ceratonia siliqua. Stomata which are found on non-foliar part (flower, fruit, seed) are non functional. Distribution of stomata on leaf surfaces varies from species to species. They may be found on both the surfaces of leaves (adaxial and abaxial) or may be restricted to only one surface. When stomata are found only on upper surface, the leaf is called epistomatic and when found exclusively on lower or abaxial surface, the leaf is called hypostomatic. Frequency of stomata differs from species to species eg 402 in Quercus calliprinos, 1198 in Qlyrata, 176 in Pistacia palaestina and 255 in P. lentiscus. It is found that with decreasing light intensity stomatal frequency decreases. Stomata are often not found on solid masses of cells where there are no intercellular spaces like sclerenchyma of leaf margins and fibre bundles of veins, as these tissues don’t provide space for diffusion of gases. There is an unusual distribution of stomata in some plants like in Saxifraga, they are present only near the leaf tip; in Daphne petraea there is a longitudinal band of stomata on both sides of midrib. A very unusual distribution is found in Mimosa cruenta, where on upper surface there is uniform distribution of stomata, however on the lower surface only one of the longitudinal halves bear stomata and the other half completely lacks them.

Non-green total parasitic (holoparasite) plants lack stomata e.g. Rafflesia (a total root parasite) and Neottia and members of family Balanophoraceae and Monotropaceae. These holoparasites lack cholorophyll, thus they are completely dependant on their host for food. Orobanchae, a achlorophyllous holoparasite possess only few stomata on the stem. Semi parasites like mistletoes (Loranthaceae) depend on host for water synthesizes their food and minerals only, have stomata but lesser in number.

Position of stomata is also governed by climatic conditions. In xerophytic conditions stomata are sunken (at lower level than other epidermal cells) to reduce the water loss. They may be found in cavities, stomatal crypts (Nerium oleander), or in grooves (Ericales) lined with epidermal hair. In some hydrophytes like Nymphaea and Nelumbo with floating leaves, stomata are found only on upper surface. However, there are no stomata in some submerged hydrophytes belonging to families Ceratophyllaceae, Nymphaeaceae, Podostemonaceae and some Ranunculaceae member. Stomata bars are found in Eucalyptus, these are protuberances of cuticle over the guard cells. Guard cells may differ from other epidermal cells in their origin and morphology but chemically they are similar to other epidermal cells. They are rich in mitochondria, endoplasmic reticulum, dictyosomes and vacuoles and fewer grana in plastids but are sufficient for the sustenance of guard cells. There is no plastid in Paphiapedilum an orchid.


Types of stomata

Depending upon the number and arrangement of subsidiary cells around the guard cells stomatal complex has been classified into following types (Tomlinson, 1961, 1974; Metcalfe and Chalk, 1979;). A species can have more than one of the following stomatal complex types, even a single leaf can have more than one type.

  1. Paracytic type– One or more subsidiary cells are arranged parallel to the guard cells. e.g.  Convolvulaceae, Leguminoseae,