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Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata. Light is the main trigger for the opening or closing. [citation needed] Each guard cell has a relatively thick and thinner cuticle [clarification needed] on the pore-side and a thin one opposite it. As water enters ...
Stoma in a tomato leaf shown via colorized scanning electron microscope image A stoma in horizontal cross section The underside of a leaf. In this species (Tradescantia zebrina) the guard cells of the stomata are green because they contain chlorophyll while the epidermal cells are chlorophyll-free and contain red pigments.
Diagram showing the position of the stoma after a laryngectomy. Date: 30 July 2014 (released by CRUK) Source: Original email from CRUK: Author: Cancer Research UK: Permission (Reusing this file) This image has been released as part of an open knowledge project by Cancer Research UK. If re-used, attribute to Cancer Research UK / Wikimedia Commons
English: The fine scale structure of a leaf featuring the major tissues; the upper and lower epithelia (and associated cuticles), the palisade and spongy mesophyll and the guard cells of the stoma. Vascular tissue (veins) is not shown. Key plant cell organelles (the cell wall, nucleus, chloroplasts, vacuole and cytoplasm) are also shown.
1-Epidermal cell 2-Guard cell 3-Stoma 4-K+ ions 5-Water 6-Vacuole a. Open stoma: stomata are the small pores in the epidermis of leaves. They are bordered by guard cells. The stomata open when the turgor pressure increases in the guard cells, causing the cells to buckle outward. This happens when water flows into the guard cells.
The leaf and stem epidermis is covered with pores called stomata (sing; stoma), part of a stoma complex consisting of a pore surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts. The stomata complex regulates the exchange of gases and water vapor between the outside air and the ...
These cells, along with the epidermal guard cells of the stoma, form a system of air spaces and chambers that regulate the exchange of gases. In some works, the cells of the leaf epidermis are regarded as specialised parenchymal cells, [ 4 ] but the modern preference has long been to classify the epidermis as plant dermal tissue , and ...
The first xylem to develop is called 'protoxylem'. In appearance, protoxylem is usually distinguished by narrower vessels formed of smaller cells. Some of these cells have walls that contain thickenings in the form of rings or helices. Functionally, protoxylem can extend: the cells can grow in size and develop while a stem or root is elongating.