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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.
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 ...
Stomatal conductance, usually measured in mmol m −2 s −1 by a porometer, estimates the rate of gas exchange (i.e., carbon dioxide uptake) and transpiration (i.e., water loss as water vapor) through the leaf stomata as determined by the degree of stomatal aperture (and therefore the physical resistances to the movement of gases between the air and the interior of the leaf).
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 ...
The thin bark often peels with scale-like plates. [8] The leaves are simple and flat. The phyllotaxis or leaf arrangement is usually spiral but may be opposite on young plants. [8] The leaves are generally lanceolate in shape and coriaceous in texture. They have a single visible midrib. Stomata are found on both surfaces of the leaf. [8] [6]
At the tip of the leaf sits a terminal leaflet which can vary in shape from the rest. [2] [4] Like other bennettitaleans, the leaf's cuticle was syndetocheilic (with guard and subsidiary cells of the stomata having the same mother cells) and hypostomatic (with stomata located entirely underneath the leaf). [5]
Leaf expansion is a process by which plants make efficient use of the space around them by causing their leaves to enlarge, or wither. This process enables a plant to maximize its own biomass, whether it be due to increased surface area; which enables more sunlight to be absorbed by chloroplasts, driving the rate of photosynthesis upward, or it enables more stomata to be created on the leaf ...
More leaves (or spines, or other photosynthesizing organs) means a bigger surface area and more stomata for gaseous exchange. This will result in greater water loss. Number of stomata: More stomata will provide more pores for transpiration. Size of the leaf: A leaf with a bigger surface area will transpire faster than a leaf with a smaller ...