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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.
A leaf (pl.: leaves) is a principal appendage of the stem of a vascular plant, [1] usually borne laterally above ground and specialized for photosynthesis.Leaves are collectively called foliage, as in "autumn foliage", [2] [3] while the leaves, stem, flower, and fruit collectively form the shoot system. [4]
The leaves of these mosses are green and generally erect and are shaped obovate or elliptic with unistratose leaf margins. They contort when dry and spread out when damp. They have brown rhizoids. Plagiomnium also have sterile stems (except for P. venustum). On the ventral side of the leaves are a costa and many lamellae.
The stomata complex regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Typically, the stomata are more numerous over the abaxial (lower) epidermis of the leaf than the (adaxial) upper epidermis. An exception is floating leaves where most or all stomata are on the upper surface.
Photosynthesis depends on the diffusion of carbon dioxide (CO 2) from the air through the stomata into the mesophyll tissues. Oxygen (O 2), produced as a byproduct of photosynthesis, exits the plant via the stomata. When the stomata are open, water is lost by evaporation and must be replaced via the transpiration stream, with water taken up by ...
The leaves ('needles') are, uniquely for a pine, usually single (not two or more in a fascicle, though trees with needles in pairs are found occasionally), stout, 4–6 cm (1 + 1 ⁄ 2 – 2 + 1 ⁄ 4 in) long, and grey-green to strongly glaucous blue-green, with stomata over the whole needle surface (and on both inner and outer surfaces of ...
The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets). [1] The edge of the leaf may be regular or irregular, and may be smooth or have hair, bristles, or ...
The twigs are yellow-gray to yellow-brown and shining. Vegetative buds are ovoid to conic, 10 x 6 mm or more on some primary branches. The leaves are two-ranked, dark green, and 15-48 x 2.5-3 mm. They are linear and flattened, twisted at the base and grooved above. Leaf stomata ore located in two wide bands on either side of the midvein.