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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.
Septoria lycopersici infects the tomato leaves via the stomata and also by direct penetration of epidermal cells. [3] Symptoms generally include circular or angular lesions most commonly found on the older, lower leaves of the plant. [1] The lesions are generally 2–5 mm in diameter and have a greyish center with brown margins.
X. vasicola pv. vasculorum enters maize leaves through the stomata and colonises the intercellular spaces. Visible symptoms are long thin lesions that run parallel to the leaf vein and have wavy or jagged margins. Lesions can be yellow, orange or brown and expand over time. When held up to the sun lesions appear translucent with a yellow halo.
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 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.
Although yellowing leaves might indicate that peace lilies are stressed by their environment, peace lily leaves naturally turn yellow as they age. This type of leaf yellowing typically occurs on ...
Also, moving from leaves to roots, e.g. of molecular signals in plants. bathyphyll A specialized leaf produced at the base of a plant, usually when the plant is immature, and which serves to anchor the plant to a substrate; especially notable in the fern Teratophyllum. Contrast acrophyll. beak
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 ...