A Leaf презентация

A Leaf

A leaf The leaf is one of the important part of the plants because it is the one which is in charge of accomplishing the photosynthesis, the respiration and transpiration. A leaf growing laterally from a stem or branch, or growing from its root. It is usually green and consists of a blade, footstalk and stipules.

STRUCTURE OF LEAF Structure of a leaf: chlorophyll containing outgrowth of a stem or branch; the site of photosynthesis. Blade (lamina): main part of the leaf. Vein: line dividing, but not completely, the leaf into sections. Midrib: line dividing the leaf in two. Leafstalk (petiole): part of the leaf that is attached to the stem. Stem: part of the plant that carries the leaves. Sheath: part of the leaf that attaches the petiole to the stem. Stipules: small appendage at the base of the petiole.

Leaf margins Leaf margins: main part of the leaf, usually large and flat. Undulate: having a wavy margin. Sinuate: with a sinous margin. Serrate: having a sharp edge. Dentate: having a toothed margin. Lobate: lobed. Scalloped: with a scalloped margin. Palmate: like the fingers of a hand spread open. Digitate: finger like. Bipinnatisect: with 2 levels of petioles which segments are sessile. Tripinnatisect: with 3 levels of petioles which segments are sessile. Pinnatisect: with similar parts on each side of the central axis and sessile. Palmatisect: with palmate veins and lobes split to the base of the blade. Pedate: palmately divided which lateral segments also divided. Palmatilobate: palmate leaf with rounded lobes. Bipartite: divided into two parts. Tripartite: divided into three parts. Palmatipartite: divided almost to the leaf margin. Pinnatifid: with pinnated divisions.

Leaf shapes Leaf shapes: main part of the leaf, usually alrge and flat. Falcate: curved like a sickle. Orbicular: circular. Cochleate: shaped like a shell. Subulate: ending in a point. Cuneate: wedge-shaped. Linear: long and narrow. Sagittate: shaped like an arrowhead. Hastate: halberd-shaped. Panduriform: violin-shaped. Lacerate and auriculate: leaf that seems to have been torn,and which is equipped with auricles Lobate: divided into lobes. Flabellate: fan-shaped. Asymmetrical: completely unsymmetrical. Acuminate: leaf that tapers into a long point. Mucronate: leaf with an extended central vein. Emarginate: notched at the end. Ovoid: egg-shaped. Obovate: resembling an upside-down egg. Cordiform: heart-shaped. Oblong: elongated shape. Spatulate: shaped like a spatula. Oval: elliptical. Lanceolate: shaped like the head of a lance. Acicular: needle-shaped.