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Leaf Structure Diagram4/23/2021
They help plants in a variety of ways, including producing food and oxygen through photosynthesis, balancing water loss, regulating gas exchange, and transporting the products of photosynthesis.A leaf has two main parts: (1) Petiole- the stalk that supports a leaf in a plant and attaches the leaf blade to the stem.
![]() The lamina contains the following parts: (i) Veins- the lines on the green flat part in a leaf that provide support for the leaf and transport both water and food. Midrib- The central, thick, linear vein that runs along the length of a leaf is called midrib. Prev Question Next Question Practice important Questions NCERT Solution for Class 6 Science Chapter 7 75 Qs Related Questions to study Which of the following part of the plant performs photosynthesis View Answer Plants take in air through tiny openings called. View Answer Match the column I with column II and select correct option. Column-I Column-II (a) Pedicel i Reduced leaf (b) Peduncle ii Stalk of the flower (c) Bract iii Stalk of the leaf (d) Petiole iv Inflorescence axis View Answer What is epidermis What is the role of epidermis (i) Aquatic plants (ii) In desert plants (iii) In terrestrial plants View Answer What is hydathode View Answer Which part of the leaf is useful for exchanging gases between the plant and the atmosphere View Answer Which one of these is not a part of a leaf View Answer View Answer View Answer VIEW MORE Revise with Concepts Basics of Leaf Example Definitions Formulaes Quick summary with Stories Leaf venation 2 mins read Parts of a leaf 2 mins read. Leaf Structure Diagram Series From BudIn temperate trees leaves are simply protective bud scales; in the spring when shoot growth is resumed, they often exhibit a complete growth series from bud scales to fully developed leaves. As the primary sites of photosynthesis, leaves manufacture food for plants, which in turn ultimately nourish and sustain all land animals. They are attached by a continuous vascular system to the rest of the plant so that free exchange of nutrients, water, and end products of photosynthesis (oxygen and carbohydrates in particular) can be carried to its various parts. Leaves are initiated in the apical bud (growing tip of a stem) along with the tissues of the stem itself. Certain organs that are superficially very different from the usual green leaf are formed in the same manner and are actually modified leaves; among these are the sharp spines of cacti, the needles of pines and other conifers, and the scales of an asparagus stalk or a lily bulb. See all videos for this article The main function of a leaf is to produce food for the plant by photosynthesis. Chlorophyll, the substance that gives plants their characteristic green colour, absorbs light energy. The internal structure of the leaf is protected by the leaf epidermis, which is continuous with the stem epidermis. The central leaf, or mesophyll, consists of soft-walled, unspecialized cells of the type known as parenchyma. As much as one-fifth of the mesophyll is composed of chlorophyll-containing chloroplasts, which absorb sunlight and, in conjunction with certain enzymes, use the radiant energy in decomposing water into its elements, hydrogen and oxygen. The oxygen liberated from green leaves replaces the oxygen removed from the atmosphere by plant and animal respiration and by combustion. The hydrogen obtained from water is combined with carbon dioxide in the enzymatic processes of photosynthesis to form the sugars that are the basis of both plant and animal life. Oxygen is passed into the atmosphere through stomata pores in the leaf surface. The process creates oxygen, which people and other animals breathe. Leaf morphology Typically, a leaf consists of a broad expanded blade (the lamina ), attached to the plant stem by a stalklike petiole. ![]() Leaves are, however, quite diverse in size, shape, and various other characteristics, including the nature of the blade margin and the type of venation (arrangement of veins ). When only a single blade is inserted directly on the petiole, the leaf is called simple. The margins of simple leaves may be entire and smooth or they may be lobed in various ways. The coarse teeth of dentate margins project at right angles, while those of serrate margins point toward the leaf apex. Leaf margins of simple leaves may be lobed in one of two patterns, pinnate or palmate. In pinnately lobed margins the leaf blade (lamina) is indented equally deep along each side of the midrib (as in the white oak, Quercus alba ), and in palmately lobed margins the lamina is indented along several major veins (as in the red maple, Acer rubrum ). Veins, which support the lamina and transport materials to and from the leaf tissues, radiate through the lamina from the petiole. The types of venation are characteristic of different kinds of plants: for example, dicotyledons such as poplars and lettuce have netlike venation and usually free vein endings; monocotyledons like lilies and bamboo have parallel venation and rarely free vein endings. Get exclusive access to content from our 1768 First Edition with your subscription.
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