Question

What are different parts of a leaf, answer the following, 4th class​

Answer 1

Answer:

Tha two different parts of leaf are:

1) The blade

2) The petiole

Answer 2

Explanation:

Most leaves have two main parts: (1) the blade and (2) the petiole, or leafstalk. The leaves of some kinds of plants also have a third part, called the stipules.

the parts of a leaf

The Blade, or lamina, is the broad, flat part of the leaf. Photosynthesis occurs in the blade, which has many green food-making cells. Leaf blades differ from one another in several ways: (1) the types of edges, (2) the patterns of the veins, and (3) the number of blades per leaf.

The Types of Edges. Almost all narrow, grasslike leaves and needles leaves have a blade with a smooth edge, as do many broadleaf plants, particularly those that are native to warm climates. The rubber plant, a common house plant, is a good example of such a plant.

The leaves of many temperate broadleaf plants have small, jagged points called teeth along the blade edge. Birch and elm trees have such leaves. Some plants have hydathodes, tiny valvelike structures that can release excess water from the leaf. The teeth of young leaves on many plants, including cottonwood and pin cherry trees, bear tiny glads. These glands produce liquids that protect the young leaf from plant-eating insects.

Some temperate broadleaf plants -- including sassafras trees and certain mulberry and oak trees -- have lobed leaves. The edge of such a leaf looks as if large bites have been taken out of it. This lobing helps heat escape from the leaf.

types of leaf edges

The Patterns of the Veins. Veins carry food and water in a leaf. They also support the blade, much as the metal ribs support the fabric of an open umbrella.

In most broad leaves, the veins form a netlike pattern, with several large veins connected by smaller ones. The smallest veins supply every part of the blade with water. They also collect the food made by the green cells.

There are two main types of net-vein patterns -- pinnate (featherlike) and palmate (palmlike or handlike). Pinnately veined leaves have one large central vein, called the midrib, which extends from the base of the blade to its tip. Other large veins branch off on each side of the midrib. The leaves of beech, birch, and elm trees have such a vein pattern. A palmately veined leaf has several main veins of about equal size, all of which extend from a common point at the base of the blade. The vein patterns of maple, sweet gum, and sycamore leaves are palmate.

Narrow leaves and needle leaves are not net-veined. Narrow leaves have a parallel-vein pattern. Several large veins run alongside one another from the base of the blade to the tip. Small crossveins connect the large veins. Needle leaves are so small that they have only one or two veins running through the center of the blade.

different vein patterns