Chapter 22, Problem 24A

Summary Introduction

To write:Some leaf modifications in terms of their functions.

Introduction:Most plants have light absorbing structures, and others that take in water and nutrients. In plants, the main function of two types of vascular tissue-xylem and phloem is the transport of food, water and other dissolved substances.Leaves have many forms and colors and their arrangements on plants are different for different species.

Explanation of Solution

The main function of the leaves is photosynthesis, and for this function, their structure is well adapted. Many other leaves have a flattened portion called blade with a relatively large area of surface. The blade might be attached to the stem by a stalk called a petiole, depending on the plant species. The vascular tissue of the petiole connects the vascular tissue of the stem to the vascular tissue of the leaf or veins. The upper leaf epidermis contains numerous chloroplasts and makes up the tissue known as palisade mesophyll. Underneath the palisade mesophyll is the spongy mesophyll, composed of irregularly shaped, loosely packed cells with areas surrounding the cell. In spongy mesophyll, oxygen, carbon dioxide, and water vapor transfer through the areas.

Conclusion

Changes to the leaves which aid them in photosynthesis. Spongy mesophyll cells possess chloroplasts, but have less per cell than mesophyll in the palisade mesophyll.