question_answer 12)

Describe the internal structure of a dorsiventral leaf with the help of labelled diagrams?

Answer:

Internal Structure of a Dorsiventral (dicotyledonous leaf) (i) It shows three main parts namely epidermis, mesophyll and vascular system. (ii) The epidermis which covers both the upper surface (adaxial epidermis) and lower epidermis (abaxial surface) are covered with thick layer of cuticle. (iii) The tissue between the upper and lower epidermis is known as mesophyll. This tissue possess chloroplasts -and carryout photosynthesis, is made up of parenchyma. (iv) The parenchyma has two types of cells, i.e., palisade parenchyma and spongy parenchyma. (v) There are large number of air cavities In between these cells. (vi) In the midrib region and in veins vascular bundles made up of xylem and phloem are present. (vii) The size of the vascular bundles are dependent on the size of veins. The veins vary in thickness in the reticulate venation of dicot leaves. (viii) The vascular bundles are surrounded by bundle sheath cells.