Question
Describe the structure of mature angiospermic pollen grain. Mention one difference between the pollen of dicot and monocot.
✓
Answer
Pollen grains or microspores are generally spherical in outline. The wall of pollen grain is called sporoderm, which is made up of two layers-An outer thick exine and an inner thin intine.
The exine is made up of sporopollenin which is biologically the most resistant substance and can withstand high temperature and strong acids and alkali. At one or more places, the exine is very thin or absent. These regions are called germ pores.
Intine is continuous layer made up of cellulose and pectin. A mature pollen grain has two cells-a vegetative cell and a generative cell. The vegetative cell is bigger and has food reserve and a large irregular nucleus. The generative cell is small, spindle shaped and floats in the cytoplasm of vegetative cell. In dicots, pollen grains are with three germ pores, while in monocots, they are with single germinal furrow.
The exine is made up of sporopollenin which is biologically the most resistant substance and can withstand high temperature and strong acids and alkali. At one or more places, the exine is very thin or absent. These regions are called germ pores.
Intine is continuous layer made up of cellulose and pectin. A mature pollen grain has two cells-a vegetative cell and a generative cell. The vegetative cell is bigger and has food reserve and a large irregular nucleus. The generative cell is small, spindle shaped and floats in the cytoplasm of vegetative cell. In dicots, pollen grains are with three germ pores, while in monocots, they are with single germinal furrow.
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