Transmission Tissue in Different Types of Stigma and Style

Introduction:
Transmission tissue is a specialized tissue that is responsible for the transfer of pollen grains from the stigma to the ovary. The structure and arrangement of transmission tissue vary in different types of stigma and style. In this article, we will discuss the characteristics of transmission tissue in different types of stigma and style.

Dry Stigma:
Dry stigma is the one that is not receptive to pollen grains. The transmission tissue in dry stigma is present in the form of papillae. Papillae are small projections that are arranged in a random manner on the surface of the stigma. They are covered with a cuticle that prevents the loss of moisture. The papillae in dry stigma do not have any intercellular spaces and are closely packed together. This arrangement of papillae does not allow the pollen tube to grow through them. Hence, the pollen grains are not able to reach the ovary and fertilization does not occur.

Wet Stigma:
Wet stigma is the one that is receptive to pollen grains. The transmission tissue in wet stigma is present in the form of a secretory zone. The secretory zone is made up of a single layer of cells that are rich in protein and other nutrients. The cells are loosely arranged, and there are intercellular spaces between them. The pollen grains germinate on the surface of the stigma and grow through the intercellular spaces. The nutrients secreted by the cells of the secretory zone nourish the growing pollen tube, which ultimately reaches the ovary and fertilizes the ovules.

Hollow Style:
A hollow style is the one in which the transmission tissue is present in the form of a central canal. The canal is lined with a single layer of cells that secrete nutrients for the growing pollen tube. The pollen tube grows through the central canal and reaches the ovary. The central canal provides a protected pathway for the pollen tube and prevents it from getting damaged.

Solid Style:
A solid style is the one in which the transmission tissue is present in the form of a solid mass of cells. The cells are densely packed, and there are no intercellular spaces between them. The pollen tube grows through the cells of the solid style and reaches the ovary. The solid style provides mechanical support to the stigma and prevents it from breaking under the weight of the pollen grains.

Conclusion:
In conclusion, the structure and arrangement of transmission tissue vary in different types of stigma and style. The presence or absence of intercellular spaces, the arrangement of cells and the type of secretion produced by the cells are the factors that determine the functionality of transmission tissue. The knowledge of transmission tissue is essential for understanding the process of pollination and fertilization in plants.