Water is forcefully pushed beyond endodermis of the root through the process of

The correct option/answer is transmembrane transport.

To understand why this is the correct answer, let us break down the pathway of water movement in plant roots and how it crosses the endodermis:

1. The Endodermis and the Casparian Strip: The endodermis is the innermost cell layer of the root cortex. Its cell walls contain a band of suberin, a waxy, waterproof material known as the Casparian strip. This strip acts as a barrier that prevents water and dissolved solutes from moving passively through the non-living parts of the tissue.

2. Apoplast vs. Symplast Pathway:
- In the apoplast pathway, water moves through the cell walls and intercellular spaces. However, when it reaches the endodermis, the Casparian strip blocks this pathway entirely.
- In the symplast pathway, water moves from cell to cell through the plasmodesmata (microscopic channels connecting cytoplasm).

3. The Role of Transmembrane Transport at the Endodermis: Because the apoplast pathway is blocked by the waxy Casparian strip, water is forced to cross the plasma membrane of the endodermal cells to enter the living cytoplasm. This cellular entry and subsequent exit into the vascular cylinder (stele) require water to cross the cell membranes directly. The process of moving across these lipid bilayers via water channels (aquaporins) or membrane proteins is known as transmembrane transport. Through this active selection and crossing of cell membranes, plants selectively control and forcefully push water and minerals into the xylem.