Question

We water the soil but it reaches the topmost leaves of the plants. Explain in brief the process involved.

Answer 1

Step 1: Understanding the Process of Water Movement in Plants:
When we water the soil, the water travels through the roots and eventually reaches the topmost leaves of the plant through a process called transpiration and the movement of water through plant tissues, known as water transport in plants.

Step 2: Water Absorption by Roots:
Water is absorbed by the roots from the soil. This absorption occurs mainly through the root hairs, which increase the surface area for water uptake. The water enters the root cells by osmosis, moving from areas of higher water concentration in the soil to areas of lower concentration in the root cells.

Step 3: Movement Through the Plant - Xylem Tissue:
Once absorbed by the roots, the water moves upwards through the plant via the xylem tissue. The xylem vessels are specialized for transporting water and minerals from the roots to the rest of the plant. The movement is driven by two main mechanisms:
1. Root Pressure: A slight pressure generated in the roots helps push the water upward.
2. Cohesion and Adhesion: Water molecules stick to each other (cohesion) and to the walls of the xylem vessels (adhesion), creating a continuous column of water that can move upward.

Step 4: Transpiration and the Pull of Water:
The primary force that pulls water upward to the leaves is transpiration. Transpiration is the process by which water evaporates from the surface of the leaves, mainly through small pores called stomata. As water evaporates from the leaves, it creates a vacuum that pulls more water from the roots through the xylem to replace the lost water.

Step 5: Conclusion:
Watering the soil initiates the movement of water through the roots, up the stem, and eventually to the topmost leaves of the plant. This process is driven by root pressure, cohesion and adhesion in the xylem, and transpiration, which creates the necessary pull to transport water to the highest parts of the plant.