Question

Prolonged water logging kills plants due to:
A. Stoppage of root respiration
B. Dilution of soil nutrients
C. Dilution of plant cell saps
D. Leaching of nutrients

Answer 1

Hint:Excess water in the root zone accompanied by anaerobic conditions is known as waterlogging. Excessive water prevents gas exchange with the environment, and biological activity utilizes the available oxygen in surface air and water.

Complete Answer:
Water is essential for all plant physiological processes and plays a vital role in all living organisms. It serves as a medium in which most of the substances are dissolved. The absorption of water and minerals is done by the root hairs that are found in millions at the tips of the roots. Root hairs are thin-walled, flexible extensions of root epidermal cells that significantly expand the surface area for absorption.

Water, along with mineral solutes, is absorbed by the root hair, through diffusion. In waterlogged soil, the diffusion of gases by soil pores is significantly affected by their water content that it does not meet the needs of growing plants. Waterlogging happens when there is too much water in the root zone of the plant, which limits the oxygen available to the roots. Waterlogging can be a significant limitation on plant growth and development and, under such circumstances, cause plant death.

Thus, the correct answer is option A i.e., Stoppage of root respiration

Note:Waterlogging decreases oxygen levels in the root region, which inhibits plant growth. It increases the potential for soil reduction and changes the chemical balance of many of the elements that then join the soil-water solution in its ionic form. Depending on the soil composition, this shift in chemical balance can cause temporary toxicity of certain soil nutrients that are normally healthy when soil is freely drained.