Study on Physiological Mechanism of Using Cottonseed Meal to Improve Salt–Alkali Tolerance of Cotton

Abstract

Saline–alkali stress is the main environmental factor restricting the growth and production of cotton, one of the most important cash crops in the world. To explore the mechanism of improving tolerance to saline–alkali stress of cotton (Gossypium hirsutum L.) using cottonseed meal, field experiment was conducted to study the compensatory effects of different amounts of cottonseed meal on the physiology and growth of cotton under saline–alkali stress of 8 g kg−1. The results showed that cottonseed meal application could maintain the ion balance of K+ and Na+ in cells, promote the growth of cotton under salt–alkali stress, increase chlorophyll content and photosynthesis, and effectively alleviate the salt–alkali stress on cotton. Principal component analysis showed that the main factors affecting the growth physiology of cotton under salt–alkali stress were antioxidant enzyme activity, K+ and Na+ contents in leaves, root length, fresh weight, dry weight, and intercellular CO2 concentration.