Increase in Drought Resistance of Cotton Seedlings Treated with Mepiquat Chloride
- X. Xu and
- H. M. Taylor
Under rainfed conditions, plant establishment is often low in cotton (Gossypium hirsutum L.) because of water limitations. Increasing drought resistance of cotton seedlings by accelerating root growth thus has important, practical implications. Much research has been devoted to modifying plant root systems for more effective use of soil water, but successful results are few. We studied the effects of mepiquat chloride (MC; 1,1-dimethylpiperidinium chloride) on drought resistance of cotton seedlings. Well-watered seedlings were irrigated with mepiquat chloride (0-40 mg kg−1), and then subjected to progressively greater water stress. Treatment with MC accelerated root growth and increased water absorption, especially at greater soil depths. The seedlings treated with MC were turgid longer and wilted less than the drought controls. In another series of experiments seeds were treated (0-4000 mg kg−1) and arising plants were assessed for growth and survival in both well-watered and water-stress conditions. A seed treatment of 500 mg kg−1 gave shorter and more compact shoots, did not affect leaf area, but increased specific leaf weight and chlorophyll content. Seed treatment with 500 mg kg−1 MC also gave the greatest enhancement of root growth, water extraction from deep soil layers, and survival of stressed seedlings. These results suggested a potential for using MC to modify root patterns and increase drought resistance of cotton seedlings. Field tests of seed treatments with MC should be conducted to determine whether seedling survival is enhanced under natural drought-stressed conditions. The responses of different cotton varieties to MC treatment also should be investigated.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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