Study on the Prevention of Chilling Injury on Water Convolvulus and Leafy Sweetpotato

• Main Authors: Yi-Hsin Chung, 鍾逸心
• Other Authors: Shu-I Lin
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/882r76

碩士 === 國立臺灣大學 === 園藝暨景觀學系 === 106 === Chilling is an abiotic stress caused by low temperature that results in inhibition of growth and development in many tropical and subtropical crops. Water convolvulus (Ipomoea aquatica Forsk.) and leafy sweetpotato (Ipomoea batatas (L.) Lam.) are both warm-season vegetables and have little tolerance toward low tempersture. Four experiments were conducted in this research. Pre-experiment aims to investigate the effects of low temperature on appearance and physiological responses of water convolvulus and leafy sweetpotato. Experiment I to III are intend to identify the most appropriate ways that can mitigate the chilling injury of water convolvulus and leafy sweetpotato through protection facility, regulating of calcium and phosphorus concentration in nutrient solution and leaf spray of calcium and phosphorus. The results in pre-experiment showed that low temperature inhibits the growth of water convolvulus, and causes oxidative stress in water convolvulus and leaf sweetpotato. The results in experiment I showed that water convolvulus with non-woven floating cover provided protection against chilling and thus had better water content than the uncovered control. Row cover provided higher soil temperature than the uncovered control, but had no effect on the horticultural characters of water convolvulus and leafy sweetpotato. Drip irrigation with 25℃ water had little benefit to cold resistance of both vegetables. In experiment II, raising the calcium concentration of nutrient solution from 2.5 mM to 3.125 mM can significantly increase the water content of water convolvulus after low temperature, and decrease the concentration of hydrogen peroxide and malondialdehyde (MDA). Increasing the phosphorus concentration of nutrient solution from 500 μM to 750 μM can reduce the decrease in water content of water convolvulus caused by low temperature and decrease the concentration of MDA. Regulating of calcium concentration in nutrient solution was unsuitable to alleviate the chilling injury on leafy sweetpotato. But plants grown in nutrient solution with 1000 μM of phosphorus have better cold resistance, which can reduced the growth inhibition caused by low temperature on the shoot, and maintain higher chlorophyll content and water content after low temperature. The results in experiment III showed that leaf spray of calcium and phosphorus before low temperature had no obvious effect on increasing the cold resistance of water convolvulus and leafy sweetpotato. In summary, water convolvulus is more suitable for non-woven floating cover, adjust the calcium concentration in nutrient solution to 3.125 mM or adjust the phosphorus concentration in nutrient solution to 750 μM to reduce the chilling injury. For leafy sweetpotato, it is recommended to use non-woven floating cover or adjust the phosphorus concentration in nutrient solution to 1000 μM to reduce the damage caused by low temperature.