Effects of Low-Light Stress on Physiological Characteristics of Fruits of Different Muskmelon Varieties

Abstract

【Objective】The study aims to explore the effects of low-light stress on the main quality characteristics of fruits of different muskmelon varieties.【Method】The content changes of carbohydrates, carotenoids and chlorophyll in different fruit positions (pedicle, areola and pulp) of three varieties (Xizhoumi No. 1, Zaohuanghou and Jiashi) of muskmelon under different light intensities (100%, 42% and 23% transmittance) at different development stages (0, 3, 7, 14, 21, 35, 40, 60 d after blooming) were investigated.【Result】Results showed that contents of fruit starch, sucrose and reducing sugar all increased continuously during fruit development and the highest contents exhibited at mature stage (35 d), and Xizhoumi No. 1 had the highest starch content (10.835%), while Jiashi had the lowest starch content (8.342%). The pulp and areola of the fruits of three varieties showed higher sucrose content than that in pedicle, but no difference in reducing sugar content. The contents of carotenoid and chlorophyll increased during fruit development but decreasedat full ripe stage (60 d after blooming). Low-light stress significantly reduced the carbohydrate content, increased carotenoid and chlorophyll contents, and most significant effect was found under transmittance 23% treatment, under which the contents of starch, sucrose and reducing sugar in Xizhoumi No. 1 muskmelon reduced by 32.3%, 29.87% and 28.02%, while contents of carotene and chlorophyll increased by 19.47% and 13.98%, respectively. The contents of starch, sucrose and reducing sugar in Zaohuanghou muskmelon reduced by 32.63%, 25.09% and 20.24%, and the contents of carotene and chlorophyll increased by 54.74% and 21.06%, respectively. The contents of starch, sucrose and reducing sugar in Jiashi muskmelon reduced by 41.08%, 32.39% and 39.1%, and the contents of carotene chlorophyll increased by 55.20% and 31.79%, respectively. Compared with Xizhoumi No. 1 and Zaohuanghou muskmelons, the Jiashi muskmelon showed the lowest starch and chlorophyll contents and the highest sucrose and reducing sugar contents, and exhibited the most significant decline of starch, sucrose and reducing sugar contents, and increase of carotenoid and chlorophyll contents, indicating that the Jiashi muskmelon was affected most significantly by low-light stress and showed poorest low-light tolerance.【Conclusion】The low-light stress reduces the commercial quality of muskmelon fruits, and the quality is worse when the light transmittance is lower. Jiashi muskmelon is most sensitive to low-light stress.

Keywords

• muskmelon
• low-light stress
• carbohydrate
• carotenoid
• chlorophyll