植物生长调节剂对低温胁迫下荔枝生理特性及产量的影响

为了探讨植物生长调剂对荔枝春季低温伤害的缓解效应,在春季低温下,叶面喷施不同浓度的植物生长调节剂,研究其对荔枝叶片生理特性及产量的影响.试验品种为'妃子笑'荔枝(树龄约10 a),调节剂为广东海洋大学化控中心研制,其主要成分为1,1-二甲基哌啶翁氯化物;设置A(植物生长调节剂2.5 mL,兑水10 kg)、B(植物生长...

Effects of Plant Growth Regulators on Physiological Characteristics and Yield of Litchi Plants under Low Temperature Stress

In order to explore the mitigating effects of plant growth regulators on the low temperature injury of litchi plants in spring, different concentrations of plant growth regulators were sprayed on leaves under low temperature in spring, and its effects on physiological characteristics and yield of litchi leaves were studied. The 10-year-old ‘Feizixiao’ litchi trees were used as the experimental material. The plant growth regulator is developed by the Chemical Control Center of Guangdong Ocean University. Its main ingredient is Mepiquat chloride. The treatments A (2.5 mL of plant growth regulator was mixed evenly with 10 kg of water, and then sprayed on a litchi tree), B (5 mL of plant growth regulator was mixed evenly with 10 kg of water, and then sprayed on a litchi tree) and C (7.5 mL of plant growth regulator was mixed evenly with 10 kg of water, and then sprayed on a litchi tree) were set up. Meanwhile, the litchi trees were sprayed with the same amount of water were used as control (CK). The leaf fresh weight, leaf dry weight, chlorophyll relative content (SPAD), net photosynthetic rate (P_n), intercellular CO₂ concentration (C_i), stomatal conductance (G_s), transpiration rate (T_r), fruit weight and yield were measured. The results showed that plant growth regulators could alleviate the low temperature injury of litchi leaves, and B treatment was the best. Compared with CK, the leaf dry weight and relative water content of B treatment had no significant changes, but the leaf fresh weight increased by 21.18%. Compared with CK, the SPAD, net photosynthetic rate (P_n) and transpiration rate (T_r) increased significantly by 7.44%, 8.40% and 3.48%, while the intercellular CO₂ concentration (C_i), stomatal conductance (G_s) and stomatal limit did not change significantly. Compared with CK, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) increased significantly by 2.27%, 18.79%, 71.32% and 80.00%, respectively, while the activity of polyphenoloxidase (PPO) decreased by 10.81%. The content of soluble protein and ascorbic acid (AsA) increased significantly by 9.53% and 15.31%, respectively, in litchi leaves. But the impact on the single fruit weight and yield per plant were not significant. To sum up, under low temperature stress, spraying appropriate amount of plant growth regulators could improve leaves photosynthesis, promote leaves mass accumulation, increase the activities of antioxidant enzymes, increase the content of soluble protein and AsA, reduce the damage of membrane lipid caused by low temperature, and improve the ability of low temperature resistance of litchi leaves.