外源5-氨基乙酰丙酸对低温胁迫下茶树叶片光合及生理特性的影响

通过对陕茶1号（耐低温型）和金牡丹（低温敏感型）2个茶树品种在冬季自然低温胁迫下喷施不同浓度（0、10、30、50 mg·L^-1）的外源5-氨基乙酰丙酸（5-aminolevulinic acid,ALA）,探究外源ALA对低温胁迫下茶树叶片光合荧光特性及生理特性的调控作用。结果表明,适宜浓度的外源ALA对低温胁迫下茶树叶片净光合速率、气孔导度、胞间CO₂浓度、蒸腾速率、PSⅡ最大光化学效率及PSⅡ潜在活性具有促进作用,能够提高水浸出物、咖啡碱、游离氨基酸、儿茶素类物质、茶氨酸、可溶性糖、可溶性蛋白等生理活性物质含量的累积;外源ALA能够提高低温胁迫下茶树光合作用的能力并改善茶叶品质,其中50 mg·L^-1的ALA处理能有效提高陕茶1号应对低温胁迫的能力,10 mg·L^-1和30 mg·L^-1的外源ALA对金牡丹应对低温胁迫具有较好的缓解效用。

Effects of Exogenous 5-aminolevulinic Acid on Photosynthetic and Physiological Characteristics of Tea Plants under Low Temperature Stress

In order to explore the effects of 5-aminolevulinic acid (ALA) on photosynthetic and physiological characteristics of tea plants under natural low temperature stress in winter, we sprayed 0, 10, 30mg·L^-1 and 50 mg·L^-1 ALA on ‘Shaancha 1’ (low temperature tolerant cultivar) and ‘Jinmudan’ (low temperature sensitive cultivar). The results show that ALA of suitable concentration could improve net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, maximum photochemical efficiency of PSⅡ and potential activity of PSⅡ. Moreover, ALA treatment could promote the accumulations of water extract, caffeine, free amino acids, catechins, theanine, soluble sugar and protein contents. Exogenous ALA could improve the photosynthetic capacity and tea quality under low temperature stress. ALA treatment (50 mgL^-1) could effectively improve the cold tolerance of ‘Shaancha 1’. While 10 mg·L^-1 and 30 mg·L^-1 ALA treatment had effects on the relief of low temperature stress in ‘Jinmudan’.