外源水杨酸对2个绣球品种耐热性影响的研究

选择2个绣球品种‘含羞叶’和‘银边’为试验材料，采用叶片喷施不同浓度水杨酸（SA）溶液（0.25、0.50、0.75 mmol·L^-1和1.00 mmol·L^-1）并结合人工气候室模拟高温胁迫43℃/33℃（昼/夜）的处理方法，从形态表现、光合色素、膜脂过氧化酶、抗氧化酶活性、渗透调节物质等方面研究外源SA在提升绣球耐热性过程中的生理功能及其作用机理。结果表明，施用SA浓度为0.50 mmol·L^-1和0.75 mmol·L^-1后，2个绣球品种叶片受热害影响程度较轻，且施用适当浓度的SA能有效抑制高温胁迫下光合色素的分解，减缓细胞膜的氧化损伤，抑制丙二醛的积累，提升超氧化物歧化酶、过氧化物酶及过氧化氢酶的活性，增加细胞内的可溶性糖、可溶性蛋白和游离脯氨酸等细胞渗透调节物质的含量，进而减轻高温胁迫对绣球造成的伤害，诱导绣球耐热性提升，以0.75 mmol·L^-1浓度的SA处理对绣球耐热性提升效果最佳。

Effects of Exogenous Salicylic Acid on Heat-tolerance of Two Hydrangea Cultivars

In this study,Hydrangea macrophylla ‘Elbtal’ and H.macrophylla‘Tricolor’ were used as test materials.Different concentrations of salicylic acid (SA) solution (0.25,0.50,0.75,and 1.00 mmol·L^-1) were sprayed on the leaves and combined with simulated high temperature stress 43℃/33℃ (day/night) in an artificial climate chamber.The physiological function and mechanism of exogenous SA in the process of improving heat resistance of H.macrophylla were studied on the aspects of morphology,photosynthetic pigment,membrane lipid peroxidation,antioxidant enzyme activity,and osmoregulation substances.The results showed that after applying different concentrations of SA solution,the leaves of two Hydrangea cultivars were less damaged by heat when SA concentration was 0.50 mmol·L^-1 and 0.75 mmol·L^-1.Application of appropriate concentration of SA could effectively inhibit the decomposition of photosynthetic pigment under high temperature stress,slow down the oxidative damage of cell membrane,prevent the accumulation of MDA,enhance the activity of SOD,POD and CAT,and increase the content of soluble sugar,soluble protein and free proline in cells.Therefore,SA could reduce damage caused by high temperature stress and improve the heat resistance of Hydrangea,especially 0.75 mmol·L^-1 SA had the best treatment effect.