水杨酸对高温胁迫下一串红耐热性的影响

Heat resistance of Salvia splendens with salicylic acid added and high temperature stress

为提高一串红Salvia splendens的耐高温性,研究了在高温胁迫下(39℃/30℃,昼/夜),喷施外源水杨酸对‘航天5号’‘Hangtian No.5’和‘展望’‘Zhanwang’的热害指数、叶片相对电解质率、抗氧化酶和叶绿素荧光参数的影响。结果表明:处理6 d时,喷施0.01 mol·L-1水杨酸后‘航天5号’热害指数较喷施清水降低了27.9%,‘展望’热害指数降低了19.7%。水杨酸喷施显著降低了相对电解质渗透率(P<0.05),提高了叶片抗坏血酸过氧化物酶(APX),过氧化物酶(CAT)的活性和可溶性蛋白质的质量分数,降低超氧化物歧化酶(SOD)和过氧化氢酶(POD)的活性。明显缓解了高温胁迫下2个品种光系统Ⅱ原初光能转换效率(Fv/Fm)的下降。这种趋势在耐热性较弱的‘航天5号’中表现得更为明显。这些结果表明:水杨酸提高一串红的耐热性可能是由于提高了抗氧化酶活性,减少了氧化伤害,缓解了对光系统Ⅱ(PSⅡ)的伤害。

To increase heat resistance with Salvia splendens, one of the most important bedding plants in south China where high summer temperatures decrease its growth, this study measured the effects of high temperature （39 ℃ day/30 ℃ night） on heat damage indexes, relative electric conductivity （REC）, antioxidant enzyme ac- tivities, and chlorophyll fluorescence parameters in two cultivars of Salvia splendens： ＇Hangtian No. 5＇ and ＇Zhanwang＇. The experimental design consisted of a control （25 ~C, day and night） and three treatments （high temperature, 0.01 mol·L^-1 SA spraying, combination of high temperature and SA spraying） was arranged in a randomized, complete block design with 3 replicates, giving a total of 48 plants, and statistical assays were car- ried out by analysis of variance （ANOVA） using SAS software. Results showed that by the 6th day compared to control plants, spraying with SA significantly （P〈0.05） decreased the heat index in ＇Hangtian No. 5＇ and ＇Zhanwang＇. Also with high temperature stress, SA significantly decreased （P〈0.05） leaf relative electrolyte leakage increases for both cultivars. Furthermore, SA increased （P〈0.05） ascorbate peroxidase （APX） and catalase （CAT） activities as well as soluble protein content more in the heat sensitive cultivar ＇Hangtian NO. 5＇ than ＇Zhanwang＇. In addition, SA treatment along with high temperature stress significantly （P〈0.05） decreased superoxide dismutase （SOD） and peroxidase （POD） activities and increased maximum efficiency of Photosystem Ⅱ could be related photo-damage of （Fv/Fm） in both cultivars. These results indicated that the increase in heat tolerance using SA to the enhancement of antioxidant enzyme activity and the decrease of oxidative damage and PS IT with high temperature. [Ch, 8 fig. 20 ref. ]