水杨酸预处理对低温胁迫下茉莉幼苗光合作用及相关生理特性的影响

Effects of salicylic acid pretreatment on photosynthesis and its related physiological parameters in jasmine(Jasminun sambac) seedlings under cold stress

为探明水杨酸(SA)提高茉莉幼苗抗寒性的生理机制,以抗寒性不同的2个茉莉品种(单瓣茉莉,低抗;双瓣茉莉,高抗)为材料,研究叶面预先喷施SA(1.0 mmol/L)对低温胁迫下茉莉幼苗光合作用及相关生理指标的影响。结果表明SA预处理能够:1)缓解因低温胁迫导致的净光合速率(Pn)、气孔导度(Gs)、PSⅡ原初光化学效率(Fv/Fm)、叶绿素和淀粉含量的下降,第15天时与CK1(低温)相比各项指标平均提高了51.2%、47.4%、28.3%、60.0%和30.0%;2)缓解因低温胁迫导致的初始荧光(Fo)、可溶性糖和脯氨酸含量的上升,第15天时与CK1相比平均减少了8.2%、6.0%和34.3%;3)缓解低温胁迫对单、双瓣茉莉伤害的生理效应期分别为6和9 d。由此可见,SA预处理能减轻低温胁迫对茉莉光合作用及相关生理特性的影响,有效提高茉莉耐寒性指标。

The objective of this study was to gain better insight into the biological mechanisms of SA （salicylic acid）- enhancement of cold tolerance in jasmine seedlings. Salicylic acid （1.0 mmol/L） was sprayed to investigate the effects of its pretreatment on photosynthesis, content of chlorophyll and osmotic solutes in leaves of two jasmine cultivars, Single petal jasmine （susceptible） and Double petal jasmine （resistant）, under conditions of cold stress. The results indicated that SA pretreatment effectively alleviated the decrease in net photosynthetic rate （Pn）, stomatal conductance （Gs）, primary conversion of light energy of photosystem Ⅱ （Fv/Fm）, and the content of chlorophyll and starch, all of which increased by 51.2,47.4, 28.3, 60.0 and 30.0% compared with water pretreatment under cold stress for]5 days. Salicylic acid pretreatment also significantly reduced the fundamental fluorescence （Fo）, content of proline and soluble sugars by 28.2, 6.0 and 34.3 %. The physiologically effective phase of SA pretreatment on cold tolerance of Single and Double petal jasmine was 6 and 9 days respectively, The cold tolerance of jasmine seedlings was enhanced with SA pretreatment through alleviating damages to photosynthetic apparatus.