外源褪黑素对臭氧胁迫下‘赤霞珠’葡萄叶片光合作用的影响

Effect of Exogenous Melatonin on Photosynthesis of ‘Cabernet Sauvigon' Grape Leaves Under Ozone Stress

以盆栽‘赤霞珠’葡萄为试验材料,浇施浓度为100 nmol·L^(-1)的外源褪黑素(melatonin)后,在110 n L·L^(-1)臭氧浓度胁迫下,测定葡萄叶片气体交换参数和叶绿素荧光快速诱导动力学曲线,并结合叶绿素荧光淬灭分析葡萄叶片光合性能的变化。结果表明:浇施褪黑素提高了臭氧胁迫下叶绿素a、b和类胡萝卜素的含量以及叶绿素a/b的比值,提高了叶片净光合速率(P_n)和叶片单位面积有活性反应中心的数量(RC/CSm),以及捕获的激子将电子传递到Q_A以后的其他电子受体的概率(Ψ_o),从而缓解了臭氧胁迫下的光抑制程度。结论:外源褪黑素缓解了臭氧胁迫下葡萄叶片叶绿素的降解,通过调节光系统的能量分配,缓解了臭氧胁迫对光合作用的伤害。

To investigate the effect of exogenous melatonin（100 nmol ？ L^（-1）） on photosynthetic characteristics of grape seedlings under ozone stress（110 nL ？ L^（-1））,potted Cabernet Sauvigon grapevine were used as materials to be irrigated with melatonin,gas exchange parameters and OJIP fluorescence transient were tested,and combined with chlorophyll fluorescence quenching analysis.The results showed that,the exogenous melatonin increased the content of chlorophyll a,chlorophyll b,carotenoids and the ratio of chlorophyll a/b under ozone stress,increased the net photosynthetic rate（P_n） of grape leaves and number of active reaction centers per unit area（RC/CS_m）,promoted the probability of a trapped exciton moves an electron into the electron transport chain beyond QA（ψ_o）,which reduced the photoinhibition under ozone stress.These results suggested that exogenous melatonin promoted the chlorophyll content under the ozone stress,reduced the damage of ozone stress on grape leaf photosynthesis by improving the energy distribution of grape leaf photosystem.