外源葡萄糖对高温强光下旺长期烤烟光合特性及碳氮代谢关键酶活性的影响

摘要

In order to investigate the regulation mechanism of exogenous glucose on the photosynthesis mechanism and carbon and nitrogen metabolism of flue-cured tobacco leaves at fast-growing stage under high temperature and high light intensity, a pot experiment in an artificial climate chamber was conducted by simulating the high temperature and high light intensity environment of flue-cured tobacco at fast-growing stage in central Henan tobacco-planting areas. The effects of exogenous glucose (0.5 mmol/L) on the contents of photosynthetic pigments, including chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll [Chl(a + b)], carotenoids (Car), the photosynthetic parameters, including net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), intercellular CO2 concentration (Ci), chlorophyll fluorescence parameters, including initial fluorescence (Fo), nonphotochemical quenching coefficient (NPQ), actual photochemical quantum efficiency of PSⅡ ( Φ PSⅡ), photosynthetic electron transfer efficiency (ETR), photochemical quenching coefficient (qp), maximum photochemical efficiency of PSⅡ (Fv/Fm), glutamine synthase activity (GS) and 1,5-diphosphate ribulose carboxylase (Rubisco) activity of flue-cured tobacco were studied. The results showed that spraying exogenous glucose under high temperature and high light intensity significantly promoted the contents of Chla, Chlb, Chl(a+b) and Car, noticeably raised Pn, Gs, E, remarkably reduced Ci, Fo and NPQ; Φ PSⅡ, ETR, qp were increased significantly, in which the increase extent of Fv/Fm was relatively smaller. Furthermore, the activities of GS and Rubisco were improved. Therefore, spraying exogenous glucose under high temperature and high light intensity promotes the photosynthetic performance, carbon and nitrogen metabolism balance and the growth of tobacco, and alleviates the adverse effects of high temperature and high light intensity stress on tobacco.%为揭示外源葡萄糖对高温强光条件下旺长期烤烟叶片光合机构及碳氮代谢过程的调控机制,在人工气候室中模拟豫中烟区烤烟旺长期高温强光条件,采用盆栽试验研究了在高温强光胁迫条件下外源葡萄糖(0.5 mmol/L)对烤烟光合色素含量{叶绿素a(Chla)、叶绿素b(Chlb)、总叶绿素[Chl(a+b)]、类胡萝卜素(Car)}、光合参数[净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(E)、胞间CO2浓度(Ci)]、叶绿素荧光参数[初始荧光(Fo)、非光化学猝灭系数(NPQ)、光系统Ⅱ(PSⅡ)实际光化学量子效率(ΦPSⅡ)、光合电子传递效率(ETR)、光化学猝灭系数(qp)、PSⅡ最大光化学效率(Fv/Fm)]、谷氨酰胺合成酶活性(GS)及1,5-二磷酸核酮糖羧化酶活性(Rubisco)的影响.结果表明,高温强光条件下喷施外源葡萄糖使烤烟Chla、Chlb、Chl(a+b)和Car含量均显著增加;Pn、Gs和E明显升高,Ci明显降低;Fo和NPQ显著降低,ΦPSⅡ、ETR和qp均显著升高,其中Fv/Fm升高幅度相对较小;同时,施用外源葡萄糖提高了高温强光胁迫下烤烟叶片中GS和Rubisco活性.因此,在高温强光条件下,通过喷施外源葡萄糖可改善烟草的光合性能,促进烟株体内碳氮代谢平衡,缓解高温强光胁迫对烟株的不利影响,促进烟株生长.