《植物生理学报》 2022, 58(3): 565-576
二个抗、感病烟草品种对赤星病胁迫的光合生理响应差异
通信作者：林英超；E-mail: linyingchao@outlook.com
摘 要：
比较不同抗性烟草品种在赤星病胁迫下的光合生理响应差异可揭示赤星病和光合作用之间的关系, 有助于进一步明确烟草赤星病的抗性机理。本实验采用盆栽方法, 分析赤星病胁迫对2个烟草抗、感病品种JYH和CBH的光合作用、叶绿素荧光特性、光合色素、光合碳同化关键酶以及叶黄素循环的影响。结果显示, 在5 d时, 赤星病胁迫对JYH的一系列光合生理活动均未产生不利影响。赤星病胁迫明显抑制9d时的JYH和5~9 d时的CBH的叶绿素荧光参数、光合色素含量、光合碳同化关键酶活性及叶黄素循环功能, 最终表现为光合作用下降。JYH的光合作用降低是由气孔限制因素引起, 而非气孔限制因素是CBH的光合作用被抑制的主要原因。与CBH相比, JYH具有较高的PSII最大光化学效率(Fv/Fm)、PSII实际光化学效率(ΦPSII)、光化学淬灭系数(qp)、非光化学淬灭系数(NPQ)和叶绿素a、叶绿素a+b、类胡萝卜素含量以及核酮糖-1,5-二磷酸羧化/加氧酶(Rubisco)、景天庚酮糖-1,7-二磷酸酯酶(SBPase)、果糖-1,6-二磷酸酯酶(FBPase)活性, 且其花药黄质(A)、玉米黄质(Z)、叶黄素循环库(A+V+Z)含量与叶黄素循环脱环氧化状态(A+Z)/(A+V+Z)也显著大于CBH。研究结果表明, 赤星病胁迫对抗病品种光合生理活动的危害程度小于感病品种, 有利于保持较高的光合作用强度, 从而具有较强的抗病性。
关键词：烟草; 赤星病胁迫; 光合作用; 光合碳同化; 叶黄素循环
收稿：2021-07-26 修定：2021-10-16
资助：贵州省科学技术基金([2020]1Y106、ZK[2021]一般110和黔科合支撑[2019]2401号)、国家自然科学基金(32160648)、中国烟草总 公司科技重大专项[11020200027(JY-10)]、贵州省公司科技项目(201801、201805、2020XM02和2020XM06)和遵义市烟草公司科 技项目(2021XM05)。
Corresponding author: LIN Yingchao; E-mail: linyingchao@outlook.com
Abstract:
Comparing the differences of photosynthetic physiological response in resistant and susceptible
cultivars under tobacco brown spot stress causing by Alternaria alternata (Fries) Keissl can reveal the relationship between brown spot and photosynthesis, which is useful to further elucidate the resistance mechanism. Pot experiment was used in our present study, the responses of photosynthesis, chlorophyll fluorescence characteristics, photosynthetic pigments, key enzymes of photosynthetic carbon assimilation and xanthophyll cycle were analyzed in two tobacco cultivars with different levels of resistance to brown spot, which were one resistant JYH and a susceptible cultivar CBH. The results showed that there were no adverse effects on this series of photosynthetic physiological activities in JYH at 5 d of brown spot stress. On the contrary, the chlorophyll fluorescence parameters, photosynthetic pigments contents, key enzyme activities of photosynthetic carbon assimilation and function of xanthophyll cycle in JYH at 9 d and in CBH at 5-9 d were all significantly inhibited under brown spot stress, respectively, which led to the eventual decline of photosynthesis. In addition, the reason for the reduced photosynthesis in JYH was stomatal limitation, nevertheless, the decreases in photosynthesis for CBH were mainly caused by nonstomatal limitation. By comparison with CBH under stress, JYH had higher values of PSII maximal photochemical efficiency (Fv/Fm), PSII actual quantum yield (ΦPSII), photochemical quenching coefficient (qp), non-photochemical quenching coefficient (NPQ), the contents of chlorophyll a, chlorophyll a+b, and carotenoid, the key enzyme activities consisting of Rubisco, SBPase, and FBPase, as well as the contents of antheraxanthin (A), zeaxanthin (Z), xanthophyll cycle pool (A+V+Z), and de-epoxidation extent of xanthophyll cycle (A+Z)/(A+V+Z). Therefore, the adverse influence of tobacco brown spot stress on these photosynthetic physiological activities in the resistant cultivar was less harmful than the susceptible one, which was beneficial to maintain higher photosynthesis. These attributes may account for the resistance to brown spot.
Key words: tobacco; brown spot stress; photosynthesis; photosynthetic carbon assimilation; xanthophyll cycle
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