中国农业科学 ›› 2024, Vol. 57 ›› Issue (21): 4205-4220.doi: 10.3864/j.issn.0578-1752.2024.21.004

• 耕作栽培·生理生化·农业信息技术 • 上一篇    下一篇

高温干旱复合胁迫抑制夏玉米光系统Ⅱ性能降低籽粒产量

郭娅(), 任昊, 王洪章, 张吉旺, 赵斌, 任佰朝, 刘鹏()   

  1. 山东农业大学农学院/黄淮海区域玉米技术创新中心,山东泰安 271018
  • 收稿日期:2024-03-13 接受日期:2024-09-18 出版日期:2024-11-01 发布日期:2024-11-10
  • 通信作者:
    刘鹏,E-mail:
  • 联系方式: 郭娅,E-mail:gyy062629@163.com。
  • 基金资助:
    国家自然科学基金(32071959); 山东省玉米产业技术体系(SDAIT02-08)

High Temperature and Drought Combined Stress Inhibited Photosystem Ⅱ Performance and Decreased Grain Yield of Summer Maize

GUO Ya(), REN Hao, WANG HongZhang, ZHANG JiWang, ZHAO Bin, REN BaiZhao, LIU Peng()   

  1. College of Agriculture, Shandong Agricultural University/Huang-Huai-Hai Regional Maize Technology Innovation Center, Taian 271018, Shandong
  • Received:2024-03-13 Accepted:2024-09-18 Published:2024-11-01 Online:2024-11-10

摘要:

【目的】探究高温干旱复合胁迫降低玉米光合作用的深层次原因,为缓解高温干旱复合胁迫提供理论依据。【方法】选用登海605为试验材料,设置2个温度水平,分别为正常温度对照(昼(8:00-18:00)/夜(18:00-次日8:00)为30 ℃/22 ℃)和高温处理(昼/夜温度为38 ℃/28 ℃);2种水分条件,分别为正常供水对照(土壤含水量为田间持水量的70%-80%)和干旱处理(土壤含水量设置为田间持水量的50%-60%)。试验共4个处理,分别为对照(CK)、高温胁迫(H)、干旱胁迫(D)、高温干旱复合胁迫(HD),于开花期(VT)开始处理,分析不同胁迫处理下叶片气体交换参数、PSⅡ性能、光合关键酶活性、植株干物质积累及籽粒产量的变化。【结果】高温、干旱及复合胁迫均导致叶片叶绿素荧光参数FK占振幅F0-FJ的比例(WK)、FJ占振幅F0-FP的比例(VJ)升高,损伤PSⅡ供体侧与受体侧,与对照相比,PSⅡ最大光化学效率(φP0)、捕获的激子将电子传递到电子传递链中超过QA的其他电子受体的概率(Ψ0)、用于电子传递的量子产额(φE0)、用于热耗散的量子比率(φD0)、用于还原PSⅠ受体侧末端电子受体的量子产额(φR0)、以吸收光能为基础的性能指数(PIABS)显著降低,抑制光能的吸收与传递;单位反应中心吸收的光能(ABS/RC)、捕获的用于还原QA的能量(TR0/RC)及耗散的能量(DI0/RC)显著增加,而用于电子传递的能量(ET0/RC)显著降低,影响反应中心能量分配,降低PSⅡ活性反应中心数目,抑制PSⅡ性能。其中复合胁迫通过损伤供体侧和受体侧及活性反应中心加剧对PSⅡ性能的抑制。同时1,5-二磷酸核酮糖羧化酶(Rubisco)和磷酸烯醇式丙酮酸羧化酶(PEPCase)活性降低,抑制光合碳同化。高温、干旱及复合胁迫通过降低PSⅡ性能及光合关键酶活性来降低净光合速率,与对照相比,VT+5 d净光合速率分别降低14.6%、31.4%、39.9%。光合速率降低抑制干物质积累及其向籽粒的转运,高温、干旱及复合胁迫下籽粒产量分别较对照降低80.3%、27.1%、84.0%。【结论】高温干旱复合胁迫主要通过抑制叶片PSⅡ性能来降低净光合速率,阻碍干物质积累,降低籽粒产量。复合胁迫对PSⅡ性能及籽粒产量的影响大于高温、干旱单一胁迫。

关键词: 高温干旱复合胁迫, 净光合速率, 光系统Ⅱ, 光合酶, 籽粒产量, 夏玉米

Abstract:

【Objective】This study aimed to explore the underlying reasons for the reduction of maize photosynthesis under the high temperature and drought combined stress, so as to provide theoretical basis for alleviating the combined stress of high temperature and drought. 【Method】Maize cultivar “Denghai 605” was selected as the experimental material for this experiment. Two temperature levels were set, namely normal temperature control (30 ℃/22 ℃ for day (8:00-18:00)/ night (18:00- 8:00 the next day)) and high temperature treatment (38 ℃/28 ℃ for day/night). The two water conditions were normal water supply control (soil water content was 70%-80% of field capacity) and drought treatment (soil water content was set to 50%-60% of field capacity). There were four treatments in the experiment, including control (CK), high temperature stress (H), drought stress (D), high temperature and drought combined stress (HD), and the treatment began at VT stage (VT). The changes in leaf gas exchange parameters, photosystem Ⅱ (PSII) performance, key photosynthetic enzyme activity, plant biomass, and grain yield under different stress treatments were analyzed. 【Result】High temperature, drought and combined stress all led to the increase of chlorophyll fluorescence parameters, the ratio of a variable fluorescence FK to F0-FJ amplitude (WK) and variable fluorescence FJ to F0-FJ amplitude (VJ), and damaged the donor side and acceptor side of PSII. Compared with the control, PSII maximum quantum yield for primary photochemistry (φP0), the probability of captured excitons transferring electrons to other electron acceptors in the electron transfer chain beyond QA (Ψ0), quantum yield for electron transport (φE0), quantum yield of energy dissipation (φD0), quantum yield for reduction of the end electron acceptors at the PSI acceptor side (φR0), and performance index based on absorption of light energy (PIABS) were significantly decreased, and the absorption and transfer of light energy were inhibited; absorbed photon flux per active PSII (ABS/RC), trapped energy flux per active PSII (TR0/RC) and dissipated energy flux per active PSII (DI0/RC) increased significantly, but the electron flux from QA to the PQ pool per active PSII (ET0/RC) decreased significantly, which affected the energy distribution of reaction centers, reduced the number of PSII active reaction centers, and inhibited the performance of PSII. Combined stress could aggravate the inhibition of PSII performance by damaging the donor side, the acceptor side and the active reaction center. At the same time, the activities of ribose 1, 5-diphosphate carboxylase (Rubisco) and phosphoenolpyruvate carboxylase (PEPCase) decreased, which inhibited photosynthetic carbon assimilation. High temperature, drought, and combined stress reduced the net photosynthetic rate by reducing the performance of PSII and the activity of key photosynthetic enzymes. Compared with the control, the net photosynthetic rate of VT+5 d was reduced by 14.6%, 31.4%, and 39.9%, respectively. The decrease in photosynthetic rate inhibited the accumulation of biomass and its transport to grains. Under high temperature, drought, and combined stress, the grain yield decreased by 80.3%, 27.1%, and 84.0% than that under control, respectively. 【Conclusion】In summary, the combined stress of high temperature and drought mainly reduced net photosynthetic rate, hindered biomass, and reduced grain yield by inhibiting leaf PSII performance. The impact of combined stress on PSII performance and grain yield was greater than that of single stress under high temperature and drought.

Key words: high temperature and drought combined stress, net photosynthetic rate, PSII, photosynthetic enzyme, grain yield, summer maize