Acta Agrestia Sinica ›› 2024, Vol. 32 ›› Issue (4): 1120-1130.DOI: 10.11733/j.issn.1007-0435.2024.04.015

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Effects of Low Temperature and Drought Stress on Photosystem II of Alfalfa Leaves

ZHAO Yao-yao, LIU Mei-jun, ZHANG Zheng, WANG Jie, WANG Yu-xiang, AN Chang-qi, WANG Tiao-xia   

  1. Pratacultural College of Xinjiang Agricultural University/Key Laboratory of Grassland Resources and Ecology of Ministry of Education in Western Arid Areas/Xinjiang Key Laboratory of Grassland Resources and Ecology, Urumqi, Xinjiang 830052, China
  • Received:2023-08-27 Revised:2023-11-08 Published:2024-05-07

低温和干旱双重胁迫对紫花苜蓿叶片光系统II的影响

赵尧尧, 刘美君, 张政, 王婕, 王玉祥, 安长奇, 王跳霞   

  1. 新疆农业大学草业学院/西部干旱区草地资源与生态教育部重点实验室/新疆草地资源与生态重点实验室, 新疆 乌鲁木齐 830052
  • 通讯作者: 刘美君,E-mail:Lebaby7@163.com
  • 作者简介:赵尧尧(1998-),男,汉族,贵州遵义人,硕士研究生,主要从事植物逆境生理研究,E-mail:1963635954@qq.com
  • 基金资助:
    农业生物育种重大专项-新疆地区耐盐碱抗旱高产苜蓿新品种设计与培育(2022ZD0401104);新疆维吾尔自治区自然科学基金项目(2022D01A185);国家自然科学基金(32360346)资助

Abstract: Alfalfa often suffers from dual stresses of low temperature and drought during its turning green period in Xinjiang. In this study,the effects of low temperature and drought stress on the photosystem II (PSII) of alfalfa leaves were studied by using the main cultivar 'Xinmu 4’ in Xinjiang as object. Taking the commercial species 'WL525HQ’ as the control,the specific influencing sites on PSII of alfalfa with different low temperature resistance were further analyzed. The results showed that the maximum photochemical efficiency of PSII (Fv/Fm) and the energy captured per reaction center for electron transfer (ETO/RC) significantly decreased at low temperature,and the fluorescence of J point in the OJIP curve increased,indicating that the decrease of PSII activity caused by low temperature was due to the damage of the acceptor side and the reaction center;Drought caused a significant decrease in Fv/Fm,and the fluorescence of J,K,and L points in the OJIP curve increased. Severe drought led to an increase in light energy absorbed by the unit reaction center (ABS/RC),energy captured by the unit reaction center for reducing QA (TRO/RC),and energy dissipated by the unit reaction center (DIO/RC),indicating that the decrease in PSII activity caused by drought was due to damage to the PSII donor/acceptor side,complexus,and the reaction center of severe drought PSII;The induced production of cis-3-Hexen-1-ol under dual stresses alleviated the degree of damage to the PSII complexus caused by a single stress;In Xinmu No.4 with a lower autumn dormancy level,dual stresses alleviated the damage caused by drought to the PSII donor side. In WL525HQ,dual stresses alleviated the damage caused by low temperature to the PSII response center and receptor side,and also alleviated the damage caused by drought to the PSII donor side and response center.

Key words: Alfalfa, PSII, Low temperature stress, Drought stress, Dual stress

摘要: 新疆紫花苜蓿(Medicago sativa L.)在返青期常遭受低温和干旱双重胁迫。本研究以新疆主栽品种'新牧4号’为材料,研究低温和干旱双重胁迫对苜蓿叶片光系统II (PSII)的影响。以商业种'WL525HQ’为对照,进一步分析双重胁迫对不同低温抗性的苜蓿PSII具体的影响位点。结果表明:低温下PSII最大光化学效率(Fv/Fmm)、单位反应中心捕获的用于电子传递的能量(ETO/RC)显著降低,OJIP曲线中J点荧光上升,表明低温导致PSII活性下降是由于受体侧和反应中心受损;干旱导致Fv/Fmm显著降低,OJIP曲线中J,K,L点荧光上升且重度干旱导致单位反应中心吸收的光能(ABS/RC)、单位反应中心捕获的用于还原QA的能量(TRO/RC)、单位反应中心耗散掉的能量(DIO/RC)增加,表明干旱导致PSII活性下降是由于PSII供/受体侧、复合体受损及重度干旱PSII反应中心受损;双重胁迫诱导产生的顺-3-乙烯醇可缓解单一胁迫对PSII的伤害程度;在秋眠级较低的'新牧4号’中,双重胁迫可缓解干旱对PSII供体侧的伤害,在'WL525HQ’中,双重胁迫可缓解低温对PSII反应中心及受体侧的伤害,同时缓解干旱对PSII供体侧、反应中心的伤害。

关键词: 紫花苜蓿, PSII, 低温胁迫, 干旱胁迫, 双重胁迫

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