植物生态学报 ›› 2021, Vol. 45 ›› Issue (4): 404-419.DOI: 10.17521/cjpe.2021.0013

• 研究论文 • 上一篇    下一篇

短期生长环境光强骤增导致典型阴生植物三七光系统受损的机制

武洪敏1,2, 双升普1,2, 张金燕1,2, 寸竹1,2, 孟珍贵1,2, 李龙根1,2, 沙本才1, 陈军文1,2,*()   

  1. 1云南农业大学西南中药材种质创新与利用国家地方联合工程研究中心, 云南农业大学云南省药用植物生物学重点实验室, 昆明 650201
    2云南农业大学农学与生物技术学院, 昆明 650201
  • 收稿日期:2021-01-12 接受日期:2021-03-14 出版日期:2021-04-20 发布日期:2021-04-14
  • 通讯作者: ORCID: *陈军文: 0000-0003-3927-6154(cjw31412@163.com)
  • 作者简介:* cjw31412@163.com
  • 基金资助:
    国家自然科学基金(81860676);国家自然科学基金(81360609);云南省科技重大专项(2016ZF001);云南省科技重大专项(2017ZF001)

Photodamage to photosystem in a typically shade-tolerant species Panax notoginseng exposed to a sudden increase in light intensity

WU Hong-Min1,2, SHUANG Sheng-Pu1,2, ZHANG Jin-Yan1,2, CUN Zhu1,2, MENG Zhen-Gui1,2, LI Long-Gen1,2, SHA Ben-Cai1, CHEN Jun-Wen1,2,*()   

  1. 1National & Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwestern China, Key Laboratory of Medicinal Plant Biology of Yunnan Proince, Yunnan Agricultural University, Kunming 650201, China
    2College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming 650201, China
  • Received:2021-01-12 Accepted:2021-03-14 Online:2021-04-20 Published:2021-04-14
  • Contact: CHEN Jun-Wen
  • Supported by:
    National Natural Science Foundation of China(81860676);National Natural Science Foundation of China(81360609);Key Science and Technology Project of Yunnan Province(2016ZF001);Key Science and Technology Project of Yunnan Province(2017ZF001)

摘要:

阴生植物突然暴露在强光下造成光损伤的情况时有发生, 但其对高光敏感的潜在机制尚不十分清楚。为阐明阴生植物无法在自然全光照环境下生存的相关机制, 该研究以典型阴生植物三七(Panax notoginseng)为材料, 将遮阴环境下(10%透光率)生长的植株转移到全日光环境下3天, 研究其相对叶绿素含量(SPAD值)、光合参数以及叶绿素荧光参数的变化。结果表明, 全光环境下三七光合日变化呈现“双峰”曲线特征, 且净光合速率在处理期间逐日降低。全日光下三七叶片SPAD值、水分利用率和光能利用率显著降低; 叶片光系统I (PSI)反应中心P700最大荧光信号、光系统II (PSII)电子传递速率、暗适应下PSII最大量子效率和光下PSII最大量子效率显著低于遮阴环境下的植株, 且至傍晚不能完全恢复。而参与调节性能量耗散的量子产量、PSI受体侧限制引起的非光化学量子产量、环式电子流则显著高于遮阴环境下的三七。此外, 生长环境光照强度骤增导致荧光诱导动力学曲线发生明显变化, 并显著升高了PSII供体侧和受体侧的荧光产量。当阴生植物三七突然暴露于全光环境下时, 强烈的光照会导致PSII供体侧的放氧复合体活性受损, 抑制受体侧的电子传递, 过度还原PSI的受体侧进而引发PSI光抑制。该研究结果揭示, 全日光导致的PSII不可逆损伤和PSI光抑制可能是典型阴生植物三七为什么不能在全日照光环境下存活的重要原因。

关键词: 阴生植物, 全日照, 光合作用, 光系统, 光保护, 三七

Abstract:

Aims Photodamage to a shade-tolerant species is common due to a sudden increase in growth light intensity. However, it is unknown about the underlying mechanism of the sensitivity of the shade-tolerant species to high light. The objective of the present study was to elucidate the mechanisms involved in the inability of the typically shade-tolerant species Panax notoginseng to survive under natural full-light condition.

Methods The relative chlorophyll content (SPAD), photosynthetic parameters and chlorophyll fluorescence parameters were continuously examined in P. notoginseng when transferred from shade (10% of full sunlight) to full sunlight for three days.

Important findings The net photosynthetic rate (Pn) of P. notoginseng exposed to full sunlight condition showed a “double-peaked” diurnal curve, and Pn decreased with the prolonged days of full light treatment. The SPAD value, water utilization efficiency and light use efficiency were significantly decreased under full sunlight condition. Furthermore, the maximum fluorescence signal of the P700 reaction center, electron transfer rate of photosystem II (PSII), the maximum quantum efficiency of PSII under dark adaptation and maximum quantum efficiency of PSII under light adaptation were significantly lower in full sunlight than those under shading condition, while the fraction of energy passively dissipated in the forms of heat and fluorescence, energy dissipation due to acceptor side limitation of PSI, and cyclic electron flow were significantly higher under the full light condition. Moreover, the sudden increase in growth light intensity caused a significant change in the fluorescence induction kinetic curve and significantly increased the fluorescence yield on the donor and acceptor side of PSII. The oxygen-evolving complex activity in the donor side of PSII was impaired under full sunlight. Furthermore, the electron transfer in the acceptor side of PSII was inhibited and the over-reduction of the acceptor side of PSI was caused by PSI photoinhibition. The study reveals that the full sunlight might induce the irreversible damage to PSII and the moderate photoinhibition to PSI in shade-tolerant species, and it may be an important underlying mechanisms why the shade-tolerant speciesP. notoginseng cannot survive under full sunlight.

Key words: shade-tolerant species, full sunlight, photosynthesis, photosystem, photoprotection, Panax notoginseng