胡杨异形叶光合系统Ⅱ叶绿素荧光特性
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引用本文:王海珍,韩 路,徐雅丽,刘艳萍,王 琳.胡杨异形叶光合系统Ⅱ叶绿素荧光特性[J].西北植物学报,2019,39(10):1795~1804
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作者单位
王海珍,韩 路,徐雅丽,刘艳萍,王 琳 (塔里木大学 植物科学学院新疆生产建设兵团塔里木盆地生物资源保护利用重点实验室新疆阿拉尔 843300) 
基金项目:国家自然科学基金(31660117, 31260058,30960033)
中文摘要:以塔里木盆地胡杨3种典型异形叶(条形叶、卵形叶与锯齿阔卵形叶)为材料,利用光合与叶绿素荧光测定技术测量胡杨异形叶气体交换与叶绿素荧光动力学参数,探讨异形叶光合机构对太阳辐射光能的利用、能量分配与耗散特性及影响其光合能力的主要因素,揭示胡杨异形叶光合生理功能的差异与生理生态适应机制。结果表明:(1)晴天正午胡杨异形叶净光合速率(Pn)、PSⅡ有效光化学量子效率(Fv′/Fm′)、实际光化学量子效率(ΦPSⅡ)、光化学猝灭系数(qP)显著降低,而PSⅡ激发能压力(1 qP)、光合功能相对限制(LPFD)则显著增大,至傍晚Fv′/Fm′、ΦPSⅡqP与光化学反应能量(P)恢复,表明荒漠强太阳辐射导致正午胡杨异形叶光合作用发生了光抑制,但并未造成PSⅡ反应中心的不可逆破坏。(2)3种异形叶采取了不同的适应方式来适应荒漠强光环境。卵形叶通过提高光能捕获与转化效率、光化学反应能量来保持叶片高光合能力以消耗多余能量、降低过剩激发能对光合机构的影响;锯齿叶通过保持高光合电子传递能力来缓解光合膜上的还原态压力并以热耗散清除过剩激发能,二者协同保护光合机构免受强光损伤从而维持较高的Pn;条形叶不耐强光,但可以通过降低光能捕获与转化效率并将吸收的光能更多用于热能和荧光辐射耗散过剩激发能来适应强光环境。(3)逐步回归分析表明,锯齿叶光合能力主要受PSⅡ反应中心光合电子传递速率和非光化学猝灭过程中的非辐射能量耗散的影响;卵形叶、条形叶分别受PSⅡ反应中心光能捕获与转化效率和非光化学猝灭过程中的过剩激发能耗散的影响。综上所述,胡杨异形叶在生长发育过程中采取了不同的生态策略来适应荒漠环境。
中文关键词:胡杨  异形叶  叶绿素荧光特性  光抑制  适应机制
 
Chlorophyll Fluorescence Characteristics of Photosystem Ⅱ of Populus euphratica Heteromorphic Leaves
Abstract:The gas exchange and chlorophyll fluorescence parameters of lanceolate, oval and serrated broad oval leaves of Populus euphratica in Tarim basis were measured with chlorophyll fluorometer (PAM 2100) and LI 6400 Portable Photosynthesis System. The characteristics of solar radiation utilization, energy allocation and dissipation in three different leaf shapes of P.euphratica were analyzed by comparing the differences in photosynthetic parameters, in order to elucidate the ecophysiological adaptation mechanisms. The result showed that: (1) under strong solar radiation of desert region, the net photosynthetic rate (Pn), PSⅡ effective, actual photochemical quantum efficiency (Fv′/Fm′ and ΦPSⅡ) and photochemical quenching coefficient (qP) decreased, and excitation pressure (1 qP), relative limitation of photosynthetic function (LPFD) increased obviously, and Fv′/Fm′, ΦPSⅡ, qP, energy of PSⅡ photochemistry transport (P) could go to near the mining level, which indicated that strong solar radiation could cause the photoinhibition of photosynthesis. However, this constituted reversible destruction to PSⅡ reaction center in three heteromorphic leaves, their PSⅡ function downregulation were an adaptation to avoid strong solar radiation damage. (2) Three typical heteromorphic leaves of P.euphratica taken different ways to adapt strong solar radiation in desert area. The oval leaves improved Fv′/Fm′, ΦPSⅡ, P to maintain higher photosynthetic capacity, in order to dissipate excess light energy and reduce the effects of excess excitation energy on photosynthetic apparatus. The serrated broad oval leaves maintained high electron transport rate (ETR) to relieve the reduced pressure of photosynthetic membrane and dissipate thermally to protect the photosynthetic apparatus avoiding light damage together, and maintain higher Pn. However, lanceolate leaves had weakness resistance for strong light, reduced Fv′/Fm′, ΦPSⅡ and allocated more absorb light energy to dissipate more excess excitation energy, further to better adapt strong solar radiation and survive. (3) Stepwise regression analysis indicated that photosynthetic capacity of serrated broad oval leaves were mainly affected by ETR and NPQ, the oval leaves and lanceolate leaves were mainly affected by Fv′/Fm′, ΦPSⅡ and NPQ, respectively. Overall, Three typical heteromorphic leaves of P.euphratica adopted different ecological strategies to adapt the desert environment with development.
keywords:Populus euphratica Oliv.  heteromorphic leaves  chlorophyll fluorescence characteristics  photoinhibition  adaptation mechanism
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