青藏高原高山嵩草光合功能对模拟夜间低温的响应  

Responses of photosynthetic function of Kobresia pygmaea to simulated nocturnal low temperature on the Qingzang Plateau

作　　者：师生波[1,3] 周党卫[1] 李天才[1] 德科加[2] 杲秀珍 马家麟 孙涛[3] 王方琳[3] SHI Sheng-Bo;ZHOU Dang-Wei;LI Tian-Cai;DE Ke-Jia;GAO Xiu-Zhen;MA Jia-Lin;SUN Tao;WANG Fang-Lin(Key Laboratory of Adaptation and Evolution of Plateau Biology,Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,China;Qinghai Academy of Animal Science and Veterinary Medicine,Qinghai University,Xining 810016,China;State Key Laboratory Breeding Base of Desertification and Aeolian Sand Disaster Combating,Gansu Desert Control Research Institute,Lanzhou 730070,China)

机构地区：[1]中国科学院西北高原生物研究所高原生物适应与进化重点实验室,西宁810001 [2]青海大学畜牧兽医科学院,西宁810016 [3]甘肃省治沙研究所甘肃省荒漠化与风沙灾害重点实验室,兰州730070

出　　处：《植物生态学报》2023年第3期361-373,共13页Chinese Journal of Plant Ecology

基　　金：青海省自然科学基金(2019-ZJ-7016);青海省创新平台建设专项(2017-ZJ-Y20和2021-ZJ-Y05);国家自然科学基金(31660237)。

摘　　要：昼夜温差大是青藏高原的典型气候特征,夜间低温作为植物生长季内非常频繁的非生物胁迫因子,对典型高山植物日间光合生理功能的影响如何,尚缺乏研究。该研究以采自青海大学-清华大学三江源高寒草地生态系统野外观测站的高山嵩草(Kobresiapygmaea)为材料,应用叶绿素荧光图像分析手段,研究了模拟夜间低温对叶片光系统Ⅱ(PSⅡ)非光化学猝灭中光诱导和非光诱导的量子产量,及慢弛豫相和快弛豫相组分的影响。结果表明:0℃夜间低温对日间PSⅡ相对电子传递速率、PSⅡ反应中心开放比率(qL)和PSⅡ非光化学猝灭系数(qNP)的快速光响应曲线影响较小;400和1 500μmol·m^(-2)·s^(-1)稳态作用光强下的比较证实,夜间低温并没有影响到光合机构活性及非光化学能量耗散过程。PSⅡ反应中心激发能分配的量子通量分析表明, PSⅡ实际光化学量子效率、PSⅡ非光化学猝灭中非调节性和调节性能量耗散量子产量的相对比率在第3天高光强下,对照组和夜间低温组分别为:36:19:45和38:19:43;较低光强下为66:22:12和66:23:11。非光化学猝灭(NPQ)中快弛豫相(NPQf)为主要组分,而慢弛豫相(NPQs)所占份额(NPQs/NPQ)在对照植株的第1天和第3天分别为11%和10%,夜间低温组则为13%和12%。因此, 0℃夜间低温后,高山嵩草PSⅡ反应中心发生光抑制的几率增大,较低光强和夜间低温能导致光合诱导时间的延长;但光化学能量转换和保护性的调节机制尚能有效分配吸收的光能,夜间低温没有加剧过剩激发能难以调节耗散的趋势。Aims Kobresia pygmaea is a perennial cushion herb from the Cyperaceae family with a height of 1-3 cm and small linear leaves about 1 mm wide.It is mainly distributed on the low slopes of the high mountains ranging from 3000 m to 5960 m on the Qingzang Plateau.Its habitat is harsh,and extreme climate conditions such as low temperature,strong wind,and high sunlight intensity are the main abiotic stresses during plants growing season.The objectives of this study were to analyze the photochemical and non-photochemical energy distribution of the photosystem II(PSII)reaction center in K.pygmaea leaves,and their quenching protection mechanism after nocturnal low-temperature(NLT)treatment.Methods Kobresia pygmaea meadow turfs(30 cm×15 cm)were collected from the Alpine Grassland Ecosystem Research Station of the Resource of Three Rivers.The turf blocks were separated into two groups,one group was kept in a culture room with a temperature of 24/18°C(day/night)as a control treatment,and another was kept in an artificial climate chamber with 0°C in the evening as an NLT treatment.During the daytime,the NLT group was moved back to the culture room and irradiated together with the control group.On day 0,day 1,day 3,and day 5 after NLT treatment,the chlorophyll fluorescence of K.pygmaea leaves including,the light-response curve,PSII photochemical efficiency at 400 and 1500μmol·m^(-2)·s^(−1) steady-state light intensities,and dark relaxation were monitored using CF imager.Then,based on the“Lake Model”,the variation of the PSII actual photochemical efficiency(ΦPSII),the quantum yield of non-regulated energy dissipation(ΦNO)and regulated energy dissipation(ΦNPQ)were explored.Additionally,the fast and slow relaxation components of PSII non-photochemical quenching were determined.Important findings Nocturnal low temperature had limited effects on the rapid light-response curves of PSII relative electron transfer rate through PSII(rETR),the fraction of open PSII centers(qL),and PSII non-photochemical quenching coeffici

关 键 词：夜间低温 光系统Ⅱ非光化学猝灭 高山嵩草 青藏高原 叶绿素荧光 

分 类 号：Q945.11[生物学—植物学]