作 者 ：柴胜丰,唐健民,王满莲,陈宗游,蒋运生,韦 霄*
期 刊 ：西北植物学报 2015年 2期 页码：322~328
Keywords:Camellia petelotii, drought stress, photosynthetic gas exchange, chlorophyll fluorescence, physiological characteristics,
摘 要 ：以金花茶一年生实生苗为材料,采用盆栽控水试验,研究不同水分处理(CK、T1、T2、T3,土壤含水量分别为田间持水量的85%~90%、65%~70%、50%~55%、35%~40%)对金花茶幼苗光合生理指标的影响。结果显示:(1)在重度干旱胁迫(T3处理)下,金花茶植株都因干旱而死亡,表明金花茶幼苗对干旱胁迫的耐受极限为田间持水量的50%~55%(土壤含水量为15.04%~16.54%)。(2)随着干旱胁迫程度的加剧,金花茶幼苗叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、气孔限制值(Ls)和PSⅡ实际光化学量子效率(ΦPSⅡ)均显著降低,胞间CO2浓度(Ci)和水分利用效率(WUE)无显著变化,干旱胁迫下金花茶光合速率降低的主要原因是由非气孔因素所致。(3)与CK相比,T1处理下叶片初始荧光(F0)、最大荧光(Fm)、PSⅡ最大光化学效率(Fv/Fm)和丙二醛(MDA)含量均无显著变化,而T2处理下F0、MDA含量显著升高,Fm、Fv/Fm 显著降低;T1处理下金花茶的PSⅡ反应中心还未受到伤害,而T2处理下其光合机构发生了不可逆的破坏。(4)叶片叶绿素总量(Chl)、叶绿素a(Chl a)、叶绿素b(Chl b)、类胡萝卜素(Car)含量、Chl a/Chl b、Car/Chl、叶片相对含水量(RWC)均随干旱胁迫的增强而降低,脯氨酸(Pro)含量随干旱胁迫的加剧呈现出先升高后降低的趋势。研究表明,金花茶对干旱胁迫极为敏感,水分稍有亏缺,便会明显抑制其光合作用;金花茶不耐干旱的生理特性可能是限制其种群扩散的一个重要原因。
Abstract:A pot experiment was conducted to study the effects of different water treatments[CK(with soil water content 85%~90% of field capacity),T1(with soil water content 65%~70% of field capacity),T2(with soil water content 50%~55% of field capacity),T3(with soil water content 35%~40% of field capacity)] on the photosynthetic and physiological characteristics of Camellia petelotii seedlings.The results showed that:(1)All plants were dead in T3 treatment,indicating that soil water content 50%~55% of field capacity is the threshold to water stress.(2)When increasing drought stress,the net photosynthetic rate(Pn),stomata conductance(Gs),transpiration rate(Tr),stomatal limitation values(Ls) and actual photosynthetic efficiency of PSⅡ(ΦPSⅡ) all significantly decreased,while the intercellular CO2 concentration(Ci) and water use efficiency(WUE) kept invariable.The decrease of Pn in drought stress of C.petelotii was mainly caused by non-stomatal inhibition.(3)Compared with CK,the minimal fluorescence(F0),maximal fluorescence(Fm),maximum quantum yield of PSⅡ(Fv/Fm) and malondialdehyde(MDA) content of leaves in T1 treatment did not change significantly,while in T2 treatment,Fm and Fv/Fm decreased significantly,F0 and MDA content enhanced significantly,which indicated that the reaction center of PSⅡ of C.petelotii was not injured in T1 treatment,while the photosynthetic apparatus was destroyed irreversible in T2 treatment.(4)The contents of total chlorophyll(Chl),chlorophyll a(Chl a),chlorophyll b(Chl b),carotenoid(Car) in leaves,Chl a/Chl b,Car/Chl,relative leaf water content(RWC) all decreased with increasing drought stress,while the proline(Pro) content increased under T1 treatment and decreased under T2 treatment.The results proved that C.petelotii was extremely sensitive to drought stress,the water deficit would restrain its photosynthesis.Intolerance to drought for C.petelotii may be an important reason to limit the spread of its population.