持续干旱对侧柏和祁连圆柏叶片水分状况及光合作用的影响  

Effects of Continuous Drought on Water Status and Photosynthesis of Leaves of Platycladus orientalis(L.) Franco and Juniperus przewalskii Kom

作　　者：马仁义[1] 张茜[1] 张强[1] 赵长明[1] 

机构地区：[1]兰州大学生命科学学院干旱与草地教育部重点实验室,甘肃兰州730000

出　　处：《干旱区研究》2010年第1期88-96,共9页Arid Zone Research

基　　金：国家自然科学基金项目(30600041;30430560);瑞典国际科学基金(IFS)项目(AD/17475)

摘　　要：以侧柏(Platycladus orientalis)和祁连圆柏(Juniperus przewalskii)2年生幼苗为材料,用盆栽实验比较持续干旱对两者叶片水分及光合生理特性的影响。研究发现:侧柏水势(ψ)、叶片相对含水量(RWC)、净光合速率(Pn)、最大光化学效率(Fv/Fm)、实际光化学效率(Φ_(PSII))、电子传递速率(ETR)和叶绿素含量(Chl a,Chl b,Chl a+b)的下降幅度均大于祁连圆柏,且游离脯氨酸含量(Pro)和叶绿素原初荧光值(Fo)上升幅度大于后者,但两者胞间CO_2浓度(Ci)和气孔限制值(Is)变化相反。这些结果表明,侧柏对干旱胁迫敏感度明显高于祁连圆柏,祁连圆柏对干旱胁迫的抵抗力更高;侧柏净光合速率的下降主要是叶绿素组分和光合器官功能的破坏等非气孔因素引起的,而祁连圆柏净光合速率的下降主要是气孔因素引起的。另外,持续干旱处理后祁连圆柏仍保持较高的瞬时水分利用效率(WUEi)和电子传递速率(ETR),表明它能够通过提高水分利用效率和光呼吸速率来减小干旱胁迫产生的伤害。这将为黄土高原区生态恢复中造林绿化树种的选择提供理论依据和实践指导。Two-year old seedlings of Platycladus orientalis （ L. ） Franco and Juniperus przewalskii Kom were planted into plastic pots and subjected to a 40-day continuous drought treatment. Then the different responses of water status, gas exchange parameters, chlorophyll fluorescence parameters and chlorophyll contents to the continuous drought were investigated. It is found that, after the continuous drought treatment, the water potential （ ψ）, relative water content （RWC）, net photosynthetic rate （Pn）, maximum photochemical efficiency of PSII （Fv/Fm） actual photochemical efficiency of PSII （ФPSII）, electron transport rate （ETR） as well as chlorophyll contents （Chl a, Chl b and Chl a ＋ b） of P. orientalis were decreased more significantly than those of J. przewalskii , and the free proline （Pro） and primeval chlorophyll fluorescence （Fo） of P. orientalis were increased more significantly than those of J. przewalskii. These results reveal that P. orientalis was more sensitive to water deficit and suffered more severe drought impact than J. przewalskii, then J. przewalskii had a stronger endurance of water stress, higher drought resistibility and higher potential delay of dehydration. The reduction of Pn of P. orientalis was caused by non-stomatal limitation factors as the intercellular CO2 concentration （Ci） was increased and stomatal limitation value （Ls） was decreased, reversely the reduction of Pn of J. przewalskii was mainly caused by stomatal limitation factors as Ci was decreased and Ls was increased. Fv/Fm, ФPSII, ETR and chlorophyll contents of P. orientalis were significantly decreased but Fo was significantly increased under the continuous drought, indicating that the components of chlorophyll of P. orientalis were decomposed, as a consequence, the interior structure of photosynthetic organs was damaged. However, the chlorophyll fluorescence parameters and chlorophyll contents of J. przewalskii were slightly changed only, so that its photosynthetic organs coul

关 键 词：干旱胁迫 叶片水分 净光合速率 气体交换 叶绿素荧光 侧柏(Platycladus orientalis) 祁连圆柏(Juniperus przewalskii) 

分 类 号：S791[农业科学—林木遗传育种]