【作者】 陈静；

【导师】 贺康宁；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2010， 硕士

【摘要】 为了探讨水分胁迫和NaCl胁迫对植物生长和光合生理特性的影响,该文以土壤-植物-大气连续系统(SPAC)理论为基础,选择黄土高寒区的三种水土保持灌木银水牛果(Shepherdia argentea)、沙棘(Hippophae rhamnoides Linn)和沙木蓼(Atraphaxis frutescens)作为研究对象。在2008年生长季期间,利用Li-6400便携式光合仪等仪器测定三种灌木的光合生理特征,分析其对水分胁迫和NaCl胁迫的反应。主要研究内容有：水分胁迫下三种灌木的生长指标的测定；水分胁迫条件下,光辐射强度对三种灌木的光合特性及水分利用效率的影响；水分胁迫下三种灌木的净光合速率、蒸腾速率及其相互关系；NaCl胁迫对三种灌木的生长及生理指标的影响；NaCl胁迫对三种灌木光合特性的影响。经研究,结果表明：1、随着水分胁迫的加剧,三种灌木的生物量(总干重和总鲜重)和单株总叶面积均显著下降,其影响程度表现为银水牛果>沙木蓼>沙棘。2、水分胁迫对三种灌木的净光合速率、蒸腾速率和水分利用效率的日过程产生显著影响。适度的水分胁迫能够提高三种灌木的水分利用效率,银水牛果和沙木蓼在土壤含水量为7.2-14.35%能保持较高水分利用效率,沙棘在土壤含水量<7.2%仍能保持较高水分利用效率。3、光辐射强度对三种灌木的净光合速率、蒸腾速率和水分利用效率产生显著影响。银水牛果在800-1800μmo1·m-2·s-1,沙棘在1200-200μmol·m-2·s-1,沙木蓼在800-2000μmol·m-2·s-1范围内具有较高的净光合速率和水分利用效率。4、NaCl胁迫使三种灌木的生物量、单株总叶面积和叶绿素含量显著下降,且同等胁迫条件下,沙棘的生理指标的下降幅度大于其他两种灌木,沙棘表现出对盐的敏感性。5、随着NaCl胁迫浓度的增加及胁迫时间的延长,三种灌木的净光合速率、蒸腾速率和气孔导度均明显下降,且同等条件下,沙棘下降的幅度大于其他两种灌木。随着NaCl胁迫时间的延长,三种灌木的Pn下降由气孔限制转为非气孔限制。更多还原

【Abstract】 In order to study the plants’physiological and photosynthetic characteristics responding to the water stress and NaCl stress, we used three water-and-soil-conservative shrubs-- Shepherdia argentea, Hippophae rhamnoides Linn and Atraphaxis frutescens-as the research objectives, based on the SPAC theory. During the growth period in 2008, Li-6400 portable photosyntometer was employed to measure the photosynthetic characteristics of the above three shrubs and their corresponding responses to the water stress and NaCl stress were also analyzed. The main study includes:measuring the growth index of the three shrubs under the water-stress condition; the influence of radiant intensity on the three shrubs’photosynthetic characteristics and the water use efficiencies under the water-stress condition; the three shrubs’ photosynthetic rates, transpirational rates and their correlations under the water-stress condition; the influence of NaCl stress on the three shrubs’growth and physiological index; the influence of NaCl stress on the three shrubs’photosynthetic characteristics.Our study results show that:(1) With the increase of water-stress levels, the three shrubs’biomass (i.e. the total dry weights and the total fresh weights) and the overall leaf areas per tree both decrease remarkably. And the influence degrees are Shepherdia argentea> Atraphaxis frutescens>Hippophae rhamnoides Linn;(2) The water stress has high influence on the three shrubs’net photosynthesis rates, transpirational rates and water use efficiency. Mediate water-stress level could increase their water use efficency. In particular, we observed that Shepherdia argentea and Atraphaxis frutescens have relatively higher water use efficiency in the soil which has a 7.2%--14.35% water content and Hippophae rhamnoides Linn showed relatively higher water use efficiency even in the soil with less than 7.2% water content;(3) The radiant intensity has high influence on the three shrubs’ net photosynthesis rates, transpirational rates and water use efficiency. In particular, Shepherdia argentea, Hippophae rhamnoides Linn and Atraphaxis frutescens showed higher net photosynthesis rates and water use efficiencies on the radiant ranges 800-1800μmol·m-2·s-1,1200-2000μmol·m-2·s-1 and 800-2000μmol·m-2·s-1 respectively.(4) The three shrubs’ biomass, the overall leaf areas per tree and chlorophyll content all decreasd remarkably with the increase of NaCl-stress levels. Besides, given the same NaCl-stress level, Hippophae rhamnoides Linn’s physiological characteristics dropped by larger amounts compared with the other two plants and it also showed sensitivity to salt;(5) With the increase of NaCl-stress levels and the stress time,the three shrubs’net photosynthesis rates, transpirational rates and stomatal conductance all extremely decreasd. Besides, given the same stress conditions, Hippophae rhamnoides Linn’s physiological characteristics dropped by larger amounts than the other two plants. And the three shrubs’Pn decrease converted from stomatal limit to non-stomatal limit with the extension of the NaCl stress time.更多还原