【摘要】 盐渍土壤中盐分的空间分布是非均匀的，具有空间异质性。为探明异质盐胁迫对杜梨生长的影响，本试验利用自制沙培分根容器，对其幼苗进行异质盐胁迫处理，研究不同盐胁迫条件下杜梨幼苗的生长特征、光合特性、叶片氮含量及叶面温度等指标的变化。结果表明：不同盐胁迫处理对杜梨植株生长影响明显，异质盐胁迫0/100处理下幼苗株高、生物量、根冠比均显著高于均匀盐胁迫和异质盐胁迫0/200处理。随着盐胁迫时间的延长，均匀盐胁迫100/100和200/200处理下植株分别在41 d和26 d后萎蔫死亡。盐胁迫降低叶片的SPAD值和光合参数；异质盐胁迫处理下叶片SPAD值、叶绿素荧光参数（Fv/Fm）、净光合速率（Pn）、气孔导度（Gs）、胞间CO₂浓度（Ci）和蒸腾速率（Tr）均高于同浓度均匀盐胁迫处理，且不同时间段内异质盐胁迫叶片的Fv/Fm、Pn、Gs和Tr与均匀盐胁迫均差异显著。异质盐胁迫处理下叶片氮含量均随胁迫时间延长表现出先升高后降低趋势，而均匀盐胁迫则呈下降趋势。异质和均匀盐胁迫下，同一时间内植株的叶面温度略高于无盐胁迫，各处理间无显著差异，并随胁迫时间的延长呈现“低-高-低”的单峰趋势。更多还原

【Abstract】 The spatial distribution of salinity in saline soil is non-uniform and has spatial heterogeneity. In order to ascertain the effects of heterogeneous salinity stress on growth of Pyrus betulifolia Bunge, the seedlings were treated with heterogeneous salinity stress by using the root-division container of sand culture made by ourselves to study the change of growth characteristics, photosynthetic characteristics, leaf nitrogen content and leaf temperature under different salinity stress conditions. The results showed that the effects on the growth of P. betulifolia under different salinity stress treatments were significant. The plant height, biomass and root-shoot ratio of seedlings under heterogeneous salinity stress of 0/100 were significantly higher than those under uniform salinity stress and heterogeneous salinity stress of 0/200. With the extension of salt stress time, the plants under uniform salinity stress of 100/100 and 200/200 wilted and died after 41 days and 26 days, respectively. The SPAD value and photosynthetic parameters of leaves were reduced under salinity stress. The SPAD value, chlorophyll fluorescence parameters Fv/Fm, net photosynthetic rate（Pn）, stomatal conductance（Gs）, intercellular CO₂ concentration（Ci） and transpiration rate（Tr） of leaves under heterogeneous salinity stress were higher than those under uniform salinity stress with the same concentration, and the Fv/Fm, Pn, Gs and Tr under heterogeneous salinity stress were significantly different from those under uniform salinity stress in different periods. The leaf nitrogen content under heterogeneous salinity stress showed an obvious trend of first increase and then decrease with the extension of stress time, while that under uniform salinity stress showed a downward trend. The leaf temperature under heterogeneous and uniform salinity stress were slightly higher than that under salt-free stress at the same time and no significant differences among the treatments, and showed a single peak trend of low-high-low with the time extension of salinity stress.更多还原