中文摘要：

耐盐植物引种和培育是开发利用盐碱地的主要方式，具有重要的研究价值。本试验以哈萨克斯坦引进的吉尔吉斯白桦（Betula kirghisorum）、欧洲白桦（B．pendula）、毛枝桦（B．pubescens）和本地的白桦（B．platyphylla Suk．）1年生幼苗为试验材料，于2014年7月在东北林业大学进行中性盐（NaCl）和碱性盐（NaHCO3）的胁迫试验，测定生长量、光合参数和叶绿素含量，并通过因子分析法，对比评价4种桦树幼苗的耐盐碱能力，筛选出综合性状优良的桦树树种，为耐盐植物引种和培育提供有价值的数据。结果表明：随着盐浓度的升高，桦树幼苗的高生长和光合效率受到显著抑制，而当浓度≥0．5％时，大部分幼苗枯死。株高增长量、基径增长量、净光合速率（Pn）、光能利用效率（SUE）、羧化效率（CUE）、表观量子效率（AQY）及叶绿素含量之间的相关性多数达到了显著水平；最后利用因子分析法分别构建了0．1％NaCl、0．3％NaCl、0．1％NaHCO3和0．3％ NaHCO3胁迫处理的综合评价公式，并分别筛选出了综合性状相对优良的单株，其中NaCl胁迫下较优单株为32、33、34、35；NaHCO3胁迫下较优单株为262、263、264、35。综合比较认为，吉尔吉斯白桦对低中浓度的中性盐的抗性最强，本地对照白桦对低中浓度碱性盐的抗性最强，而吉尔吉斯白桦和毛枝桦对高浓度碱性盐抗性较强。

英文摘要：

Introducing and breeding salt-tolerant plants are a main way to exploit saline land with an important research value. We used one-year seedlings of Betula kirghisorum, B. pendula, B. pubescens brought from Kazakhstan and local B. platyphylla Suk. as the test materials. Neutral salt （NaCl） and alkaline salts （NaHCO3 ） stress tests were conducted in July 2014 in Northeast Forestry University. We measured growth, photosynthesis and chlorophyll content. We used factor analysis method to compare and evaluated the salt tolerance of four kinds of birch seedlings. At last, we screened the birch species with an excellent comprehensive performance. As the salt concentration increases, the high growth and photosynthetic efficiency of birch seedlings were significantly inhibited and while the concentration ≥ 0.5%, most seedlings withered. Correlation of height and diameter-increment, net photosynthetic rate （Pn）, photosynthetic-light-use efficiency （SUE）, carboxylation efficiency （CUE）, apparent quantum yield（AQY） and chlorophyll content reached a significant level. We obtained the following comprehensive evaluation formula for salt stress treatment of 0.1% NaCl, 0. 3% NaCl, 0. 1% NaHCO3 and 0.3% NaHCO3 and screened out the best individual plants with exceptional comprehensive characters. The optimum individual plants for NaCl stress were 32, 33, 34 and 35, and for NaHC03 stress were 262, 263, 264 and 35, respectively. B. kirghisorurn had the strongest resistance to neutral salt and B. platyphylla Suk. had the strongest resistance to alkaline salt with low concentration, and B. kirghisorum and B. pubescens had more resistance to alkaline salt with high concentration.