3种杂交杨在不同盐碱地上的生长和生理适应性研究

杂交杨树是松嫩平原盐碱地重要的园林和造林树种，野外长期监测是评价和优选优良品种的关键。本研究在自然条件下（5~12月），以大庆不同盐碱地上生长的青山杨(Populus pseudo-cathayana×P. deltodides cv. Shan Hai Guan)、小黑14（Populus×xiao hei T. S. Hwang et Liang ‘14’）及中黑防(Populus deltoids×P. cathayana)的4年生扦插苗为研究对象，通过对3种杂交杨生长量、根系活力、根呼吸量和叶绿素含量的对比和分析，探讨其在盐碱地生长的适应性及耐盐能力的差异。结果表明，随盐碱胁迫加强（土壤电导率609.33~910.48 μs·cm^-1，pH值（8.92~8.98），各杂交杨的生长量受到明显抑制，其中中黑防和小黑14株高均下降达到40%，而青山杨的株高只下降了20%，是前者的一半。随盐碱胁迫加强，根系活力和呼吸作用增强，青山杨、中黑防和小黑14的根系活力分别提高了10.75%、15.90%和33.17%，而根系呼吸青山杨仅上升3.59%，中黑防和小黑14则上升了24%以上。但是盐碱胁迫对于叶绿素含量影响较小，年平均值稍有降低，叶绿素a/b的比值则增大，不同品种间差异较小。综合对3种杂交杨的各项指标的研究，青山杨的耐盐碱能力更强，生长量显著高于目前在盐碱地区较为普遍应用的小黑14和中黑防，比较而言，青山杨是盐碱地区造林与绿化树种的优良杂交杨品种。

Growth and Physiological Adaptability of Three Hybrid Poplars Planted in Different Saline-alkali Soil

The hybrid poplar is the important garden and afforestation tree species on Songnen Plain saline-alkali land, long-term field monitoring is the key to evaluate and optimize superior varieties. Under the natural conditions, different four-year-old cutting seedlings of Qing Shan Yang (Populus Pseudo-cathayana×P. deltodides cv. Shan Hai Guan), Xiao Hei 14 (Populus×xiao hei T.S. Hwang et Liang ‘14’) and Zhong Hei Fang (Populus deltoids×P. cathayana) that grew at different saline-alkali land in Daqing City were used as the research (study) materials. Through the comparison and analysis of the growth (height and basal diameter), root activity, root respiration and chlorophyll content, the growth adaptability and salinity tolerance differences in the saline-alkali soil were explored. The results show that, with the saline-alkali stress(soil electrical conductivity from 609.33 μs·cm^-1 to 910.48 μs·cm^-1 and pH from 8.92 to 8.98) enhanced, the growth of hybrid poplar was restrained obviously,the tree heights of Qing Shan Yang merely declined 20%,only one half of that for Zhong Hei Fang and Xiao Hei 14.With the saline-alkali stress enhanced, root activity and root respiration were enhanced, the root activity of Qing Shan Yang, Zhong Hei Fang and Xiao Hei 14 improved 10.75%,15.90%and 33.17% respectively, root respiration of Qing Shan Yang merely increased 3.59%, that of the other two varieties increased more than 24%.However, in saline-alkali stress the chlorophyll content was less affected, the annual mean was decreased slightly，Chla/b ratio was increased, smaller differences existed between different species. Comprehensive researches of various indices of three hybrid poplars,the ability of tollerance to saline-alkali stress of Qing Shan Yang is stronger than the other two. The growth of Qing Shan Yang is obviously better than Zhong Hei Fang and Xiao Hei 14, which were generally applied on saline-alkali land at present. Comparatively speaking,Qing Shan Yang is an improved hybrid poplar variety for afforestation and greening on saline-alkali land.