中文摘要：

该文利用盐敏感的群众杨，研究在盐胁迫条件下吸水剂对树木抗盐性的影响．实验中使用的是德国Stoekhausen化学公司研制生产的新型吸水剂：Stoeksorb 500 XL（钾-聚丙烯酸脂-聚丙烯酰胺共聚体）．土壤中施用0．5％吸水剂（干重）提高了群众杨的抗盐性．在盐胁迫期间，吸水剂处理显著抑制了有害盐离子Na^＋和Cl^-在苗木叶片中的积累，提高了苗木的气孔导度（Gs）、蒸腾速率（TRN）和光合速率（In），使苗木能够维持超氧化物歧化酶（SOD）同工酶和过氧化物酶（POD）同工酶的活性，保持了活性氧清除能力．NaCl处理苗木在处理后25d叶片出现盐害，Stoeksorb 500 XL型吸水剂使苗木盐害出现的时间推迟20d．吸水剂能调控植物对离子的吸收，主要源于吸水剂对盐分的缓冲作用和离子选择吸附作用：①Stoeksorb 500 XL自身超强的吸水能力起到了稀释土壤盐分的作用，形成了植物根系生长的低盐环境；②通过对离子的选择吸附，吸水剂胶体富积了钙和镁，屏蔽了Na^＋离子．另外，Stoeksorb 500 XL自身含有可被植物根系吸收利用的K^＋．所以，根系生长在这样的环境中，无疑将减少对有害盐离子的吸收、转运和积累，而增加对营养元素的吸收和利用，最终提高了植物的抗盐性．

英文摘要：

The effects of hydrogel on salt resistance of a salt-sensitive woody species, Populus popularis ‘35-44＇, were investigated under saline conditions. The hydrogel used was Stoeksorb 500 XL （crosslinked poly potassium-co-（acrylic resin polymer）-co-polyacrylamide hydrogel） manufactured by Stoekhansen GmbH Krefeld （Germany）. Amendment of saline soil （dry weight） with 0.5% Stocksorb 500 XL enhanced salt tolerance of the tested poplar genotype. Hydrogel-treatment markedly limited the buildup of salt ions （Na^＊ and CI^- ） in leaves of P. popularis ‘35-44＇ , but increased stomatal conductance （Gs）, transpiration rate （TRN） and net photosynthetic rate （Pn） of the genotype. Moreover, application of hydrogel assisted P. popularis ‘35 -44＇ to maintain the activity of superoxide dismutase （SOD） and peroxidase （POD） isoenzymes, thus remaining the capacity to eliminate salt-induced reactive oxygen species （ROS） under salt stress. NaCl-treated P. popularis ‘ 35-44＇ plants exhibited leaf necrosis after 25 days of salt stress, whereas the hydrogel amendment delayed the occurrence of leaf injury for 20 days. The reduction of salt uptake by hydrogel amendment was the results of salt-buffering and ion-selective uptake capacity： I） Stoeksorb 500 XL diluted Na~ and CI- concentration in the gel matrix due to the water-holding capacity of hydrogel, allowing roots to grow in an environment of lower salinity; 2） the enrichment of nutrients Ca^2＋ and Mg^2＋, instead of Na^＋ , was accounted for the cationexchange character of Stocksorb 500 XL. Furthermore, Stocksorb 500 XL contains K^＋ that can be taken up by plant roots. Collectively, root aggregation in hydrogel allows good contact with a source of lower salinity but with higher K^＋ , therefore, the absorption, transportation and accumulation of salt ions in plant tissues were reduced, but the uptake of nutrients was increased. As a result, the salt resistance of plants is consequently increased.