中文摘要：

在松嫩平原重度盐碱地上,选择通过土壤改良使得盐碱成分降低、结构显著改善的土壤作为处理样地（pH值9.17;电导率388μscm-1;土壤紧实度1170kPa）,邻近未改良重度盐碱地为对照样地（pH值10.15;电导率1220μscm-1;土壤紧实度2199kPa）,对生长在对照和处理样地上的银中杨不同器官叶绿素和C4光合相关酶研究发现：1）生长在处理样地的银中杨叶片叶绿素a＋b、叶绿素a/b、类胡萝卜素含量显著高于对照未处理,但树枝和树皮绿色组织内这些指标的差异远小于叶片;2）所测定3种C4光合酶结果显示,当以单位鲜重表示时,3种器官以及盐碱化程度对结果影响较小;3）当以单位叶绿素酶活性表示时,不同器官以及盐碱化程度对酶活性影响显著：树皮和树枝磷酸烯醇式丙酮酸酶（PEPC）活性是叶片的4.4和3.1倍,盐碱地改良使这一差异变成8.6和2.6倍;对照样地内树皮、树枝的苹果酸酶（NADP-ME）活性是叶片的1.7和2.1倍,盐碱地土壤改良使得这一差异达到17.2和6.4倍;与此类似,在对照盐碱地上,树皮和树枝内苹果酸脱氢酶（NADP-MDH）活性是叶片的1.7和1.4倍,盐碱地土壤改良使得这一差异变为6.4和13.7倍。上述结果说明,银中杨树干和树枝绿色组织内C4相关酶含量较叶片高出很多,而且受盐碱胁迫程度影响显著,盐碱化程度轻的情况下,这种差异会增大,这些酶的变化可以作为植物响应土壤盐碱程度变化的一种生理生化指示指标。

英文摘要：

The heavy saline-alkali land in the Songnen plain of NE China was selected as the control（pH,10.15; EC,1220μscm-1; soil compaction degree,2199kPa）and adjacent saline-alkali land after soil amelioration（pH,9.17; EC, 388μscm-1; soil compaction degree,1170kPa） was selected as treatment site.3-yr-old Yinzhong poplar（Populus alba×P.berolinensis） grown in these two sites over 1 year were analyzed and we found that： 1） chlorophyll a＋b, chl.a/b and total carotenoids of the leaf in ameliorated soil were much higher than those in the untreated saline-alkali soil, while the differences in stem bark and branch were far smaller than those in the leaf; 2） All the three C4 enzymes expressed at a basis of fresh weight showed small differences among leaf, branch and stem bark, and the influences from saline-alkali soil amelioration treatment were rather slight; 3） When the unit was expressed as chlorophyll basis, significant differences among different organs as well as between two soil treatments were observed, i.e., PEPC in stem bark and branch was respectively 4.4 fold and 3.1 fold higher than those in leaf in the untreated control, while these differences became 8.6 fold and 2.6 fold in the ameliorated soil treatment. In the untreated control land, NADP-ME in stem bark and branch were 1.7 fold and 2.1 fold higher than those in leaf, while these difference became 17.6 fold and 6.4 fold in the ameliorated soil treatment. Similarly, NADP-MDH in stem bark and branch in the untreated saline-alkali land were respectively 1.7 fold and 1.4 fold higher than those in leaf, while they became 6.4 fold and 13.7 fold in the ameliorated soil treatment. Our findings manifest that non-photosynthetic organs （such as stem and branch） had much higher content of C4 pathway-related enzymes comparing with the leaf lamina. Moreover, such differences could be adjusted by soil saline-alkali degree, i.e. the differences could be dramatically enlarged in the ameliorated saline-alkali land. Possibly, the changes in C4-related