山地表生过程与生态调控重点实验室知识库

为杨柳科的柳属和杨属植物对氮素缺乏的形态和生理响应不同.本文通过川滇柳和青杨远缘嫁接,研究不同嫁接组合幼苗在氮缺乏条件下的成活率、生长状况、生物量累积与分配、气体交换参数及非结构性碳水化合物的差异响应,分析杨柳科植物远缘嫁接的可行性及嫁接对植物抗缺氮能力的影响.结果表明:川滇柳和青杨远缘嫁接的亲和性较好,川滇柳/青杨(S/P)和青杨/川滇柳(P/S)嫁接组合的成活率分别为74%和96%;缺氮显著降低了所有嫁接组合幼苗的成活率,其中S/P幼苗的成活率降低最明显,仅为53.3%,而P/S幼苗的成活率为86.7%.无论对照还是缺氮条件下,青杨做接穗的嫁接组合(P/P和P/S)的株高、基茎、生物量积累、净光合速率均大于川滇柳做接穗的嫁接组合(S/S和S/P);缺氮显著减少了所有嫁接组合的生长、生物量及净光合速率.川滇柳做砧木的嫁接组合(S/S和P/S)的根冠比显著高于青杨做砧木的嫁接组合(S/P和P/P),表明川滇柳可将更多的光合产物分配到地下部分,而青杨则将更多的光合产物投入到地上部分.各嫁接组合根中非结构性碳水化合物受缺氮胁迫最明显,除S/P嫁接组合外,P/P、S/S和P/S根中的淀粉、果糖、蔗糖和可溶性总糖浓度均显著升高,且表现为P/P和P/S显著高于S/S和S/P.

Morphological and physiological responses ofSalix plants are different fromPopulus to nitrogen (N) deficiency. In this study, grafting technology was used in S. rehderiana and P. cathayana to investigate the graft compatibility of Salix andPopulus, and whether grafting could improve the resistance to N deficiency in Salicaceae plants. The survival rate, growth, biomass accumulation and allocation, gas exchange parameters and nonstructural carbohydrates (NSCs) were measured to evaluate the resistance to N deficiency among different grafting combinations. The results showed that the graft compatibility betweenS. rehderiana and P. cathayana was quite high. The survival rate was 74% and 96% in S/P (S. rehderiana was used as scions andP. cathayana as rootstocks) and P/S (P. cathayana was used as scions andS. rehderiana as rootstocks) combinations, respectively. N deficiency reduced the survival rate in all grafting combinations, which were 53.3% and 86.7% in S/P and P/S, respectively. The survival rate of S/P was lower than that of the other grafting combinations. Under control and Ndeficient conditions, the height, basal diameter, biomass and net photosynthetic rate (P_n) of P/P and P/S combinations were higher than those of S/S and S/P combinations. N deficiency significantly reduced growth rate, biomass accumulation andP_n in all grafting combinations. The rate between root biomass and aboveground biomass ofS. rehderiana rootstock combinations (S/S and P/S) was significantly higher than those ofP. cathayana rootstock combinations (P/P and S/P) under both control and N deficient conditions. It indicated that more photosynthates might be allocated to belowground in S. rehderiana, while to aboveground inP. cathayana. The NSCs in roots of all grafting combinations were more sensitive to N deficiency than in stems and leaves. Except for the S/P combination, the starch, fructose, sucrose and total soluble sugar concentrations were significantly increased in roots in P/P, S/S and P/S combinations. Additionally, under N deficient condition, the NSCs contents were significantly higher in P/P and P/S combinations than in S/S and S/P combinations.