通过沙培和水培实验,采用原子吸收分光光度计法和离子吸收动力学方法,对NaCl胁迫下坪山柚(Citrus grandis Osbeck ‘Pingshanyou’) 和福橘(C. reticulate Blanco ‘Fuju’)实生苗矿质营养吸收特性进行研究。结果表明,随NaCl浓度增加,坪山柚和福橘幼苗地上部及根部Na⁺、Cl^-含量明显增加,K⁺、Ca²⁺含量降低。相同浓度NaCl胁迫下,坪山柚地上部及根部Na⁺、Cl^-含量分别低于福橘,而根部K⁺、Ca²⁺含量及地上部K⁺含量、K⁺/Na⁺值、Ca²⁺/Na⁺值均高于福橘。NaCl胁迫下,坪山柚、福橘幼苗Na⁺吸收量高于Cl^-吸收量,Na⁺及Cl^-的吸收速率均随NaCl浓度的增大而增加。相同浓度NaCl胁迫下,坪山柚对Na⁺、Cl^-的吸收速率低于福橘,这与坪山柚对Na⁺、Cl^-的吸收具有较大的Km值及较小的V_max值一致,表明坪山柚幼苗比福橘幼苗耐盐性强。

By sand culture and hydroponics culture experiments and by using atomic absorption

spectrophotometer and ion absorption kinetics method, the effects of NaCl stress on the characteristics of mineral nutrition absorption in seedlings of Citrus grandis Osbeck `Pingshanyou' and C. reticulata Blanco `Fuju' were studied. The results showed that Na⁺ and Cl^- contents in both root and the above-ground part of C. grandis and C. reticulata seedlings increased obviously with the increase of NaCl concentration, but the contents of K⁺、Ca²⁺ decreased. The contents of Na⁺, Cl^- in root and the above-ground partof C. grandis seedlingswere lowerthan that in C. reticulata respectively, but the contents of K⁺、Ca²⁺ in root, the content of K⁺ and the value of K⁺/Na⁺,Ca²⁺/Na⁺ in above-ground part of C. grandis seedlings were higher than that in C. reticulata under the same NaCl concentration. The absorption amount of Na⁺ was higher than that of Cl^- in C. grandis and C. reticulata, respectively, the absorption rate of Na⁺, Cl^- in C. grand is and C. reticulata seedlings increased as the NaCl concentration increased. The absorption rate of Na⁺ and Cl^- in C. grandis was lower than that in C. reticulata underthe same NaCl concentration,which coincided with the

result that the C. grandis seedlings had higher Kmvalue and lower Vmaxvalue than that in C. reticulate seedlings under the same NaCl stress. It suggests that the salt tolerance of C. grandis seedlings is stronger than that of C. reticulata seedlings.