硝酸镧提高黑麦草种子活力和幼苗生物量的生理效应

研究了不同浓度硝酸镧对黑麦草种子萌发和幼苗生长的影响及其生理生化变化。结果表明，低浓度硝酸镧（1000mg·L^-1）处理能够提高黑麦草种子的活力和萌发种子的淀粉酶、蛋白酶和脂肪酶活性及IAA、GA和CTK含量；促进幼苗光合速率提高和干物质积累，这可能与硝酸镧提高幼苗叶片叶绿素含量和叶绿体希尔反应活力，促进光合电子传递和磷酸化反应及激活Rubisco羧化活性、PEP羧化酶活性有密切关系，其中以30mg．L^-1浓度处理的效果最佳；高浓度硝酸镧（70-100mg·L-1）处理则降低种子活力和抑制幼苗生长。而10-100mg．L-1硝酸镧对种子的萌发率、ABA含量和Rubisco的加氧活性影响不大。由此可见，低浓度硝酸镧可通过参与萌发和光合过程的调控提高黑麦草种子的活力，促进幼苗生长。

Physiological Effects of La（NO3）3 on Increasing Seed Vigor and Seedling Biomass of Ryegrass

Effects of La（NO3）3 on seed germination and seedling growth of ryegrass and it＇s physiological and biochemical changes were studied. The results showed that 10-50 mg.L1 La（NO3）3 could increase seed vigor and activities of amylase, proteinase and lipase, and contents of auxins （IAA）, gibberellins （GA） and cytokinin （CTK） during seed germination. The growth and photosynthetic rate of seedlings in Hoagland solution with La（NO3）3 cultured were promoted, which were closely related to the increases of chlorophyll content, Hill activities, chloroplast electron transport rates, photophosphorylation levels and the activities of Rubisco car- boxylase and PEPCase in seedling leaves. The optimal concentration of La（NO3）3 was 30 mg-L1, but inhibition when the concentration of La（NO3）3 were 70-100 mg.L-1. However, 10 to 100 mg.L-1La（NO3）3 had little effects on the germination rate, abscisic acid （ABA） content and Rubisco oxygenase activity. It was concluded that the suitable concentration La（NO3）3 could increase seed vigor and seedling biomass of ryegrass via regulating and controlling germination and photosynthetic physiological metabolism.