不同浓度NH_4^+和K^+处理对拟南芥突变体amos2侧根发育的影响  

The Effects of Different Concentrations of NH_4^+ and K^+ Treatments on Lateral Root Development of Arabidopsis amos2 Mutant

作　　者：冯晓宇[1,2] 李光杰[1,2] 董刚强[1,2] 施卫明[1] 

机构地区：[1]土壤与农业可持续发展国家重点实验室,中国科学院南京土壤研究所,南京210008 [2]中国科学院大学,北京100049

出　　处：《植物生理学报》2013年第5期463-468,共6页Plant Physiology Journal

基　　金：国家自然科学基金青年科学基金项目(31200189);中国科学院南京土壤研究所知识创新工程领域前沿项目(ISSASIP1103)

摘　　要：K+在缓解植物NH4+毒害过程中扮演着重要的角色。本文研究培养基中添加不同浓度(0.6、1.2和5.0mmol·L-1)的K+时,高NH4+(30或40mmol·L-1)对拟南芥野生型Col-0和NH4+超敏感突变体amos2侧根生长的影响。结果表明,在较低外源K+浓度(0.6和1.2mmol·L-1)下,30mmol·L-1NH4+使amos2的侧根数量减少85%~90%,超过对Col-0的2倍;外源K+浓度提高到5.0mmol·L-1时更显著缓解高NH4+对amos2侧根数量的抑制作用。高NH4+对Col-0和amos2新生根区侧根数量的抑制比对成熟根区的大。时间动态的结果表明:在低K+条件下,高NH4+处理的初始阶段,amos2侧根的发育已开始受到比Col-0更显著的抑制,且amos2侧根的出现受到更明显的延时;将外源K+浓度提高到5.0mmol·L-1能缓解这种延时效应。可见,在低K+条件下,AMOS2位点可能在拟南芥抵抗高NH4+对侧根的抑制过程中发挥作用,降低NH4+/K+比可能是提高拟南芥高NH4+抗性的手段。K＋ plays an important role in the process of protecting plant species from NH4＋ toxicity. In this arti- cle, lateral root （LR） development of Arabidopsis wild type （Col-0） and amos2 mutant （which is overly sensi- tive to NH4＋ supply） was analyzed under excessive NH4＋ （30 or 40 mmol.L-1） with different concentrations of K＋ （0.6, 1.2 and 5.0 mmol.L-1） added in agar medium. The results showed that high NH4＋ could inhibit the rela- tive number of LRs of amos2 by 85%-90% on the low external K＋ （0.6 or 1.2 mmol-Ll）, it was twice higher than that of Col-0. However, the LR development of Arabidopsis under NH4＋ stress could be recovered by high- er external K＋ （5.0 mmol.L-1）, especially to amos2. Furthermore, high NH4＋ had more significant inhibition on the LR development of distal portion than that of proximal portion. The LRs of amos2 had been more signifi- cantly inhibited by high NH4＋ at the initial phase of treatment than that of Col-0, and there was also an obvious time delay on the LR development of amos2 under high NH4＋ and low external K＋. Higher external K＋ （5.0 mmol·L-1） could relieve the time delay of LR development under NH4＋ stress. All the results indicate that the AMOS2 locus plays an important role in the resistance to high NH4＋, particularly at low external K＋, and the decrease in NH4＋/K＋ ratio is a vital cause for plants to resist NH4＋ toxicity.

关 键 词：拟南芥突变体 K^+ 根发育 浓度 侧根生长 延时效应 NH4^+ 抑制作用 

分 类 号：Q945[生物学—植物学]