不同水稻品种根尖吸收NO_3^-过程中表皮细胞膜电位变化特征  

MEMBRANE POTENTIAL CHANGES OF EPIDERMAL CELLS IN THE ROOT TIPS OF RICE CULTIVARS DURING THE UPTAKE OF NITRATE

作　　者：尹晓明[1] 范晓荣[1] 贾莉君[1] 沈其荣[1] 

机构地区：[1]南京农业大学资源与环境科学学院,南京210095

出　　处：《土壤学报》2005年第2期278-285,共8页Acta Pedologica Sinica

基　　金：国家自然科学基金项目 (3 0 2 70 790;3 0 3 90 0 82 )

摘　　要：越来越多的结果表明给水稻提供部分硝酸盐营养可促进水稻的氮素总吸收量并明显改善水稻的生长发育。利用微电极技术分别测定了4个水稻品种即农垦5 7(粳稻)、泗优917(杂粳)、扬稻6号(籼稻)和汕优6 3(杂籼)幼苗根尖表皮细胞在3种NO-3 浓度(0 .1mmolL-1、1mmolL-1、10mmolL-1)处理过程中膜电位的变化特征。结果表明:水稻根系吸收NO-3 引起膜的去极化,去极化到一定程度出现复极化。去极化程度随外界处理液中NO-3 浓度的增加而加强,0 .1mmolL-1NO-3 处理产生的去极化值平均为7mV ,1mmolL-1NO-3 处理的平均为11mV ,10mmolL-1NO-3 处理的平均为2 1mV ;就复极化来说,0 .1mmolL-1NO-3 处理自动出现复极化,1mmolL-1NO-3 处理和处理10mmolL-1NO-3 处理只有当除去NO-3 时才出现复极化。就单位时间膜电位变化大小而言,扬稻6号对外界NO-3 较敏感,3种NO-3 浓度引起的去极化值均高于其他3个品种,表现出对NO-3 的吸收能力较强;泗优917和汕优6 3表现出相似的去极化大小和相似的反应时间,而农垦5 7对NO-3 相对不敏感,3种NO-3 浓度引起的去极化值均低于其他3个品种,表现出对NO-3的吸收能力较弱。另外,有部分品种的水稻根在吸收NO-3 以后表现为膜电位先超极化后去极化。上述结果表明用根系对NO-3 响应的细胞膜电位变化来研究?More and more evidence showed that rice plant could grow better if provided in part with nitrate (NO - 3). Changes of the membrane potential of epidermal cells in root tips of four rice (Oryza Sativa L.) cultivars, i.e., Nongken 57 (Japonica), Siyou 917 (Hybrid Japonica), Yangdao 6 (Indica), Shanyou 63 (Hybrid Indica) were monitored using microelectrodes in different concentrations of NO - 3(0.1 mmol L -1 , 1 mmol L -1 and 10 mmol L -1 , respectively). The results were as follows. The absorption of NO - 3 by the roots made the membrane potential depolarized, and then repolarized. The magnitude of depolarization increased with the increasing of NO - 3 concentrations and the average depolarization were 7 mV, 11 mV and 21 mV under the concentrations of 0.1 mmol L -1 NO - 3, 1 mmol L -1 NO - 3 and 10 mmol L -1 NO - 3, respectively. Repolariztion appeared 20 minutes after the treatment of 0.1 mmol L -1 NO - 3 while it did only after the NO - 3 was withdraw in the treatment of 1 mmol L -1 NO - 3 and 10 mmol L -1 NO - 3. Among the four rice cultivars tested, Yangdao 6 was most sensitive to NO - 3 with its higher level of depolarization and less time to reach the maximum of membrane potential, while Nongken 57 was less sensitive to NO - 3 with its lower level of depolarization and more time to reach the maximum of membrane potential. Siyou 917 and Shanyou 63 exhibited the similar manner on the two aspects. This suggested that Yangdao 6 has the strongest capability to take up NO - 3 while Nongken 57 has the poorest absorption of NO - 3. Besides, hyperpolarization followed by depolarization was found in parts of rice roots during the absorption of NO - 3. The results obtained in this experiment implied that response of electro potentials of cell membranes to NO - 3 could be a feasible way to the study of nitrate nutrition in rice plants.

关 键 词：NO3^- 水稻品种 种根 汕优63 扬稻6号 浓度 吸收 平均 超极化 膜电位 

分 类 号：S511[农业科学—作物学] O657[理学—分析化学]