摘要
利用微电极技术分别测定了2个水稻品种即武育粳3号(粳稻)和扬稻6号(籼稻)幼苗根尖细胞在吸收不同NH4+浓度(0.0250、.05、0.1、0.5、1.0和1.5 mmol/L)下膜电位的变化特征。结果表明,水稻根系吸收NH4+引起膜的去极化,去极化到一定程度出现部分复极化,有一小部分根系还有超极化现象。去极化大小随外界处理液中NH4+浓度的增加而加强,达到一定程度以后趋于平稳,吸收进程符合Michaelis-Menten动力学特征。两个品种产生的去极化程度不同,武育粳3号产生的去极化大小平均为16.5 mV,扬稻6号产生的去极化大小平均为22.6 mV。在低浓度NH4+(<1.0 mmol/L)处理下,扬稻6号对NH4+较敏感,产生的去极化大小平均为17.5 mV,高于武育粳3号(去极化大小平均为10.9 mV),两个品种产生的去极化大小差异显著(p<0.05)。研究结果表明,扬稻6号吸收NH4+的能力比武育粳3号强,这与吸收动力学的结果是一致的。
Changes of the plasma membrane potential on 3 （Japonica） and Yangdao 6 （Indica） were monitored root tips of two rice （Oryza sativa L）cultivars, i.e., Wuyujing using microelectrodes under different concentrations of NH4^＋ （0.025, 0.05,0.1,0.5,1.0 and 1.5 mmol/L）. The results were as follows： NH4^＋ uptake by the roots made plasma membrane potential depolarized; however, depolarization to the certain degree, it appeared the partial repolarization and hyperpolarization in some parts of rice roots during the absorption of NH4^＋ . The magnitude of depolarization increased with the increasing of NH4^＋ concentrations until a stable state. The course of NH4^＋ uptake process conformed to Michaelis- Menten kinetics. The two rice cultivars had different depolarization modes in which the average values depolarized were 16.5 mV （Wuyujing3） and 22.6mV （Yangdao 6）. Under low concentration of NH4^＋ （ 〈1mmol/L）, with its higher average level of depolarization（17.5mV）, Yangdao 6 was more sensitive to NH4^＋ being higher compared to Wuyujing 3 （10.7 mV）, and there existed a significant difference in the size of depolarization between these two cultivars （p 〈 0.05）. This suggested that Yangdao 6 had the stronger capability to take up NH4^＋ than Wuyujing 3. The results obtained in this experiment were consistent with those of kinetics of NH4^＋ influx.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2005年第6期769-773,共5页
Journal of Plant Nutrition and Fertilizers
基金
国家自然科学基金项目(30270790
30390082)资助
关键词
微电极
水稻根系
NH4^+
浓度
膜电位
microelectrodes
rice roots
NH4^＋ concentration
membrane potential
