摘要
以ＣａＳＯ４０．５ｍｍｏｌＬ－１溶液培养高粱得到低钾植株，在渗透胁迫下当ＰＥＧ－１０００使外界渗透势下降时，刺激了高粱根高Ｋ＋亲和系统的净Ｋ＋积累，其表观Ｋｍ值和Ｔｍａｘ值分别为１８μｍｏｌＬ－１和４９．６μｍｏｌｇ－１ＤＷｈ－１。此高亲和系统不受可渗物质乙二醇和外界ｐＨ变化的影响，为蛋白质合成抑制剂环己酰亚胺抑制。
Low K+ sorghum plants were cultured in 0. 5 mmol L-1 CaSO4 solution.The low K+ roots of these plants hadtwo K+ uptake systems: a high-affinitycomponent and a linear low - affinitycomponent (Fig. 1 ). A decrease of theexternal osmotic potential, caused byPEG- 1000 solution, stimulated K+ accumulation completed by a new transport system with appearant K. and Vmaxvalues of 18 μmol L-1 and 49. 6 μmolg-1 DW h-1, respectively (Fig. 2). Therelationship between H+efflux and K+accumulation showed that the highaffinity system was driven directly byATP, while the low-affinity systemwas coupled to H+ extrusion (Table 1,Fig. 6). The inhibition of this processby cycloheximide, a protein synthesisinhibitor, indicated that the highaffinity component was formed through de mevo synthesis under PEG-1000 stress(Fig. 5). Therefore, it is suggested thatosmotic stress can induce the formationof a high-affinity K+ transport system.
基金
国家自然科学基金重点
关键词
高粱
渗透胁迫
根
钾吸收
osmotic stress, sorghum roots, K+ uptake, H￣+ secretion
