作 者 ：王晓琴1;2;袁继超1;柯永培1;刘从军1;熊庆娥1
期 刊 ：植物营养与肥料学报 2005年 11卷 1期 页码：27-32
Keywords:osmoticstress, maize, rootvigor, K+uptakekineticsparameter,
摘 要 ：本试验以三个抗旱性不同的玉米品种作为试验材料,以26％聚乙二醇Polyethylene.glycol(PEG)(分子量4000)溶液对幼苗进行模拟渗透胁迫,研究了渗透胁迫对3个抗旱性不同的玉米品种幼苗根系活力及对K+吸收的动力学的影响。结果表明,玉米幼苗根系对K+的吸收速度符合Michaelis-Menten动力学方程;短期(24h内)的渗透胁迫可在一定程度上促进根系的生长,根系活力增强,NR活力升高,根系与离子的亲和力增加(Km下降),抗旱性强的品种促进程度大于抗旱性弱的品种;较长时间(超过48h)的渗透胁迫则抑制根系的生长,根系活力、NR活性等降低,根系与离子的亲和力下降(Km升高)。抗旱性强的品种受抑程度轻,Km值的升幅小,而抗旱性弱的品种受抑程度重,Km值的升幅大。玉米幼苗根系吸收K+的Km与根数、根重、根系活力、吸收面积、NR活力等极显著相关,可作为玉米抗旱性强弱的指标。
Abstract:Maize may suffer a good many nature disasters and serious drought stress during its growth period. Drought brings about more output reduction than the sum of that caused the other nature disasters. Drought affects the process of physiology metabolizability, i.e., cell growth, photosynthesis, respiration, hormone and enzyme metabolizability, and the absorbability, transportation, translation, accumulation of water, mineral element and organic compound. Kalium ion is the most important osmotic regulation substance that can improve osmotic regulation of plant which increases plant resistance to drought. The kalium nutrition of plant is mostly derived from soil and root is a main organ for kalium absorption. The growth of root and its ability of gaining kalium affect the status of plant kalium nutrition to a certain extent. The ability of absorption and utilization of water is related to plant kalium nutrition closely. The lack of kalium could inhibit water and nutrition utilization in plant and root growth. Many researches regarding the osmotic stress on growth and physiology metabolizability have been reported, but few researches are reported regarding the effects of osmotic stress on kinetics parameters of K+ uptake of root. Three hybrid varieties with different drought resistant abilities were used as experimental materials. We used 26% Polyethylene glycol(PEG) (MW4000) to cause osmotic stress to study the effects of osmotic stress on root vigor and kinetics parameters of K+ uptake of maize seedling. The results were as follows: the K+ uptake rate of maize seedling root can be described by Michaelis-Menten kinetics equation. Short-term (in 24hours) osmotic stress promoted the growth of root, increased root vigor, inspired NR activity and enhance the appetency between root and ion enhanced (Km value of K+ uptake decreased) . High drought-resistant variety had more positive response to short-termosmotic stress than that of low drought-resistant variety. After 48 hour, osmotic-stress inhibited the root growth; decreased root vigor, reduced NR activity, and depressed the appetency between root and ion (Km value of K+ uptake increased) . The stress caused by the long term osmotic stress on high drought-resistance variety was small and Km value increased slightly, while the damp on low drought-resistant variety was more serious, and Km value increased more. There was a significant correlation between Km value of K+ uptake and number of roots, root weight, absorbs area of root, root vigor and NR activity. The Km value of K+ uptake can be used as an index for the drought-resistant ability of plants.
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