外源柠檬酸作用下大豆根尖铝积累规律的研究  

Localized Accumulation of Aluminum in Soybean(Glycine max Merrill)Root Tips under Exogenous Citric Acid

作　　者：金婷婷[1] 刘鹏[1] 孙婷[1] 刘春生[1] 金海华[1] 

机构地区：[1]浙江师范大学植物学重点实验室,浙江金华321004

出　　处：《大豆科学》2008年第4期581-587,共7页Soybean Science

基　　金：国家自然科学基金资助项目(30540056);浙江省自然科学基金资助项目(305186;303461)

摘　　要：耐铝性大豆根系柠檬酸的分泌被认为是缓解铝胁迫的重要方式。设置外源柠檬酸协同铝处理,检测根尖铝积累的荧光染色、根尖铝的相对含量以及处理液中3种不同铝形态的变化情况,旨在探索柠檬酸与大豆根系环境中铝的作用规律,进一步揭示大豆根系分泌物缓解铝毒的机理。结果表明:大豆根尖细胞细胞壁积累铝的现象十分明显,且随着铝处理浓度的增加和处理时间的延长,细胞壁固定的铝逐渐增多;外源柠檬酸存在下,细胞壁铝积累明显减少,浙春3号尤为显著。浙春3号和浙春2号铝积累量随着铝浓度的增大和铝处理时间的延长而呈不同的变化趋势。从铝形态结果分析,可以判断Ala和Alb活性铝的含量变化趋于相同,外源柠檬酸作用下,各浓度梯度的活性铝形态含量均较单铝胁迫时有所降低。综合试验结果可知,植物在接触铝胁迫的初期,自身缓解铝毒的机制是需要时间而呈周期性波动的过程;外源柠檬酸对浙春3号的缓解作用比浙春2号强,一定比例的外源柠檬酸加入可改变大豆自身的耐铝能力,但是超过一定比例就会在某种程度上对植物产生新的酸化毒害。It is well known that the important role of citrate in the mechanism for Al resistance in soybean. The effect of alu- minum plus exogenous citrate acid on fluorescence detection, aluminum comparative concentration of soybean root tips and aluminum speciation in treated solution,were all investigated using hydroponic culture, to discover the effect of citrate with aluminum which exists in the rhizosphere of soybean and the mechanism of alleviating aluminum toxicity by soybean root exudation. Results showed it was significant that aluminum accumulated in the cell wall of soybean root tip cells, and it became more and more remarkable with dose and time incroased;in the present of exogenous citric acid, the content of aluminum accumulated in the cell wall decroased,especiaUy in Zhechun No. 3. The change of comparative Al content in root tips of Zhechun No. 3 and Zhechun No. 2 did not play the same pattern in dose- and time- dependent manner. From the analysis of aluminum speciation,it could be seen that the change pattern of the content of Al, and Albwere parallel;the content of the two form decreased but Ale increased with exogenous organic acids. Thus it could be concluded that it needs time and displayed as fluctuating periodically in the mechanism of detoxification aluminum, when plants meet aluminum for the initial stages. Exogenous citric acid was more effective to Zhechun No. 3 than to Zhechun No. 2 under aluminum stress. At the same time, only proper proportion of exogenous citric acid could avail to detoxification of aluminum for soybean; Yet it may result in the fact of serious toxicity on plants overstep some extent of exogenous citric acid.

关 键 词：铝积累 细胞壁 荧光检测 铝形态 Al-Ferron逐时络合比色法 

分 类 号：S565.1[农业科学—作物学]