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Studies on the evasive strategy for acid-soil stress by the extracellular released materials operating in the process of root elongation

根系伸长过程中细胞外释放物质规避酸性土壤胁迫策略的研究

基本信息

批准号：
04660065
负责人：
WAGATSUMA Tadao
金额：
$ 1.34万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

(1) Elucidation of the primary specific site for Al^<3+> : Experiments were carried out by utilizing the difference of the order of ionic potential ; Al^<3+>>Yb^<3+>>La^<3+>. The amount of beta-glucan synthesizd on the surface of protoplasts from root tip was in the order of Al>Yb>La ; a universal deposition of beta-glucan on that from Al-tolerant, but a heterogeneous dotted deposition from al-sensitive plant species. The beta-glucan synthesized was composed in part of 1, 3-beta-glucan. FDA viability of root treated with metals was in the order of Al<Yb<La, and the accumulation of metals in the outer portions of roots was considerable in the order of Al>Yb>La. La induced most heavily the irreversible plasmolysis, the inhibition of root elongation, and the loss of K from roots. The aggregation of protoplasts in non-synthesizing conditions of beta-glucan was higher in the order of Al>Yb>La. These results indicate the plasma membrane of the outer and tip portions of roots as the primary specific site for Al^<3+>. (2) Isolation of Al-tolerant root cells based on the surface negativity of plasma membrane from root tip : Al tolerance was not correlated with CEC of root tip, but megatively correlated with the negativity of plasma membrane. Non-toxic Al(OH)_3 was mixed with silica microbeads (Al-SMB) ; the pH of the highest positive charge of Al-SMB was 5.3. Purified protoplasts from root tip were mixed with Al-SMB at this pH, and finally viable Al-tolerant protoplasts were isolated predominantly in the bottom fraction by centrifuging with a discontinuous gradient. (3) Preparation of solid medium without Al and the analysis of organic acids released from roots : By adding the nutrient solution to SMB, agar-like solid medium without Al was prepered ; physical properties of it resembled the actual soil conditions. Organic acids released from roots were collected by filtering the Al-SMB.(4) Relationship between Al olerance and organic acids rel

(1)Al^3+主要特异位点的阐明：利用离子势级差进行实验； Al^<3+>>Yb^<3+>>La^<3+>。根尖原生质体表面β-葡聚糖的合成量顺序为Al>Yb>La； β-葡聚糖普遍沉积在耐铝植物上，但铝敏感植物物种上存在异质点状沉积。合成的β-葡聚糖部分由1, 3-β-葡聚糖组成。经金属处理的根部的 FDA 活力顺序为 Al<Yb<La，并且根部外部金属的积累量相当大，顺序为 Al>Yb>La。 La最严重地诱导了不可逆的质壁分离、根伸长的抑制以及根中钾的损失。非β-葡聚糖合成条件下原生质体聚集程度较高，顺序为Al>Yb>La。这些结果表明根的外部和尖端部分的质膜是Al 3+ 的主要特异性位点。 (2)根据根尖质膜表面负性分离耐铝根细胞：耐铝性与根尖CEC不相关，但与质膜负性显着相关。无毒的Al(OH)_3与二氧化硅微珠(Al-SMB)混合； Al-SMB最高正电荷的pH值为5.3。在该 pH 值下将来自根尖的纯化原生质体与 Al-SMB 混合，最后通过不连续梯度离心，主要在底部部分分离出存活的耐铝原生质体。 (3)无铝固体培养基的制备及根部释放有机酸的分析：将营养液加入SMB中，制备无铝琼脂状固体培养基；其物理性质与实际土壤条件相似。通过过滤Al-SMB收集根部释放的有机酸。(4)Al耐受性与有机酸相对值的关系