权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Mechanisms on the Al tolerance and accumulation of plants adapted to low pH soils

低pH土壤植物对铝的耐受和积累机制

基本信息

批准号：
09460035
负责人：
OSAKI Mitsuru
金额：
$ 2.5万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09460035/
关键词：
Aluminum sensitive plants Aluminum excluder plants Aluminum require plants Al accumulator plants low pH adapted plants low pH tolerant plants Al感受性植物 Al排除植物 Al要求性 Al集積植物

项目摘要

The effects of N-source and Al on the growth of seedlings of Melastoma malabathricum, Acacia mangium and Melaleuca cajuputi, which are tropical woody plants and are very tolerant to Al, and barley (Hordeum vulgare), which is a typical Al-sensitive plant, were investigated. The Al and N treatments consisted of the application of either 0 or 0.5 mM Al, and 2 mM NH_4^+ or NO_3^-, respectively. Growth of the tropical plants was enhanced by Al and NH_4 application. Excised roots of M.malabathricum dissolved insoluble Al with NH_4 application and absorbed Al mainly from root tips. Al did not affect the leaf N concentration except in the case of barley. Roots of M.cajuputi exuded a large amount of citrate, which slightly increased by the +Al treatment. In A.mangium, the reactivity of soluble Al to PCV (pyrocatecholviolet) decreased in the culture solution of the +Al+NH_4 treatment and Al concentration of roots in this treatment was very low. Roots of M.malabathricum released H+ along with Al uptake as well as NH_4^+ uptake. It is concluded that Al and NH_4^+ exert beneficial effects on the growth of tropical tree seedlings.Al appeared mostly in apoplastic fraction in excised melastoma roots treated with 0.1 mM Al for 180 min, and CCCP did not affect the Al uptake, indicating that Al uptake in the excised roots occurs mostly through passive accumulation in the apoplast. The Al ion displaced 3H^+ on carboxyl groups in the melastoma root apoplast when it was taken up, a finding not observed in barley. This adsorption site had a higher affinity to the Al ion compared with Ca^<2+> or La^<3+>. On the other hand, three months after Al exposure, Al concentration in the symplastic and residual fractions of the melastoma roots was very high and surpassed that in the apoplastic fraction. From the results in the present and previous studies, a hypothesis of the Al uptake mechanism in melastoma roots was proposed.

研究了氮源和铝对耐铝的热带木本植物马来青花、马相思和千层木以及典型铝敏感植物大麦幼苗生长的影响。Al和N处理分别为0或0.5 mM Al和2 mM NH_4^+或NO_3^-。施用Al和NH_4能促进热带植物的生长。在NH_4处理下，断根对不溶性铝有溶解作用，铝主要从根尖吸收。除大麦外，铝对叶片氮浓度无显著影响。枸橼酸根分泌量较大，+Al处理后略有增加。在mangium中，+Al+NH_4处理的培养液中，可溶性Al对邻苯二酚的反应性降低，且根中Al浓度很低。根释放H+，同时吸收Al和NH_4^+。结果表明，Al和NH_4^+对热带树木幼苗的生长有有益的影响。在0.1 mM Al处理180 min后，Al主要出现在褪黑瘤离体根的外胞体部分，CCCP不影响Al的吸收，说明离体根对Al的吸收主要是通过外胞体的被动积累进行的。当Al离子被吸收时，在黑色素瘤根外质体的羧基上置换3H^+，这在大麦中没有观察到。与Ca^<2+>或La^<3+>相比，该吸附位点对Al离子具有更高的亲和力。另一方面，暴露3个月后，黑色素瘤根的共塑部分和残留部分的Al浓度非常高，超过了外塑部分。根据目前和以往的研究结果，提出了一种关于黑色素瘤根部铝吸收机制的假设。