ALUMINUM TOLERANCE IN WHEAT (TRITICUM-AESTIVUM L) .1. UPTAKE AND DISTRIBUTION OF ALUMINUM IN ROOT APICES
ALUMINUM TOLERANCE IN WHEAT (TRITICUM-AESTIVUM L) .1. UPTAKE AND DISTRIBUTION OF ALUMINUM IN ROOT APICES
复制标题
DOI：
10.1104/pp.103.3.685
复制
发表时间：
1993-11-01
期刊：
影响因子：
7.4
通讯作者：
RANDALL, PJ
中科院分区：
文献类型：
--
作者：
DELHAIZE, E;CRAIG, S;RANDALL, PJ
研究了近等基因小麦(Triticum aestivum L.)根尖对铝的吸收和分配。在同一基因座(ALT1：耐铝性)上耐铝性不同的品系。幼苗生长在含有100亩铝的营养液中，然后用苏木素进行染色，苏木素是一种在体外与铝结合形成有色络合物的化合物。铝敏感品种的根尖在短期铝暴露(10min和1h)后染色，而耐铝幼苗的根尖在相同的铝暴露后染色较弱。差异染色先于观察到的根伸长或根尖(根末端2-3 mm)的总铝浓度的差异。在营养液中暴露4h或100亩铝后，铝敏感品种的根尖总铝积累量高于耐铝品种，且随着时间的延长差异更加显著。对冻干根尖进行X射线微区分析表明，铝进入铝敏感植物根尖，并在表皮层和紧邻表皮层的皮质层中积累。长期暴露于铝溶液中(24小时)，敏感尖端的铝分布与K的缺乏相吻合。铝在皮层中的定量结果表明，在相同时间内，敏感尖端积累的铝是耐受尖端的5-10倍。这些数据与ALT1编码的一种将Al从根尖排除在外的机制的假设是一致的。
We investigated the uptake and distribution of Al in root apices of near-isogenic wheat (Triticum aestivum L.) lines differing in Al tolerance at a single locus (Alt1: aluminum tolerance). Seedlings were grown in nutrient solution that contained 100 mu M Al, and the roots were subsequently stained with hematoxylin, a compound that binds Al in vitro to form a colored complex. Root apices of Al-sensitive genotypes stained after short exposures to Al (10 min and 1 h), whereas apices of Al-tolerant seedlings showed less intense staining after equivalent exposures. Differential staining preceded differences observed in either root elongation or total Al concentrations of root apices (terminal 2-3 mm of root). After 4 h or exposure to 100 mu M Al in nutrient solution, Al-sensitive genotypes accumulated more total Al in root apices than Al-tolerant genotypes, and the differences became more marked with time. Analysis of freeze-dried root apices by x-ray microanalysis showed that Al entered root apices of Al-sensitive plants and accumulated in the epidermal layer and in the cortical layer immediately below the epidermis. Long-term exposure of sensitive apices to Al (24 h) resulted in a distribution of Al coinciding with the absence of K. Quantitation of Al in the cortical layer showed that sensitive apices accumulated 5- to 10-fold more Al than tolerant apices exposed to Al solutions for equivalent times. These data are consistent with the hypothesis that Alt1 encodes a mechanism that excludes Al from root apices.