Stimulation of Root Growth Induced by Aluminum in Quercus serrata Thunb. Is Related to Activity of Nitrate Reductase and Maintenance of IAA Concentration in Roots
Stimulation of Root Growth Induced by Aluminum in Quercus serrata Thunb. Is Related to Activity of Nitrate Reductase and Maintenance of IAA Concentration in Roots
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DOI：
10.4236/ajps.2012.311196
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发表时间：
2012-11
期刊：
影响因子：
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通讯作者：
Rie Tomioka;C. Takenaka;M. Maeshima;T. Tezuka;M. Kojima;H. Sakakibara
中科院分区：
文献类型：
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作者：
Rie Tomioka;C. Takenaka;M. Maeshima;T. Tezuka;M. Kojima;H. Sakakibara
铝是地壳中含量最丰富的金属。土壤酸化释放的过量Al3+被认为是许多栽培植物的生长限制因素，但已有报道称，在一定浓度的Al3+下，对某些作物和树种的生长有促进作用。此前，我们曾报道铝处理促进了根的发育、从生长介质中的吸收和体内的硝酸还原酶(NR)活性。硝酸还原酶是植物氮素代谢的关键酶之一，是植物硝酸盐同化的第一步。本研究对铝诱导锯缘栎苗早期根系发育的过程进行了研究，重点研究了铝和钙处理1h后，锯缘栎幼苗根中硝酸还原酶(NR)活性、吲哚-3-乙酸(IAA)和细胞分裂素含量的变化。在铝处理的根中，硝酸还原酶(NR)活性增加，生长素(IAA)浓度与处理前持平，IAA降解的代谢中间产物吲哚-3-乙酰-L-天冬氨酸(IA-Asp)在根中未检测到。在钙处理的根中，随着IA-Asp浓度的增加，NR活性增加，而IAA含量降低。因此，铝处理根中IAA浓度的维持似乎是IAA分解过程中受到抑制的结果。铝处理增加了次生根的长度和数目，而钙处理则没有增加。结果表明，铝诱导的早期根系发育与硝酸还原酶活性和IAA浓度的维持有关。第3名：
Aluminum (Al) is the most abundant metal in the earth’s crust. Excess Al 3+ released by soil acidification in soil solution is thought to be a growth limiting factor to many cultivated plant species, but it has been reported to stimulate plant growth in some crop and tree species in certain concentration of Al 3+ . Previously, we had reported that Al treatment enhanced root development, uptake from growth media and in vivo nitrate reductase (NR) activity of roots. NR is one of the key enzymes in nitrogen metabolism and acts at the first step of nitrate assimilation in plants. In this study, we investigated the process of Al-induced root development in an early stage, focusing on the change in in vitro NR activity, and indole-3-acetic acid (IAA) and cytokinins concentration in roots of Quercus serrata seedlings, which were treated for 1 h with Al or Ca. In Al-treated roots, NR activity increased and IAA concentration was maintained at the same level as pretreatment, and indole-3-acetyl-L-aspartic acid (IA-Asp), which is a metabolic intermediate of IAA degradation, was not detected in roots. In Ca-treated roots, NR activity increased, but IAA concentration decreased as IA-Asp concentration increased. Thus, the maintenance of IAA concentration in Al-treated roots seems to result from suppression in the process of IAA decomposition. Al treatment increased the length and number of second lateral roots but Ca treatment did not. We concluded that root development induced by Al in the early stage was related to NR activity and maintenance of IAA concentration. 3 NO