Rhizosphere effect and root growth of two maize (Zea mays L.) genotypes with contrasting P efficiency at low P availability
Rhizosphere effect and root growth of two maize (Zea mays L.) genotypes with contrasting P efficiency at low P availability
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DOI：
10.1016/j.plantsci.2004.02.026
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发表时间：
2004-08-01
期刊：
影响因子：
5.2
通讯作者：
Zhang, FS
中科院分区：
文献类型：
--
作者：
Liu, Y;Mi, GH;Zhang, FS
开发农作物遗传资源是利用土壤中有效磷的一条途径，也是解决磷矿粉短缺的一条途径。作物耐低磷性存在基因型差异，这是由不同的生理和形态机制造成的。在这项研究中，低磷耐性的两个玉米基因型，已被确定为具有对比的磷效率（籽粒产量）在石灰性土壤中进行了调查。测定的参数是生物量积累，根系生长和根系分泌的有机酸，根酸性磷酸酶（APase）活性，根际pH值在缺磷（-P）和磷充足（+P）条件下的溶液培养。结果表明，-P处理提高了两种基因型的根系生物量（第6 ~ 15 d）、根冠比、侧根长、根内和根表APase活性，但降低了根系分泌的有机酸和根际pH值。在两种磷处理下，磷高效系181的根系重量和侧根长度均大于磷低效系197，表明磷高效系181的根系形态是适应低磷胁迫的一个有利但非特异的性状。基因型181，当生长与P显着降低溶液和rizhosphhere的pH值，并增加AP酶活性的根和根表面。令人惊讶的是，根系分泌的有机酸减少-P在这两种基因型。两种磷处理下，181的有机酸渗出率均低于197。得出的结论是，有效地利用磷在石灰性土壤中的181是其大的根系，更大的能力，酸化根际，和AP酶的生产和排泄低磷条件下的积极响应。(C)2004爱思唯尔爱尔兰有限公司保留所有权利。
Exploring the genetic resource of crops is one alternative way to utilize the less available phosphorus (P) in soils, and copy with the incoming shortage of rock phosphate (Rock P). Genotypic differences in low-P tolerance exist in many crop species and result from various physiological and morphological mechanisms. In this study, low-P tolerance of two maize genotypes that had been identified to have contrasting P efficiency (grain yield) in a calcareous soil was investigated. Parameters measured were biomass accumulation, root growth and root exudation of organic acids, root acid phosphatase (APase) activity, and rhizosphere pH under P-deficient (-P) and P-sufficient (+P) conditions in solution culture. The results showed that -P treatment increased root biomass (from 6th to the 15th day), root to shoot ratio, lateral root length, and APase activity in roots and on the root surface, but reduced root exudation of organic acids and pH in rhizosphere for both genotypes. The P-efficient line 181 had a larger root system in terms of root weight and lateral root length than the P-inefficient line 197 in both P treatments, indicating root morphology of line 181 is an advantageous but non-specific trait in adaptation to low P stress. Genotype 181, when grown with -P markedly reduced the pH of the solution and rizhosphere and increased the APase activity in the roots and on the root surfaces. Surprisingly, root exudation of organic acids was reduced by -P in both genotypes. Exudation rate of organic acids in 181 was lower than that of 197 under both P treatments. It was concluded that efficient use of P in the calcareous soil by 181 is related to its large root system, greater ability to acidify the rhizosphere, and positive response of APase production and excretion to low P conditions. (C) 2004 Elsevier Ireland Ltd. All rights reserved.