Phosphorus (P) uptake and growth of a root hairless barley mutant (bald root barley, brb) and wild type in low- and high-P soils
Phosphorus (P) uptake and growth of a root hairless barley mutant (bald root barley, brb) and wild type in low- and high-P soils
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DOI：
10.1046/j.1365-3040.2003.01093.x
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发表时间：
2003-10-01
影响因子：
7.3
通讯作者：
Nielsen, NE
中科院分区：
文献类型：
--
作者：
Gahoonia, TS;Nielsen, NE
最近分离的无根毛突变体大麦（大麦L），秃根大麦，brb提供了一个独特的可能性，以量化根毛的重要性，从土壤中吸收磷（P）。在本研究中，BRB和野生型，大麦基因型Pallas生产正常根毛消耗根际土壤中的P的能力进行了研究和理论的扩散和质量流应用到比较预测和测量耗尽配置文件的可扩散P. Pallas耗尽两倍多的P从根际土壤BRB。Pallas的磷消耗曲线均匀地延伸到距根表0.8mm处，与根毛长度（RHL）相等。基于扩散和质量流理论的模型解释了brb的磷素耗竭剖面和Pallas根毛区外的磷素耗竭，表明该模型仅适用于根毛区外根际土壤中的磷素迁移。在低磷土壤（P在土壤溶液中3 M）brb没有存活30天后，而小兔八哥继续增长，证实了在植物生长的重要性，根毛在磷限制的环境。在高磷土壤（P在土壤溶液中10 M）都brb和小行星保持其增长，他们能够产生种子。在高磷浓度下，Pallas的RHL从0.80 +/- 0.2降低到0.68 +/- 0.14 mm。在低磷土壤中，Pallas的根系吸收磷的速率为4.0 x 10（-7）g mm（-1）d（-1），brb为1.9 x 10（-7）g mm（-1）d（-1），这与Pallas根际土壤中磷的消耗量是brb根际土壤的两倍相吻合。在高磷土壤中，brb和Pallas根系对磷的吸收速率分别为3.3和5.5 × 10（-7）g mm（-1）d（-1）。这些结果明确地证实了在低磷环境中，根毛在磷的吸收和植物的存活中具有重要的作用，但在高磷环境中，它们可能被破坏。大麦表型brb和Pallas的特征以及再生种子的能力为定位大麦根毛形成和生长的QTL和候选基因提供了独特的可能性。
The recently isolated root-hairless mutant of barley (Hordeum vulgare L), bald root barley, brb offers a unique possibility to quantify the importance of root hairs in phosphorus (P) uptake from soil. In the present study the ability of brb and the wild-type, barley genotype Pallas producing normal root hairs to deplete P in the rhizosphere soil was investigated and the theory of diffusion and mass flow applied to compare the predicted and measured depletion profiles of diffusible P. Pallas depleted twice as much P from the rhizosphere soil as brb. The P depletion profile of Pallas uniformly extended to 0.8 mm from the root surface, which was equal to the root hair length (RHL). The model based on the theory of diffusion and mass flow explained the observed P-depletion profile of brb, and the P depletion outside the root-hair zone of Pallas, suggesting that the model is valid only for P movement in rhizosphere soil outside the root-hair zone. In low-P soil (P in soil solution 3 m M) brb did not survive after 30 d, whereas Pallas continued to grow, confirming the importance of root hairs in plant growth in a P-limiting environment. In high-P soil (P in soil solution 10 m M) both brb and Pallas maintained their growth, and they were able to produce seeds. At the high-P concentration, RHL of the Pallas was reduced from 0.80 +/- 0.2 to 0.68 +/- 0.14 mm. In low-P soil, P-uptake rate into the roots of Pallas was 4.0 x 10(-7) g mm(-1) d(-1) and that of brb was 1.9 x 10(-7) g mm(-1) d(-1), which agreed well with the double amount of P depleted from the rhizosphere soil of Pallas in comparison with that of brb. In high-P soil, the P uptake rates into the roots of brb and Pallas were 3.3 and 5.5 x 10(-7) g mm(-1) d(-1), respectively. The results unequivocally confirmed that in a low-P environment, root hairs are of immense importance in P acquisition and plants survival, but under high-P conditions they may be dispensable. The characterization of phenotypes brb and Pallas and the ability to reproduce seeds offers a unique possibility of molecular mapping of QTLs and candidate genes conferring root-hair formation and growth of barley.