Effect of phosphorus availability on basal root shallowness in common bean
Effect of phosphorus availability on basal root shallowness in common bean
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DOI：
10.1023/a:1010381919003
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发表时间：
2001-01-01
期刊：
影响因子：
4.9
通讯作者：
Lynch, JP
中科院分区：
文献类型：
--
作者：
Liao, H;Rubio, G;Lynch, JP
根向重力性可能是植物对磷有效性反应的一个重要因素，因为它决定了根在肥沃的表层土层中的觅食，从而决定了磷的获取。在这项研究中，我们试图在二维纸袋和沙土培养的三维固体介质中检验这一假设。五种菜豆(Phaseolus Common garis L.)在生长袋中，在生长6天以上，在沙培和土壤培养中，在生长4周以上，评估了对低磷有效性有对比适应的基因型。在所有三种基质中，磷的有效性以一种依赖于基因型的方式调节基根的向重反应。在袋、沙和土壤中，磷低效基因DOR 364在磷胁迫下的根较深，而磷高效基因G19833通过产生较浅的根来响应磷胁迫。沙培对磷胁迫的响应最强，0-3 cm和3-6 cm土层的相对根系分配率随磷胁迫的增加而增加50%，在3-6 cm(3-6 cm)和500%(0-3 cm)之间变化较大。我们的结果表明：(1)磷有效性调节纸质和固体基质中根的向重生长，(2)幼苗对营养生长的反应持续到整个营养生长，(3)根向重力性对磷有效性的响应因基因型而异，(4)对低磷有效性的基因适应与磷胁迫下将根分配到浅层土壤的能力有关。
Root gravitropism may be an important element of plant response to phosphorus availability because it determines root foraging in fertile topsoil horizons, and thereby phosphorus acquisition. In this study we seek to test this hypothesis in both two dimensional paper growth pouch and three-dimensional solid media of sand and soil cultures. Five common bean ( Phaseolus vulgaris L.) genotypes with contrasting adaptation to low phosphorus availability were evaluated in growth pouches over 6 days of growth, and in sand culture and soil culture over 4 weeks of growth. In all three media, phosphorus availability regulated the gravitropic response of basal roots in a genotype-dependent manner. In pouches, sand, and soil, the phosphorus-inefficient genotype DOR 364 had deeper roots with phosphorus stress, whereas the phosphorus-efficient genotype G19833 responded to phosphorus stress by producing shallower roots. Genotypes were most responsive to phosphorus stress in sand culture, where relative root allocation to the 0-3- and 3-6-cm horizons increased 50% with phosphorus stress, and varied 300% (3-6 cm) to 500% (0-3 cm) among genotypes. Our results indicate that (1) phosphorus availability regulates root gravitropic growth in both paper and solid media, (2) responses observed in young seedlings continue throughout vegetative growth, (3) the response of root gravitropism to phosphorus availability varies among genotypes, and (4) genotypic adaptation to low phosphorus availability is correlated with the ability to allocate roots to shallow soil horizons under phosphorus stress.