Rice Genotype Differences in Tolerance of Zinc-Deficient Soils: Evidence for the Importance of Root-Induced Changes in the Rhizosphere.
Rice Genotype Differences in Tolerance of Zinc-Deficient Soils: Evidence for the Importance of Root-Induced Changes in the Rhizosphere.
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DOI：
10.3389/fpls.2015.01160
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发表时间：
2015
影响因子：
5.6
通讯作者：
Wissuwa M
中科院分区：
文献类型：
--
作者：
Mori A;Kirk GJ;Lee JS;Morete MJ;Nanda AK;Johnson-Beebout SE;Wissuwa M
缺锌是水稻生产的一个主要制约因素，在以大米为基础的饮食中，人类也经常缺乏锌。培育锌效率更高的水稻的努力受到对缺锌耐受性机制认识不足的制约。在这里，我们评估了根生长和根锌吸收效率的贡献，并试图从特定的机制来解释结果。我们在菲律宾高度缺锌的水稻土壤上进行了田间试验，测定了耐缺锌和敏感基因水稻的生长、锌吸收和根系发育。我们还测量了种植密度的影响。耐性品种每株产生更多的冠根，单位根表面积的吸收速率更大；后者对总体耐性的重要性至少与根数一样重要。种植密度越大，耐性和敏感品种对锌的吸收越多。单位根表面积的较大吸收和种植密度效应只能通过根系诱导的根际变化来解释，根际变化要么溶解锌，要么中和阻碍锌吸收的毒素(可能是Fe2+)，或者两者兼而有之。这些性状和冠根数是潜在的育种目标。
Zinc (Zn) deficiency is a major constraint to rice production and Zn is also often deficient in humans with rice-based diets. Efforts to breed more Zn-efficient rice are constrained by poor understanding of the mechanisms of tolerance to deficiency. Here we assess the contributions of root growth and root Zn uptake efficiency, and we seek to explain the results in terms of specific mechanisms. We made a field experiment in a highly Zn-deficient rice soil in the Philippines with deficiency-tolerant and -sensitive genotypes, and measured growth, Zn uptake and root development. We also measured the effect of planting density. Tolerant genotypes produced more crown roots per plant and had greater uptake rates per unit root surface area; the latter was at least as important as root number to overall tolerance. Tolerant and sensitive genotypes took up more Zn per plant at greater planting densities. The greater uptake per unit root surface area, and the planting density effect can only be explained by root-induced changes in the rhizosphere, either solubilizing Zn, or neutralizing a toxin that impedes Zn uptake (possibly or Fe2+), or both. Traits for these and crown root number are potential breeding targets.