Genetic variability in phosphorus acquisition and utilization efficiency from sparingly soluble P-sources by Brassica cultivars under P-stress environment
Genetic variability in phosphorus acquisition and utilization efficiency from sparingly soluble P-sources by Brassica cultivars under P-stress environment
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DOI：
10.1111/j.1439-037x.2008.00326.x
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发表时间：
2008-10-01
影响因子：
3.5
通讯作者：
Adachi, T.
中科院分区：
文献类型：
--
作者：
Akhtar, M. S.;Oki, Y.;Adachi, T.
植物展示了一系列经典的策略，以最大限度地提高磷酸盐（Pi）收购难溶性磷源。通过优雅的Pi饥饿诱导（PSI）调节来适应Pi压力将减少我们目前对昂贵的、污染的和不可再生的Pi肥料的过度依赖。然而，不同物种溶解微溶磷源的能力差异往往已被证明;品种间的变化几乎没有记录。芸苔属植物是一种有效的、非菌根的难溶性磷源利用者。在四个实验中，使用水培和石英砂培养基，测定了遗传多样的芸苔属品种的各种生长参数和生物量积累。PSI根介导的pH值的变化，有机阴离子（OAs）的分泌和改变的根结构中的动员和收购的难溶性P-形式[约旦岩P（RP）在2克升（-1）和Ca-3（PO 4）（2）（TCP）在0.2克升（-1）分别]的作用进行了研究。品种间在生物量积累、各种生长参数和根冠比等方面表现出较大的遗传变异。不同品种间的吸磷量、吸磷总量、吸磷比、磷转运速率和磷利用效率差异极显著（P < 0.001），干物质积累量与吸磷量呈极显著正相关（r = 0.94**，达极显著水平）。耐磷品种表现出显着降低溶液介质pH值，因为H+外流和渗出更多的羧酸比低磷敏感品种下磷饥饿。品种的磷吸收量随pH值的降低而线性增加。磷饥饿植物根系分泌的OAs的数量和类型与磷充足环境下生长的植物不同。在分盆研究中，与TCP和RP提供空间分离的其他养分，高效品种仍然能够动员RP和TCP比低效品种更有效。在根箱试验中，缺磷处理使初生根的伸长速率下降，而侧根长度和初生根分支区的伸长速率增加。供试品种表现出遗传多样性的访问，动员，收购和利用磷的难溶性磷形态。一个安排婚姻的植物性状可以解释品种的访问不同形式的难溶性P，除了改变侧根拓扑结构和增强P-吸收和PUE，增强H+流出和OAs分泌的关键因素在Pi清除细胞外难溶性P-形式。
Plants display an array of classical strategies to maximize phosphate (Pi) acquisition from sparingly soluble P sources. Acclimation to Pi-stress via elegant Pi-starvation induced (PSI) adjustments would reduce our current overreliance on expensive, polluting and non-renewable Pi-fertilizers. Nevertheless, differences in the ability of various species to solubilize sparingly soluble P-sources have been often evidenced; inter-cultivar variations are scarcely documented. Brassica is known as an effective, non-mycorrhizal user of sparingly soluble P-sources. Various growth parameters and biomass accumulation by genetically diverse Brassica cultivars were determined in four experiments using hydroponics and quartz sand culture media. Role of PSI root mediated pH changes, organic anions (OAs) exudation and altered root architecture in mobilization and acquisition of sparingly soluble P-forms [Jordan rock-P (RP) at 2 g l(-1) and Ca-3(PO4)(2) (TCP) at 0.2 g l(-1) respectively] was investigated. Cultivars showed considerable genetic variations in biomass accumulation, various growth parameters and root-shoot ratio. Concentration and total uptake of P, specific absorption rate of P, P-transport rate and P-utilization efficiency (PUE) were also significantly (P < 0.001) different for various cultivars and their dry matter was significantly correlated with P-uptake [r = 0.94** (significant at 1% level)]. P-tolerant cultivars showed substantial decrease in solution media pH because of H+ efflux and exuded more carboxylates than low P-sensitive cultivars under P-starvation. P-uptake by cultivars increased linearly with decreasing pH. The amount and types of OAs exuded from the roots of P-starved plants differed from those of plants grown under P-sufficient environment. In split pot study, with TCP and RP supplied spatially separated from other nutrients, efficient cultivars were still able to mobilize RP and TCP more efficiently than inefficient cultivars. In rhizobox study, the elongation rates of primary roots decreased but the elongation rates of the branched zones of primary roots and the length of lateral roots increased under P-starvation. Tested cultivars showed genetic diversity in accessing, mobilization, acquisition and utilization of Pi from sparingly soluble P forms. An arrange marriage of plant traits can explain cultivar's access to different forms of sparingly soluble P, and in addition to altered lateral root topology and enhanced P-uptake and PUE, enhanced H+ efflux and OAs exudation are key factors in Pi scavenging from extra cellular sparingly soluble P-forms.