The barrier to radial oxygen loss from roots of rice (Oryza sativa L.) is induced by growth in stagnant solution
The barrier to radial oxygen loss from roots of rice (Oryza sativa L.) is induced by growth in stagnant solution
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DOI：
10.1093/jexbot/49.325.1431
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发表时间：
1998-08-01
影响因子：
6.9
通讯作者：
Tinh, TK
中科院分区：
文献类型：
--
作者：
Colmer, TD;Gibberd, MR;Tinh, TK
本文报道了在充气和停滞的营养液中生长对4个水稻品种根的不定根孔隙率和径向O-2损失(ROL)模式的影响。都进行了评估。所研究的基因类型通常是在耕作系统中种植的，这些耕作系统的土壤淹水和洪水程度明显不同。不同水稻品种的不定根在通气液中的组成孔隙率(气孔率)不同(最低为16%，最高为30%)，而在停滞条件下生长的根的孔隙率在28%-38%之间。在4个品种中，有3个品种的不定根在通气液中生长的ROL随着根尖后距离的增加而增加，而在静止溶液中生长的不定根的ROL随着根尖后的距离而减小，这表明通气组织与外部介质之间的扩散阻力很高。例如，在根尖后35 mm处，在停滞条件下生长的‘深水’品种的根的ROL是其充气根的0.7%，‘低地’品种是5.6%，而‘旱地’品种是43.6%。因此，四种不同类型中的三种不定根对ROL的屏障是通过在停滞的营养液中生长而诱导的。在无氧环境中，根基带的低ROL率具有适应价值，因为O-2向根尖的纵向扩散会增强，从而使根更多地渗透到厌氧土壤中。
The present report describes experiments in which the effects of growth in aerated and stagnant nutrient solutions on adventitious root porosities and patterns of radial O-2 loss (ROL) from the roots of four genotypes of rice (Oryza sativa L.) were evaluated. The genotypes studied are usually cultivated in farming systems which differ markedly in their degree of soil waterlogging and flooding. Rice genotypes were found to differ in the constitutive porosity (% gas space) of their adventitious roots when grown in aerated solutions (lowest was 16%, highest was 30%), and the roots grown in stagnant conditions had porosities between 28% and 38%. ROL from the adventitious roots raised in aerated solution increased with distance behind the tip in three of the four genotypes; whereas for roots raised in stagnant solution, ROL decreased with distance behind the tip which is indicative of a high resistance to diffusion between the aerenchyma and external medium. For example, at 35 mm behind the root tip the ROL from roots of the 'deepwater' cultivar grown in stagnant conditions was 0.7% of the rate of its aerated roots, for the 'lowland' cultivar it was 5.6%, and for one of the 'upland' cultivars it was 43.6%. Thus, the barrier to ROL from the adventitious roots in three of the four genotypes was induced by growth in stagnant nutrient solution. A low rate of ROL from the basal zones of roots in an O-2-free environment is of adaptative value since longitudinal diffusion of O-2 to the root apex would be enhanced which, in turn, enables greater penetration of roots into anaerobic soils.