OSMOREGULATION, SOLUTE DISTRIBUTION, AND GROWTH IN SOYBEAN SEEDLINGS HAVING LOW WATER POTENTIALS
OSMOREGULATION, SOLUTE DISTRIBUTION, AND GROWTH IN SOYBEAN SEEDLINGS HAVING LOW WATER POTENTIALS
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DOI：
10.1007/bf00386543
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发表时间：
1981-01-01
期刊：
影响因子：
4.3
通讯作者：
BOYER, JS
中科院分区：
文献类型：
--
作者：
MEYER, RF;BOYER, JS
大豆（G. max (L.)）当根部周围的水供应有限时，幼苗会进行渗透调节。渗透调节包括溶质积累（渗透调节）通过下胚轴伸长区。渗透调节过程中生长、溶质积累与溶质分配的关系。黑苗移栽到含水量为对照1/8（0.13倍）的蛭石上。在12-15 h内，延长区渗透电位降至-12 bar，而对照组为-7 bar。这种渗透调节涉及到下胚轴真正的溶质积累，因为无论水分状况如何，细胞体积和膨胀实际上是相同的。低水势的下胚轴伸长缓慢，但当失去子叶时，不伸长，也不积累溶质。溶质的子叶起源和缓慢生长对渗透调节的依赖。非呼吸干物质从子叶向幼苗轴的转运不受水分有效性的影响，但分配发生了改变。由于对生长的溶质利用减少而对溶质的吸收继续，下胚轴的伸长区发生了渗透调节。当溶质吸收量随之下降，吸收量随之平衡利用时，调整完成。因此，渗透调节的控制是溶质利用率和吸收率。尽管膨胀和底物与渗透调节有关，但伸长受到未知因素的抑制。剩余的缓慢伸长取决于渗透调节，在抑制溶质积累和建立幼苗所需的生长之间表现出某种最佳。
Soybean (G. max (L.) Merr.) seedlings osmoregulate when the supply of water is limited around the roots. The osmoregulation involves solute accumulation (osmotic adjustment) by the elongating region of the hypocotyls. The relationship between growth, solute accumulation and the partitioning of solutes during osmoregulation. Dark grown seedlings were transplanted to vermiculite containing 1/8 (0.13 .times.) the water of the controls. Within 12-15 h, the osmotic potential of the elongating region had decreased to -12 bar but it was -7 bar in the controls. This osmoregulation involved a true solute accumulation by the hypocotyls, since cell volume and turgor were virtually the same regardless of the water regime. The hypocotyls having low water potentials elongated slowly but, when deprived of their cotyledons, did not elongate or accumulate solute. A cotyledonary origin for the solutes and a dependence of slow growth on osmotic adjustment. The translocation of nonrespired dry matter from the cotyledons to the seedling axis was unaffected by the availability of water but partitioning was altered. Osmotic adjustment occurred in the elongating region of the hypocotyls because solute utilization for growth decreased while solute uptake continued. Adjustment was completed when solute uptake subsequently decreased and uptake then balanced utilization. The control of osmotic adjustment was therefore the rate of solute utilization and the rate of uptake. Elongation was inhibited by unknown factor(s) despite the turgor and substrates associated with osmotic adjustment. The remaining slow elongation depended on osmotic adjustment and represented some optimum between the necessary inhibition for solute accumulation and the necessary growth for seedling establishment.