International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), 500 016, Hyderabad, A.P., India.
Planta. 1979 Jan;145(2):113-7. doi: 10.1007/BF00388706.
Segments of mesocotyls of Avena sativa L. transported [1-(14)C]indol-3yl-acetic acid (IAA) with strictly basipetal polarity. Treatment of the segments with solutions of sorbitol caused a striking increase in basipetal auxin transport, which was greatest at concentrations around 0.5 M. Similar effects were observed with mannitol or quebrachitol as osmotica, but with glucose or sucrose the increases were smaller. Polar transport was still detectable in segments treated with 1.2 M sorbitol. The effects of osmotic stress on the polar transport of auxin were reversible, but treatment with sorbital solutions more concentrated than 0.5 M reduced the subsequent ability of mesocotyl segments to grow in response to IAA. The increased transport of auxin in the osmotically stressed segments could not be explained in terms of an increased uptake from donor blocks. The velocity of transport declined with higher concentrations of osmoticum. The reasons for the enhancement of auxin transport by osmotic stress are not known.
燕麦中柱鞘节段将[1-(14)C]吲哚-3-乙酸（IAA）沿严格的向基极性运输。用山梨糖醇溶液处理这些节段会显著增加向基生长素的运输，在大约 0.5 M 的浓度下最大。用甘露醇或奎那醇作为渗透剂也观察到类似的效果，但用葡萄糖或蔗糖时增加较小。在处理 1.2 M 山梨糖醇的节段中仍能检测到极性运输。渗透胁迫对生长素极性运输的影响是可逆的，但用浓度高于 0.5 M 的山梨糖醇溶液处理会降低中柱鞘节段随后对 IAA 响应生长的能力。在渗透压胁迫的节段中生长素的增加运输不能用从供体段增加摄取来解释。运输速度随渗透压的升高而下降。渗透胁迫增强生长素运输的原因尚不清楚。
