THE COURSE OF THE GEOTROPIC REACTION OF WHEAT ROOTS
THE COURSE OF THE GEOTROPIC REACTION OF WHEAT ROOTS
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DOI：
10.1111/j.1399-3054.1957.tb07624.x
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发表时间：
1957-01-01
影响因子：
6.4
通讯作者：
RUFELT, H
中科院分区：
文献类型：
--
作者：
RUFELT, H
测定了小麦根系在营养液中发生地向性反应的时间过程。可以证明曲率不仅由一个正反力决定，而且由两个负反力决定。在15℃下，约1小时后，根尖开始出现正反应。2-3小时后，弯曲被第一个负反应所抵消。7-8小时后，在引起第一次负反应的同一组细胞中出现了新的负反应，但此时由于根的纵向生长，细胞被定位在伸长区的第一部分。第二个负极反应在拉伸过程结束后与正极反应一起维持在根内，正极反应在根内基本延伸，并放置在负极反应的远端。因此，在有利的条件下，根略呈s形。进一步可以看出，正反应和负反应都主要是由于凹侧的生长抑制，前者局限于根的下侧，后者局限于根的上侧。讨论了负反应的特点；发现它们不可能是一般意义上的自向性，而必须认为是由地向性刺激引起的某种过程引起的。结果表明，在营养液的不同pH值下，正负反应的相互强度是不同的。
The time course of the geotropic reaction of wheat roots taking place in a nutrient solution has been determined. It could be shown that the curvature is not only determined by a positive reaction but also by two negative reactions. The positive reactions starts in the roots apex after about one hour at 15 C. After 2-3 hours the bending is counteracted by the first negative reaction. After 7-8 hours a new negative reaction appears in the same group of cells which have given rise to the first negative reaction, but at this time the cells are localized to the first part of the elongation zone as a consequence of the longitudinal growth of the roots. The second negative reaction is maintained in the root after the end of the stretching process together with the positive reaction, which has been extended basipetally in the roots and is placed distal to the negative one. As a result the roots under favourable conditions is slightly S-shaped. It could further be shown that the positive reaction and the second negative reaction both are due mainly to a growth inhibition on the concave sides, which in the first case is localized to the lower side and in the second case to the upper side of the root. The character of the negative reactions is discussed; it is found that they cannot be autotropic in the common sense of this term, but must be regarded as due to some process which is initiated by the geotropic stimulus. Finally it was shown that the mutual strength of the positive and the negative reactions are different at different pH values in the nutrient solution.