Abstract
THE relation between various types of hormone distribution is the internal regulating mechanism of a plant."This conception underlies the theory of the transverse reactions of plants which Georg Borgstrom discusses in a recent publication1. He emphasizes the physiological importance of transverse hormone distribution in relation to polar transport. Starting from the discovery that treatment with ethylene upset the normal transport of auxins and caused a transverse flow out of the phloem into the surrounding tissue with consequent swelling of the cells, Borgstrom studied various natural conditions which produced similar effects. He found that light of short wave-lengths, high humidity, high and low temperature, action of specific chemical substances, mechanical stimulation of the phloem and the age of the plant organ were factors which influenced the direction of auxin distribution, by diverting the normal polar stream into transverse channels with resulting reaction in the plant. Among these "transverse reactions" of the plant he classes tropistic growth responses, the light-growth reaction, secondary growth, root formation, root contraction, water transport, fruit development and leaf fall. He also discusses various other physiological and morphological problems in the light of his theory and suggests that the transverse distribution of hormones is responsible for various ecological types; the strength of the reaction being governed by the extent to which normal growth is upset by the transverse effect.
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References
Borgström, Georg, "The Transverse Reactions of Plants: Outlines of a New Interpretation of the Significance of Growth Hormones for Life-Processes in Plants" . Pp. 230. (Lund: C. W. K. Gleerup; Copenhagen: Ejnar Munksgaard; London: Williams and Nor-gate, Ltd., 1939.) 6.00 kr.
Brain, E. D., New Phytol, 33, 3 (1939).
Zollikofer, C., Ber. deutsch. Bot. Ges., 53, 152–157 (1935)
Heyn, A. N. J., Jb. wiss. Bot, 79, 753–787 (1934).
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BRAIN, E. Transverse Distribution of Hormones in Plants. Nature 145, 316–317 (1940). https://doi.org/10.1038/145316a0
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DOI: https://doi.org/10.1038/145316a0
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