Auxin induced ethylene production

Brassinosteroids are reported to stimulate overall plant growth and development, especially under stress conditions, to enhance auxin-induced growth as well as auxin-induced ethylene production (5, 6). Brassinosteroids interact with most of the phytohormones, such as cytokinins and gibberellins, and in particular with auxin. 

Imaseki H, Kondo K, Watanabe A (1975) Mechanism of cytokinin action on auxin-induced ethylene production. Plant Cell Physiol 16 777-787 Itai C, Vaadia Y (1965) Kinetin-like activity in root exudate of water-stressed sunflower plants. Physiol Plant 18 941-944... 

Kang BG, Newcomb W, Burg SP (1971) Mechanism of auxin-induced ethylene production. Plant Physiol 47 504-509... 

Sakai S, Imaseki H (1971) Auxin-induced ethylene production by mung bean hypocotyl segments. Plant Cell Physiol 12 349-359... 

Yang SF (1980) Regulation of ethylene biosynthesis. Hortscience 15 238-243 Yeoman MM, Brown R (1971) Effects of mechanical stress on the plane of cell division in developing callus cultures. Ann Bot 35 1101-1112 Yu Y-B, Adams DO, Yang SF (1979) Regulation of auxin-induced ethylene production in mung bean hypocotyls role of 1-aminocyclopropane-l-carboxylic acid. Plant Physiol 63 589-590... 

Ethylene is now considered to be one of the main plant-hormones involved in fruit development. Many responses formerly believed to result from the presence of auxins are now ascribed to induced ethylene production.425 The biosynthetic pathway for formation of ethylene from methionine, in a wide variety of plant tissues, including shoots of mung bean,426 tomato,427 and pea427 carrot427 and tomato428 roots and the fruits of apple,429,430 tomato,427 and avocado,427 has been elucidated, and is as follows. 

Defoliation. Interest in defoliation has been low in recent years. One relatively new development is the "wiltant which is applied only shortly before harvest (51). As an outgrowth of some basic studies, several auxin transport inhibitors, TIBA, DPX-1840, Alanap (N-l-naph-thylphthalamate), and morphactins (2-chloro-9-hydroxyfluorene-9-car-boxylic acid), were shown to promote ethylene- and ethephon-mediated leaf abscission (52, 53). Subsequently, CA3 was found to be even more active in promotion of ethylene-induced abscission (54). It now appears that the CA3 counteracts the inhibitory effect of auxin on ethylene-induced leaf abscission (55) thus, CA3 might improve the performance of any defoliant that achieves part of its action by stimulating stress-induced ethylene production and lowering the natural auxin content of the dam-... 

Thus, cell enlargement, for instance, depends upon auxin and involves the uptake of water, extension of the cell membrane and protein synthesis. The auxin dose-response curve consists of two peirts promotion by low concentrations and inhibition by higher concentrations via the formation of ethylene. Cytokinins and abscisic acid may possibly induce also, under special conditions, the production of ethylene. Many publications deal with effects of these plant hormones, especially of auxin, on ethylene biosynthesis in plants which occurs after a lag phase of 30 - 60 minutes and is specifically blocked by rhizobitoxin as well as by inhibitors of ENA and protein synthesis indicating that a continuous synthesis of protein is required for high rate of ethylene production (Eef. 20). 

It was not until 1968 that Burg and Burg [3] offered the basis of such an explanation. They noted firstly that applied auxin was known to promote the liberation of ethylene in seedlings. Secondly, in their experiments the ethylene was mainly localized at the nodes, and thirdly, applied ethylene inhibited lateral bud development in decapitated pea seedlings. They therefore suggested that the bud inhibition that resulted when lAA was applied to decapitated plants could be actually due to the ethylene production that was induced. 

Hag L, Curtis RW (1968) Production of ethylene by fungi. Science 159 1357-1358 Imaseki H, Pjon C-J (1970) The effect of ethylene on auxin-induced growth of excised rice coleoptile segments. Plant Cell Physiol 11 827-829 Imaseki H, Pjon C-J, Furuya M (1971) Phytochrome action in Oryza sativa L. IV. Red and far-red reversible effect on the production of ethylene in excised coleoptiles. Plant Physiol 49 631-633... 

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