Exogenous auxins, effect

Morris DA (1979) Effects of temperature on the velocity of exogenous auxin transport in intact chilling-sensitive and chilling-resistant plants. Planta 146 603-605 Morris DA, Kadir GO (1972) Pathway of auxin transport in the intact pea seedling Pisum sativum L.). Planta 107 171-182... 

Liu, W., Hildebrand, D. F., Graybum, W. S., Phillips, G. C. and Collins, G. B. (1991). Effects of exogenous auxins on expression of lipoxygenases in cultured soybean embryos. Plant Physiol. 97, 969-976 Park, T. K. and Polacco, J. C. (1989). Distinct lipoxygenase species appear in the hypocotyl/radical of germinating... 

Lateral translocation of exogenous auxin in response to unilateral irradiation was demonstrated early on with hypocotyls of radish and, subsequently, with Zea coleoptiles, epicotyls of PisumJ The apical part of coleoptiles (1 mm below the tip) represents the most light-sensitive zone, and at the same time, the zone that is most effective with respect to lateral auxin translocation. ... 

Exogenously applied auxin (0.1-1 p,M lAA) was found to inhibit root growth and to reorient specifically the CMTs of root cells from the transverse to the longitudinal arrangement [37,39]. This change consistently occurred in the cortex, whereas epidermis and stele parenchyma cells were less sensitive. Treatment of maize roots with benzoic acid (10 p,M), however, did not reorient the CMTs, suggesting that the auxin-mediated effects on MT arrangements were not due to an increased acidification but do indeed represent... 

Auxins are also involved in so-called long term responses which may be more directly gene-mediated responses. Auxins stimulate and sustain mRNA and protein synthesis to form enzymes that catalyze the production of cell wall materials, sugars, and other cellular components. Applied lAA has induced mRNA and protein synthesis in Avena coleoptiles (16), yeast cells (17), pea stem sections (18), and bean endocarp (19). Artichoke tuber disks responded to exogenously applied lAA with growth and a substantial amount of new RNA and protein synthesis. When the metabolic inhibitors actinomycin D and 8-azaguanine were added simultaneously with lAA, effects of the auxin were negated (20). 

Fig. 7.2 A-E. Interactions of lAA with ABA, GA, TIBA, and zeatin (ZEA), alone or in combination, as evidenced by effects upon the wavelike pattern of auxin efflux from the basal ends of successive 6-mm-long pine stem sections. Protocol as in Fig. 7.1. Test substances were applied for 100 min prior to sectioning and positioning for 10-min auxin basal efflux period. Test substances were applied apically only in A, C, D, and E, but both apically (a) and basally (b) in B. Controls had no exposure to exogenous substances. (A, B, C, and D adapted from Wod-ziCKi and Wodzicki 1981 E from WoDZiCKi et al. 1979)...

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