Coleoptile elongation

Pan, L. Kawai, M. Yano, A. Uchimiya, H. Nucleoside diphosphate kinase required for coleoptile elongation in rice. Plant Physiol., 122, 447-452 (2000)... 

Examples of antagonistic interaction include the effects of ABA and auxin on root tip surface charge (Tanada 1972) the effects of ABA and kinetin on coleoptile elongation (Khan and Downing 1968), the effects of GA and tannins on enzyme biosynthesis (Jacobson and Corcoran 1977) and the effects of ethylene and either GA3 or cytokinin on fruit senescence (Goldschmidt et al. 1977). 

Kim, J-B., Caipita, N.C. (1992), Changes in esterification of the uronic acid groups of cell wall polysaccharides during elongation of maize coleoptiles. Plant Physiol. 98, 646-653. 

Terminal complex consolidation has also been reported in vascular plants as loosely aligned files of rosettes associated with secondary wall formation (13,14,34,35). Similar rosette files were also observed during primary wall formation in rapidly elongating regions of Avena coleoptiles... 

A long-chain dihydroxy compound, isolated from Avocado mesocarp, inhibited soybean callus growth and induced elongation of wheat coleoptiles. This compound was identified as 1-acetoxy-2,4-dihydroxy-n-heptadeca-16-ene, otherwise known as avocado inhibitor (14). 

Portulal (Figure 8) is a novel diterpene containing a perhydroazulene nucleus and was isolated from Portulaca grandi-flora Hook. It inhibits the elongation of Avena coleoptile sections induced by IAA. It also accelerates adventitious root formation of Azukia epicotyl cuttings. 

Matthyssee and Phillips (20) isolated two nuclear proteins, from tobacco cells, that bound specifically to 2,4-D. Receptor proteins for auxins, kinetins, and GA have been found (21). Sub-cellular fractions from bean leaves were recently shown to bind abscisic acid (22). Preliminary experiments (22) indicated that maximum ABA binding activity coincides with the activities of membrane-bound Mg -dependent, K+-stimulated ATPase and glucan synthetase. Table I of Biswas and Roy (21) lists hormone receptor proteins reported in plant tissue. For a protein to qualify as a receptor molecule, it should have a high stereo-specific binding capacity (Kd 10 6 to 10 SM) for its particular hormone. In com coleoptiles, both IAA and NAA are equally effective in inducing cell elongations fractions of plasma membrane and endoplasmic reticular membrane contain receptor proteins with Kd values of 10 M to 10 M for auxins (5, 18). When one considers procedural... 

Figure 1. Effects of CaCl2 on bioassays for auxin, gibberellin, and cytokinin. A effects of CaCl2 on elongation of oat coleoptile sections in the presence and absence of indoleactic acid B effects on elongation of lettuce hypocotyls in the presence and absence of gibberellic add and C effects on enlargement of Xanthium cotyledon pieces in the presence and absence of benzyladenine (13).

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