Kinetin

About: Kinetin is a research topic. Over the lifetime, 7856 publications have been published within this topic receiving 135550 citations. The topic is also known as: Kinetin.

The histological basis for inhibition of axillary buds inPisum sativum and the effects of auxins and kinetin on xylem development

Abstract: This investigation continues the s tudy of the effects of auxins and kinet in on growth regulat ion and xy l em differentiat ion in the second internode of the pea epicotyl (S o r o k i n, M a t h u r and T h i m a n n 1962). The earlier p a p e r descr,ibed the ana t om y of the internode and its changes during growth, while the present wort~ concerns the ana tomica l development of the t ranspor t sys tem between the int 'ernode and the la teral bud. The growth of the bud was ini t iated b y releasing it ei ther f rom na tu ra l apical dominance b y decapi ta t ion, or f rom auxininduced inhibit ion b y app ly ing kinetin. There will be described, first, the ana t omy of the inhibi ted ax i l l a ry buds on excised pea stem segments, and, second, the changes which occur dur~ing growth on a simple medium containing sucrose, auxins and kinetin, alone or in combination. These changes concern pa r t i cu la r ly the development of vascular connections, which have been studied ( for convenience ~in microscopic identification) as xy lem. Whether the format ion of ph loem accompanies that of xy l em was not determined, but t h e funct ion herein ascribed to x y l e m m a y ac tua l ly be pe r fo rmed b y the combined xy lemphloem structure in a vascular bundle.

Hormonal Control of Differentiation of Shoots, Roots and Embryos in Leaf and Stem Cultures of Petunia inflata and Petunia hybrida

Abstract: Factors influencing adventitious bud and root development, callus induction and embryogenesis were investigated in stem and leaf cultures of Petunia inflata R. E. Fries and Petunia hybrida cv. Cascade and cv. Rose du ciel grown on a synthetic nutrient medium. Indoleacetic acid caused limited callus development and root formation whereas naphthaleneacetic acid Induced abundant roots. 2,4-Dichlorophenoxyacetic acid promoted callus growth and differentiation of embryos which eventually developed into plantlets. Cytokinins such as benzyladenine, zeatin and kinetin induced bud development. A combination of auxins and cytokinins caused an interaction which was manifested in altered morphogenetic response. Thus 2,4-dichlorophenoxyacetic acid in conjunction with benzyladenine caused suppression of bud development and retarded differentiation of embryos. Likewise, when benzyladenine was used with indoleacetic acid root development was totally inhibited and abundant buds were produced.

Somatic embryogenesis and in vitro rosmarinic acid accumulation in Salvia officinalis and S. fruticosa leaf callus cultures

Abstract: The effect of explant age, plant growth regulators and culture conditions on somatic embryogenesis and rosmarinic acid production from leaf explants of Salvia officinalis and S. fruticosa plants collected in Greece was investigated. Embryogenic callus with numerous spherical somatic embryos could be induced on explants derived from both species and cultured for 3 weeks on a Murashige and Skoog (MS) medium supplemented with 1.8–18 μm 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (Kin) or 10.5–21 μm 1-naphthalenacetic acid and 6-benzyladenine. Only explants from young plants (with six to eight leaves) responded to the culture treatments and, in general, low light intensities (50 μmol m–2 s–1) favoured callus formation and induction of somatic embryos. Somatic embryos were further developed on the same medium. Heart- and torpedo-shaped embryos (1–2 mm long) were subcultured on a growth-regulator-free MS medium for maturation. Maximum rosmarinic acid accumulation in S. officinalis and S. fruticosa callus cultured on 4.5 μm 2,4-D and 4.5 μm Kin was 25.9 and 29.0 g/l, respectively.

Acidification of the Medium Associated with Normal and Fusicoccin-Induced Seed Germination

Abstract: Fusicoccin, a toxin stimulating cell enlargement and inducing proton extrusion in various plant tissues, has been shown to replace kinetin, gibberellic acid and red light in breaking seed dormancy. It also removes the inhibitory effect of abscisic acid. The present data also show that the stimulating effect of fucicoccin on embryo growth of decoated radish (Raphanus sativus L.) and maize (Zea mays) seeds and on the development of maize embryos is accompanied by an early, significant acidification of the medium. Acidification of the medium is also observed when fusicoccin reverses the abscisic acid-induced inhibition of germination. These results support the hypothesis that the mode of action of fusicoccin in promoting germination involves, as in stimulation of cell enlargement, the activation at the cell membrane level of proton extrusion processes. The physiological significance of fusicoccin-induced release of protons at the onset of germination is discussed in comparison with the results concerning the mechanism of action of fusicoccin on cell enlargement in other plant materials.

Two sites of hormonal action during germination of Chenopodium album L. seeds

Abstract: During the overall germination process in the light-requiring seeds of Chenopodium album L. two sites of hormonal action can be distinguished. The start of visible growth is induced in darkness by the gibberellins 4 and 7 (GA4+7) or by ethylene. Added cytokinins are inactive although 8-14C-kinetin shows rapid penetration into the seed and rapid turnover. The induction of growth by GA4+7 and the uptake of 8-methylene-14C-GA3 are enhanced at lower pH values. Prolonged incubation in darkness results in a decreased responsiveness of the seeds towards GA4+7 and ethylene. A second site of hormonal action is located during the progress of growth inside the covering structures. ABA inhibits radicle growth, while GA4+7, GA3, kinetin, zeatin and ethylene reduce the inhibition.