Zeatin

About: Zeatin is a research topic. Over the lifetime, 2467 publications have been published within this topic receiving 64092 citations. The topic is also known as: Zeatin & (E/Z)-zeatin.

Involvement of endogenous plant hormones in the effect of mixed nitrogen source on growth and tillering of wheat

Abstract: A Chinese spring wheat (Triticum aestivum L. cv. Yang Mai 158) was grown hydroponically with nitrogen (N) supplied as all ammonium (NH4 +), all nitrate (NC3 ‐), and a mixture (NH4 +‐N:NO3 ‐‐N=30:70) of each form. Wheat plants produced more tiller and more dry matter, and showed a higher shoot/root dry matter ratio when grown with mixed N than with either N form alone. In addition, all‐NH4 +‐grown plants produced more tillers and dry matter as compared to all‐NO3 ‐‐grown plants. Subsequently, endogenous levels of isopentenyladenine and isopentenyladenosine, zeatin and zeatin riboside, dihydrozeatin and dihydrozeatin riboside, indole‐3‐acetic acid (IAA), gibberellin A, and gibberellin A3 (GA1+3) and abscisic acid (ABA) in the shoot and the root was determined by enzyme‐linked immunosorbent assays. It was found that the levels of cytokinin in both the shoot and the root of mixed‐N‐grown plants were higher than those of all‐NO3 ‐‐grown and all‐NH4 +‐grown plant, whereas ABA level was similar among pl...

Hormones and shifting ecology throughout plant development

Abstract: Hormones modulate complex suites of ecologically relevant behaviors through interactive cascades of signal transduction; evolutionary changes in the function of a single hormone can result in multiple changes in plant traits. Sites of hormone action and tissue sensitivity change throughout plant ontogeny, as embryos, seedlings, and reproductively mature plants cope with shifting suites of environmental variables and resource availability. Phenotypic plasticity and correlations and trade-offs between life history traits (such as resource use efficiency and allocation to growth and differentiation of meristems) also change as plants age; hormonal changes are central to these shifts. I synthesize evidence from the molecular and physiology literature and present novel data on mangrove propagules, seedlings, saplings, and trees. Together, these data demonstrate that several ecologically important traits are hormonally mediated (both in the short term and over evolutionary time) in the diversification of plant lineages. I focus on two hormones with contrasting action: (1) abscisic acid (ABA), which regulates internal plant osmotic stability, membrane integrity, seed dormancy, and stomatal conductance; and (2) cytokinins (zeatin and allied adenine derivatives), which promote cell division, stimulate growth, delay leaf senescence, enhance the capacity of tissues to act as N sinks, and help to transduce signals of light and nutrient availability. ABA and cytokinin levels are correlated with patterns of osmotic tolerance, photosynthesis, growth, and leaf longevity, and their concentrations in specific tissues change throughout plant development. Ecologists and evolutionary biologists are in a strong position now to creatively comprehend, predict, and potentially engineer plant strategies and adaptive trade-offs over plant lifetimes in light of emerging knowledge of hormones.

Influence of the antibiotic timentin on plant regeneration of tomato (Lycopersicon esculentum Mill.) cultivars.

Abstract: Cotyledon explants of tomato (Lycopersicon esculentum Mill. cvs 'Santa Clara', 'Firme' mutant, 'IPA-5' and 'IPA-6') were excised from 8- to 10-day-old in vitro-grown seedlings. Four different shoot induction media supplemented with timentin (300 mg l–1) were screened. When cotyledon explants were cultured on MS-based medium with 1.0 mg l–1 zeatin plus 0.1 mg l–1 IAA and supplemented with timentin, higher regeneration frequencies and a greater number of elongated shoots were obtained. It was observed that timentin caused an increase in the morphogenesis of in vitro cotyledon explants of tomato cultivars. In two of three cultivars tested, rooting of shoots was positively influenced, both in the presence and absence of timentin in the rooting medium, among shoots regenerated from explants derived from timentin-supplemented medium. The results confirm those of a previous investigation on the beneficial effects of this class of antibiotics on tomato regeneration and, consequently, its reliability for use in the transformation of this species.

Adventitious shoot regeneration from leaf, stem and root explants of commercial cultivars of Gentiana.

Abstract: Several culture conditions were examined for promoting efficient plant regeneration from explants of Gentiana. Adventitious shoot regeneration from leaf explants of cv. WSP-3 was very superior on MS medium, compared to B5 medium, supplemented with four cytokinins (TDZ, 4PU-30, BA and zeatin). An auxin / cytokinin combination was required for regeneration. TDZ was the most effective cytokinin, while NAA was more effective than IAA or 2,4-D. Optimum conditions for regeneration from explants (leaf, stem and root) of cv. WSP-3, evaluated in terms of regeneration frequency and number of regenerated shoots per explant, were TDZ and NAA in combination, 5–10 mg/l and 0.1 mg/l for leaf and stem explants, and 10 mg/l and 1 mg/l for root explants, respectively. Application of these conditions to eight other commercial cultivars resulted in 30–100% regeneration from leaf explants. The number of chromosomes in each of ten regenerated plants of each cultivar was diploid, 2n=26. Shoots regenerated in vitro were rooted in phytohormone-free medium and transferred to soil.

Plant regeneration from cultured immature embryos of Sorghum bicolor (L.) Moench.

Abstract: Immature embryos of 20 sorghum genotypes were cultured on MS 5 medium containing MS mineral salts supplemented with 2,4-D, zeatin, glycine, niacinamide, Ca-pantothenate, L-asparagine, and vitamins. For regeneration, calli were transferred onto the same medium with the exception that IAA was substituted for 2,4-D. In general, immature embryos obtained 9–12 days after pollination resulted in the best redifferentiation. Ability of calli to regenerate varied among genotypes; cultivars C401-1 and C625 had the highest redifferentiation frequencies. Ability to redifferentiate was heritable and acted as a dominant trait. At least two gene pairs were involved. Regenerated R0 plants were planted in a greenhouse and their selfed (R1 and R2) progenies were planted in the field and examined for morphological and cytological variations. The majority of the phenotypic variations noted in R0 were not transmitted to later generations. However, variants for plant height, degree of fertility, and midrib color persisted in R1 and R2 generations. A variation in tallness was attributable to one dominant mutant gene. Short stature and male sterility variants appeared to be consequences of recessive mutant genes controlling those traits. Minor variations in peroxidase banding patterns were found among R0 plants.