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.

Plant Regeneration from the Segments of Petioles of Cacalia firma

Abstract: Cacalia firma recently has been used increasingly as leaf vegetables but endangered in natural forest. In this work, we established the plant regeneration via adventitious shoot formation from petiole segments of seedling and in vitro plantlets. Wounding of seed coats and treatments were effective to induce in vitro germination of seeds, whereas, seed did not germinate at all without these treatment. When cotyledon, leaf, petiole, and root segments of seedling were cultured on medium with 2 benzyl adenine (BA) and 0.5 naphthaleneacetic acid (NAA), petiole segments showed highest number of shoots per explant among the other segments. Among the various kinds of cytokinins, BA, isopentyl adenine (2-ip), kinetin, zeatin, thidiazuron (TDZ), TDZ and BA treatments were effective to induce high frequency of adventitious shoot formation from petiole segments of in vitro propagated plants. NAA stimulated the frequency of adventitious shoot formation but not for number of adventitious shoots per explants compared to TDZ or BA treatment alone. Most of adventitious shoots were developed directly from surfaces of explants. Adventitious shoots were transferred on medium with IBA for root formation, thereafter the plantlets were successfully transferred to soil.

Micropropagation of Japanese Chestnut (Castanea crenata Sieb. et Zucc.)

Abstract: Japanese chestnut (Castanea crenata Sieb. et Zucc.) was micropropagated from nodal explants of 2-month-old seedlings, and the regenerated plantlets were acclimatized after potting. For in vitro establishment, 5 µM zeatin was more effective than 5 µM BA or TDZ, and Sato's (BW) medium was as effective as MS(½NO 3 ) medium. Driver-Kuniyuki walnut medium produced more shoots showing hyperhydricity symptoms. In the multipli- cation culture, the higher the concentration of zeatin added to BW medium, the greater the number of shoots showing hyperhydricity, although the longest shoot was obtained when 6.9 µM zeatin was added. After planting in ½BW medium with 15 µM IBA for 5 d to induce rooting, shoots planted in ½BW medium plus vermiculite gelled with Gellan Gum (SV substrate) rooted better than those in either the gelled medium without vermiculite (S substrate) or vermiculite plus liquid medium (V substrate). One third of the shoots planted in the V substrate died, although 62% of the surviving shoots rooted well. Of the shoots planted in the S substrate, 83% survived, but only 35% of these survived rooting. Shoots rooted in the SV and V substrates survived well after the completion of acclimatization, and shoots rooted in the SV substrate grew more vigorously after potting. Chemical names used: 6-benzyladenine (BA); 6-(4-hydroxy-3-methyl-but-2-enylamino)purine (zeatin); indole-3- butyric acid (IBA); 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea (thidiazuron, TDZ). Japanese chestnut (Castanea crenata Sieb. et

Endogenous indole-3-acetic acid and trans-zeatin ribosides in relation to axillary bud formation in standard chrysanthemum

Abstract: The lateral buds of non-branching chrysanthemum cultivars are affected by temperature and exogenous plant growth regulator (PGR) treatment. The number of axillary buds, endogenous indole-3-acetic acid (IAA) and t-zeatin riboside (t-ZR) concentrations by planting date and PGR treatments were investigated in three genotypes. Two non-branching genotypes, ‘Iwanohakusen’ and ‘01B1-8’ and branching type ‘Jinba’ were planted on May 2 and June 29. ‘Jinba’ always bore axillary buds and ‘01B1-8’ showed stronger non-branching traits than ‘Iwanohakusen’. Only 22.9% viable buds developed in the axils of ‘01B1-8’ whereas 68.7% developed in ‘Iwanohakusen’ on the May 2 planting date group. When planting was delayed from May 2 to June 29, the number of axillary buds decreased in both non-branching genotypes. Endogenous IAA concentrations remained unchanged and t-ZR concentrations decreased in all the three genotypes when the planting date was delayed. This reduced t-ZR level corresponds to the increased ratio of IAA/t-ZR. The number of viable axillary buds increased from 21.7% to 50.1% upon ethephon treatment and to 30.3% by synthetic cytokinin 6-benzylaminopurine (BAP) treatment in ‘01B1-8’. Viable axillary buds of ‘01B1-22’ increased from 17.1% to 25.1% and 29.1% respectively. Ethephon and BAP application decreased endogenous IAA contents and increased t-ZR contents. Elevated concentrations of t-ZR rather than IAA probably account for axillary bud formation in non-branching chrysanthemum. Just as the non-branching genotypes, the branching type cultivar ‘Jinba’ showed similar changes in IAA and t-ZR contents according to planting date and exogenous PGR treatments. These results showed that genotypic difference of branching patterns is not a result of concentration-dependent reaction.

In Vitro Propagation of the Mount Parnitha Endangered Species Sideritis raeseri subsp. Attica

Abstract: Over the past few decades, both wildfires and human-sparked fires have ravaged Mount Parnitha, destroying the mountain’s unique natural ecosystem, applying pressure to its flora, and subjecting the vulnerable populations of Sideritis raeseri subsp. attica to excessive stress. The present study aims to establish an efficient micropropagation method starting from in vitro-grown seedlings. The in vitro germination study carried out during the production of seedlings revealed a higher germination rate (34.0% and 37.0%, respectively) at 20.0 °C and 25.0 °C. The in vitro-derived seedlings studied were used as the starting material for the establishment of various media. Murashige and Skoog (MS) media, hormone-free and containing 0.5 mg L−1 6-benzyladenine (BA), led to the satisfactory (84.0–89.0%) establishment of plantlets. During the multiplication phase, the study used BA in conjunction with α-naphthaleneacetic acetic acid and four different cytocinins (BA; kinetin (KIN); 6-(γ-γ-dimethylallylamino) purine; zeatin) at low concentrations (0.5 mg L−1). During the second subculture, a high multiplication index (7.3 and 6.4, respectively) was found for the hormone-free MS medium and the MS medium containing KIN at 0.5 mg L−1. Hyperhydricity took place on the media supplemented with hormones. Rooting occurred on the half-strength MS medium (51.0%). After two months, the plants’ survival rate stood at 100.0%, as did their ex vitro acclimatisation rate, which also registered at 100.0%. The present results could encourage not only the introduction of S. raeseri subsp. attica into the industry of floriculture as a new ornamental plant but also its ex vitro conservation.

Application of a System for Targeting Fe-Dependent Superoxide Dismutase and Choline Oxidase Enzymes to Chloroplast as a Strategy for Effective Plant Resistance to Abiotic Stresses

Abstract: The plastids involved in photosynthesis and other essential metabolic processes are the cellular compartments most susceptible to abiotic stress factors with adverse effects in plants. In order to protect the chloroplast compartment, the plants of the Belyi Naliv tomato cultivar and the Darenka potato cultivar were transformed with genes for Fe-dependent superoxide dismutase and choline oxidase with the use of the method for plant genetic engineering. These target genes were equipped with signal sequences directing the proteins into the plastid compartment. The experimental results have demonstrated the optimization of the agrobacterium-mediated transformation method for the analyzed tomato and potato cultivars. The naturally growing leaves and stems of the mature plants proved to be the most effective explants to obtain the regenerants. The highest regeneration frequency in the explants was reached with the use of a medium containing 5 mg L–1 BAP, 0.1 mg L–1 NAA, and 1 mg L–1 zeatin. Augmentin and timentin were equally efficient among the antibiotics tested for the inhibition of the agrobacterium; the concentration of 200 mg L–1 in the culture medium was sufficient to eliminate the agrobacterium. In addition, they had no inhibitory effects on the shoot regeneration process. However, the cefotaxime concentration required to inhibit the agrobacterium should be 500 mg L–1 and higher. Moreover, this antibiotic at the concentration of 100 mg L–1 was proven to inhibit the regenerant growth.