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.

Overexpression of the Wheat TaPsb28 Gene Enhances Drought Tolerance in Transgenic Arabidopsis

Abstract: Psb28 is a soluble protein in the photosystem II (PSII) complex, but its role in the drought stress response of wheat remains unclear. Here, we functionally characterized the TaPsb28 gene, which positively regulates drought tolerance in wheat. When the full-length 546-bp TaPsb28 cDNA was transferred into Arabidopsis thaliana, it was located in the guard cell chloroplast around the stroma. Overexpression of TaPsb28 conferred drought tolerance, as exhibited by the increases in the survival rate. Transgenic plants maintained lower MDA content and higher chlorophyll content by inducing chlorophyll synthase (ChlG) gene transcription. The content of abscisic acid (ABA) and zeatin increased significantly in wild-type (WT) plants under drought stress, and the transcriptional expression levels of RD22, dihydroflavonol 4-reductase (DFR) and anthocyanin reductase (ANR) genes were induced, thus enhancing the contents of endogenous cyanidin, delphinidin, and proanthocyanidins. However, in transgenic plants, although anthocyanins were further aggregated, the ABA increase was inhibited, zeatin was restored to the control level under drought stress, and stomatal closure was promoted. These findings indicate ABA and zeatin have opposite synergistic effects in the process of drought tolerance caused by TaPsb28 because only after the effect of zeatin is alleviated can ABA better play its role in promoting anthocyanin accumulation and stomatal closure, thus enhancing the drought tolerance of transgenic plants. The results suggest that overexpression of TaPsb28 exerts a positive role in the drought response by influencing the functional metabolism of endogenous hormones. The understanding acquired through the research laid a foundation for further in-depth investigation of the function of TaPsb28 in drought resistance in wheat, especially its relationship with anthocyanidin accumulation.

Biostimulant Activity of Sargassum sp. Extracts on Early Growth of Zea mays L. and the Phytohormones Content Analysis

Abstract: Seaweed has been gaining global interest in agriculture for the development of marine-based plant biostimulants. This research aimed to study the effect of three different liquid extracts of Sargassum sp., acidic, alkaline, and water extract, on the germination and early growth of maize and to evaluate the phytohormones content responsible for the growth. Phytohormones content including Indole-3-acetic acid (IAA), gibberellins (GA), kinetin and zeatin were analyzed using high-performance liquid chromatography (HPLC) and bioassay was performed twice on maize. Parameters observed on the bioassay were germination percentage, number of roots, shoot length, shoot weight and root weight under 4 different concentrations with 0.5; 1.5; 3.5; and 5% in the first bioassay and 3.5% concentration in the second bioassay. Both bioassays following randomized complete design and the data were analyzed using one-way ANOVA using post hoc test of Duncan Multiple Range Test (DMRT) at error probability of 5% in Genestat software. Phytohormones content in the seaweed extract indicated that alkaline extract was rich in IAA, gibberellin, and zeatin content, while water extract showed the highest kinetin content. The first bioassay indicated that lower concentration of the seaweed extracts gave better growth in all extracts, therefore a 3.5% concentration was chosen for the second bioassay with higher replication for each treatment. The second bioassay confirmed alkaline extract resulted in the highest germination while the highest seedling height, number of roots, shoot and root weight were resulted from acidic extract treatment. In conclusion, Sargassum sp. extracts obtained from acidic, alkaline, and water-based extraction methods, were able to improve the shoot and root growth of maize plants. The acidic extract showed the highest growth promotion among other extracts with the lowest phytohormones content.

Influence of zeatin, glutamin and auxins on root and shoot organogenesis of Guava (Psidium guajava L.) cv. safeda seedling explants

Abstract: An experiment was conducted to develop a regeneration protocol from seedling explants of higher yield Psidium guajavacv. safeda. Initially surface sterilized guava seeds were germinated inside the conical flasks. Explants taken from 49-day old seedlings were cultured on MS-medium modified with different concentration of plant growth regulators. Maximum explants showing shoot response (48%) was observed on MS-medium supplemented with 6-benzyladanin (BA) 1.0 mgl-1combined with 0.5 mgl-1ziatin. On the same media after 38-days of culturing, maximum number of 3.6 shoots per explant, 2.6 cm long was also recorded. On MS containing combination of BA (2.0 mgl-1) and zeatin (1.0 mgl-1), 37% explants responded which produced 2.3 shoot per explant after 42 days of culturing. Whereas on MS containing glutamin 250 mgl-1, 25% explants responded and gave 2.2 shoots per explants after 46-days. However, when the concentration of glutamin alone was increased from 250 to 500 mgl-1 the shoot formation potential of explant decreased to 10%. Addition of BA, glutamin and zeatin alone to MS medium was less effective. However, combination of BA with zeatin was effective in shooting response, number of shoot/explants and shoot length. Maximum number of explants (76.6%) responded to rooting with 1.5 mgl-1 IAA in combination with 1.0 mgl-1 NAA. On average, maximum of (2.5) roots were also recorded per explants in 42 days. In vitro plantlets were acclimatized and shifted to soil successfully. Keywords: Psidium guajava L; Micropropagation; Zeatin; Glutamin and auxins http://dx.doi.org/10.19045/bspab.2017.60014

Influence of cytokinin and ammonium nitrate on elongation of adventitious buds in Norway Spruce (Picea abies)

Abstract: The capability of different cytokinins (BA, kinetin, zeatin, 2iP) to stimulate the induction and development of adventitious buds was determined after single and repeated induction steps with hypocotyl explants. BA was the most effective cytokinin as far as it concerned the number of induced adventitious buds. Zeatin, although less effective for this pattern, promoted the elongation of buds even after repeated induction cycles contrary to BA. This is important to get propagating bud clusters with the ability to form elongating shoots. A five-year-old propagating clone line of adventitious bud clusters was used to study the influence of zeatin and ammonium nitrate on the shoot elongation. Three induction variants (6.84, 13.68, 20.52 μmol·L-1 zeatin, each with 0.69 μmol·L-1 kinetin for 4 weeks) were tested. The highest zeatin concentration induced the largest number of elongating buds. The influence of one subculture step with an enhanced ammonium nitrate concentration during the growth regulator free shoot development period (4 subcultures) was tested. A subculture on a medium free of growth regulators with a low ammonium nitrate concentration (2.5 mmol·L-1) followed the cytokinin containing induction medium. The next subculture medium was supplemented with 2.5, 7.5, 12.5 and 17.5 mmol·L-1 ammonium nitrate. An 8-week period (2 subcultures) followed with 2.5 mmol·L-1 ammonium nitrate. The treatment with 7.5 mmol·L-1 ammonium nitrate formed the highest number of elongating buds. This was identical for all zeatin concentrations used for induction. Increased ammonium nitrate concentrations during this treatment (12.5 mmol·L-1 and 17.5 mmol·L-1) decreased the number of elongating buds.