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 immature and mature embryo derived calli of Hordeum marinum

Abstract: Callus cultures were obtained from immature and mature embryos of Hordeum marnium on MS media containing 0.5 mg l-1 parachlorophenoxyacetic acid or 2 mg l-1 2,4-dichlorophenoxyacetic acid. Regeneration occurred after transferring calli to MS either devoid of hormones or supplemented with 1 mg l-1 indole-3-acetic acid and 1 mg l-1 zeatin. The regeneration capacity of the immature embryo derived calli (94%) was about 5 times higher than that of mature embryo derived calli (17%). A total of 30 and 964 plantlets were obtained from 21 mature and 59 immature embryo derived calli, respectively. Low frequency (less than 1%) of albino plantlets was obtained from both explants after 3–9 months in culture. Plants expressing transient chlorophyll deficiency were produced from immature embryo derived cultures at a frequency of 10%. However, when transferred to soil, these plantlets became green.

Effect of various bud induction treatments on elongation and rooting of adventitious shoots of Canary Island pine ( Pinus canariensis )

Abstract: Three-day-old cotyledonary explants of Pinus canariensis were subjected to 30 induction treatments using half-strength Bornman's medium containing various combinations of N6- benzyladenine, zeatin, kinetin and 2-isopentenyl-adenine. The highest numbers of buds were obtained with 10 μM 6-benzyladenine, but both kinetin and zeatin influenced shoot elongation. Shoots were maintained on half-strength Schenk and Hildebrandt medium with 2% sucrose and 0.05% activated charcoal. For rooting, shoots were pulsed for 4 h in a 100 μM indole-3-butyric acid aqueous solution (pH 4.2–4.5), and planted in peat:vermiculite:perlite (1:1:1). After 8 weeks, the numbers of rooted shoots were similar for most treatments. Therefore, the bud induction treatments did not significantly influence rooting of adventitious shoots of Canary Island pine.

Changes in Concentrations of Cytokinins (CKs) in Root and Axillary Bud Tissue of Miniature Rose Suggest that Local CK Biosynthesis and Zeatin-Type CKs Play Important Roles in Axillary Bud Growth

Abstract: Involvement of cytokinins (CKs) in axillary bud growth of miniature rose was studied. Variation in root formation and axillary bud growth was induced by two indole 3-butyric acid (IBA) pretreatments in two cutting sizes. At six physiological developmental stages around the onset of axillary bud growth, concentrations of CKs were determined in both root and axillary bud tissue by liquid chromatography combined with electrospray tandem mass spectrometry (LC-ESP-MS/MS). Chronological early onset of axillary bud growth occurred in long cuttings pretreated at low IBA concentration, whereas physiological early root formation was associated with long cuttings and high IBA concentration. The CKs zeatin (Z), isopentenyl adenine (iP), zeatin riboside (ZR), dihydrozeatin riboside (DHZR), isopentenyl adenosine (iPA), zeatin O-glucoside (ZOG), zeatin riboside O-glucoside (ZROG), zeatin riboside 5′-monophosphate (ZRMP), and isopentenyl adenosine 5′-monophosphate (iPAMP) were detected. Concentrations of CKs in axillary bud tissue far exceeded those in root tissue. Indole 3-butyric acid pretreatment influenced the concentration of CKs in axillary bud tissue more than did cutting size, whereas pretreatments only slightly affected CKs in root tissue. The dominant CKs found were iPAMP and ZR. An early and large increase in iPAMP indicated rapid CK biosynthesis in rootless cuttings, suggesting that green parts, including the axillary bud, can synthesize CKs. At the onset of axillary bud growth an increase in concentration of Z, ZR, ZRMP, ZOG, and ZROG was largely coincident with a decrease in iPAMP, iPA, iP, and DHZR. After the onset of axillary bud growth, CK content largely decreased. These results strongly indicate a positive role for CKs in axillary bud growth, and presumably ZRMP, ZR, and Z are active in miniature rose.