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.

Some physiological effects of podolactone‐type inhibitors

Abstract: Podolactone-type inhibitors, including harringtonolide and lycoricidinol, affect several bioassays at 1 to 10 μM. Although these compounds were less active than abscisic acid in inhibiting growth of coleoptiles of wheat embryos, podolactone A significantly decreased the number of mature spikelets of Lolium temulentum at a lower concentration than abscisic acid. Lycoricidinol was more active than podolactone E, the most active of the podolactones, in three bioassays. Inhibition of growth induced by gibberellic acid or zeatin with podolactone-type compounds was not competitive. Harringtonolide was a strong inhibitor of growth at higher concentrations but did not affect auxin transport, while podolactone E and lycoricidinol inhibited it. Lycoricidinol, podolactone E and harringtonolide did not retard senescence of leaf-discs. The promotive effects of gibberellic acid in the barley endosperm bioassay were counteracted by podolactone A.

Effects of Cytokinins on the Nucleic Acids of Tobacco Pith

Abstract: Cylinders of pith of Nicotiana tabacum var Wis 38 were aseptically isolated and grown on a mineral-sucrose medium in the presence and absence of either kinetin or zeatin On medium containing kinetin (5 x 10-6 M) the increase in the residual dry weight of cylinders was greater than that on control medium after 2 d culture and this was maintained at 5 d At 2, 5, and 7 d there were increments in the DNA and RNA levels of cylinders due to kinetin treatment and these increased progressively A double-labelling method coupled with acrylamide gel electrophoresis was used to study the effects of kinetin at 5 X 10 " M and zeatin at 10~6 M on the incorporation of radioactive pre cursors into the RNA of cylinders given a 4-h label pulse No effects of zeatin were observed after 1 d nor of kinetin at 2 d but after 4 d zeatin stimulated incorporation into ribosomal, transfer and poly-disperse RNA and kinetin did likewise after 5 d Incorporation measured at 7 d was reduced in cylinders from which kinetin had been removed at 5 d compared to those to which it had been supplied continuously Scans at 260 nm of the electrophoretic fractionations of RNA after 2,5,7, and 9 d of culture showed that both in the absence and in the presence of kinetin the proportion of 4S RNA increased from about 20 per cent to over 50 per cent of the total between 2 and 5 d of culture and after 5 d the ribosomal RNA gave aberrant scans apparently indicative of degradation These aberrant scans persisted in RNA extracted after 27 d culture in both the presence and absence of kinetin

In vitro culturing and assessment of somaclonal variation of Solanum tuberosum var. desiree

Abstract: Aim: Genetic variability frequently occurs in micropropagated plants. In the present study, random amplification of polymorphic DNA technique is used to assess somaclonal variation in Solanum tuberosum var. desiree. Detection of somaclonal variants at an initial phase of growth can be valuable in establishing better tissue culture and transformation system in potato by quality control. Materials and Methods: Callus culturing conditions optimized at different hormonal concentrations. Three growth regulators 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BAP) and zeatin were used in different concentrations and combinations. Maximum callus regeneration (90%) was observed at 2.5 mg/L 2,4-D while minimum growth was monitored at 1.5 mg/L Zeatin and 1.0 mg/L BAP combination. Potato plant was also regenerated from callus cells with best results on Murashige and Skoog basal media supplemented with both 1.0 mg/L BAP and 1.5 mg/L Indole acetic acid. Genetic variability in in vitro cultured callus at different hormonal concentrations was assessed by using random amplification of polymorphic DNA technique. Results: Ten different decamer oligonucleotide primers generated 111 reproducible amplified products. The similarity coefficient values calculated through Simqual subprogram of numerical taxonomy system of multivariate software ranged from 0.419-0.838. Cluster analysis divided five samples into two groups, an in group and an out group. Maximum polymorphic bands were revealed by using hormonal combination Zeatin 1.5 mg/L and BAP 1.0 mg/L in calli cultures. Conclusion: Results indicate that random amplification of polymorphic DNA is an effective technique for the assessment of genetic variability in in vitro cultured calli.

Induction of Androgenesis as a Consequence of Wide Crossing in Chickpea

Abstract: Androgenesis was observed in a wide cross of Cicer arietinum × C. pinnatifidum. Hybrids between C. arietinum × C. pinnatifidum were obtained after rescuing the hybrid embryos in vitro. The hybrids were initially devoid of any chlorophyll pigment and were albinos. Upon continuous culture in a zeatin-rich medium and in the presence of light, the hybrids turned semi-green. Hybrid shoots were grafted to chickpea rootstocks to obtain hybrid plants. None of the hybrid plants flowered. When the nutrient solution with zeatin (1.0 mg/litre) was added, flower buds were observed on hybrid plants. Flower buds were fragile, albino to semi-green, but with normal morphology. Anthers were squashed in acetocarmine and divisions were observed in some of the microspores. The number of divisions varied from 4 to 6. Adding nutrient solution with zeatin (1.0 mg/litre) to in vivo-grown chickpea plants did not induce division in the microspores. Sixteen hybrid plants were obtained. The number of microspores/pollen grains in an anther varied from 11 to 151, compared to more than 500 pollen grains in cultivated chickpea. The number of pollen grains that had undergone microsporogenesis and induction of androgenesis varied from plant to plant. Percent androgenic pollen grains varied from 0 to 100%. Plant nos. 8, 11 and 12 did not have any androgenic pollen grains, whereas in plant nos. 14 and 16, all the pollen grains were androgenic or had multicellular microspores. The number of cells in multicellular microspores in plant nos. 14 and 16 varied from 8 to 10 unlike 4-6 cells in multicellular microspores in other hybrid plants that had androgenic microspores. This is the first report of the production of multicellular microspores as a result of wide crossing.