Growth Zeatin

Tables VIII and IX show responses of hydrilla explants to various plant growth regulators and to solstitialin. GA3, BA and solstitialin enhanced elongation at 10-4 or 10 5 M. Zeatin, on the other hand, dramatically increased new shoot initiation in apical explants but had little effect on 2-node explants.

Zearalenone growth promotant veterinary use, 1, 219 ( )-Zearalenone synthesis, 1, 479 Zeatin... 

Zeatin (frans-iV -[4-hydroxy-3-methylbut-2-en-l-yI]adenine) [1637-39-4] M 219.3, m 207-208, 209-209.5 , pKi 4.4 (basic), pK2 9.8 (acidic). Purified by recrystn from EtOH or H2O. The UV has A-max at 207 and 275nm (e 1400 and 14650) in O.IN aqueous HCl 212 and 270nm (e 17050 and 16150) in aqueous buffer pH 7.2 220 and 276nm (e 15900 and 14650) in O.IN aq NaOH. Thepicrate has m 192-194 (from H2O) from which zeatin can be recovered by treatment with Dowex 1 x8 (200-400 mesh, OH form). [Letham et al. Aust J Chem 22 205 1969 Proc Chem Soc (London) 230 7964 Shaw and Wilson Proc Chem Soc (London) 231 7964.] It is a cell division factor (plant growth regulator) [Letham and Palni Ann Rev Plant Physiol 34 163 1983] and inhibits mitochondrial function [Miller Plant Physiol 69 1274 7982]. Its 9-riboside is a cytokine [McDonald and Morris Methods Enzymol 100 347 7985]. 

Figure 4. Effect of 24-epiBR, IAA, GA, and trans-zeatin on growth of the bean second internode.

Plant growth factors rra s-Zeatin Zeatin riboside ... 

However, wheat protoplasts have no other demonstrable responses to cytokinin and, therefore, the lack of a cytokinin effect on calcium transport is not a decisive test. Zhao and Ross [69] used zeatin induced growth and chlorophyll formation in excised cucumber cotyledons as cytokinin responses to examine the effects of calcium chelators, ionophore and several anti-calmodulin drugs. None of these drugs affected the two cytokinin responses unless used at concentrations high enough to cause indirect damage. 

C10H9N5O, Mr 215.21, mp. 267°C. K. belongs to the cytokinin group and is a derivative of adenine it occurs in various higher plants and yeasts and acts as a cell division factor. Like the closely related zeatin, K. is still active at million-fold dilutions and is thus considered to be a plant hormone. K. is isolated from autoclaved, aqueous slurries of deoxyribonucleic acids and is sometimes considered to be an artefact. K. is used as a plant growth regulator and also for inducing callus formation in plant cell cultures, etc.. ... 

Zeatin. trans-Z. [( )-2-methyl-4-(9//-purin-6-yl-amino)-2-buten-l-ol, CioHuNjO, Mr 219.25, mp. 212-213 °C (207-208°)], like kinetin, is a cytoki-nin and was originally isolated from corn ears (Zea mays) as well as from many other plants. In higher plants, trans-Z. acts as a promoter of cell division and, together with plant growth substances, has a regulating effect on various processes of plant growth. It is the most effective, naturally occurring cytokinin and at least 50-fold more active than the cw-form. 

Classically, there are five main categories of naturally occurring PGR, the auxins (lAA, NAA, IBA, 2,4-dichlorophenoxyacetic add), gibbereHins (GA), cytoM-nins (kinetin, benzyladenin, zeatin), ethylene, and growth inhibitors like abscisic acid (ABA). 

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