The effect of growth regulator Rastim 30 DKV on the level of endogenous phytohormones in tomato (Solanum lycopersicum L.)

Rastim 30 DKV is a plant growth regulator with a wide spectrum of biologica l effects, Its effective substance is 3-(benzyloxycarbonyl-methyl)-2-benzot hiazolinone (30% v/v). The influence of Rastim 30 DKV on ripening and quant itative yield parameters (number and weight of fruits) the levels of endoge nous cytokinins, free IAA and production of ethylene of tomato (Solanum lyc opersicum L.) were studied in field and small plot trials. The preparation was applied as spray to tomato cv. Imun and Titan prior to flowering and 10 -14 days after the initial application in the dose of 15 and 30 ml in the a pplied volume of 500 l.ha(-1). The dose of active substance was thus 4.5 an d 9 g.ha(-1), respectively. The content of endogenous cytokinins was determ ined in leaves, roots and fruits, while that of free IAA level and ethylene production only in the leaves. Phytohormones were determined by TLC combin ed with a bioassay, by GLC or HPLC with fluorimetric detection or combined with a bioassay. Following application of Rastim 30 DKV, the content of end ogenous cytokinins was found to be increased in the leaves and fruits and d ecreased in the roots of the treated plants, The identified cytokinins were trans-zeatin, trans-zeatin riboside, trans-zeatin-O-glucoside, 2-isopenten yladenine and 2-isopentenyladenosine. An enhanced ethylene production, as w ell as a higher free IAA content were observed in leaves of the more sensit ive Titan as compared to the more resistant Imun variety. The treated tomat o plants had a significantly higher number of buds and total yield (123% of the control), but a lower mass of fruits (94.6% of the control). The compo und accelerated and synchronized the process of crop maturation.