Effects of Tomatex (Triacontanol) on chlorophyll fluorescence and tomato (Lycopersicon esculentum Mill.) yields

The influence of triacontanol in a form of Tomatex preparation on basic ind ices of chlorophyll fluorescence in tomato leaves (Delfina cv.), yield of f ruits, and dry matter content in fruits was evaluated in a pot experiment s ituated in vegetation hall in 1999. Tomatex was applied into roots at seedl ing stage (6-7 leaves) or at the stage of seedling and flowering of the 2(n d) inflorescence bunch. Plants were given by 0.3, 3.0, and 30 mu g triacont anol per pot at a single dosage. Results obtained have shown that triaconta nol regardless of the dose applied, significantly increased the maximal eff iciency of PSII photochemistry in the dark (Fv/Fm), the efficiency of excit ation capture by open PSII reaction centers (Fv'/Fm), the actual quantum yi eld of PSII electron transport in the light-adapted state (Phi(PSII)), the photochemical quenching coefficient (Q(p)) However, non photochemical quenc hing coefficient (Q(n)) and non-radiative dissipation (NPQ) were decreased. Plants treated with triacontanol at the doses of 0.3 and 3.0 mu g had sign ificantly higher yields of fruits than control. No differences were found b etween plants treated once and twice with the growth regulator. Triacontano l did not show univocal effects on dry matter content in fruits either.