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

Abstract

The influence of triacontanol in a form of Tomatex preparation on basic indices of chlorophyll fluorescence in tomato leaves (Delfina cv.), yield of fruits, and dry matter content in fruits was evaluated in a pot experiment situated in vegetation hall in 1999. Tomatex was applied into roots at seedling stage (6–7 leaves) or at the stage of seedling and flowering of the 2^nd inflorescence bunch. Plants were given by 0.3, 3.0, and 30 µg triacontanol per pot at a single dosage. Results obtained have shown that triacontanol regardless of the dose applied, significantly increased the maximal efficiency of PSII photochemistry in the dark (F_v/Fm), the efficiency of excitation capture by open PSII reaction centers (F_v’/F_m’), the actual quantum yield of PSII electron transport in the light-adapted state (Φ_PSII), the photochemical quenching coefficient (Q_p). However, nonphotochemical quenching coefficient (Q_n) and non-radiative dissipation (NPQ) were decreased. Plants treated with triacontanol at the doses of 0.3 and 3.0 µg had significantly higher yields of fruits than control. No differences were found between plants treated once and twice with the growth regulator. Triacontanol did not show univocal effects on dry matter content in fruits either.