Effect of β-alanine hydrazide derivatives on Phaseolus vulgaris photochemistry and CO 2 assimilation

The effect of synthetic growth regulators β -alanine hydrazide derivatives on kidney bean (Phaseolus vulgaris L.) photosynthesis was investigated employing CO 2 assimilation and chlorophyll fluorescence analysis. Foliar application of the experimental growth regulator β-alanine hydrazide derivative st-120 on kidney beans significantly increased the photosynthesis rate and quantum efficiency of CO 2 assimilation. After decoding slow chlorophyll fluorescence induction kinetics, we determined a pronounced and statistically significant effect of st-120 on kidney bean maximal quantum yield of PSII (photosystem II) photochemistry and an effective quantum yield of photochemical energy conversion in PSII, associated with an increased number of oxidized PSII reaction centres. The β -alanine hydrazide derivative st-119 also enhanced the above-mentioned parameters, but the effect was not statistically significant.