Studying the Slow Induction of Chlorophyll Fluorescence for Separation Tomato Fruits by their Maturity

Abstract

The maturity of tomatoes serves as a basic parameter that determines their quality. Available maturity monitoring tools allow to measure the reflection coefficients of light from the surfaces of tomato fruits at certain wavelengths. These devices have the disadvantage of insufficient reliability in assessing the stages of maturity of tomatoes, they do not take into account their internal quality and structure. (Research purpose) The research purpose is in studying the dependence of the maturity of tomatoes on the level of slow induction of chlorophyll fluorescence. (Materials and methods) The article proposes a new method for separating tomato fruits according to their maturity, eliminating the inaccuracies of existing methods, based on the physical phenomenon of slow induction of chlorophyll fluorescence. During the experiment, three botanical varieties of tomatoes with different colors of mature fruits were used: “Alcazar” (red); “Wild rose” (pink); “Orange” (yellow). Five levels of maturity of single-sized tomato fruits were selected for each variety. Authors performed a variance analysis and comparison of the average values for the Duncan criterion with the significance level at α ≤ 0.05 using statistical analysis of the SPSS V. 20 software. (Results and discussion) The article presents general pattern for these tomato varieties: as the fruit matures, the value of their maximum fluorescence induction Fm and the coefficient of specific photosynthetic activity of tomatoes Kf decreases. The differences between the maturation stages with Fm and Kf are statistically significant at α ≤ 0.05. Regardless of the botanical variety, there are high negative correlations obtained for parameters of slow chlorophyll fluorescence induction, such as Fm and Kf with maturity. (Conclusions) The dependence of the decrease in the maximum fluorescence levels of chlorophyll with an increase in the maturity of tomato fruits was found. The proposed method allows to reliably separate tomato fruits with any color of mature fruits.