Calcium carbonate particle films and water regimes affect the acclimatization, ecophysiology and reproduction of tomato

Abstract

Tomato is one of the world´s more important vegetables and demands a high consumption of water in production. Climate conditions with high levels of temperatures, solar radiation, and water restriction events affect plant physiology, reproduction, and fruit quality. Particle films (PF) of kaolin have been demonstrated to be an alternative and efficient technology to promote tomato protection. However, researches with PF from calcium materials are scarce, and when considering the physiological needs of calcium throughout the crop cycle, can be strategic. The objectives of this study were to identify the isolated effects of artificial shading using different concentrations of calcium carbonate particle films on the acclimatization, ecophysiological, and reproductive parameters of tomato plants associated with two water regimes. The treatments used were calcium carbonate films (CaCO3) at concentrations of 5%, 10% and 15% (w/v) and without film or 0% (control), and two irrigation water regimes based on crop evapotranspiration (ETc), restoring 100% of ETc (WW) or 50% of ETc (WS) to simulated water stress. The research was into two experiments: the first allowed evaluating acclimatization effects by artificial shading with PF on Falker chlorophyll indices and canopying temperature in three successive applications. The second involved the combination of water regimes and PF concentrations and evaluated gas exchange, chlorophyll transient fluorescence, and flowering/fructification parameters. The results suggest that PF were able to provide acclimatization to tomato plants by artificial shading evidencing significant increases of chlorophylls and reduction in the chlorophyll a/b ratio. The associated effects of PF and water regimes indicated that PF produced a significant antitranspirant and photoprotective effect, mainly under WS, also providing physiological regulation of tomato plants during flowering/fruiting, 10% of CaCO3 accumulated better results in this sense. Particle films of CaCO3 promised to be an additional protection tool in tomato cultivation.