Características fisiológicas, produtivas e qualidade pós-colheita do tomateiro em resposta à adubação com silicato de cálcio

Abstract

Productive, physiologic and post-harvest quality of two tomato hybrids were evaluated in function of doses of calcium silicate. The experiment was conducted in a protected environment from August up to December 2017, in a randomized block design and in a factorial scheme 2 x 5, with four replicates, being the two tomato hybrids (“Ivety” and “Natália”) the first factor and the calcium silicate doses (0; 150; 300; 450 and 600 kg ha-1) the second, with the doses applied on the same day that the pots were filled. The fruits were evaluated for number, longitudinal and transversal diameter, average fruit mass and for commercial, non-commercial and total yield. Plants were evaluated for leaf number, stem diameter, aerial length, foliar area, damage of membrane integrity, lignin content, stem and leaves dry mass, accumulation and content of silicate, calcium and magnesium in the leaves and these contents in the fruits of tomatoes. For the gas exchange indexes, it was measured the CO2 liquid assimilation rate (A), foliar transpiration (E), stomatal conductance (gs), internal CO2 content (Ci), water use efficiency (WUE), intrinsic water use efficiency (iWUE) and instantaneous carboxylation efficiency (iCE), besides being evaluated the SPAD index and the photosynthetic pigment contents carried in the first flowering stage (17 DAT), full bloom (58 DAT) and full fructification (78 DAT). Besides these, fruit evaluations were made, namely: ethylene production, fruit’s respiration, firmness, number of locus, polygalacturonate activity, total carotenoids, lycopene, phenolic compounds, soluble solids content, pH, titratable acidity and the ascorbic acid content. The increase in the calcium silicate doses influenced the tomatoes non-commercial yield, damage of leaf membrane integrity, A, gs, E, iCE, chlorophylls a, b and total contents and the ethylene production and the fruit’s respiration, showing a reduction of these as the doses increased. There was also an increase in the silicon and calcium content in the fruit ‘Natália’, which presented low polygalacturonate activity, even though the silicate showed differences, which was due to the genetic variability. The contents of lycopene, phenolic compounds, soluble solids, pH, titratable acidity and ascorbic acid of fruits increased in response to crescent doses of calcium silicate for ‘Ivety’. Based on these results, it is concluded that the hybrids presented different performances on the influence of fertilization with calcium silicate in tomato, reducing the fruits noncommercial yield and being able to increase the post-harvest conservation.