Kaolin-based particle film technology affects tomato physiology, yield and quality

Environmental stress call affect development and yield of tomato plants. This Study was undertaken to investigate the underlying mechanism asserted by kaolin on tomato physiology by evaluating its effect oil leaf, canopy and inner fruit temperatures, gas exchange at the leaf and canopy scales, above ground biomass, yield and fruit quality. The study was carried out under field conditions in Southern Italy. Treatments were plants treated with kaolin-based particle film (Surround (R) WP) Suspension and Untreated plants (control). Kaolin application slightly increased leaf and canopy scale temperatures by 1.0 and 0.4 degrees C, respectively, transpiration rate decreased at both scales. Oil calin days (wind speed < 0.5 m s(-1)) with a prevalently clear sky at midday, inner fruit temperature (t(f)) of kaolin-treated plants was 4.4 C lower than the t(f) of control plants, while in days with clear sky-windy, and cloudy-calm, the t(f) did not differ. At leaf scale, net assimilation was reduced by 26% in kaolin-coated treatments. Stomatal conductance decreased by 53%, resulting in reductions of 34 and 15% in transpiration and internal CO2 concentration, respectively. Gas exchange parameters measured at canopy scale were similarly affected. In kaolin-treated plants. assimilation and evapotranspiration rates were reduced by 17 and 20%, respectively, while dark respiration was not affected. Above ground city biomass decreased by 6.4%. Marketable yield in kaolin-treated plants was 21% higher than those measured in control plants: this is possibly related to the 96 and 79% reduction ill Sunburned fruit and those damaged by insects, respectively, and to the 9% increase in mean fruit weight. Kaolin treatment increased lycopene fruit content by 16%, but did not affect total Soluble solids content, fruit dry matter, juice pH. titratable acidity or tomato fruit firmness. The use of kaolin-based particle film technology would be all effective tool to alleviate heat stress and to reduce water stress in tomato production under arid and semi-arid conditions. (c) 2009 Elsevier B.V. All rights reserved.