Kaolin particle film on peach leaf physiology

Abstract

Hot summers, typical of the Mediterranean region, negatively affect temperate zone tree productivity. Kaolin particle films are used to alleviate heat stress under these conditions. We investigated the effect of kaolin particle film on peach leaf physiological characteristics and functions in central Greece. Kaolin particle film was applied periodically from early June to early August 2011 on 'Royal Glory' peach trees. Leaf temperature and available radiation as well as various leaf parameters and functions were measured from June until late September. The presence of kaolin on leaf surfaces reduced incident radiation and leaf temperature, and increased reflected radiation compared to control leaves. At the beginning of kaolin application in June, leaves treated with kaolin had similar leaf functions to control leaves. From July until late September, even after rains removed most of kaolin in September, peach leaves treated with kaolin had higher stomatal conductance, transpiration and photosynthetic rates than control leaves. In addition, from mid-July until late September leaves treated with kaolin had decreased chlorophyll (a, b and total) concentration per m2 leaf surface compared to control leaves, while specific leaf area remained unchanged due to kaolin presence. It appears that the reduction of incident radiation and leaf temperature in the presence of kaolin reduced heat stress, which, in turn, increased leaf productivity in this early to mid-season ripening peach cultivar. © 2015 ISHS.