Effects of foliage applications of KH₂PO₄ and glucose on photosynthesis and sucrose metabolism of tomato

Liaoyuanduoli and cherry tomato Hongyu were applied with KH₂PO₄(K), Glucose(G) and KH₂PO₄ plus Glucose(K+G) in order to study the effect of K, G and K+G on photosynthesis and sucrose metabolism of the two varieties. The results showed that foliage applications of KH₂PO₄ and a mixture of glucose and KH₂PO₄ increased chlorophyll content and net photosynthetic rate of tomato leaves. The KH₂PO₄ alone and the KH₂PO₄ plus glucose treatments were more effective than the glucose alone treatment. At the same time, fructose and glucose contents of two tomato varieties were enhanced by foliage application. Acid and neutral invertases activities in two tomato varieties were increased at varying degrees. So did sucrose synthase(SS) and sucrose phosphate synthase(SPS). Spraying glucose alone was less effective compared with two other treatments. This implied that under foliage application tomato fruit sink strength was increased by enhancing the activities of four enzymes. With increased tomato fruit sink strength, phytosynthate translocation and dry matter accumulation were accelerated.