BIOLOGICAL EFFECTS OF FOLIAR FERTILIZERS ON CUCUMBER PLANT

Both pot experiments using 15N labeling technique and field trials were conducted to study the effects of different foliar nutrient components on major nutrients uptake and distribution, leaf photo physiology and yield and quality of cucumber fruit. The main results obtained were as follows: (1) Cueumber was capable of rapidly absorbing N. P and K through its leaves and markedly increasing their contents in the plants. Natural plant growth stimulators(NPGS) had a function of increasing the uptuke of N, P and K. especially in the case of mixed foliar application of NPGS with nutrients. (2) Each of the applications of suitable concentration of NPGS, (NH4)2SO4 and KH2PO4 nearly had the same effects of significantly enhancing the chlorphyll content and photosynthesis rates of dipping leaves, with NPGS having more rapid but shorter continuing function than(NH4)2SO4 and KH2PO4. The significant differences of photosynthesis rate and chlorophyll in different treatments could reach maximum at the time of 48 hours and 72 hours respectively and maintained for about 108 hours after dipping of foliar nutrients. Which showed the effects of foliar nutrition on photosynthesis of crops generally occurred after three days (72 hours) of foliar fertilizer applied. (3) Application of different foliar fertilizers could increase biological and fruit yields of cucumber, contents of protein.soluble sugar and Vc and decrease the content of crude fiber of cucumber fruit. (4) Among the different combination of foliar nutrients. the rational mixture of sultuble concentration of nutrient elements with NPGS had the most optimum results in both effects of stimulating leaf photosynthesis and improving fruit quality and increasing the yield, which showed a markedly positive interaction between the follar supplement of nutrients and NPGS.