Effects of HCO_3~-,K~+ and HSO_3~-on Photosynthesis of Cucumber Seedlings

Effects of HCO3-,K+ and HSO3-on photosynthesis of cucumber seedlings was studied in this research. It is tried that HCO3-in KHCO3 be used as a carbon source to supplement the shortage of CO2. At the same time,NaHSO3 was used to restrain photorespiration to increase photosynthetic rate of cucumber seedlings. The results showed that HCO3-can serve as a carbon source to supplement the lack of atmospheric CO2. HCO3-,K+ and HSO3-can promote photosynthetic rate,raise content of soluble sugar,improve the contents of chlorophyll a,b and total chlorophyll content in the leaves,and thus enhance the initial response of photosynthesis. HCO3-,K+ and HSO3-can significantly improve the electron transport activity of PSI and PSII,enhance ATP enzyme activity and photosynthetic electron transfer rate. HCO3-,K+ and HSO3-enhance RuBPCase activity,and PEPCase activity and content,and debase RuBPOase activity and speed up the fixation and reduction of CO2.