Different Application Ways of Calcium on Photosynthesis and Antioxidant Enzymes Activities of Tomato under Low Night Temperature

In bid to study the regulation mechanism of calcium on photosynthesis of tomato under low night temperature (LNT at 6 degrees C).The response of gas exchange parameters, antioxidant enzyme activity to LNT in tomato seedlings were treated with distilled water, and the different application concentrations and ways of CaCl2 were investigated. The results showed that CaCl2 treatment either sprayed to leaves or irrigated into root led to an increase in photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration(Ci), transpiration rate (Tr), super oxygen dehydrogenises (SOD), peroxidase (POD) and catalase (CAT) activity, and decreased MDA content, being affected by irrigating root with 40 mL 0.5% CaCl2\ overmatches other ways. In summary, application of CaCl2 enhanced adaptation of tomato seedling to LNT.