Abstract: To figure out the physiological regulation mechanism of tomato cold resistance,we used two type tomatoes which one is cold resistance wild tomato LA1777 and the other is low temperature sensitive cultivated tomatoes LA2706 as our test materials to study the influence of low temperature on antioxidant metabolism and carbon assimilation. Results showed that under the stress of low temperature,the contents of superoxide-anion radical (O₂^·),hydrogen peroxide(H₂O₂),malondialdehyde(MDA),dehydroascorbic acid(DHA)increased,and it that in LA2706 was about 0.3%-21.0%,1.2%-17.3%,13.4%-36.9%,and 13.3%-21.0% higher than LA1777,that speeded up the process of membrane lipid peroxidation. The contents of reduced ascorbic acid(AsA)had a slight upward trend with cryogenic processing time extended;the activity of superoxide dismutase(SOD)decreased by 55.3% and 28.2% 7 d after treatment in LA2706 and LA1777,LA2706 fell obviously than LA1777;the peak of ascorbic acid catalase(APX)in LA1777 was significantly higher than LA2706,and about is 1.7 and 4.0 times that of LA2706 in 1 and 7 d after treatment. With the extension of low temperature processing time,the total sugar content,acid invertase activity,neutral invertase activity and sucrose phosphate synthase all raised,LA2706 had a significantly higher increment than LA1777,and about was 5.8,4.8,10.2 and 1.7 times in 7 d that of 0 d after treatment.Low temperature made LA2706 to have a large number of decomposition starch into sugar,to alleviate the stress of low temperature environmental damage.

Key words: Tomato, Low temperature, Leaf, Antioxidant metabolism, Carbon assimilation

CLC Number: 

• S641.2