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| Effects of Root-zone Temperature Stress on Tomato Seedling Root System Growth and Sucrose Metabolism |
| LIU Bingzhu，ZHANG Feng，LEI Lei，MENG Xianmin，ZHANG Mengxia，DONG Chunjuan，SHANG Qingmao* |
| （Institute of Vegetables and Flowers，Chinese Academy of Agricultural Sciences，Key Laboratory of Biology and Genetic Improvement of Horticultural Crops，Ministry of Agriculture and Rural Affairs，Beijing 100081，China） |
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Abstract Taking high and low temperature tolerant tomato cultivar‘Jiulyu 787’and high and low temperature intolerant tomato cultivar‘Yingfen No.8’as test matierials；root-zone temperatures of normal cultivation（average 20 ℃）as the contrast，this paper studied the effects of root-zone temperature including 10 ℃ low temperature and 34 ℃ high temperature on the phenotype，sugar content and activities of sucrose metabolism related enzymes in tomato seedling root system．The results showed that 10 ℃ low and 34 ℃ high root-zone temperatures stress had inhibited the root system growth of both‘Jiulyu 787’and‘Yingfen No.8’to various degrees．But the inhibition degree of root system phenotype and bioaccumulation of‘Jiulyu 787’seedlings was lower than that of‘Yingfen No.8’．Under 10 ℃ low temperature stress the glucose，fructose，and sucrose contents in both cultivars root system were significantly increased．The active responsive enzymes in sucrose metabolism were SPS and SAI．34 ℃ high temperature mainly promoted the accumulation of sucrose in root system．The activities of sucrose metabolic decomposing enzymes（SS-I，CWIN，SAI and NI）were all significantly inhibited．Under root-zone temperature stress，the sugar content in‘Jiulyu 787’root system was higher than that in‘Yingfen No.8’，but the growth rate was lower than that of‘Yingfen No.8’．This might be due to the inhibition degree of‘Jiulyu 787’fine root（≤ 0.5 mm）growth being lower than that of‘Yingfen No.8’．It needed to decompose sugar to provide energy and other substances，while the soluble sugar in root system of‘Yingfen No.8’mostly played a role in stress resistance by osmotic regulators．
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Received: 12 April 2022
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