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．

Key words: tomato, root-zone temperature, high temperature stress, low temperature stress, root system growth, sucrose metabolism

摘要： 以番茄耐高低温品种久绿787和不耐高低温品种硬粉8号为试材，以正常栽培的根区温度（平均20 ℃）为对照，研究了根区10 ℃低温和34 ℃高温对番茄幼苗根系表型、糖含量、蔗糖代谢相关酶活性的影响。结果表明，根区10 ℃低温和34 ℃高温胁迫对久绿787和硬粉8号根系生长均产生了不同程度的抑制，久绿787根系表型和生物积累量的受抑制程度要低于硬粉8号。在10 ℃低温胁迫下，2个品种幼苗根系中葡萄糖、果糖和蔗糖含量均显著增加，蔗糖代谢中积极响应的酶为SPS和SAI；34 ℃高温主要促进了根系中蔗糖的积累，蔗糖代谢分解酶（SS-I、CWIN、SAI和NI）活性均受到显著抑制。根区温度胁迫下，久绿787根系中糖含量高于硬粉8号，但增长率却低于硬粉8号，这可能与久绿787细根（≤ 0.5 mm）生长受抑制程度低于硬粉8号，其需要靠分解糖来提供能量和其他物质，而硬粉8号根系中可溶性糖多以渗透调节物起抗逆作用有关。

关键词: 番茄, 根区温度, 高温胁迫, 低温胁迫, 根系生长, 蔗糖代谢