外源硝态氮提高淹水甜樱桃根系糖含量及蔗糖相关酶活性

 以‘大青叶’（Prunus pseudocerasus var. Daqingye）嫁接甜樱桃‘岱红’(P. avium. ‘Daihong’) 为试材，研究了淹水条件下外源硝态氮对甜樱桃根系蔗糖、葡萄糖、果糖和淀粉含量及蔗糖合酶（SS）合成和分解、蔗糖中性转化酶（NI）、蔗糖酸性转化酶（AI）活性的影响。结果表明，淹水过程中处理与对照根系蔗糖、葡萄糖、果糖和淀粉含量均呈先升后降趋势；与对照相比，外源NO₃^-提高了根系中蔗糖、葡萄糖、果糖和淀粉的含量，蔗糖、葡萄糖、果糖和淀粉达到最大值时，处理比对照分别高18.02%、21.97%、25.27%和11.41%。淹水过程中根系SS分解活性呈先升后降趋势，而SS合成活性、NI和AI活性呈下降趋势；加NO₃^-后，4种酶活性均高于对照。这些结果表明，淹水条件下外源NO₃^-可通过调控根系的糖代谢而增强甜樱桃耐低氧能力。

Exogenous NO3- Enhanced Sugar Contents and Sucrose Correlated Enzymes Activity in Roots of Sweet Cherry Under Waterlogging Condition

Effects of exogenous NO₃^-on sucrose, glucose, fructose and starch contents as well as sucrose synthase(SS) disassemble activity, sucrose synthase synthesis activity, neutral invertase activity（NI）and acid invertase activity（AI）in roots of sweet cherry ( Prunus. avium. 'Daihong') with P.pseudocerasus var Daqingye as rootstock under water-logging condition were studied. The results showed that under water-logging condition, sucrose, glucose, fructose and starch in roots of sweet cherry increased significantly in the early period and then decreased in the later period in both treatment and control. Exogenous NO₃^-enhanced the contents of sucrose, glucose, fructose and starch, which were higher than control, while to the maximum, which were 18.02%, 21.97%, 25.27% and 11.41% higher than that of control respectively when reached to the maximum. The sucrose synthase disassemble activity in roots of sweet cherry increased to the highest level and then declined gradually in both treatment and control. Meanwhile, the sucrose synthase synthesis, NI and AI activities decreased gradually, but four enzymes activities of treatment were higher than that of control after using exogenous NO₃^-. We conclude that the addition of NO₃^- can enhance the tolerance of the roots of sweet cherry to hypoxia through regulation of sugar metabolism.