烤烟幼苗响应温度胁迫的部位差异

Responses of Different Organs of Flue-cured Tobacco Seedling to Temperature Stress

为了比较烤烟幼苗不同部位响应低温和高温胁迫的差异，测定了不同温度胁迫时的组织电导率，拟合Logistic方程求得半致死温度（L50），并以LT50作为主要评价指标分析烟草的部位差异。结果表明，在短期（1h）低温处理时，抵抗低温的能力排序为芽〉叶≥茎〉根，长期（24—72h）低温处理时，最易受到伤害的部位是根部，其次是茎，再次是芽和叶片；短期（15min）高温处理时，芽抵抗能力最强，其次是叶片和根，茎部抗高温的能力最弱。因此，在实际生产中烤烟幼苗遭受温度胁迫时，应在其较敏感部位未受到致命伤害之前采取相应的增温或降温措施。

In order to compare the response of different organs of flue-cured tobacco seedling to low or high temperature stress, the relative conductivity of tissues at different temperatures was measured to obtain the half lethal temperature （LT50） through Logistic equation fitting, and LT50 was served as a main parameter to evaluate the difference between organs. The results showed that the organs in the order of resistance to short term （1 hour） low-temperature stress were bud 〉 leaf ≥ stem 〉 root, and long term （24-72 hours） lowtemperature treatment would injure root first, stem the next, and then bud and leaf. In the case of short term （15 minutes） high temperature stress, the organs in the order of their resistance to temperature stress were bud 〉 leaf 〉 root 〉 stem. Therefore, in practice, the relevant measures should be taken to adjust the ambient temperature before the more susceptible organ of tobacco seedling was lethally injured.