光照与飞蝗卵耐寒性的关系

Egg Cold Hardiness of the Migratory Locust Locusta migratoria L.Under Different Photoperiod Conditions

用热电偶法测定长光照 (L∶D =14∶10 )和短光照 (L∶D =10∶14 )条件下饲养的飞蝗所产卵的过冷却点 ;并对长、短光照组分别设置 5个温度 (0、 - 5、 - 10、 - 15和 - 2 0℃ )处理 ,每一温度又设置 5个时间(6h ,1、 3、 5和 10d)处理 ,然后检查其 2 8℃的孵化数 ,以此计算低温存活率和半致死温度。长、短光照组卵的过冷却点没有差异 ;两种光照条件下的低温存活率随着卵处理温度的降低和时间的延长而下降 ,在 - 5和- 10℃时短光照组的低温存活率显著高于长光照组 ;卵的半致死温度随低温处理时间的延长而升高 ,短光照组的半致死温度明显低于长光照组。接受短光照的飞蝗母本能产出耐寒性较高的卵 ,暗示秋天所产的卵能更成功地越冬。

Eggs laid by migratory locusts reared under conditions of long photoperiod (LP) (L∶D=14∶10) and short photoperiod (SP) (L∶D=10∶14) were collected.Supercooling points of some eggs were measured using a thermocouple method.The remained eggs were treated with a series of low temperatures (0,-5,-10,-15 and -20?℃) in different periods of time (6?h,1,3,5 and 10?d),and then incubated at 28?℃.The number of surviving eggs could be judged with that of incubated nymphs,and then the survival ratio of eggs in low temperature (SL) and low-lethal temperature causing death of 50% of the eggs (LT 50) were calculated.No difference was found in the supercooling points between LP and SP groups;SL decreased with the decline of treated temperature and the increase of treated time and SL in SP group was higher than that in LP group at -5 and -10?℃;LT 50 increased with increase of time in low temperature,and LT 50 of SP group was lower than that of LP group.The results suggest that the cold hardiness of locust eggs could be induced by a short photoperiod experienced by parents,that is,eggs produced in autumn would better overwinter.