【摘要】 本实驗証明:蝗卵的耐干、耐热性能,常因胚胎发育阶段而異。已吸水的越冬卵,在30℃恆温下可以在2.5％含水量的土壤内正常孵化;未吸水卵在同样温度下,則需要土壤含水量在8％以上才能正常孵化。吸水卵在土壤含水量适宜的情况下,可耐受短期的高温(60℃);而未吸水卵只能耐受55℃以下温度的处理。二者发育的最高温度界限都在41.5℃左右,超越此限,蝗卵孵化率的递減梯度,除随温度上升的幅度而加大外,并与高温的持續时間和土壤含水量的变化有关。更多还原

【Abstract】 The eggs of Locusta migratoria manilensis absorb a certain amount of water from the surrounding soil throughout their development, and then the water will be lost again as the soil moisture is very low. The rate of gain or loss of water is affected by temperature, being more rapid as the latter goes up. The susceptibility of eggs to desiccation in soil, taking percentage of hatching as a standard, varies with the stage of development of the embryos, being the least for newly-laid eggs, and the greatest for eggs which have their embryos in the overwintering stage. The increase in susceptibility to desiccation which occurred in eggs in overwintering stage is related mainly to the increase in water content within the eggs, for instance, eggs that have absorbed water give normal percentage of hatching under 30℃ constant temperature with only 2.5 per cent of soil water content, while for the newly-laid eggs, 8 per cent of water content is needed as a minimum. The stage of development of embryos is also important in relation to the susceptibility of the eggs to high temperature. Eggs with embryo in revolution stage have proved to be more enduring than those newly laid ones. But such susceptibility is affected by the water content of the surrounding soil. For newly laid eggs, it increases with the slight increase of water content from 3 per cent to 16 per cent. For eggs in overwintering stage, it decreases as the water content rises from 16 per cent to 30 per cent. Thermal death point for eggs in overwintering stage has been found approximately at 55℃, while for the newly laid eggs is somewhere about 50℃. The upper limit of optimal temperature for the development of eggs found in these experiments is 41.5℃ and may be slightly varied with the changes of soil moisture.更多还原