Studies On Cold Hardiness Of The Eggs Of Pararcyptera Micropterameridionalis (Ikonnikov) And Oedaleus Decorus Asiaticus B. Bienko

Using thermocouple’s method, we measured the supercooling point and freezing point of the eggs of Pararcyptera microptera meridionalis (Ikonnikov) and Oedaleus decorus asiaticus B. Bienko. The results showed that the supercooling points of the eggs of P. microptera meridionalis were-24.2±0.63℃,-23.6±0.39℃and-23.7±0.40℃, respectively; its egg’s freezing points were-13.0±0.93℃,-11.7±0.62℃and-10.4±0.66℃,respectively, in the dry soil, the wet soil and the4℃Freezer conditions. The supercooling point and freezing point of the eggs of O. decorus asiaticus were-21.4±3.11℃and-18.2±3.66℃, respectively. The former’s supercooling point was lower than the latter’s but the freezing points were reverse. With the water content of their eggs increasing, the supercooling points and freezing points had a rising trend but the correlation did not reach the significant level at p=0.05.Gas Chromatography showed that the contents of eight kinds of small molecular cold-tolerant substances in the eggs of P. microptera meridionalis were higher than these of O. decorus asiaticus. The composition proportion of eight small molecular cold-tolerant substances of the former’s eggs with different supercooling point was almost the same. The sorbitol content was the most, the inositol and trehalose contents were the second and the mannitol content was the least. The former’s supercooling points declined with the increase of glycerol, erythrose, glucose, mannitol, sorbitol, inositol and trehalose but the correlation did not reach the significant level at p=0.05. There was a significant positive correlation between the supercooling points and the fructose content.The composition proportion of eight small molecular cold-tolerant substances in the latter’s eggs with different supercooling points was almost the same. The trehalose content was the most, the inositol content was the second and the sorbitol content was the least. The former’s supercooling points declined with the increase of erythrose, fructose, glucose, sorbitol and inositol in the eggs but the correlation did not reach the significant level at p=0.05.