Effects Of Deoxypodophyllotoxin On Integument In Mythimna Separate Walker

Deoxypodophyllotoxin is an important chemical compound of lignans, it was mainly found in some perennial plants of Berberidaceae such as Podophylloideae Dysosma, Sinopodophyllum, Diphylleia, Podophyllum. In this paper, Deoxypodophyllotoxin was extracted from non-essential oils of Sabina vulgris Ant. By the Research and Development Center of Biorational Pesticide of NWSUAF and its effects on epidermis in Mythimna Separate were studied by histology and physiology methods. Further studies on the mechanism of its growth and development inhibition were also discussed. The main results are as follows:1. Deoxypodophyllotoxin has strong growth inhibition function towards larvae of M. Separate. Treated larva grew slowly, The growth inhibition rates is 90.1% at the concentration of 5mg·mL-1; The larva periods were prolonged obviously. Exuviation times of the treated larvae is prolonged 1.5 days than CK. The treated larvae presented abnormal exuviations: 10%～20% of treated larvae could not molt head capsule, chest cuticle and abdomen cuticle, which finally led to their death.2. Deoxypodophyllotoxin has obvious influence on components of integument. Compared with CK, the contents of fats of treated larva are 3.6 and 1.8 time to CK at the middle stage 5th instar and the initial molt stage 6th instar. The contents of cuticle protein are 63.3% and 75.0% to CK; While the contents of cuticle chitin were not significantly different from that of CK.3. Deoxypodophyllotoxin has different influence on the five types of proteins in cuticle. It can reduce the contents of several cuticle protein, especially that of water-soluble proteins, Hydrogen-bond conbined proteins and Covalent-bond conbined proteins. The proportionality of the five types of proteins was also changed4. Deoxypodophyllotoxin can change the ratios of the water-soluble protein and Hydrogen-bond combined, and it has not obvious effects on the ratios of weak bond combined protein.: Gel electrophoresis studies showed that the protein composition of Deoxypodophy -llotoxin-treated larvaes was found in the water-soluble protein; two normal proteins were disappeared in Hydrogen-bond combined. The precipitation and recovery of normal proteins were delayed in Deoxypodophyllotoxin-treated larvaes5. pared with CK, the activity of phenoloxidase (PO) of Deoxypodophyllotoxin-treated larvae was activated at the initial molt stage 5th instar, then restrained, and was activated at the initial molt stage 6th instar; The activity of chitinase was restrained at first, then activated. All amino acid were restrained except Pro. The inhibition rates of Cyr, Val, Met and Ile are 24.6%, 22.3%, 17.0% and 11.7%. Compared with CK, the content of DNA was reduced in the middle stage in the 5th instar,and increased at the initial molt stage 6th instar. The contents of RNA was decreased rapidly and so did the ratio of RNA/DNA.6. Based on above results, the mechanism of Deoxypodophyllotoxin on integument can be concluded as follows:Deoxypodophyllotoxin interfered the RNA,→made RNA/DNA lower→influenced the synthesis and deposited of the cuticle protein→affected the contents of cuticle protein→changed the characters of cuticular chitin and protein, finally changed the physiology characters of integument→died.