| Acid rain is a natural precipitation con+taining some acidic substances such as rain, snow, hail, fog and so on, and its pH values are often below 5.6. With the rapid development of modern industry, intensely increased population and tendency of urbanization, more and more exhaust gas, sulfide and oxynitrogen, are emitted and acid rain resulted from the exhaust gas are much more serious than ever. The threat of acid rain to the global biosphere has become an environmental problem of worldwide importance. It not only harms to people's health and erodes buildings, but also influences organism growth. Except for exerting direct effects on plants, acid rain induces and sharpens the occurrence and damages of plant diseases and insect pests in forestry and agriculture ecosystems as well. The subsequent economic loss is even greater than the direct loss of pollutants. Furthermore, its potential harm to the ecosystem of forestry and agriculture is well worth attention. Due to its economic importance, the effects of acid rain on insects (mites) have become one of focus studies in this field.The carmine spider mite, Tetranychus cinnabarinus (Boisduval), a serious mite pest of over 100 species of economical crops and ornamental plants, for example cotton, tobacco, and fruit trees, is widely distributed. In areas seriously polluted by acid rain, the damage of this mite is more and more serious and it does great harm to the agricultural production especially to suburb vegetables. In this study, the direct effects of acid rain on the mite and the indirect effects of acid rain through altering the physiological metabolism of host plants were investigated systematically. Meanwhile, the ethological, physiological and biochemical mechanisms of the mites adaptable to acid rain and its ecological fitness were also studied, respectively. We analyzed the comprehensive effects of acid rain on the mite and its host plant, which not only deepens the acquaintance of life phenomena of plants and insects (mites) under environmental impact establishing the basis of convergent evolutionbetween insects (mites) and plants, but also helps occurrence forecast and integrated management of the mite. This study was supported in part by National Natural Science Foundation of China (30170617), and lasted about 3 years, the main results are as follows: 1. Eeffects of acid rain on major enzymes and energy sources of T. cinnabarinusThe simulated acid rain treatments were pH5.6, 4.0, 3.0 and 2.5, and the deionized water was used as the control. In all experiments, simulated acid rain of different pHs were sprayed to the mite and its host plants at the same time. The plants were sprayed every two days. The activities of major protective, hydrolytic and group- transferring enzymes, isozyme zymogramsand energy source contents of mites from each treatment were measured, respectively, after 15, 30 and 45 d treatments. Through" the comparison of enzyme activities and energy source contents of mites under different acid rain and impact periods, the physiological and biochemical mechanisms of this mite adaptable to acid rain were clarified.1.1 Effects of simulated acid rain on three protective enzyme activities of T. cinnabarinusThe elevated activity of the protective enzymes (superoxide dismutase: SOD, peroxidase: POD, catalase: CAT) is considered to be an important physiological and biochemical mechanism of organisms against adverse environment. The results indicated that compared to the control, the protective enzyme activities of the mites under acid rain impact were increased significantly. With the increasing of acidity, SOD and POD activities ascended at the beginning and then declined, The highest activity was recorded at pH3.0 or 4.0 treatment, respectively. In contrast. CAT activity ascended throughout the experiment. As impact period prolonged, the activity ascending ratio values of three protective enzymes all decreased. This suggested the corresponding stress reaction of acid rain on the carmine spider mite was quite significant.
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