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Temperature directly affects the growth, survival, and development rates of poikilothermic insect herbivores; it may also have an important indirect impact, via the activities of plant defensive enzymes. The effects of wounding birch leaves and temperature on the growth and development rates of a Lepidopteran moth, Epirrita autumnata, were studied. We also examined the activities of a mountain birch (Betula pubescesns spp. czerepanovii) defensive enzymes, specifically the polyphenoloxidases (PPOs), in relation to temperature and wounding. The optimal temperature for early instars in terms of survival and developmental rates was between +15 and 20 degrees C. Wounding treatment had different effects on birch PPO activity depending on the temperature: at +12 degrees C, wounding decreased the activity, suggesting induced amelioration at that temperature, whereas at +25 degrees C, wounding increased the activity, suggesting induced resistance. However, larval growth was retarded slightly, but significantly, on the leaves of wounded twigs at both temperatures. Both PPO activity and larval growth rates were affected within 12 h, indicating the existence of a transcription- and translation-independent defense system in birch leaves. We suggest that underlying the increase in PPO activity and the decrease in larval growth rate may be H2O2, which has been shown to accumulate in response to wounding. Our results also provide a possible biological mechanism for the hypothesis that low temperatures promote the success of E. autumnata and other Lepidopteran larvae via decreased defensive enzyme activities of host plants at lower temperatures.

Aims: The aim of the study was to examine oxidative responses in subarctic mountain birch, Betula pubescens subsp. czerepanovii, induced by herbivory and manual wounding., Methods: Herbivory-induced changes in polyphenoloxidase, peroxidase and catalase activities in birch leaves were determined. A cytochemical dye, 3,3-diaminobenzidine, was used for the in situ and in vivo detection of H2O2 accumulation as a response to herbivory and wounding. To localize peroxidase activity in leaves, 10 mm H2O2 was applied to the dye reagent., Key Results: Feeding by autumnal moth, Epirrita autumnata, larvae caused an induction in polyphenoloxidase and peroxidase activities within 24 h, and a concomitant decrease in the activity of antioxidative catalases in wounded leaves. Wounding also induced H2O2 accumulation, which may have both direct and indirect defensive properties against herbivores. Wound sites and guard cells showed a high level of peroxidase activity, which may efficiently restrict invasion by micro-organisms., Conclusion: Birch oxidases together with their substrates may form an important front line in defence against herbivores and pathogens.

Through solution culture and soil culture experiments, effects of Tongling copper mine tailings on seed germination and seeding growth of five legumes species were studied in this paper. The results showed that the seeds of five legumes species could germinate in the normal and acidified tailings extracted solution, but germination percentage was lower than that under control. It indicated that tailings extracted solution had inhibition effect on seed germination, however, acidified tailings extracted solution promoted absorbing water of the seeds in early stage. In five amelioration substrates between tailings and soils, the tailings also inhibited seed germination of the five species. No dead seedlings of Glycine max, Phaseolus angularis, P. calacaratus were found within 70 days.