Lindroth R L, Hofman R W, Campbell B D, McNabb W C, Hunt D Y
Department of Entomology, 237 Russell Labs, 1630 Linden Dr., University of Wisconsin, Madison, WI 53706, USA e-mail:
AgResearch, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand, , , , , , NZ.
Oecologia. 2000 Jan;122(1):20-28. doi: 10.1007/PL00008831.
White clover growing in New Zealand is experiencing increasing levels of ultraviolet-B (UV-B) radiation as a result of ozone depletion. We evaluated the effects of UV-B radiation on the foliar chemistry of two populations of white clover (Trifolium repens L.), 'Huia' and 'Tienshan,' and the consequences for the performance of armyworms (Spodoptera litura) and cutworms (Graphania mutans). Plants were grown in controlled environment rooms with and without supplemental UV-B radiation at a dose of 13.3 kJ m day, corresponding to a 25% mid-summer ozone depletion above Palmerston North, New Zealand. In both white clover populations, UV-B radiation elicited changes in foliar chemistry, including slight increases in nitrogen concentrations and decreases in carbohydrate concentrations. In addition, the 'Huia' population showed decreases in fiber concentrations and marked increases in cyanogenic activity. No change in UV-absorbing compounds was detected in either population. Long- and short-term feeding trials were conducted to assess dietary effects on insect growth, consumption, and food utilization. Changes in the performance of both insect species were generally small. The most pronounced effect was a 36% reduction in weight of S. litura after 2 weeks of feeding on Huia grown at high UV, but larval development times were only slightly prolonged and pupal weights were unaffected. S. litura short-term performance was affected by differences in white clover population. The long-term performance of G. mutans was not affected and its short-term performance (stadium duration and consumption rate) was only marginally affected by the high-UV treatment. We conclude that the effects of elevated UV-B radiation on white clover plant chemistry can be specific to certain plant populations. The differences in sensitivity of the two generalist insect species suggest that effects may also be specific to certain plant-herbivore associations. These results indicate that future UV-B herbivory studies should examine genotypic effects in both plants and animals.
由于臭氧损耗，生长在新西兰的白三叶草受到的紫外线B（UV-B）辐射水平不断增加。我们评估了UV-B辐射对两个白三叶草（Trifolium repens L.）种群‘Huia’和‘天山’叶片化学性质的影响，以及对粘虫（Spodoptera litura）和夜蛾（Graphania mutans）生长表现的影响。植物在可控环境室中生长，分为有和没有剂量为13.3 kJ m²天的补充UV-B辐射两组，这一剂量相当于新西兰北帕默斯顿仲夏臭氧损耗25%的情况。在两个白三叶草种群中，UV-B辐射都引起了叶片化学性质的变化，包括氮浓度略有增加和碳水化合物浓度降低。此外，‘Huia’种群的纤维浓度降低，氰化物活性显著增加。两个种群中均未检测到紫外线吸收化合物的变化。进行了长期和短期的取食试验，以评估饮食对昆虫生长、食量和食物利用率的影响。两种昆虫生长表现的变化通常较小。最显著的影响是，以高UV条件下生长的‘Huia’为食2周后，粘虫体重减轻了36%，但幼虫发育时间仅略有延长，蛹重未受影响。粘虫的短期生长表现受白三叶草种群差异的影响。夜蛾的长期生长表现未受影响，其短期生长表现（龄期持续时间和取食率）仅受到高UV处理的轻微影响。我们得出结论，UV-B辐射增加对白三叶草植物化学性质的影响可能因特定植物种群而异。两种多食性昆虫物种敏感性的差异表明，影响也可能因特定的植物-食草动物组合而异。这些结果表明，未来关于UV-B与食草动物关系的研究应考察植物和动物的基因型效应。
