大气二氧化碳浓度变化对禾谷缢管蚜种群动态的影响

利用开顶式熏气室研究了大气CO₂浓度和土壤水分对禾谷缢管蚜Rhopalosiphum padi (L.)种群动态的影响，并分析了禾谷缢管蚜密度与被处理小麦叶片化学成分的关系。结果表明：（1）禾谷缢管蚜种群密度随CO₂浓度升高而持续增大并与土壤水分密切相关，各CO₂浓度下均以60%田间持水量时的密度最大；（2）CO₂和土壤水分对小麦叶片化学成分有明显的影响，麦叶水分、可溶性蛋白质、可溶性糖、淀粉含量随CO₂浓度和土壤水分含量上升而增加，纤维素含量随CO₂浓度上升而增加、随土壤水分含量上升而降低，单宁、丁布（DIMBOA）含量在CO₂浓度为550 μl/L时最高，但单宁含量随土壤水分上升而增加，丁布含量在60%田间持水量时最低；（3）禾谷缢管蚜密度与叶片水分、可溶性蛋白质、可溶性糖、淀粉含量呈正相关，与丁布、单宁含量呈负相关。结论：在未来的气候条件下，随着CO₂浓度升高禾谷缢管蚜种群可能会持续增长，这种增长在半干旱区更加突出。禾谷缢管蚜种群增长的原因之一是大气CO₂和土壤水分条件改变了植物的化学成分构成。

Effects of elevated atmospheric CO2 concentrations on population dynamics of thewheat aphid, Rhopalosiphum padi ( L.)

Effects of atmospheric CO₂ concentrations (350, 550 and 700 μl/L) and soil water levels (40%, 60% and 80% field water capacities, FWC) on the population dynamics of the wheat aphid, Rhopalosiphum padi (L.) feeding on spring wheat were examined in open topped field chambers. Results showed that: (1) Aphid density increased significantly with rising atmospheric CO₂ concentrations, the highest density occurring on wheat grown at 700 μl/L CO₂ and 60% FWC treatment; (2) Atmospheric CO₂ concentration and soil water level had significant effects on chemical components in the wheat foliage: water, soluble proteins, soluble carbohydrates, starch and tannin increased with the rising atmospheric CO₂ and FWC. Content of DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3 one) increased as atmospheric the CO₂ concentration rose with the lowest DIMBOA content occurring in the 60% FWC treatment; (3) Aphid density was positively correlated with the contents of water, soluble proteins, soluble carbohydrates and starch, and negatively correlated with the contents of DIMBOA and tannin, in foliage of treated wheat. These results suggest that aphid populations will grow more rapidly in future climate conditions, especially in semiarid areas since increasing CO₂ and changes in soil moisture will alter the chemical composition of host plants.