空心莲子草及其天敌莲草直胸跳甲对高含量CO2的响应

摘要

为明确CO2含量升高对入侵杂草空心莲子草及其天敌莲草直胸跳甲的影响,测定了3种不同CO2含量(420、550、750 μL·L-1)对空心莲子草生长特性和体内营养物质、莲草直胸跳甲幼虫体重增长和成虫取食选择性的影响.结果表明:CO2含量升高条件下,空心莲子草生长速度加快,种植42 d后,550、750 μL·L-1 2个高含量CO2条件下空心莲子草的株高分别达35.60 cm和40.04 cm,分别为对照组(当前大气CO2条件420 μL·L-1下)空心莲子草株高(19.83 cm)的1.75倍和2倍;CO2含量升高,空心莲子草叶片SPAD值显著增加,光合作用能力增强;叶片的可溶性总糖含量升高,含氮化合物(蛋白质、总氨基酸)含量降低,叶片的碳氮比增加,单宁酸含量降低.取食高含量CO2条件下培育的空心莲子草,天敌莲草直胸跳甲幼虫的体重增加速度较对照组显著加快;同期羽化的莲草直胸跳甲雌、雄成虫均偏好取食高CO2含量(750 μL·L-1)条件下培育的空心莲子草.%The growth characteristics of alligator weed,Alternanthera philoxeroides, and the larvae development and adult feeding habit of Agasicles hygrophila under elevated atmospheric CO2were investigated.Three CO2 concentrations,i.e., 420, 550 and 750 μL·L-1, were applied in a closed chamber for the experiment.It was found that A.philoxeroides grew faster at higher CO2 concentrations.On the 42nd day, the heights of the weeds were 35.60 cm and 40.04 cm at 550 μL·L-1 CO2 and 750 μL·L-1CO2, respectively.As compared to that of control (19.83 cm), the weed height was 1.75 times higher under 550 μL·L-1CO2, and two times higher under 750 μL·L-1CO2.In an elevated CO2environment, the leaves of the weeds showed increases on the SPAD, photosynthesis, soluble sugars, and C/N ratio, but decreases on the nitrogen-containing compounds (such as, proteins and amino acids) and the tannin content.When fed on A.philoxeroides under elevated CO2, the weight of A.hygrophila larvae was higher than that of control, while the emerged adults, male or female, appeared to prefer A.philoxeroides grown under 750μL·L-1CO2.