CO_2浓度升高条件下不同程度豌豆蚜危害对紫花苜蓿叶片营养物质和次生代谢物质的影响

Effects of elevated CO_2 concentration on nutrients and secondary metabolites in Medicago sativa leaf under different damage degrees of pea aphid(Acyrthosiphon pisum, Hemiptera: Aphididae)

由于人类大量开采使用石油、煤炭、天然气等化石燃料,使大气CO_2浓度升高,这不但加速全球变暖,还将影响地球上动植物的生存和分布,从而对整个生态系统产生深远影响。为探明CO_2浓度升高与豌豆蚜(Acyrthosiphon pisum)虫口密度对紫花苜蓿(Medicago sativa)叶片内化学物质的影响,明确CO_2浓度升高和蚜虫密度在紫花苜蓿生理生化中的作用,试验在CO_2光照培养箱内设置380μL·L^(-1)(对照)、550μL·L^(-1)和750μL·L^(-1) 3个CO_2浓度培育苜蓿幼苗并接入10日龄成蚜10头·株^(-1)、20头·株^(-1)、30头·株^(-1),并以0头·株^(-1)作为空白对照,1周后测定植物体内营养物质和次生代谢物质含量。结果表明,随CO_2浓度升高,蚜虫密度为30头·株^(-1)时紫花苜蓿可溶性蛋白、可溶性糖以及淀粉含量均上升,在750μL·L^(-1 )CO_2浓度下分别比CK上升11.62倍、0.49倍和0.24倍;黄酮、总酚和简单酚含量也显著上升。随蚜虫危害程度加重,同一CO_2浓度下紫花苜蓿淀粉、简单酚含量先上升后下降,高CO_2浓度蚜虫密度为30头·株^(-1)时比0头·株^(-1)时可溶性糖、总酚以及单宁含量上升1.66倍、1.49 mg·g^(-1)和1.09 mg·g^(-1),差异均显著(P<0.05)。说明具有固氮作用的豆科植物更易于适应CO_2浓度升高的变化,从而在受到刺吸胁迫后增强自身诱导抗虫性以抵御害虫为害。

Due to massive exploitation and use of fossil fuel such as petroleum,coal and natural gas,atmospheric CO2 concentration has been increasing,which not only accelerated global warming,but also affected the survival and distribution of animals and plants on the earth with far-reaching impacts on the ecosystem.This research was carried out to explore the effects of elevated CO2 concen tration and pest population density of Acyrthosiphon pisum on chemical substances in the leaves of Medicago sativa.The objective was assessed the effects of elevated CO2 concentration and pea aphid density on the physiology and biochemistry of M.sativa.The nutrients and secondary metabolites in M.sativa leaves were determined by cultivating M.sativa seedlings attacked by10-day old pea aphids of10head·plant^-1,20head·plant^-1,30head·plant^-1and0head·plant^-1(CK)for one week under three CO2concentrations[380μL·L^-1(CK),550μL·L^-1and750μL·L^-1]in CO2gradient chamber.The results indicated that the contents of soluble protein,soluble carbohydrate and starch increased after aphid sucking of30head·plant^-1with increasing CO2 concentration.At750μL·L^-1CO2concentration,they were respectively11.62times,0.49times and0.24times higher than those under CK,respectively.Also the contents of flavone,total polyphenols and simple phenols increased significantly.Furthermore,the contents of starch and simple phenols increased and then decreased with increasing degree of damage under the same CO2concentration.Comparatively,contents of soluble carbohydrate,total polyphenols and tannin were significant differences between aphid densities of30head·plant^-1and0head·plant^-1,which increased by1.66times,1.49mg·g^-1and1.09mg·g^-1(P<0.05)compared with those of CK under the highest level of CO2concentration.The results indicated that nitrogen fixing legume plants were more likely to adapt to increased CO2concentration and thereby enhanced self-induced resistance to insect pests.