Department of Environmental Science and Technology, University of Maryland, College Park, Maryland, USA.
Environ Health Perspect. 2010 Sep;118(9):1223-8. doi: 10.1289/ehp.0901867. Epub 2010 Apr 22.
Although the effect of elevated carbon dioxide (CO2) concentration on pollen production has been established in some plant species, impacts on fungal sporulation and antigen production have not been elucidated.
Our purpose was to examine the effects of rising atmospheric CO2 concentrations on the quantity and quality of fungal spores produced on timothy (Phleum pratense) leaves.
Timothy plants were grown at four CO2 concentrations (300, 400, 500, and 600 micromol/mol). Leaves were used as growth substrate for Alternaria alternata and Cladosporium phlei. The spore abundance produced by both fungi, as well as the size (microscopy) and antigenic protein content (ELISA) of A. alternata, were quantified.
Leaf carbon-to-nitrogen ratio was greater at 500 and 600 micromol/mol, and leaf biomass was greater at 600 micromol/mol than at the lower CO2 concentrations. Leaf carbon-to-nitrogen ratio was positively correlated with A. alternata spore production per gram of leaf but negatively correlated with antigenic protein content per spore. At 500 and 600 micromol/mol CO2 concentrations, A. alternata produced nearly three times the number of spores and more than twice the total antigenic protein per plant than at lower concentrations. C. phlei spore production was positively correlated with leaf carbon-to-nitrogen ratio, but overall spore production was much lower than in A. alternata, and total per-plant production did not vary among CO2 concentrations.
Elevated CO2 concentrations often increase plant leaf biomass and carbon-to-nitrogen ratio. Here we demonstrate for the first time that these leaf changes are associated with increased spore production by A. alternata, a ubiquitous allergenic fungus. This response may contribute to the increasing prevalence of allergies and asthma.
虽然已经确定了高二氧化碳（CO2）浓度对花粉产生的影响，但尚未阐明其对真菌孢子形成和抗原产生的影响。
我们的目的是研究大气 CO2 浓度升高对梯牧草（Phleum pratense）叶片上产生的真菌孢子数量和质量的影响。
梯牧草植物在四种 CO2 浓度（300、400、500 和 600 μmol/mol）下生长。叶片用作交链孢霉（Alternaria alternata）和枝孢霉（Cladosporium phlei）的生长基质。定量测定了两种真菌产生的孢子丰度，以及交链孢霉的大小（显微镜）和抗原蛋白含量（ELISA）。
500 和 600 μmol/mol 时叶片碳氮比更大，600 μmol/mol 时叶片生物量比低 CO2 浓度时更大。叶片碳氮比与每克叶片产生的交链孢霉孢子数呈正相关，但与每孢子的抗原蛋白含量呈负相关。在 500 和 600 μmol/mol CO2 浓度下，交链孢霉产生的孢子数是低浓度下的近三倍，每株植物产生的总抗原蛋白是低浓度下的两倍多。枝孢霉孢子的产生与叶片碳氮比呈正相关，但总体孢子产生量远低于交链孢霉，而且每株植物的总产生量在 CO2 浓度之间没有差异。
升高的 CO2 浓度通常会增加植物叶片的生物量和碳氮比。在这里，我们首次证明这些叶片变化与交链孢霉产生的增加有关，交链孢霉是一种普遍存在的过敏原真菌。这种反应可能是导致过敏和哮喘发病率增加的原因之一。
