Microevolutionary responses in experimental populations of plants to CO2-enriched environments: parallel results from two model systems.

摘要: Abstract Despite the critical role that terrestrial vegetation plays in Earth's carbon cycle, very little is known about potential evolutionary responses of plants to anthropogenically induced increases concentrations atmospheric CO2. We present experimental evidence rising CO2 concentration may have a direct impact on genetic composition and diversity plant populations but unlikely result selection favoring genotypes exhibit increased productivity CO2-enriched atmosphere. Experimental an annual (Abutilon theophrasti, velvetleaf) temperate forest tree (Betula alleghaniensis, yellow birch) displayed were both strongly density-dependent genotype-specific. In competitive stands, higher resulted pronounced shifts composition, even though overall CO2-induced enhancements small. For species, quantitative estimates response under competition 3 times at elevated level. However, highest growth when grown absence did not fitness stands. suggest intensified interplant favored with greater ability compete for resources other than Thus, while enhance rates competing plants, it evolution responsiveness or operate as important feedback global cycle. intensity drift driven by levels populations.