Architectural and physiological mechanisms of reduced size inequality in CO2‐enriched stands of common ragweed (Ambrosia artemisiifolia)

摘要: Testing whether and how subordinate individuals differ from dominants in the utilization of enriched CO2 atmospheres is important for understanding future stand community structure. We hypothesized that dominant Ambrosia artemisiifolia L. (Asteraceae) (common ragweed) plants growing dense stands would not equally acquire or utilize carbon gains CO2-enrichment, resulting disproportionate growth to subordinates reduce size inequalities competing stands. grew experimental A. either ambient (360 μL L−1) twice (720 μL L−1) levels atmospheric CO2. compared relative growth, photosynthetic capacity, architecture each treatment, assessed using stand-level coefficient variation (CV). In elevated CO2, larger, but shifted more mass upper stem allocation than dominants. Dominant demonstrated reduced leaf-level with plants. Reduced CVs plant reflected smaller proportional by over vs. conclude differences architectural physiological responses ragweed competition allow catch up conditions.