Elevated CO2 Accelerates Phosphorus Depletion by Common Bean (Phaseolus vulgaris) in Association with Altered Leaf Biochemical Properties

摘要

Phosphorus (P) is a major limiting factor for plant productivity in many ecosystems and agriculture.The projected increase in atmospheric CO2 is likely to result in changes in plant mineral consumption and growth.We studied P depletion by common bean (Phaseolus vulgaris) cultured hydroponically under ambient (377 ± 77 μmol mol-1) or elevated (650 ± 32 μmol mo1-1) CO2 in media of low or high P.Under elevated CO2 compared to ambient CO2,the maximum P depletion rate increased by 98％ at low P and 250％ at high P,and P was depleted about 2-5 weeks sooner;leaf acid phosphatase (APase) activity and chlorophyll content both increased significantly;root-to-shoot ratio increased significantly at high P,although it was unaffected at low P;lateral root respiration rate showed no change,suggesting that CO2 did not affect P depletion via metabolic changes to the roots;the total biomass at final harvest was significantly higher at both low and high P.Our data showed that the increased rate and amount of P depletion during plant growth under elevated CO2 occurred in association with alterations in leaf biochemical properties,i.e.,enhanced activities of leaf APase and increased leaf chlorophyll content.