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The effects of CO 2 and nutrient enrichment on photosynthesis and growth of Poa annua in two consecutive generations
Author(s) -
Bezemer T. Martijn,
Jones T. Hefin
Publication year - 2012
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-012-0961-5
Subject(s) - nutrient , poa annua , photosynthesis , biology , acclimatization , biomass (ecology) , germination , zoology , botany , poaceae , agronomy , horticulture , ecology
We studied short‐ and long‐term growth responses of Poa annua L. (Gramineae) at ambient and elevated (ambient +200 μmol mol −1 ) atmospheric CO 2 . In experiment 1 we compared plant growth during the early, vegetative and final, reproductive growth phases. Plant growth in elevated CO 2 was significantly enhanced during the early phase, but this was reversed in the reproductive phase. Seed mass and percentage germination were significantly reduced in elevated CO 2 . Experiment 2 tested for the impact of transgenerational and nutrient effects on the response of Poa annua to elevated CO 2 . Plants were grown at ambient and elevated CO 2 for one or two consecutive generations at three soil nutrient levels. Leaf photosynthesis was significantly higher at elevated CO 2 , but was also affected by both soil nutrient status and plant generation. Plants grown at elevated CO 2 and under conditions of low nutrient availability showed photosynthetic acclimation after 12 weeks of growth but not after 6 weeks. First‐generation growth remained unaffected by elevated CO 2 , while second‐generation plants produced significantly more tillers and flowers when grown in elevated CO 2 compared to ambient conditions. This effect was strongest at low nutrient availability. Average above‐ and belowground biomass after 12 weeks of growth was enhanced in elevated CO 2 during both generations, but more so during plant generation 2. This study demonstrates the importance of temporal/maternal effects in plant responses to elevated CO 2 .