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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCING SUSTAINABILITY OF FOOD PRODUCTION SYSTEMS IN THE NORTHEAST Title: Elevated CO2 affects plant responses to variation in boron availability

Authors
item Mishra, Sasmita -
item Heckathorn, Scott -
item Frantz, Jonathan

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 30, 2011
Publication Date: July 12, 2011
Citation: Mishra, S., Heckathorn, S., Frantz, J. 2011. Elevated CO2 affects plant responses to variation in boron availability. Plant and Soil. 10.1007/s11104-001-0888-6.

Interpretive Summary: Effects of elevated CO2 on nitrogen in plants are well studied, but effects on other nutrients, especially micronutrients like iron, boron, and zinc, are not. We investigated effects of elevated CO2 on response to variation in boron (B) availability in three diverse species: geranium, barley, and water fern. Geranium was grown at high and ambient CO2 and low, medium, and high B. The influence of CO2 depended on the B supply for leaf, stem, and total plant mass, root:shoot mass, leaf [B], B uptake rate, root [Zn], and photosynthesis. High CO2 stimulated growth at medium B, but decreased it at high B and did not affect it at low B. Photosynthesis was stimulated by high CO2 only at medium B and chlorophyll was enhanced only at high B. High CO2 decreased leaf boron concentration and B uptake rate, especially when B was also high. These interactive effects of B and CO2 on growth were confirmed in barley and water fern, wherein growth at high CO2 was stimulated only at low and medium B. Thus, low and high B both may limit growth stimulation under high vs. ambient CO2, and B deficiency and toxicity, already common, may increase in the future.

Technical Abstract: Effects of elevated CO2 on N relations are well studied, but effects on other nutrients, especially micronutrients, are not. We investigated effects of elevated CO2 on response to variation in boron (B) availability in three unrelated species: geranium (Pelargonium x hortorum), barley (Hordeum vulgare), and water fern (Azolla caroliniana). Geranium was grown at two levels of CO2 (370, 700 ppm) and 4.5, 45, and 450 micromolar B. There were interactive effects (P<0.05) of B and CO2 on leaf, stem, and total plant mass, root:shoot mass, leaf [B], B uptake rate, root [Zn], and photosynthesis (Pn). Elevated CO2 stimulated growth at 45 micromolar B, but decreased it at 450 micromolar B and did not affect it at 4.5 micromolar B. Pn was stimulated by elevated CO2 only at 45 micromolar B and chlorophyll was enhanced only at 450 micromolar B. Soluble sugars increased with high CO2 only at 4.5 and 45 micromolar B. High CO2 decreased leaf [B] and B uptake rate, especially at 450 micromolar B. Though CO2 and B individually affected the concentration of several other nutrients, CO2xB interactions were evident only for Zn in roots. Interactive effects of B and CO2 on growth were confirmed in (1) barley grown at 0, 30, or 1000 micromolar B, wherein growth at high CO2 was stimulated more at 30 micromolar B, and (2) azolla grown at 0, 10, and 1000 micromolar B, wherein growth at high CO2 was stimulated at 0 and 10 micromolar B. Thus, low and high B both may limit growth stimulation under elevated vs. current [CO2], and B deficiency and toxicity, already common, may increase in the future.

Last Modified: 10/21/2014
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