ibclogo XVI International Botanical Congess

Abstract Number: 6130
Poster No. = 2522


SOYBEAN GROWS WELL AS HIGH AS 40C DAYTIME TEMPERATURE UNDER A DOUBLING OF ATMOSPHERIC CO2


J. Vu, R. Gesch, L. Allen, G. Bowes, and K. Boote, U.S. Dept. of Agriculture and University of Florida, Gainesville, FL 32611 USA


Global warming up to 6C is predicted within the next century. Soybean (Glycine max L.) was grown at day/night max/min temperatures of 28/18, 32/22/ 36/26, 40/30, 44/34/, or 48/38C, and at 350 or 700 ppm CO2. High CO2 increased leaf activities of RuBisCO, ADPG-PPase, SPS, and acid invertase (Al), and contents of starch and sucrose. Photosynthesis and midday RuBisCO protein and activity decreased above 40/30C, but predawn RuBisCO activity and midday RuBisCO rbcS transcript level declined from 28/18 to 48/38. Midday activities of ADPG PPase, SPS, and AI, and contents of starch and sucrose were greatest at 36/26 to 40/30C but declined at higher or lower temperatures. Biomass growth continued through 44/34C before failing, but seed yield declined above 36/26 to zero at 44/34C.

HTML-Version made 7. July 1999 by Kurt Stüber