Poster Session #49: Elevated CO2 II.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC


Interspecific variation in CO2 effects on seed quality, germination rate and early seedling physiology.

Kline, Kerry*,1, BassiriRad, Hormoz1, 1 University of Illinois at Chicago, Chicago, IL

ABSTRACT- Plant establishment and survival are, in large part, influenced by seed quality, germination and seedling vigor. Few studies have examined these aspects in response to rising CO2 concentration and of those, most have involved a single species. We examined how CO2 affects seed carbon (C), nitrogen (N) and germination rate. Seeds of three species, soybean, sorghum and wheat were obtained from two Free Atmosphere Carbon dioxide Enrichment (FACE) projects. N concentration was significantly lower in wheat seeds produced under elevated CO2 compared to ambient produced seeds. However, the opposite was true for soybean. In sorghum, seed C and N did not respond to growth CO2. At least 80% of soybean and wheat seeds germinated regardless of the treatments, but sorghum seeds had a maximum germination of 20%. Wheat seeds produced under elevated CO2 germinated significantly less than ambient grown seeds. In contrast, soybean seeds produced under high CO2 germinated better compared to those produced under ambient. Seed germination in sorghum was distinctly insensitive to growth CO2. Because of the dramatic CO2 effects on wheat seed quality and germination rate, we also examined its ability to acquire NO3- following germination. The time required to completely induce NO3- transporters was significantly longer and the maximum root NO3- uptake capacity was significantly lower in high compared to ambient CO2 progeny. The results indicate that elevated CO2 affects seed quality, germination rate and early seedling development of the progeny, but the effect is highly species dependent.

KEY WORDS: Seed germination, Seed quality, Nutrient uptake, Elevated CO2