New insights into plant nutrient signaling and adaptation to fluctuating environments

Over the past 50 years,the Green Revolution and exploitation of heterosis have allowed cereal grain yield to keep pace with worldwide population growth.Unfortunately,plant growth and crop productivity are heavily dependent on the application of synthetic fertilizers.In the next 50 years,global population is projected to be 50%larger than at present and global food demand is projected to double(Tilman et al.,2002).Further increases in fertilizer supplies are unlikely to be effective in improving grain yield because