3.3.4. Temperature

 3.3.4. Temperature

 

  Germination involves numerous enzymatically controlled processes of catabolism and anabolism and hence is highly responsive to temperature. The cardinal temperatures-maximum, optimum, minimum- for germination of most crop seeds are essentially those of normal vegetative growth. The maximal and minimal temperatures are those temperatures that just permit germination whereas the optimal temperature is considered the one that permits the highest percentage of germination in the shortest period of time. A majority of studies have indicated that the maximum, the minimum, and the optimum temperaures for rice are 42-44˚C, 8-10˚C, and 30-32˚C, respectively. Warm temperature is needed to increase the growth activities inside seeds. Low temperature decreases activities inside seeds. Very high temperature decreases the gemination percentage. Too much heat can kill sprouting seeds.