ANALYSIS OF GLUCOSE-METABOLISM IN THE HETEROTIC VIABILITY IN SEEDLINGGROWTH OF MAIZE F(1) HYBRID

We have analyzed seedling growth of maize F1 hybrids, CO2 evolution fr om kernels and glucose metabolism in embryonic cells during the germin ation process, and compared these factors with equivalent factors for their parental inbred lines. The heterotic F1 hybrid (Oh545 X W22) ger minates and grows faster than parental inbred lines. The evolution rat e of CO2 from germinating kernels was also higher in the heterotic F1 hybrid. However, these trend were not seen in the non-heterotic F1 hyb rid (Oh545 x Oh45). Glucose metabolism in the embryonic cells was eval uated by in vivo labelling of CO2 and cellular components with [U-C-14 ] glucose. In the heterotic F1 hybrid, the assimilation rate of radioa ctivities from [U-C-14] glucose into amino acids, proteins, nucleic ac ids, organic acids and CO2 was significantly higher than that of the p arental inbred lines after 24 hrs of germination. These results show t hat quick activation of metabolic function in the embryo after the ons et of water uptake is due to the heterotic F1 hybrid genotype, and is one of the key factors in the mechanism by which the heterotic F1 hybr id expresses its hybrid vigor in the germinating process.