查看文章

Glycinebetaine (GB) accumulation has been suggested to be an adaptive response to several abiotic environmental stresses. Genetic and metabolic studies of GB accumulation in maize (Zea mays L.) indicate that recessive alleles of a single locus are responsible for the phenotype of GB nonaccumulation. The present study was undertaken to determine whether a similar genetically determined range of GB levels exists in the related C₄ species Sorghum bicolor (L.) Moench. In a preliminary analysis of 240 sorghum genotypes, sampled at the postflowering stage, total quaternary ammonium compound (QAC) levels in the betaine fraction of the flag leaves were found to range from as low as 0.1 μmol g⁻¹ FW to as much as 33 μmol g⁻¹ FW. Stable isotope dilution desorption chemical ionization mass spectrometry of six genotypes with high QAC levels and five genotypes with low QAC levels confirmed that this …