Studies on the Ribonucleic Acid From Wheat Leaves and Chloroplasts

The chloroplast, leaf ribosomal, and leaf total RNA from seedlings of 2 varieties of Triticum durum and 3 varieties of Triticum vulgare were compared. For a given RNA preparation the major nucleotide composition was the same for all varieties. Irrespective of the variety, the chloroplast total RNA had a higher cytidylic and a lower adenylic acid content than the leaf ribosomal RNA, whereas, the guanylic and uridylic acid content of all RNA preparations was essentially the same. Pseudouridylic acid was present in all RNA preparations and was consistently higher in the durum than the vulgare varieties for leaf ribosomal RNA and leaf total RNA. The leaf ribosomal RNA of all varieties had 2 sub-units with sedimentation coefficients of approximately 18 S and 25 S. The molecular weight of the faster sedimenting subunit was about 2 times that of the slower sedimenting subunit.