The reduction division in PMC's was studied in 6 interspecific hybrids: N. tabacum×N. otophora, N. tabacum×N. longiflora, N. paniculata×N. tabacum, N. knightiana×N.tabacum, N. gossei×N. tabacum and N. megalosiphon×N. tabacum. 1) F1of N. tabacum (n=24)×N. otophora(n=12) At MI in PMC's of F1 of N. tabacum×N. otophora, the number of bivalents and trivalents per cell was 12 in total. It then seems that the genome of N. otophora is the same as one of the genomes of N. tabacum. This finding is generally in agreement with Good-speed's data (1954) on hybrids between N. otophora and two varieties of N. tabacum. 2) F1 of N. tabacum (n=24)×N. longiflora(n=10) At MI in PMC's of F1 of N. tabacum×N. longiflora, 0-4 chromosome pairs were found, with the mode at 0-1. The frequency of PMC's with 2 bivalents followed that of PMC's with 1 bivalent. PMC's with 3 bivalents were occasionally found and those with 4 bivalents were very rare. Considering such number of bivalents it is difficult to determine whether the few chromosomll affinities are allosyndetic between the genomes of the parents or autosyndetic. between the 2 genomes of N. tabacum. However, Kostoff (1943) found usually 5 to 7 bivalents and rarely 8 or 9 bivalents in this hybrid combination. The cause of the difference between Kostoff's and my own results is unknown. 3) F1 of N. paniculata (n=12)×N. tabacum(n=24) At MI in PMC's of this hybrid, 0-4 bivalents were found, with the mode at 1. PMC's without bivalents and with 2 bivalents were very frequently observed, but those with 3 and 4 pairs very rarely.
The comparison of contents of the eighteen amino acids of the seeds are presented in this report. The seeds of thirty one species belonging to Gramineae covering Pharoideae, Pooideae, Eragrostoideae and Panicoindeae were investigated with respect to their amino acid contents. Complete hydrolysates of seed powder were subjected to the microbiological assay using lactic acid bacteria. The results obtained were discussed from the point of view of their taxonomic relationships. It was indicated that the conspicuous relationship existed between the amino acid pattern of the seed and the plant species. The subfamily Panicoideae showed an amino acid pattern characterized by high alanine and leucine levels, in marked contrast to those observed in other subfamilies. The seed of Panicoideae also showed lower lysine and arginine levels as well as those of Eragrostoideae when compared with other two subfamilies. Among the species belonging to Pooideae, differences in amino acid pattern being considered to characterize the tribes were also observed. Pharoideae and Pooideae gave similar pattern with exceptions of lower glutamic acid and proline level, and of higher aspartic acid level in the former.