Mode of propagation and chromosomal peculiarities in Scotch material of Poa alpina

Abstract

In Great Britain Poa alpina L. is usually viviparous, but among specimens received from Scotland there was also a seed-producing plant. In the seminiferous offspring from this individual, there was a high degree of sexual reproduction but also the occurrence of total or partial apomictic seed formation. Root tips of 55 plants were examined with regard to chromosome number and chromosome morphology. There was a very pronounced variation in somatic chromosome number between plants, ranging from 2n=32 to about 70. There was also a frequent occurrence of intra-plant variation in chromosome number. This variation was largely caused by a variable number of dot-like minute chromosomes. Comparison between the Scotch material and diploid and sexual strains of Poa alpina from central Europe carrying B chromosomes, indicates that also the minute chromosomes in the Scotch material are B chromosomes or derivatives from such chromosomes.