Environmental modification of flowering and viviparous proliferation in festuca vivipara and festuca ovina
Oikos 51(2): 171-178
ISSN/ISBN: 0030-1299 Accession: 005368986
Environmental modification of flowering and viviparous proliferation of two populations of the viviparous Festuca vivipara (L.) Sm. and one population of the seminiferous (flowering) F. ovina L. have been studied in controlled environments. Both species responded to short days (SD) at low or moderate temperatures with initiation of inflorescence primordia while long days (LD) were required for culm elongation and heading. Low temperature vernalization in LD at 3 and 6.degree.C were also effective in primary induction of F. vivipara. The two populations of this species differed greatly in their sensitivity to inductive conditions. Details on these responses are presented and discussed. In both species the degree of normal flowering and viviparous proliferation could be widely modified. By optimal induction, both primary and secondary, more than 40% of the florets of F. vivipara produced normal flowers but the proportion decreased again with further extension of induction. In F. ovina on the other hand, a high proportion of viviparous panicles resulted from marginal LD induction either by a marginally inductive number of LD cycles or a marginally inductive photoperiod. The versatility of vivipary as an adaptation to arctic-alpine environments is discussed.