Abstract
Multiples in three different interchanges of Luzula elegans (syn. L. purpurea) with holokinetic chromosomes and post-reductional meiosis revealed the constant preferential orientation at second metaphase. Alternate orientation was common in interchange multiples contain unequal size interchange chromosomes and led to less reduced or almost complete fertility. In interchange multiple containing equal size interchange chromosomes, alternate and adjacent orientations occurred with about equal frequency and led to usually approximately 50 per cent fertility. It is suggested that the equilibrate orientation along the equator at second metaphase may be neccessary for orderly segregation at second metaphase. The equilibrate orientation along the second metaphase equator of interchange multiples containing interchange chromosomes of unequal size is alternate orientation. On the contrary, the equilibrate orientation in interchange multiples containing interchange chromosomes of equal size is either alternate or adjacent orientation. It is therefore true that such preferential orientation observed in interchange multiples containing unequal size interchange chromosomes of Luzula depends on (1) identical size and shape of original chromosomes, and on (2) holokinetic activity of chromosome per se.
