Meiotic investigations in pollen mother cells of Norway spruce cultivated in a plastic green house

Abstract

Three clones of Norway spruce cultivated in a plastic green house were studied with respect to meiotic development in the pollen mother cells. On an average the passing of diplotene took place almost simultaneously in the three clones. A pronounced difference in this respect between the grafts belonging to the same clone was observed. Efforts were made to determine the temperature sum responsible for passing the diplotene stage. Stickiness of C-type (cf. Eriksson 1968) was the predominant irregularity. Most of the stages diakinesis–telophase I and prophase II–telophase II were shown to be highly temperature-sensitive. The high temperatures (>20° C) were probably responsible for the induction of the irregularities. The possibilities for a proper pollen formation in a plastic green house were discussed.