[Investigations on gigas mutants ofOenothera berteriana andOenothera odorata].
1. Seedlings of the following Oenotherae were treated with colchicine:Oe. berleriana (B.l),Oe. odorata (v.l), a B.l with plasma ofodorata and plastids ofberteriana, a v.I with plasma and plastids ofBerteriana, and B.I andl.v obtained from reciprocal crossings of B.l x (x) v.I, selfed over and over again. 2. The gigas mutants thus obtained had the characteristics described previously. It is remarkable that those differences caused by plasma and plastids in the diploid pairs serving for comparison could also be demonstrated in the corresponding tetraploid forms. 3. The Bl.vI obtained from crossings B.l 4 n×v.I 4 n showed that in B.l 4 n there is predominantly a production of B.l sexual cells, and in v.I 4 n a production of v.I sexual cells. A BI.lv identical with Bl.vI was obtained from the cross B.I 4 n×l.v 4 n. 4. Part of the seedlings from v.I 4 n×B.l 4 n were variegated. Thusberteriana-plastids capable of becoming green were transferred by the Bl pollen tubes. Because of the odorata plastids which can not grew fully green, the leaves of this vI.Bl very much resembled those of v.I 4 n. 5. Pictures of the pollen showed that the genetic constitution of the tetraploids and triploids producing the pollen grains helps to determine the number of their pores. 6. Cytological studies showed that there is surprisingly often a normal 14+14 distribution of the 28 chromosomes during meiosis in the tetraploid forms. This results in the high degree of constancy obtained from selfing. Yet to be studied is how this predominantly normal distribution of chromosomes is accomplished.
Botanisches Institut der Universität Erlangen-Nürnberg, Erlangen-Nürnberg, Deutschland.
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Schwemmle