Karyotype Alteration and Phylogeny. IV

Abstract

(1) The karyotypes of nineteen genera in the Amaryllidoideae, namely Haerrzanthus (2n=16, 18), Grij inia (2n=77), Clivia (2n=44), Galanthus (2n=24, 25, 28, 48), Leucojum (2n=14, 22), Nerine (2n=22, 33), Amaryllis (2n=22), Zephyranthes (2n=12, 24, 38), Sternbergia (2n=22) Crirzum (2n=22, 33), Cyrtanthus (2n=22) Eucharis (2n=68), Hymenocallis (2n=46, 69), Narcissus (2n=14, 21, 22, 32), Paracratium (2n=44), Sprekelia (2n=ca. 117), Hippeastrum (2n=44), Habranthus (2n=21) and Lycoris (2n=27) have been analyzed from the point of karyotype alteration (cf. Table 1). Many genera such as Grinia, Clivia, Leucojum, Nerine, Amaryllis, Stervbergia, Crinum, Cyrtanthus, Pancratiurn, Hippeastrunz, Habranthus and Lycoris have the 11-series of chromo-somes, in the ether word 11 is their basic number of chromosomes which indicates the intimate relationship existing between these karyotypes. More striking is the fact that various karyotypes be-longing to the same genus, for instance Leucojutm (b=7, 11), have been explicitly explained by the dislocation hypothesis of Navashin (1932). By further reference to this hypothesis it may be possible to suggest the derivaticn of karyotypes in other genera.(2) The karyotypes of Hymenocallis (2n=46, 69) and Eucharis (2n=68) clearly indicate their derivation from the 11-series by the duplication of chromosomes and the secondary balance. The similar secondary polyploid appeared in Zephyranthes (b=6), i.e., Z. candicla (2n=38). All genera except Haernanthus in the Amaryllidoideae may be concluded to have some karyotypical resemblances, when the karyotype alteration such as fusion, fragmentation, duplication, translocation, inversion, elimination and deficiency have been taken into consideration. The karyotypes of Haemanthus resemble those of Scilla in the Liliaceae or Alstroemeria in the Hypoxidoideae.(3) The karyotypes of five genera in the Agavoideae, namely Bravoa, Polianthes, Agave, Fourcroya, and Beschorneria are similar (so-called the Yucca-Agave karyotype) (5 long and 25 short chromo-somes) (cf. Table 2). The karyotype of Dorjanthes (4 long and 44 short chromosomes) is different from the Yucca-Agave type, but some similarities are suggested, although difference in chromosome sizes can clearly be detected. The karyotypes of the Agavoideae are generally speaking different from other ones in the Amaryllidaceae and rather resemble those of Yuccae in the Liliaceae.(4) The karyotypes of Alstroenteria (2n=11) and Bornalia (2n=18) in the Hypoxidoideae are similar to those of Haemanthus (2n=16), especially in respect to the SAT-chromosomes.(5) The hypothesis of the SAT-chromosome has been adopted in the present analysis of karyotypes in the Amaryllidaceae and has brought about successful results. Various hypotheses of karyotype alteration were discussed and such karyotype alterations are con-cluded to be genotypically controlled (cf. Levitskij 1937). The genotypic control of karyotype alteration and the secondary balance seem to play an important role in the process cf evolution.(6) The relation between the nucleoli and the SAT-chromosomes was discussed and the hypothesis of the SAT-chromosome was extended to reconcile it with the conception of the nucleolar chromosome. The presence of the SAT-chromosome was emphasized by the observation of satellites or secondary constrictions in many species which had usually been overlooked cr neglected by previous investigators.The writer wishes to express his thanks to Ass. Prof. Y. Sinoto under whose direction this investigation has been carried out.