Akinori Uchino

Phylogeography of Hynobius yatsui (Amphibia: Caudata) in Kyushu, Japan.

The salamander Hynobius yatsui from southwestern Japan was formerly regarded as a small-sized group of H. naevius, but has recently been resurrected as a distinct species. We investigated the phylogeography of H. yatsui from Kyushu Island using partial sequences of the mitochondrial cytochrome b gene. We detected 49 haplotypes in 181 individuals from 24 localities covering the entire geographic distribution of this species on Kyushu. These haplotypes were grouped into two lineages, a northern lineage from northern and central regions, and a southern lineage from the southern region; no haplotypes were shared between the lineages. We surmise that the divergence of the two lineages was induced by volcanic activity that started in the Beppu-Shimabara Graben, between the areas occupied by these two lineages. From the results of a nested clade phylogeographical analysis, we surmise that the high intrapopulation genetic variation observed in the non-volcanic Kyushu Mountains was generated by alternation of contiguous range expansion or long-distance dispersal, and isolation. The current distribution and the observed complicated genetic structures of H. yatsui in Kyushu seem to have been affected first by volcanic activities since the late Pliocene, but subsequent climatic oscillations during the Pleistocene may also have some effects, although it is impossible at this time to differentiate the effects of these two factors.

The flavonoid chemistry of the genusTrillium

Four flavonol glycosides (Fig.1) were isolated from the leaves ofTrillium tschonoskii Maxim. By means of UV, NMR, and mass spectral analyses, they were identified to be acetylated kaempferol 3-O-arabinosylgalactoside (TK-1), kaempferol 3-O-arabinosylgalactoside (TK-2), acetylated quercetin 3-O-arabinosylgalactoside (TQ-1) and quercetin 3-O-arabinosylgalactoside (TQ-2). High performance liquid chromatography (HPLC) profiles of 172 specimens ofT. tschonoskii collected from nine different places in Japan were grouped into three different types based on the flavonoid components: type I and type II containing TK-1 and TQ-1, and TK-2 and TQ-2, respectively, as main component, and type III containing all of four flavonol glycosides. Those results show that the intraspecific variation ofT. tschonoskii with different geographical distribution has not only been found by the analysis of karyotype, but also that of flavonoid components.

Structure and dynamics of natural populations of polyploid Trilliums.

To confirm predominant self-pollination in natural populations ofTrillium apetalon (2n=4x=20, SSUU), chromosome constitutions of endosperms (2n=30, SSSUUU) fertilized in nature were analyzed for the patterns of H-segments of cold-treated chromosomes. The endosperms were of two kinds: homo-constitutions in which three chromosomes in each of the ten sets of homologues were of the same patterns of H-segments and hetero-constitutions in which one chromosome in a set of three homologous chromosomes was different from the other two. Out of 30 endosperms, 27 (90%) were of homo-constitutions and only three (10%) were of hetero-constitutions. Since the population consisted of various homokaryotypes in which each of the ten pairs of homologous chromosomes was homozygous for the patterns of H-segments, the endosperms of homo-constitutions were the result of self-pollination, and those of hetero-constitutions were from cross-pollination.Due to pollination tests conducted in two natural populations, many good seeds were found in the fruits from both open-pollinated flowers and those covered with cotton-bags. In striking contrast, no good seeds were found in the fruits from flowers castrated and pollinated in the open-air.An additional evidence of predominant self-pollination and occasional cross-pollination was given by analyzing spatial distribution of plants of various karyotypes in a population.

Variation in seed shape and husk color in Japanese native cultivars of common buckwheat (Fagopyrum esculentum moench)

Abstract The variation in seed shape and husk color was investigated in 56 Japanese native cultivars of common buckwheat. Analysis of variance revealed highly significant differences among the cultivars in seed shape characteristics and husk colors. The 1000-seed weight (1000-SW) ranged widely, from 20.4 to 39.0 g, among the cultivars. The cultivars collected from the Kanto region of the mainland had a large length and width of seed and heavy 1000-SW. On the other hand, the cultivars from the Chugoku and Shikoku regions of Japan had a small length and width of seed. The length and width of seeds showed a high positive correlation. The cultivars with a high 1000-SW showed a slight difference between length and width of seed and were typically the triangular type in seed shape. The length/width ratio (L/W) depended on the width rather than the length of seed, though both were negatively correlated with the L/W. Highly positive correlations were found among the L*, a* and b* husk color value. The L* showed a highly positive correlation with growth duration, and the husk color of the cultivars became more deep black as growth duration decreased. The husk color of the cultivars from the Kyushu region (long growth duration) was grayish brown, but that of the cultivars from Nagano Pref. (the shortest growth duration) was characterized as typically deep black. The cultivars collected at lower latitude regions tended to have a lighter color of husk than those from higher latitude regions. The cultivars from the Tohoku region showed a smaller variation for seed size characteristics and 1000-SW, and the cultivars from the Kyushu region showed a smaller variation for husk color.

Occurrence of aneuploid progenies from an asynaptic amphidiploid ofScilla scilloides (lindley) druce II. Mechanism of production of the various aneuploid progenies

The mechanism of production of the various aneuploid progenies was clarified in the asynaptic amphidiploid plants (2n=34+4f+2F, AABB) ofScilla scilloides. Its asynaptic nature and chromosomal stickiness lead to the unequal segregation at anaphase I (AI) in PMCs. The observed values in 18 segregation patterns, 17:17 to 0: 34, were different from the expected values estimated from random segregation of chromosomes. Nevertheless, the preferential transmission of special chromosomes among genomes A (x=8=a1−a8) and B (x=9=b1−b9) had not occurred. As the result of unequal segregation, the pollen grains with various chromosome numbers were observed. Almost all of the 200 pollen grains contained chromosome numbers more than 17 (range 8 to 34). The observed values of each chromosome number were roughly similar to the expected values of containing the complete set of genome A or B in the random distribution without preferential segregation of chromosomes at AI. The difference between the index of polien mitosis and the pollen fertility was significant in the Wilcoxon matched-pairs signed rank test and suggested the selection for some genomically unbalanced pollen grains during maturation. Consequently, viable pollen grains with various chromosome constitutions are a few (mean pollen fertility of 5.8%) but might produce many aneuploids by self- and cross-pollination.