Carallia, Gynotroches, 及びPellacalyx(ヒルギ科, Gynotrocheae)の染色体の研究 Chromosomes of Carallia, Gynotroches, and Pellacalyx (Rhizophoraceae; Gynotrocheae)

ヒルギ科の内陸性植物群Gynotrocheaeの全3属Carallia, Gynotroches, Pellacalyxの染色体数と核形態を, それぞれ1種か2種における若い葉の体細胞の分裂像の観察に基づいて初めて報告する。それによると, Carallia brachiataは2n=112(多分x=14の八倍体), Gynotroches axillarisは2n=28(x=14), Pellacalyx axillarisとP. saccardianusは2n=26(x=13)をもつ。形態形質や分子系統解析によって推定されるヒルギ科内の系統関係に基づいて検討すると, Gynotrocheaeの中のx=14は, Crossostylideae(Crossostylis)(x=14)とRhizophoreae(4属, x=18)の共通の祖先で獲得された古い基本数であり, x=13は派生形質であるという可能性が示唆される。

The chromosome number and karyomorphology of Carallia, Gynotroches, and Pellacalyx, all tribe Gynotrocheae of Rhizophoraceae, are reported for the first time on the basis of one or two species each and using somatic cells of young leaves. The chromosome number is 2n=112 (probably an octoploid with x=14) in Carallia brachiata, 2n=28 (x=14) in Gynotroches axillaris, and 2n=26 (x=13) in Pellacalyx axillaris and P. saccardianus. Based on comparisons with other Rhizophoraceae in cytological and other characters, the possibility is discussed that x=14 is an ancestral basic number for the tribe acquired in a common ancestor with Crossostylideae (Crossostylis) (x=14) and Rhizophoreae (x=18), and that x=13 is a derived one.