Abstract

Karyotypes of Ophiopogon reversus (Convallariaceae) collected from four localities in Taiwan and one locality on Yonaguni-jima Island in the southern Ryukyus of Japan were reported for the first time. Those of O. jaburan collected from three major islands (Amami-oshima, Tokuno-shima and Okinawa-jima) of the central Ryukyus were also investigated for comparison. All plants of O. reversus and O. jaburan investigated were diploid (2n = 36) based on the basic chromosome number of x = 18. Among 36 chromosomes of O. reversus, one pair of short chromosomes with submedian centromeres had secondary constrictions at the proximal region of the long arms. Based on this character, O. reversus is cytologically distinguishable from O. jaburan, in which one pair of short metacentric chromosomes had secondary constrictions at the proximal region of the short arms.

中文摘要

本文首次報導採自臺灣 (四個採集點) 與日本琉球南部與那國島 (一個採集點) 之鈴蘭科高節沿階草 (Ophiopogon reversus, Convallariaceae) 之核型；同時與採自琉球中部三個主要島嶼 (奄美大島、德之島、冲繩島) 之闊葉沿階草 (O. jaburan) 之核型做比較。根據本屬植物之染色體基數x = 18 可知，本研究中所調查的高節沿階草與闊葉沿階草的個體，均屬於二倍體 (2n = 36)。高節沿階草的36 條染色體，在其中一對短的近端中結染色體上，位於長臂基部的區域具有二次狹窄(或稱次級收縮區)；而闊葉沿階草則在其中一對短的中央中結染色體上，位於短臂基部的區域具有二次狹窄。依據此一特徵，高節沿階草可以和闊葉沿階草從細胞學上加以區分。

Keyword: Chromosome number, Convallariaceae, Karyotype, Ophiopogon jaburan, Ophiopogon reversus, The Ryukyu Archipelago, Taiwan.