雜種水稻之花葯培養及二倍體花葯植株來源之探討

Abstract

中文摘要 將十種雜種水稻的花滿培養於MS培養基（培養基中無機塭類的macro-elements） 含量減半, NAA含量4mg/e，kinetin 含量 2mg/e ）中，以誘導癒合組織之?生。花葯形成癒合組織的百分率因雜交組合之不同而有很大的差異，台南 5 號 × H － 124 的花葯產生癒合組織之百分率最高（ 40 ％），嘉和11 號 × H － 124 的花葯僅 0. 5 ％形成癒合組織。 將癒合組織移植於分化培養基（ MS 培養基加添 1 － 2mg / e 之 NAA 及 2mg / e 之 kinetin ）後，有些癒合組織分化成植株。這些植株中，除綠（紫）苗外，尚包括大量的白化苗。將成活的綠（紫）苗經根尖染色體數目檢定，發現有單倍體、二倍體、三倍體及四倍體等四種。其中三倍體及四倍體植株出現的頻率較低，而二倍體及單倍體植株出現的頻率較高，但其頻率則因雜交組合之不同而有差異。 同一雜交組合花葯培養所得的二倍體植株在某些遺傳性狀上有分離的現象，但將這些二倍體分別自交，卻發現每一植株之後代均無分離的情形，故認為水稻花滿培養所得的二倍體植株源自花粉。推測花粉在早期發育過程中經核融合或核內染色體加倍再分裂發育而成二倍體植株，這些二倍體是完全同基因型的個體，故其自交後代沒有分離的現象。

Abstract Anthers of 10 interspeoific hybrids of rice were cultured on a modified MS medium in which the macro—elements of the inorganic salts were reduced to half of their original strengths and 4 mg/l NAA and 2 mg/l kinetin were added. Callus was successfully induced from anthers of all cross combinations. The percentage of anthers that produced callus varied from 40% for Tainan 5 x H—124 to 0.5% for Chianung Shien 11 x H—124. After the callus was transferred to MS medium supplemented with 1—2 mg/l NAA and 2 mg/l kinetin, plantlets developed. Chromosome counts revealed that most of the plants were diploid or haploid; triploid and tetraploid were relatively infrequent. The diploid plants derived from anthers of each cross combination varied considerably in many phenotypic characters. However, their - progenies were very uniform. These results indicate that all the diploid plants obtained from this study have been originated from pollen. Nuclear fusion and endoreduplication during callus formation were postulated as the possible mechanisms of diploidization.