Development of inflorescence in Balanophora laxiflora (Balanophoraceae)

• Main Authors: Chen, Tsai-Ru, 陳采如
• Other Authors: Hsiao Shu-Chuan
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/53955120154180227375

碩士 === 國立中興大學 === 植物學系 === 86 === Balanophora laxiflora Hemsl.(Balanophoraceae) is the holoparasitic plant on roots of the woody plants, and is widely distributed in middle altitudes overTaiwan. It has no ordinary roots, stems or leaves. It consists of a single or branching tubers and spicate, flesh inflorescence. Floral composition is verysimple, especially in female flowers which consist only of single ovaries. Theaim of this study is to understand the development of Balanophora laxiflora inflorescence, its reduction of floral organs, and to provide more informationfor other studies on Balanophoraceae plants. We used the techniques for SEM,paraffin and plastic sectioning to conduct the investigations. Balanophora laxiflora is a dioecious plant. Both male and female inflorescence primordia develop in the schizogenous cavity of the tuber. After most floralorgans have differentiated and becomes emerged, the inflorescence bud breaksthrough the epidermal layers of the tuber. All floral organs of the inflorescenceare acropetally initiated. In the male inflorescence, leaf-like bracts are initiated prior to male flower primordia or simultaneously, followed by tepal primordia andstamen primordia, orderly. Stamens have numerous connate anthers on the androeciumreceptacle, but no filaments. The anther wall only has epidermis and tapetum differentiated. Microsporogenesis is similar to that of common flowering plants. Based on the analysis of variances, the numbers of tepals and anthers are highly variable among individuals. In the female inflorescence, numerous spadicles are initated first. They areconsidered as reduced bracts ontogeneticly. The female flower primordia aremainly initiated on the inflorescence axis. Female flowers have no tepalsdeveloped but functional pistils. The ovary has one layer of ovary has onelayer of ovary wall and 2-3 layers of tapetum, but without a typically developedovule. However, the development of megaspore is monosporic type, which is similar as seen in most flowering plants. In summary, development of inflorescence in Balanophora laxiflora displaysno special differentiation of both sexes in a flower, stamen filament, andany floral organs but an overy in the female flower, and has no rudimentsexisted. Terefor such phenomena of losing floral organs might have occurredduring the early stage of evoluton.