https://scholars.lib.ntu.edu.tw/handle/123456789/140583
標題: | 玉葉金花類花瓣構造之花部器官決定基因表現研究 Expression patterns of floral organ identity genes in petaloid structure of Mussaenda spp. (Rubiaceae) |
作者: | 呂佳穎 Lu, Chia-Ying |
關鍵字: | 類花瓣;花部器官決定基因;花部發育;玉葉金花;Mussaenda;MADS-box genes;ABC model;floral organ identity | 公開日期: | 2004 | 摘要: | 花是植物最醒目的構造之一,她擔負著被子植物種族繁衍的角色,其重要性自不待言,一直以來,科學家更下了釵h奶狾b研究花鮮豔的色彩及多變樣貌在生理及生態上的意義。自然界中有釵h植物以一整個花序替代一朵花作為傳粉的單位,而在這樣的花序中常常會有某些構造花瓣化來替代原來花瓣的弁遄C玉葉金花是一個非常有趣的例子,這一屬的植物常具有膨大的花萼裂片,其形狀類似葉子但多具有鮮豔色彩,且細胞形態及細胞排列均相當類似於花瓣,在弁鄐W一般均認為與花瓣無異。大部分高等真雙子葉植物的花部器官是以四輪排列的方式呈現,由外到內分別為花萼、花瓣、雄蕊及心皮,根據Theißen所提出的ABCDE model,A、B、C、D、E五群花器決定基因以單獨或共同作用的方式,分別來決定四輪花器的發育,而其中花瓣的發育是由A、B及E群的基因共同表現所決定的。有趣的是,Pelaz在2001年證明,阿拉伯芥中的A、B及E 群的基因過量表現可以造成葉子瓣化(petaloid)的現象,提供了一個植物類花瓣形成的可能調控機制。本論文即以玉葉金花屬植物為材料,觀察此一類花瓣構造的形成是否與花瓣決定同源基因的異位表現相關,進而探討其背後的遺傳控制機制。 本論文選殖出五個毛玉葉金花花器同源基因,其中A群基因AP1的同源基因MupAP1在兩型花萼、花瓣及雄蕊、心皮、果實中有表現,E群基因SEP3的同源基因MupSEP則在所測部位均有表現,B群基因中,AP3的同源基因MupDEF及TM6的同源基因MupTM6在兩型花萼、花瓣及雄蕊、心皮及果實中均有表現,另一個B群基因,PI的同源基因MupGLO則在花瓣及雄蕊、心皮、果實及小花萼中有表現,但在膨大花萼中並沒有偵測到表現。以上結果顯示玉葉金花類花瓣花萼的發育過程可能有A群、E群及部分的B群基因參與調控,雖不排除有其他因子參與的可能性,但其調控機制是否能以現有的模式解釋尚待更進一步的研究。 Flowers are functional irreplaceable and above all, the most important structure of angiosperms. Some of the inflorescences replace the function of a flower in a way forming pseudanthium, meanwhile, some organs replace the function of petals by enlarged and being petaloid. The enlarged showy calyx-lobes in Mussaenda (Rubiaceae) are good examples. The calyx-lobes, so called calycophylls, are mostly leaf-shaped, but have bright color, papillate epidermis, and loose mesophylls, features generally only found in petals. In higher eudicots, floral organs are typically arranged in four different whorls, namely sepals, petals, stamens and carpels. According to the ABCDE model proposed by Theißen, organ identities are specified by these five class of floral homeotic genes solely or in a combinatory way. According to this model, petal identity is specified by A, B and E class genes. Research in Arabidopsis showed overexpression of A, B and E class genes caused the formation of petaloid leaves, suggested a general mechanism that might be found in other petaloid structures in plants. My thesis is to examine the correlation between the formations of petaloid sepals in Mussaenda and the petal identity genes, i.e. ABE class genes. Five floral organ identity genes of Mussaenda pubescens were cloned and their expression patterns among different organs were detected by RT-PCR. The AP1 homologue, MupAP1, is expressed in enlarged and small sepals, petals and stamens, carpels and fruits; the SEP3 homologue, MupSEP is strongly expressed in all floral organs and weak in leaves as well. Two of the B class gene, AP3 homologue MupDEF and TM6 homologue MupTM6, were detected expressed in all floral organs, however, the other B class gene, MupGLO, homologous to PI, were detected expressed in small sepals, petals and stamens, carpels and fruits, but not in enlarged sepals. Though there might be other factors involved, results suggest the formation of petaloid sepals in Mussaenda still required A, E, and some B class genes, but further survey for addition factors and functional assay for identified genes are needed. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/55090 | 其他識別: | zh-TW |
顯示於: | 生態學與演化生物學研究所 |
檔案 | 描述 | 大小 | 格式 | |
---|---|---|---|---|
ntu-93-R90226015-1.pdf | 23.31 kB | Adobe PDF | 檢視/開啟 |
在 IR 系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。