臺灣產旋花科植物之核型分析

Karyotype Analysis of the Convolvulaceae in Taiwan

葉修珍(H. -co Yeh) ； 蔡進來(J. -L. Tsai)

《臺灣省立博物館年刊》 38卷 (1995/12) Pp. 55-77

https://doi.org/10.6548/ATMB.199512_38.0003

摘要

旋花科植物全世界約有50屬1800種，分布於熱帶、亞熱帶及温帶地區，數量極多，但染色體方面的研究不多，目前僅約10%的種類曾經研究過。臺灣原生之本科植物有13屬34種，馴化的有2屬9種，而其染色體之研究只有4種。本研究以臺灣原生和馴化之旋花科植物其實驗的對象，取材自根尖或胚芽的分生組織，利用醋酸洋紅壓片技術，觀察有絲分裂中期之染色體。共研究7屬21種2亞種，發現染色體數目在屬內及種內皆有一致性：2n=30是最普遍的數目，見於吊鐘藤屬、牽牛屬、菜欒藤屬及盒果藤屬共17種材料；而菟絲子2n = 28、九爪藤2n = 28、假中華牽牛2n = 60、藍花娥房藤2n = 18、菜欒藤2n = 58為較特殊者。菟絲子、假中華牽牛、槭葉小牽牛、變葉姬旋花及戟葉菜欒藤五種材料之染色體特徵為首次發表者。本科植樹之染色體具有短小和對稱性高的特點。最小的染色體為馬鍗金的0.7μ，最大的則為藍花娥房藤的3.5μ。除牽牛花全為中位中結染色體外，所有材料皆由中位中結和近中位中結染色體組成。多基數的情形在本科很普遍，根據目前的研究資料顧示，染色體切生基數可能為7，之後經由雜交和多倍體化，才衍生出現在基數X =14、15、28等。然而多倍體出現頻度極低，本研究僅發現假中華牽牛和菜欒藤為四倍體，佔8.7%。B染色體見於海牽牛、牽牛花、野牽牛、假中華牽牛、槭葉小牽牛和戟葉菜欒藤中，數量少且不穩定。隨體染色體則出現於天茄兒、番仔藤、海牽牛、假中華牽牛、槭葉小牽牛及藍花娥房藤六種材料。菟絲子屬的演化方向與其他各屬不同，為獨立演化的一群，但由染色體基數及形態來看，仍以歸入旋花科為宜。吊鐘藤屬、牽牛屬、菜欒藤屬和盒果藤屬之染色體相似性高，親緣關係很近，各種之間則關係複雜，形成網狀的關聯性。娥房藤屬較為原始，其外部形態雖與旋花族中的各屬相似，但染色體特徵卻有很大的差異，應將之獨立出來而提昇至族的地位。馬蹄金屬為本科中較進步的一屬，而以歸群在旋花亞科中之一族的地位為妥。

關鍵字

旋花科 ； 染色體 ； 核型分析

並列摘要

The family Convolvulaceae consists approximately of 1800 species in 50 genera in the world, mostly distributing in the tropical, subtropical and temperate regions. With its ill-defined generic limits, it is cytologically less known. Data are available for only about 10% of the total number of species. There are 34 species beloning to 13 genera found to be indigenous in Taiwan, and 9 species in 2 genera are naturalized. Only 4 species were cytologically investigated. This thesis have studied the chromosome characteristics of these indigenous and naturalized plants, including 7 genera 21 species 2 subspecies. The materials were collected from the roots and buds of those plants. For investigating the somatic metaphase chromosomes, the aceto-carmine squash technique were used. The chromosome numbers are similar among different species within a genus and identical among the different populations of each species. The chromosome number 2n=30 is the most general one, which occurs in the 17 species of Hewittia , lmpomoea, Merremia and Operculina. Cuscuta australis (2n=56), Dichondra micrantha (2n=28), Ipomoea pes-tigridis (2n=28), I. plebeia (2n=60), Jacquemontia tamnifolia (2n=18) and Merremia gemella (2n=58) are different from the others. The chromosome numbers of C. australis, I. plebeia, I. wrighiii, M. hirta and M. tridentata subsp. hastata are reported for the first time. The chromosomes of this family are small in size and symmetrical in shape. The smallest chromosome (0.7μ) is found in D. micrantha and the biggest one (3.5μ) in J. tamniIolia. Except for I. nil with exclusively metacentric chromosomes, all the other species have the karotypes composed of metacentric and submetacentric chromosomes. Di-or polybasic numbers are common in this family. According to the present data, the primary basic number may be b=7. The present basic numbers X= 14, 15, 28 are derived by meanns of hybridization and polyploidization. The frequency of polyploids is low, only 8.7%. Both I. plebeia and M. gemella are tetraploids. B chromosomes are less common and unstable which could be found in I. gracilis. I. nil, I. obscura, I. plebeia, I. wrightii and M. tridentata subsp. hastata. Satellites are found in I. alba. I. cairica , I. gracilis, I. plebeia, I. wrightii and J. tamnifolia. The genus Cuscuta has its chromosomes quite different from the other genera. But it still belongs to the Convolvulaceae based on the primary chromosome basic number. Hewittia, Ipomoea, Merremia and O perculina are similar in cytological data. This fact probably indicates that these genera have close relationships. The interrelationships among those plants are very commplex in network. Jacquemontia is more primitive. Though its morphology resembles the other genera of this family, there are many differences in the chromosome characteristics. The genus Jacquemontia should be grouped to the Jacquemontieae separating from the Convolvuleae. Dichondra is more advanced in the family, and should be grouped into the Convolvuloideae as the tribe Dichondraeae.

並列關鍵字

Convolvulaceae ； chromosome ； karyotype analysis