岩桐屬植物花朵與葉脈顏色之遺傳

Inheritance of Flower Characteristics and Leaf Vein Color in Sinningia

甘培玟(Pei-Wen Kan)

指導教授 ： 葉德銘

國立臺灣大學/生物資源暨農學院/園藝暨景觀學系/碩士(2017年)

https://doi.org/10.6342/NTU201701610

摘要

大岩桐[Sinningia speciosa (Lodd.) Hiern]為重要室內盆花，本研究以重瓣品種絲織品(Brocade)，單瓣品種愛娃(Avanti)與其他具特殊性狀之原生種與單株為材料，觀察其花朵形態並進行分類，探討重瓣花瓣起源與半重瓣花不同雄蕊類型之花粉的發芽率。另進行雜交探討後代花型、花色及葉斑之分離比，以及其他岩桐屬植物花萼瓣化的遺傳模式。
大岩桐依花瓣層數可分成單瓣(一層花瓣)、半重瓣(兩層花瓣)與重瓣(三層花瓣)。半重瓣可分成Type 1與Type 2。Type 1可依雄蕊的瓣化程度再分成三類：完全瓣化雄蕊(Type 1-A)、花絲瓣化雄蕊合生(Type 1-B)與未合生的退化雄蕊(Type 1-C)。而Type 2則有器官重複的現象，具兩輪花瓣與一輪雄蕊；重瓣(Type 3)依雄蕊的瓣化程度可分成兩類：三層花冠筒且無雄蕊(Type 3-A)與兩輪花冠筒與一輪未合生的退化雄蕊(Type 3-B)。經解剖觀察可知，大部分類型的半重瓣與重瓣花是由雄蕊瓣化而來。
黃花岩桐(S. richii Clayberg ‘Robson Lopes’)、大岩桐絲織品-紅(Brocade Red)與大岩桐歡樂鈴-藍(MultiBells Blue)之花粉於去離子水培養，其發芽率甚低，在BK培養基中參試品種花粉發芽之適合蔗糖濃度為10%-15%。分別取半重瓣‘Brocade Purple/white bicolour’之正常雄蕊、花絲瓣化雄蕊與退化雄蕊三種類型之花粉，以內含10%蔗糖之BK培養基、於25℃黑暗下培養2小時，結果顯示正常花藥與花絲瓣化雄蕊之花粉外觀飽滿，皆可正常發芽；而退化雄蕊之花粉外觀乾癟，無法發芽。
將兩側對稱之花朵親本雜交與自交，其後代花朵兩側對稱：輻射對稱花朵之分離比為1：0或3：1。以輻射對稱之花朵親本自交或互相雜交，其後裔皆為輻射對稱，推測大岩桐對稱性是由一對偶基因C、c所控制，兩側對稱花為顯性，基因型為CC或Cc，輻射對稱花為完全隱性，基因型為cc。
取單瓣親本自交或雜交，共計8個雜交組合，其後代皆為單瓣。而以單瓣與半重瓣親本雜交，其雜交後裔重瓣：半重瓣：單瓣，之分離比為0：1：1。以半重瓣品種自交或雜交，其雜交後代分離出重瓣、半重瓣與單瓣，分離比為1：2：1。推測重瓣大岩桐是由一對基因D、d所控制，當基因型為DD時，表現型為重瓣花，Dd時為半重瓣花，dd結合時為單瓣花。
紫色裂片親本自交、紅色裂片與紫色裂片親本雜交，雜交後代紫色裂片：紅色裂片後代之植株數分離比為1：0或1：1。紅色裂片親本雜交與自交，後代裂片顏色皆為紅色，推測紫色裂片與紅色裂片是由一對基因R、r所控制，當基因型為R¬_，裂片呈現紫色，當基因型為rr，裂片呈現紅色。
淡紫色裂片花朵與紅色裂片親本雜交，後代紫色裂片：紅色裂片：淡紫色裂片：淡紅色裂片之花朵，分離比為1：1：1：1。紫色裂片與淡紫裂片親本雜交，後代紫色裂片、紅色裂片、淡紫色裂片與淡紅色裂片之花朵，分離比為3：1：3：1。淡紫色裂片親本自交，後代紫色裂片：紅色裂片：淡紫色裂片：淡紅色裂片：白色裂片之花朵，分離比為3：1：6：2：4。白色裂片與紅色裂片親本雜交，後代皆為淡紅色裂片。白色裂片親本自交或雜交，後代皆為白色裂片，推測淡色花是由一對基因W、w所控制，為R、r的上位基因，當基因型為WW，裂片花色深，花色分布均勻，當基因型為Ww，花色變淡，花色分布不均。基因型為ww，花朵為純白色，無任何斑點與斑塊。
花瓣無白覆輪親本自交或雜交，後代花瓣無白覆輪：白覆輪數之分離比為3：1或1：0。花瓣有白覆輪之品種自交後代皆有白覆輪，推測白覆輪的有無是由一對偶基因Wm、wm所控制，同質隱性結合(wm wm)花朵具白覆輪。
取斑點分布於花冠筒內之品種雜交，後代斑點皆分布於花冠筒內。取斑點分布於花冠筒與斑點分布於花冠筒與裂片上的品種雜交，斑點分布於花冠筒內與花冠筒與裂片上之植株分離比為0：1或1：1。推測斑點分布是由一對基因Sp、sp所控制，當基因型為SpSp與Spsp，斑點分布在花冠筒內部與裂片上，當基因型為spsp，斑點僅分布於花冠筒內。
白色葉脈親本自交後代皆具白色葉脈，白色葉脈與綠脈之親本雜交，後代亦皆具白色葉脈。以綠脈品種雜交或自交，後代皆為綠脈，推測大岩桐白色葉脈係由一對偶基因所控制，相對於綠脈為顯性性狀。切片觀察顯示白色葉脈處上表皮細胞與柵狀組織間具有氣隙，而綠色組織之上表皮與柵狀組織間緊密相連。
以3種花萼正常之原生種岩桐與3種花萼瓣化之品種雜交，後代正常花萼：瓣化花萼之分離比約1：1，推論花萼瓣化為顯性性狀，由一對基因H、h所控制，並與雌蕊畸形連鎖，當基因型為Hh，花萼瓣化，伴隨雌蕊畸形；當基因型為hh，為正常花萼，雌蕊亦正常。
本研究由‘Brocade Purple’自交後代選育具特殊性狀單株大岩桐Gm01。其花徑約7 cm，為半重瓣花，開花株能同時著生4朵以上花朵，花朵中心之花瓣緊密，且最外層花瓣緣具綠色覆輪斑，為特殊之新穎性狀，有別於目前市場上之流通品種。

關鍵字

苦苣苔科 ； 雜交 ； 重瓣花 ； 花色 ； 花萼瓣化

並列摘要

Gloxinia [Sinningia speciosa (Lodd.) Hiern] is an important indoor plant. Double- flowered cultivar Brocade, single-flowered cultivar Avanti, native Sinningia species and other hybrid with special traits were included in this study. The objectives were to 1) observe and classify different flower types, 2) determine the origin of double-floweredness and pollen germination rate from different stamen types, 3) record the segregation ratio for flower type, flower color, leaf vein color, and petaloid calyx inheritance in selfed and crossed progeny.
Gloxinia flowers could be categorized as single-flower (one corolla whorl, Type 0), semi-doubled flower (two corolla whorls, Type 1 and 2), and double-flower (three corolla whorls, Type 3). Type 1 was further classified as 1-A, 1-B, and 1-C with completely petaloid stamen, petaloid filament, and staminoide, respectively and all have deformed pistil. Type 3 can be divided as 3-A and 3-B, with corolla and staminoide in the inner whorl, respectively. All double- and semi-double flowers had inner petal whorls originated from stamens.
Few pollen of Sinningia richii Clayberg ‘Robson Lopes’, ‘Brocade Red’ and ‘MultiBells Blue’ germinated in deionized water, while pollen germinated well in BK media with 10%-15% sucrose. Pollen from normal stamen, petaloid filament and staminoide of ‘Brocade Purple/white bicolour’ were cultured in BK media with 10% sucrose for 2 h in dark. Results showed that pollen in anthers from normal and petaloid filament stamen germinated, but not for those from staminoide.
Crossing or selfing zygomorphic-flowered Sinningia species/cultivars resulted in a 3:1 or 1:0 ratio (zygomorphic : actinomorphic). Selfing actinomorphic-flowered parents resulted in all actinomorphic progeny. Flower symmetry was proposed as controlled by a single allele (C, c). Genotype C¬_ resulted in zygomorphic flower, and cc for actinomorphic flower.
Crossing or selfing single-flowered Sinningia species/cultivars resulted in all single- flowered progeny. Crossing semi-doubled flower and single-flowered parents resulted in 1 semi-double flower : 1 single-flower ratio. Crossing or selfing semi-doubled flower parents resulted in a 1 double-flower : 2 semi-double flower : 1 single-flower ratio. Flower type was proposed as controlled by a single allele (D, d). Genotype DD, Dd, and dd resulted in double, semi-double, and single flower, respectively.
Selfing purple limb parents or crossing with red limb parents resulted in a 1:0 or 1:1 ratio (purple : red). All progeny had red limb from crossing or selfing red limb parents, suggesting that purple limb (R_) is dominant to red limb (rr).
Progeny from crossing light purple and red limb parents resulted in a 1:1:1:1 ratio (purple : red : light purple : pink). Progeny from crossing purple and light purple limb parents resulted in a 3:1:3:1 ratio (purple : red : light purple : pink). Progeny from selfing light purple limb resulted in a 3:1:6:2:4 ratio (purple : red : light purple : pink : white). All progeny had pink limb from crossing white limb and red limb parents. All progeny showed white limb after crossing and selfing white limb parents. Light-colored flower is proposed as controlled by a single allele (W, w) and is epistasis to R, r genes. The WW, Ww, and ww genotypes yielded deep, light color, and pure white without any spot or pattern, respectively.
Crossing or selfing non-picotee parents resulted in a 1:0 or 3:1 ratio (non-picotee : picotee). Crossing or selfing picotee parents resulted in all picotee progeny. The presence of white picotee flower was proposed as controlled by a single allele (Wm, wm), the wm wm genotype resulted in phenotype with white picotee flower.
All progeny had the parental spot distribution after crossing or selfing parents with spot distributed in corolla tube. Crossing or selfing parents with spot distributed in corolla tube and those distributed both in corolla tube and limb resulted in a 1:0 or 1:1 ratio (spot only distributed in corolla tube : spot distributed in corolla tube and limb). The spot distribution was proposed as controlled by a single allele (Sp, sp). The Sp_ genotype had spots on corolla tube and limb, the spsp genotype had spots distributed only in corolla tube.
Crossing or selfing white leaf vein and green leaf vein parents, all progeny had white vein. Crossing or selfing green leaf vein parents, all progeny had green vein. Leaf vein color was proposed as controlled by a single allele (Vw, Vg). The Vw_ genotype showed white leaf vein, the VgVg genotype showed green leaf vein. Anatomy results revealed that air space existed between epidermal and palisade cells in the while vein tissue but not for the green tissue.
Selfing normal calyx Sinningia spp. resulted in all normal calyx progeny. Crossing petaloid calyx and normal calyx parents resulted in a 1 petaloid calyx : 1 normal calyx ratio. Petaloid calyx was proposed as controlled by a single allele (H, h). A single dominant gene expressed in HH or Hh state resulted in petaloid calyxed phenotype and the hh genotype showed normal calyx. Petaloid calyx is linked with deformed pistil.
After selfing ‘Brocade Purple’, Sinningia Gm01 was selected since it had big (7-cm diameter) double-flowers, 4 or more simultaneous flowers, compact inner whorl corollas, and green picotee on the outer corolla.

並列關鍵字

Gesneriaceae ； hybrid ； double-flower ； flower color ； petaloid calyx

參考文獻

徐駿逸. 2015. 鼠尾草屬植物之花器生物學、生殖系統與種間雜交. 國立臺灣大學園藝暨景觀學系碩士論文. 臺北.

張芳綺. 2005. 粗肋草之開花授粉、斑葉遺傳及親緣分析. 國立臺灣大學園藝學系碩士論文. 臺北.

劉明宗. 2016. 重瓣及香氣孤挺花品種之選育. 國立臺灣大學園藝暨景觀學系博士論文. 臺北.

留欽培. 2008. 韭蘭屬物種之種間雜交. 國立中興大學園藝學研究所碩士論文. 臺中.

郭孟樺. 2012. 夏菫與毛葉蝴蝶草種間雜交胚之拯救與多倍體化. 國立臺灣大學園藝暨景觀學系碩士論文. 臺北.