暗紫贝母花器官特征及有性繁育系统研究

Studies of the floral organ characteristics and sexual breeding system of Fritillaria unibracteata

采用田间试验与显微镜检相结合的方法,对漳县人工栽培的暗紫贝母花器构造和传粉生物学进行研究,旨在揭示其花器官特征和有性繁育系统,为暗紫贝母的育种提供科学依据。结果表明,经鳞茎播种栽培3年的暗紫贝母植株单花顶生,偶见2花,花两性,初现花蕾绿色,花暗紫色,有淡黄色格纹,开花期5-6月,单花寿命6~8d,花钟形,同被花,花被6,2轮,离生雄蕊6枚,5枚紧围雌蕊,1枚外围,子房上位,柱头3裂,短裂片外露,毛状有分泌物。开花前柱头高于雄蕊,开放后雄蕊高出柱头,开花当天花粉量最大,活力最高并维持3d时间。花被长1.5cm的绿蕾柱头已具较强可受性。花药开裂与强柱头可受性同步,但后者持续期更长(6d以上)。单花花粉数约6000粒、胚珠数在160颗以上,花粉胚珠比(P/O)37.5,杂交指数(OCI)为4。传粉媒介为风媒和虫媒,访花者为蜂类、蝇类和蜘蛛,但数量极少,有性繁育系统应属于部分自交亲和,异交,需要传粉者。

To determine the flower characteristics and sexual breeding system for Fritillaria unibracteata, a combination of field tests and microscopy examination was used to study the flower conformation and pollination biology in order to provide scientific information to assist in plant breeding. This species has a single bisexual flower borne at the stem apex. Occasionally there are two flowers when cultivated for three years from bulbs. The immature bud is green and then turns a darker purple covered with light yellow flecks. The flower- ing period is from May to June but single flowers bloom only 6--8 days. The bell-shaped flower has six peri- anth segments in two whorls and six apopetalous stamens within, five of which are tightly circumfused to the pistil and the other independent. The epigynous ovary has three short splits on its hairy chapiter which are se- cretory. The ovary stands higher than the stamens in the young bud, but becomes shorter in mature, open flowers. The pollen quantity, and vigor is maximal on the first day of flowering and pollen is produced for three days. The pistil stigma in a 1.5 cm long green bud was already receptive. Anther dehiscence coincided with the peak in stigma receptivity but stigma receptivity lasted longer （over 6 days） than pollen production. The flower has over 6000 pollen grains and 160 ovules in single flower, resulting in a pollen to ovule （P/O） ratio of 37.5. The out crossing index （OCI） was 4 according to the flower size and behavior. Pollinators included wind and a few wasps, bees, spiders and other miscellaneous insects. Our results suggest that this species should possess a sexual breeding system with partial self-compatibility, heterogamy, and required pollinators.