大花紫薇花部綜合特征和繁育特性1)

孫陽 袁娟

(廣西大學，南寧，530000) (廣西壯族自治區桂林市龍勝各族自治縣偉江鄉人民政府)

郭萍 朱栗瓊 招禮軍

(廣西國有欽廉林場) (廣西農業職業技術大學) (廣西大學)

In order to understand the flowering and reproductive traits of Lagerstroemia speciosa, and to promote the process of hybrid breedingand improve its ornamental value, we conducted a series of experimental studies. The floral syndrome of L. speciosaand pollinators were observed and recorded, and the pollen vitality, stigma receptivity and artificial pollination test were investigated. The major flowering stage of L. speciosawas from May to August, with a single flowering period of 2 to 8 d. Flowers generally opened in the early morning. The single flowering process can be divided into four stages: namely, the calyx dehiscenting stage, petals expanding stage, anther shedding pollen stage, and flower withering stage. The pollen-ovule ratioof L. speciosawas 5 445.45, and the hybridization index was 4. The stigma had highest receptivity when pollen viability peaked. The seed setting rate of L. speciosa in nature was 72%, while the seed setting rates of artificial self-pollination, artificial cross-pollination of the same plant, and artificial cross-pollination of different plants were 68%, 74% and 90%, respectively. From above results, it is concluded that the breeding system of L. speciosawas based on a mixed mating system with mainly outcrossing and partial self-compatibility, and it required pollinators to finish the pollination process. The main pollinators were bees, fliesand butterflies, such as bumblebee and Chinese bee.

繁殖是保持種群延續的基本途徑，是進化過程的核心部分，也是研究生物進化問題的關鍵。植物的繁育系統一般指直接影響后代遺傳組成的所有有性特征[1]，包括花部綜合特征、花開放式樣和交配系統等。這些有性特征在外界環境因素的影響下，與傳粉者共同影響植物生殖成功率，進而影響種群的進化[2-4]。此外，植物花部特征和傳粉者之間的相互適應被認為是花進化的重要推動力[5]，具體體現在：不同物種因花部特征差異而吸引不同類群的傳粉者，傳粉者在傳粉過程中又會促進物種花部特征的演化[6]。

大花紫薇(Lagerstroemiaspeciosa)為千屈菜科(Lythraceae)紫薇屬(Lagerstroemia)落葉喬木，其樹形優美，開花時花大色艷，花期較長，極具觀賞價值，是我國南方地區重要的園林綠化樹種。因花色單一、有著較強的抗逆性和大花徑性狀，大花紫薇常被用于與同屬的紫薇(Lagerstroemiaindica)進行雜交，以獲得花大色艷的新品種[7]。大花紫薇結實率高，但開裂的朔果經久不落，影響第二年的觀賞效果，且其自然狀態下種子極易老化[8]，幼樹幼苗缺乏，限制了林下自然更新。除雜交育種外，目前關于大花紫薇的研究還涉及栽培、生理生化、化學成分、藥理作用等[9-11]，但傳粉和繁育特性方面的研究鮮有報道，僅有任翔翔等[12]對大花紫薇開花和花粉特性做了研究。……