单瓣与重瓣垂丝海棠花器官形态发育比较观察

Comparison of Floral Organ Morphology and Development of Single and Double Petaled Malus halliana

为探究垂丝海棠重瓣花成花原因,该研究以单瓣垂丝海棠和重瓣垂丝海棠为实验材料,应用体式显微镜和扫描电镜观察垂丝海棠单瓣、重瓣品种花器官分化过程;解剖观察重瓣垂丝海棠大蕾期的花与盛开的花,统计其花器官的形态与数目;应用R语言对重瓣垂丝海棠的花瓣数目与其余各轮花器官数目进行相关性分析。结果显示:(1)单瓣和重瓣垂丝海棠的花器官分化均分为萼片原基分化期、花瓣原基分化期、雄蕊原基分化期、雌蕊原基分化期,且各轮花器官按照向心顺序依次分化发育。(2)在花瓣原基分化期,单瓣垂丝海棠仅分化出一轮(5枚)均匀分布于两枚萼片交汇处的花瓣原基,而重瓣垂丝海棠分化出两轮分布散列的花瓣原基,第一轮为5~7枚,第二轮为7~10枚。(3)在重瓣垂丝海棠各轮花器官中存在较多萼片瓣化、雄蕊瓣化、雌雄蕊异常发育的情况。(4)重瓣垂丝海棠各轮花器官数目间相关性分析结果显示,其花瓣数目与雄蕊数目以及瓣化中的雄蕊数目间存在明显的正相关关系,该现象与常规雄蕊瓣化植物表现的雄蕊数目减少、花瓣数目增多的现象不同。研究表明,重瓣垂丝海棠花瓣数目的增多并不完全依赖于雄蕊变瓣,暗示垂丝海棠重瓣花成花原因的多元性与复杂性。

In order to explore the reason for flower formation of Malus halliana var.parkmanii,this study took single and double petaled M.halliana as experimental materials,and observed the flower organ differentiation process of singlepetaled and doublepetaled M.halliana by means of stereomicroscope and scanning electron microscope;The flowers in bud stage and blooming stage of M.halliana var.parkmanii were observed anatomically,and the morphology and number of flower organs were counted;The R was used to analyze the correlation between the number of petals of M.halliana var.parkmanii and the number of floral organs of other circles.The results were as follows:(1)the floral organ differentiation of single and doublepetaled M.halliana can be divided into sepal primordium differentiation,petal primordium differentiation,stamen primordium differentiation and pistil primordium differentiation,each floral organ differentiated and developed in a centripetal order.(2)In the differentiation stage of petal primordium,M.halliana only differentiated one round of 5 petals primordia evenly distributed at the junction of two sepals.However,M.halliana var.parkmanii differentiated two rounds of hashed petal primordia,with 5-7 in the first round and 7-10 in the second.(3)In M.halliana var.parkmanii,there are many cases of sepal petalization,stamen petalization,and abnormal development of pistil and stamen.(4)The correlation analysis of the number of floral organs in each cycle of M.halliana var.parkmanii showed that the number of petals was positively correlated with the number of stamens and the number of stamens in petrification.This phenomenon is different from the phenomenon that the number of stamens decreases and the number of petals increases in the conventional stamen petalization plants.These results showed that the increase of the number of petals was not completely dependent on the stamen petrification,which revealed the diversity and complexity of the reasons for the formation of M.halliana var.parkmanii.