玉铃花开花动态与繁育系统特征

【目的】研究玉铃花Styrax obassia的开花动态，揭示其繁育系统的基本特征，认识其生物学特性，为玉铃花杂交育种、生境保护提供理论依据，也为城市园林绿化应用推广提供技术支持。【方法】田间观测玉铃花开花动态特征、花部结构、昆虫访花特性，采用TTC染色法和联苯胺-过氧化氢法，分别测定花粉活力和柱头可授性，运用杂交指数(OCI)、花粉胚珠比(P/O)等方法确定其繁育系统类型。【结果】(1)玉铃花的花期为4月中旬至5月初，始花期为4月15—18日，盛花期为4月19—26日，末花期为4月27日—5月2日，单花花期约3～5 d。(2)总状花序下垂，开花顺序由花梗基部向先端分2～3区段开放, 30个总状花序的小花数量平均为(25.3±1.8)个。(3)开花1 d后的花粉活力最强，雌雄蕊成熟时间部分重合，P/O为(646.30±64.35),OCI为4。(4)访花昆虫主要有中华蜜蜂Apis cerana、日本弓背蚁Camponotus japonicus等。【结论】玉铃花开花始于4月中旬，结束于5月初，盛花期持续1周时间，其繁育系统属于兼性异交、需要传粉者的类型，部分为自交亲和。图3表1参25

Flowering dynamics and breeding system of Styrax obassia

  Objective  With an investigation of the flowering dynamics of Styrax obassia, this study is aimed to reveal the basic characteristics of its breeding system for a better understanding of its biological characteristics so as to provide theoretical basis for cross breeding and habitat protection of S. obassia as well as technical support for the application and popularization of urban landscaping.   Method  Observations were made of the flower dynamic characteristics, floral structure and insect visiting characteristics before the pollen viability and stigma receptivity were determined employing TTC staining and benzidine hydrogen peroxide method whereas the breeding line type was determined using hybridization index (OCI) and pollen ovule ratio (P/O).   Result  (1) With a single flowering period of about 3 to 5 days, the flowering period of S. obassia is from mid-April to early May with April 15 to 18 being the initial flowering period, April 19 to 26 being the full flowering period and April 27 to May 2 being the final flowering period. (2) With the racemes drooping, its flowering sequence was divided into 2?3 segments from the base of the pedicel to the apex and the average number of florets in 30 racemes was (25.3±1.8). (3) The pollen vigor was the strongest one day after flowering, and the mature time of male and female stamens partially coincided, with a P/O of (646.30±64.35) and an OCI of 4. (4) The flower visiting insects mainly include Apis cerana and Camponotus japonicus.   Conclusion  The flowering period of S. obassia began in mid-April and ended in early May with the bloom lasting for a week and the breeding system is featured with facultative outcrossing and pollinator and is partially self-compatible. [Ch, 3 fig. 1 tab. 25 ref.]