锈叶杜鹃的开花特性及繁育系统研究

2012年对锈叶杜鹃自然居群进行了开花物候及访花昆虫的调查，分析了其开花特性；并运用杂交指数、花粉-胚珠比和人工控制授粉方法，对其繁育系统进行了研究。结果表明，锈叶杜鹃开花时间为2月初至7月，其单花花期、单花序花期及单株花期分别为7.06±2.74 d，12.33±2.37 d和16.17±4.24 d。锈叶杜鹃的雌、雄性器官具有同熟性，但两者的最佳活性时间不同，花粉活力在开花第1天的活力最高，而柱头可授性在开花第4～6天最好。锈叶杜鹃的繁育系统为异交型，自交亲和，需要传粉者；同株异花授粉是其主要的授粉方式。锈叶杜鹃的有效传粉昆虫主要为蜂类，而象甲类、蚁类、叶蜂类昆虫是侵害性昆虫，严重影响其传粉；传粉昆虫访花频率低，可能是导致锈叶杜鹃自然杂交结实率低的主要原因。

Flowering Characteristics and Breeding System of Rhododendron siderophyllum

The flower phenology and flower-visiting insects of Rhododendron siderophyllum population were investi-gated and studied , and the flowering characteristics was analyzed .Through regulating outcrossing index , pollen-o-vule ratio and artificial pollination , the reproductive system of Rhododendron siderophyllum was studied.The re-sults showed that Rhododendron siderophyllum flowered from the beginning of February to July , the flowering span of individual flower , single flower truss and plant were 7.06 ±2.74 d, 12.33 ±2.37 d and16.17 ±4.24 d re-spectively .The pollens and the pistil matured at the same time at anthesis , but the time of the most vigourous was different.The best pollen vigour was the first day at anthesis and the best pistil receptivity was from the fourth to sixth day at anthesis .The breeding system of Rhododendron siderophyllum was outcrossing with self-compatibility , pollinators were necessary .Geitonogamy was the dominant pollinated method .Bees were the main effective polli-nators of Rhododendron siderophyllum.However , weevil beetles , ants and sawflies were invasive insects , serious-ly affected its pollination .The low frequency of pollinator visiting might be the main reason of the low natural hy-brid seed setting rate .