广西特有属——异裂菊属开花生物学及繁育系统特征

Study on the Floral Biology and Breeding System of Heteroplexis Plants

以异裂菊属5个种的实生苗为试验材料,通过田间观察,采用TTC法、联苯胺-过氧化氢法、杂交指数、花粉-胚珠比等方法,对异裂菊属的开花物候、花部特征、繁育系统及访花昆虫行为进行了研究。结果表明：（1）绢叶异裂菊的花期最早,为6~7月份;小花异裂菊和柳州异裂菊花期为6~8月份;凹脉异裂菊和异裂菊的花期为8~12月份,整个花期持续约5个多月,单花花期约为3d,单个花序花期约为5d。（2）异裂菊属的花粉在开花后1~18h具有活力,柱头的可授性持续约48h;杂交指数OCI为4,花粉/胚珠比（P/O）为1 450~2 250,繁育系统属于异交、部分自交亲和,需要传粉者。（3）传粉昆虫主要是食蚜蝇科灰带管食蚜蝇和胡蜂科黑尾胡蜂,昆虫访花高峰期在上午10：00~12：00,每次可连续访问多朵花,每朵花访问时间约为2~10s。

Field investigation was performed on the floral syndrome,pollination characteristics,pollinator behaviors and breeding system of Heteroplexis by continuous observations,TTC method,Benzidine-H2O2 method,out-crossing index,pollen-ovule ratio.The result as follows：（1）Under natural conditions,the flowering stage of Heteroplexis vernonioides was about 60 days from April to June,Heteroplexis microcephala and Heteroplexis incana were about 60 days from April to August,Heteroplexis impressinervia and Heteroplexis vernonioides were about 150 days from August to December.The life span of a single flower was about 3 days and the inflorescence was 5 days.（2）Pollen had vigor after the 1-18 hof anthesis.Stigma was receptive after 48 hours of anthesis.The out-crossing index was 4,P/O was 1 450-2 250.The breeding system of five species were given priority to out-crossing,part self-compatibility,insects pollinator dependent.（3）Eristalis cerealis and vespa ducalis are effective pollinators.The visiting frequency showed triple-climax was 10：00-12：00 and the visiting time was 2-10 sper flower.