3个伞房属树种的开花动态及繁育系统研究OA

[Objective]Corymbia citriodora,C.torelliana,and C.ptychocarpa are the species of Corymbia that have been introduced to China for many years and are undergoing genetic improvement,but the lack of research on the breeding system of this genus is not conducive to the scientific understanding and sustainable utilization of this genus.The aim of this study is to characterize the flowering and breeding systems of the three species of Corymbia and to provide a basis for the conservation and improvement of genetic resources of Corymbia in China.[Method]Three species of C.citriodora,C.torelliana,and C.ptychocarpa were analyzed for their flowering mode,flower structure,pollen viability,stigma pollination,hybridization index,etc,and the Eucalyptus urograndis clonal DH32-29 was used as a control for the commonly used forestation species in China to study the differences in floral structure and reproductive system among species and genera.[Result]The three Corymbia species differed significantly in flowering pattern and mating characteristics,moreover,apart from the mating system type,they all differ significantly from the control varieties.All three Corymbia species are continuously flowering,biannual;corymb inflorescences,buds obovate,different from the control's quarter of the year and conical flower buds.There were significant differences in corolla diameter,pistil length,ovary diameter,ovary length and spatial distance of anthers from the stigma among the three species of Corymbia;Pollen viability of the three species of Corymbia and the control species was highest at the stage of operculum loosening,and was above 80%;Stigma acceptability was basically highest at the stage of operculum loosening,and was only highest at the stage of first blooming in C.citriodora and the stigma acceptability of C.citriodora was lower than those of the other species in all the stages.According to the mating type criteria,the OCI values of the three Corymbia species and the control species were all 4,and all of them were outbreeding,partial self-crossing affinity.[Conclusion]The flowering dynamics and breeding systems of the three Corymbia species share common characteristics that significantly differentiate them from the control,all belong to plants that bloom twice a year,with flowers and fruits appearing simultaneously,and with a relatively large number of buds in a single inflorescence.but there are differences among the three species in terms of flower morphology and structure,and flowering period,however the mating systems of all three species are heterogamous,as in the control.