title: Microsporogenesis and flower development in Eucalyptus urophylla × E. tereticornis.
abstract: We compared microsporogenesis and flower development in Eucalyptus urophylla × E. tereticornis. In this study, although microsporogenesis and cytokinesis occurred simultaneously during meiosis of pollen mother cells, we observed a strong asynchronism in different anthers from a flower bud. The developmental period of microsporogenesis in anthers originated from the long thrum before the short thrum. Flower development was also asynchronous at different locations on a branch. The flower buds grew on the lower side of the branch and showed greater increases in diameter. In addition, we observed a relationship between microsporogenesis development and flower bud diameter growth. Generally, when the pachytene stage was first observed in a small single flower bud growing on top of a flowering branch, the remaining microsporogenesis stages (from diplotene to tetrad) in the whole branch occurred over the next 5-9 days. Thus, the start of microsporogenesis in E. urophylla × E. tereticornis could be determined, which may be applicable to future breeding studies.
authors.affiliation: National Engineering Laboratory for Tree Breeding, Beijing Forestry University , Beijing 100083 , P R China ; Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University , Beijing 100083 , P R China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: National Engineering Laboratory for Tree Breeding, Beijing Forestry University , Beijing 100083 , P R China ; Key Laboratory for Genetics and Breeding of Forest Trees and Ornamental Plants, Ministry of Education, Beijing Forestry University , Beijing 100083 , P R China.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Kang
keywords: Eucalyptus urophylla × E. tereticornis; flower development; microsporogenesis