Fertilization and embryogeny in Agapanthus praecox ssp. orientalis (Leighton) Leighton

Abstract

Fertilization and embryogeny in Agapanthus praecox ssp. orientalis are described for the first time, and embryogenic characters of Agapanthus are discussed. The main results are: (1) The pollen tube enters the embryo sac and discharges two sperm 44–48 h after pollination. (2) The sperm fuse with the egg cell and polar nuclei, forming zygote and primary endosperm nucleus, approximately 50 h after pollination. The zygote then enters a short period of dormancy. (3) Seven days after pollination, the zygote starts division. The first division of the zygote is transversal. (4) The embryo undergoes globular stage, rod-shaped stage, and finally forms a monocotyledonous embryo. (5) The suspensor cells are ephemeral and degenerate at the globular embryo stage. (6) Endosperm cells contain massive starch grains as nutrition for embryo development. (7) Embryogeny conforms to the Onagrad type, and endosperm formation is of the nuclear type; the whole process of embryogeny and endosperm development needs approximately 60 days in A. praecox ssp. orientalis. (8) Dicotyledonous together with monocotyledonous forms of embryo morphogenesis in Agapanthus supports the concept of homology of monocots and dicot cotyledons.

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Acknowledgments

The authors are highly grateful to the School of Agriculture and Biology of Shanghai Jiaotong University for providing field and laboratory facilities. This study enjoyed generous support from the Research Fund for the Doctoral Program of Higher Education of China (200802250010), the National Science Fund of China (30571475) and the Key Project of the Shanghai Agricultural Committee (2006-4-9).

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Correspondence to Li-Huan Zhuo.

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Zhang, D., Ren, L., Shen, XH. et al. Fertilization and embryogeny in Agapanthus praecox ssp. orientalis (Leighton) Leighton. Plant Syst Evol 293, 25–30 (2011). https://doi.org/10.1007/s00606-010-0378-y

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Keywords

  • Agapanthus praecox ssp. orientalis
  • Fertilization
  • Embryogeny
  • Endosperm development