Reproductive cycle and seed production in Agathis dammara (Lambert) Rich
1999
Komar, T.E.
A. dammara has two years of reproductive cycle. It takes 15 to 18 months from pollination to seed maturity or 22 to 24 months from megaspore mother cell stage. Pollination occurs throughout the year with two to three peaks of pollination period. Pollen development from pollen mother cell to pollination takes 5-6 months. Pollen is yellow and non-saccate. Soon after pollination, pollen germinates and pollen tube grows through nucellus, in many cases the pollen tube found branches. Pollen tube contains many prothallial cells and a body cell. Body cell later divides and forms two male gametes one of which fuses with egg nucleus during fertilization. Ovule development is as follows: mature megagametophyte contains 1 to 10 archegonia per megagametophyte, 4-6 archegonia is more frequently found. Various stages of archegonial development in one megagametophyte is common. After fertilization, the formed zygote develops to proembryo and early embryo stage. At these stages, the embryo contains cap cells, central cells and suspensors. Simple polyembryony derived from fertilization of each archegonium occurs before maasive embryo stage, whereas cleavae polyembryony does not occur. An observation conducted in Gunung Walat Sukabumi releaved that ovule abortion in A. dammara reaches over 60 percent, while seed cone abortion reaches 30 percent. The causes of this abortion is not known and need to be further studied
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