The Reproductive biology of Indonesian Dammar (Agathis Dammara (Lambert) Rich.)
Date
1996
Authors
Komar, Tajudin Edy
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
This project utilized a planted monoculture stand to study the reproductive biology oflndonesian Dammar (Agathis da.mmara (Lambert) Rich.). The reproductive cycle, pollination, seed production and embryology were studied. Seed cones and pollen cones were tagged, measured and observed monthly or twice monthly to determine the cycle and sequence of cone and seed development. Fixed and sectioned specimens were used to study the developments from pollination to seed maturity using light microscopy.
Pollination occurs almost at any time of the year but the peak periods occur two to three times a year, from February through March, August through September and October through November. It took 5 to 6 months to develop from the pollen mother cell to mature pollen. Pollen is non saccate. Pollen tubes enter the nucellus and branch. Pollen tubes contain several prothallial cells and a body cell. The body cell forms two male gametes. More than one pollen tube is common in an ovule.
The Dammar reproductive cycle is similar to that of temperate Agathis. It took 15 to 18 mo from pollination to seed maturity. Cone abortion is over 30% and seed abortion over 60%. Ovule development is similar to other species within the Araucariaceae. Up to 10 archegonia per megagametophyte are found, but 4 to 6 are more common. Mature archegonia, proembryo and early embryo stages are frequently found in one megagametophyte. Proembryogeny and early embryogeny in Dammar are similar to that in other members of the Araucariaceae with the presence of cap cells, central cells and suspensor. Simple polyembryony was found before massive embryo stage, whereas cleavage polyembryony did not occur in Dammar.