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Title: The reproductive biology and ecology of Johannesteijsmannia Lanceolata J. Dransf. (Arecaceae)
Authors: Chan, Yoke Mui
Keywords: Johannesteijsmannia lanceolata
Peninsular Malaysia
Deforestation
Ecology
Pollen
Issue Date: Mar-2009
Publisher: University of Malaya
Abstract: Johannesteijsmannia lanceolata is a rare species endemic to Peninsular Malaysia, and is threatened by deforestation and seed harvesting for the ornamental trade. Before proper conservation strategies can be implemented for this species, the understanding of its reproductive biology and ecology is crucial for the assessment and prediction of the population viability under such threats. Thus, this thesis aimed to investigate its phenology, breeding system, embryology, and its distribution across topography (ridge, slope and valley) in a 3.2 ha plot in the Angsi Forest Reserve, Negeri Sembilan. Possible conservation measures were discussed. The wild population showed seasonal flowering, while the cultivated population exhibited steady state flowering. Flowering was weakly correlated with rainfall. The reproductive cycle from flowering to fruiting took 14–15 months. Flowers were homogamous, with peak anthesis from 0730–1100 hours, while the stigma was receptive for only one day. Potential pollinators were stingless bees (Trigona sp.) and small flies (Phoridae and Cecidomyiidae). The palm was facultatively selfing with very low fruit set (<0.05 %). The pollen was elliptic, monosulcate with a smooth exine, and lost its viability after one day. The microspore tetrads were tetrahedral (rarely isobilateral), and formed by simultaneous cytokinesis. The ovule was anatropous, crassinucellate and bitegmic. Twin archesporia and T-shaped megaspore tetrads were rare. The embryo sac development was of the monosporic, 8-nucleate Polygonum type. The distribution of the palm differed across topography, with the density highest in valleys (65 individual ha-1), and is likely influenced by seed recruitment, interspecies competition and topographic features. In-situ conservation and a sustainable seed harvesting regime of Johannesteijsmannia lanceolata are strongly recommended, because the species is narrowly endemic, and has a long reproductive cycle with very low fruit set (2–6 mature fruits per fruiting season). ABSTRAK Johannesteijsmannia lanceolata adalah spesies jarang dan endemik di Semenanjung Malaysia, yang menghadapi ancaman daripada pembukaan hutan dan pengutipan biji benih untuk perdagangan tumbuhan hiasan. Sebelum kita dapat melaksanakan strategi pemuliharaan yang sesuai untuk spesies ini, pemahaman mengenai biologi pembiakan dan ekologi palma ini adalah mustahak bagi menilai dan meramal kemandirian populasi di bawah ancaman tersebut. Maka, tesis ini bertujuan mengkaji fenologi, sistem pembiakan, embriologi dan taburan spesies tersebut melintang topografi (rabung, cerun, lembah) di plot kajian 3.2 ha di Hutan Rizab Angsi, Negeri Sembilan. Saranan-saranan pemuliharaan juga dibincangkan. Populasi liar berbunga secara bermusim, manakala populasi yang di tanam berbunga secara berterusan. Korelasi pembungaan dengan jumlah hujan adalah lemah. Kitar pembiakan dari bunga ke buah mengambil masa 14–15 bulan. Bunga adalah homogami, dengan kemuncak antesis dari jam 0730–1100, manakala stigma kekal reseptif selama satu hari sahaja. Kelulut (Trigona sp.) dan lalat kecil dari keluarga Phoridae and Cecidomyiidae berkemungkinan besar adalah agen pendebungaan. Palma tersebut berupaya kacuk sendiri dan kacuk luar dengan penghasilan buah matang yang sangat rendah (<0.05%). Debunga adalah eliptik, monosulkat dengan eksin licin, dan hilang kemandiriannya selepas satu hari. Tetrad mikrospora adalah tetrahedral (jarang isobilateral), dibentuk oleh sitokinesis serentak. Ovul adalah anatropus, krasinuselat dan bitegmik. Arkesporia kembar dan tetrad megaspora berbentuk T jarang ditemui. Perkembangan pundi embrio adalah jenis monosporik Polygonum. Taburan palma tersebut adalah berbeza apabila melintang topografi, dengan kepadatan maksima di lembah (65 individu ha-1), dan mungkin dipengaruhi oleh rekrut biji benih, persaingan interspesies dan ciri-ciri topografi. Pemuliharaan in-situ dan rejim pengutipan biji benih Johannesteijsmannia lanceolata secara lestari adalah sangat disarankan, kerana spesies tersebut adalah endemik, dan mempunyai tempoh kitar pembiakan yang panjang dengan penghasilan buah matang yang sangat rendah (2-6 biji per musim buah).
Description: Dissertation -- Faculty of Science, University of Malaya, 2009.
URI: http://dspace.fsktm.um.edu.my/handle/1812/788
Appears in Collections:Masters Dissertations : Science

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