Systematic study on the Genus Plagiostachys Ridl.(Alpinioideae: Zingiberaceae) of Borneo

Avelinah Julius (2006) Systematic study on the Genus Plagiostachys Ridl.(Alpinioideae: Zingiberaceae) of Borneo. Masters thesis, Universiti Malaysia Sabah.


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The genus Plagiostachys of Borneo was revised. Morphological characteristics in living plants were observed to find new significant characters for the genus classification. This study showed that several characters, such as the shape and the presence or absence of anther crest, the branching pattern, and the bracteole shape were consistent within a species and taxonomically important to differentiate between the closely related species. Seven new species and one new variety were recognized, described and illustrated, namely P. brevicucullata A. Julius &. A. Takano, P. longicaudata A. Julius &. A. Takano, P. megacarpa A. Julius &. A. Takano, P. pustulosa A. Julius &. A. Takano, P. roseiflora A. Julius &. A. Takano, P. subulata A. Julius &. A. Takano, P. viridisepala A. Julius &. A. Takano and P. breviramosa J. Cowley var. ecristata A. Julius &. A. Takano. A key to species of Bornean Plagiostachys was constructed based on morphological characteristics. Molecular phylogenetic analysis using nudear DNA sequence data of internal transcribed spacer region (1TS1, 1TS2) and 5.8S gene was conducted to examine the phylogenetic status of the genus. The strict consensus tree (Length = 1216; CI = 0.4120; RI = 0.7395; RC = 0.3047) obtained from parsimony analysis of the ITS sequence data showed that the species of Plagiostachys made a strongly supported dade with some Alpinia species which befong to section Alpinia (BS = 92 %). On the other hand, species of Plagiostachys comprise three subclades and each subdade Is moderately to strongly support with relatively high bootstrap value: Plagiostachys subdade A (BS = 70%), Plagiostachys subclade B (BS = 81%) and Plagiostachys subdade C (BS = 99%). Alpinia is not included into the subdades. It suggests that the Plagiostachys is a different entity from Alpinia but more data is needed to verify this. Therefore, Plagiostachys remains in its current status until further analysis Is carried out The ITS sequences also provided new data for inferring relationships within Plagiostachys and allow new interpretations of capsule character (pubescence or glabrous capsule) that maybe of value in future classification.

Item Type: Thesis (Masters)
Keyword: Borneo, ITS, Plagiostachys, systematic, Zingiberaceae
Subjects: Q Science > QK Botany
Department: INSTITUTE > Institute for Tropical Biology and Conservation
Date Deposited: 13 Jan 2015 11:29
Last Modified: 30 Oct 2017 11:29

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