Conclusions SPECIFIC DELIMITATION AND RELATIONSHIP AMONG SPECIES

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7.4. Conclusions

All species Diplazium have monolete, bilateraly symmetrical, heteropolar, polar outline elliptical, perinates with laesura concealed by its perine. Perine ornamentation varied from alate to costate alate and rugulate with variation of additional decoration such as ciliae, coralline, echinae, and fenestrae. Perine ornamentations support in delimitating Diplazium species. Nevertheless morphological variation of spore is inadequate to depict natural relationship among Diplazium species. Superficial similarity of mature perispores would not indicate on systematic relationship among species as similar surface pattern it derived through different development pathways. 146

CHAPTER 8 MOLECULAR SYSTEMATIC OF DIPLAZIUM FROM WEST MALESIA

8.1. Introduction

The lack of informative morphological characters in ferns led to the search for new sources of characters in molecular data, including restriction site and nucleotide sequence data, to infer phylogenetic relationships Eastwood et al 2004. Phylogenetic analysis on Diplazium based on morphological characters Chapter 6 revealed that Diplazium has only a little informative morphological characters and a hight homoplasy HI=0.76. The lack of the informative morphological characters and the high of homoplasy suggests that additonal caharcters are required to asses the relationship within this genus. Advances in molecular biology have provided systematists with a valuable source of characters. Correlating in inferring phylogeny of the vascular plants, plant sistematists are depending upon chloroplast genome. Most phylogenetic reconstructions in plant systematics conducted so far is based on molecular data from cpDNA genes. The chloroplast genome is well suited for evolutionary and phylogenetic studies, because: 1 the chloroplast genome is small typically between 120 and 200 kb, making it relatively easy to examine the entire genome via ristriction site analysis; 2 it contains primarily single copy genes; 3 has a conservative rate of nucleotide subtitution; and 4 extensive background for molecular information on the chloroplast genome is available Soltis Soltis 1998. The most common gene used to provide sequence data for plant phylogenetic analysis is the plastid-encoded rbcL gene Chase et al 1993. It is located in the large single-copy region of the chloroplast genome and encodes the large subunit or ribulose 1,5-bisphosphate carboxylaseoxygenase RUBISCO. This single copy gene is aproximately 1430 base pairs in length; insertions or deletions indels are extremely rare.