Arundina graminifolia var. revoluta (Arethuseae, Orchidaceae) has fern-type rheophyte characteristics in the leaves
Morphological and molecular variation between Arundina graminifolia var. graminifolia and the dwarf variety, A. graminifolia var. revoluta, was examined to assess the validity of their taxonomic characteristics and genetic background for identification. Morphological analysis in combination with field observations indicated that A. graminifolia var. revoluta is a rheophyte form of A. graminifolia characterized by narrow leaves, whereas the other morphological characteristics described for A. graminifolia var. revoluta, such as smaller flowers and short stems, were not always accompanied by the narrower leaf phenotype. Molecular analysis based on matK sequences indicated that only partial differentiation has occurred between A. graminifolia var. graminifolia and A. graminifolia var. revoluta. Therefore, we should consider the rheophyte form an ecotype rather than a variety. Anatomical observations of the leaves revealed that the rheophyte form of A. graminifolia possessed characteristics of the rheophytes of both ferns and angiosperms, such as narrower palisade tissue cells and thinner spongy tissue cells, as well as fewer cells in the leaf-width direction and fewer mesophyll cell layers.
KeywordsAnatomy Arundina graminifolia Arundina graminifolia var. revoluta Leaf structure matK Rheophyte Taxonomy
The authors thank the Secretariat of Permission for Foreign Research, the Ministry of Research and Technology, Republic of Indonesia (RISTEK), Maliau Basin Management Committee and Sabah Biodiversity Council, for permission to conduct the field research in West Kalimantan and Sabah. We thank the Indonesian Institute of Science (LIPI) and the Betung-Kerihun N. P. office for kindly allowing this study to take place in Betung-Kerihun N. P., West Kalimantan. We also thank Dr. Dedy Daernadi of LIPI, Dr. Marlina Ardiyani and Mr. Ujang Hapid of Herbarium Bogoriense (BO), and Mr. Mustarrudin, Suherman, Jon, Anong, Mazid, and Eddy for helping to conduct the botanical surveys during the expedition in West Kalimantan. We thank Dr. Monica Sleiman and Ms. Palasiah Jofan of Universiti Malaysia Sabah, and Mr. Wittona Raili, Rohit Kakoh and Johnlee Paul of Maliau Basin Conservation Area for their assistance with our botanical surveys in Maliau Basin, Sabah. Mr. Arief Hidayat of Herbarium Bogoriense kindly guided us through the complex procedure of obtaining research permission. Ms. T. Shimabukuro of Kinjo Ryokan kindly sent us samples grown in her garden, via an introduction from Prof. Masatsugu Yokota of Ryukyu University. Dr. Keiko Sakakibara of Hiroshima University also sent us samples cultivated at the University. Curators of the Botanical Gardens, the University of Tokyo permitted us to analyze samples cultivated in the greenhouse. A part of the research budget was supported by Mitsubishi Foundation.
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