Systematic Studies On Garnotia

The Garnotia is annual or ennial herbaceous which belongs to Gramineae.There are about 30 species around the world,mainly distribute in eastern or southern Asia,northeastern Australia to the Pacific Islands.There are six species in China,and most of them are distributed in south and southwest provinces.The systematic position of Garnotia has been disputed for a long time.In order to study the systematic position of Garnotia,the morphological and molecular methods were conducted respectively.In morphology analysis,glumes and lemmas morphology of Garnotia and its related genera were observed under the scanning electron microscope.Leaves were treated by dry ashing method,and the morphology of phytoliths were observed under optical microscope.In molecular study,phylogenetic trees were constructed based on ITS sequences of nuclear genome and Matk sequences of chloroplast genome.The results were as follows:The epidermal morphology of glumes and lemmas were analyzed by the scanning electron microscope.According to the character of intercostal long cells,stomatal apparatus,intercostal short cells,papillae,prickle hairs,micro-hairs,silica bodies and hairs,the 123 species which belongs to 62 genera were divided into 3 types 5 subtypes and 5 types 6 sutypes respectively.Garnotia was divided into subtype ? of type ? and subtype ? of type ?.With the results of cluster analysis of micro-morphological coding showed that the Garnotia was closely related to Arundinaceae,and it should be a member of Panicoideae.The light microscope was used to examine the features of phytolith.Based on morphology,arrangement,the number of particles contained,length-width ratio and other characteristics,the experimental materials included 86 species which belongs to 50 genera,were divided into ? types and ii subtypes,The morphological analysis of phytoliths consistent with the conclusion of the micro-morphological analysis of the glumes and lemmas,which supports this genus to be divided into Panicoideae and closely related to Arundinaceae.Finally,the ITS sequence and Matk chloroplast genome sequence were used to discover the systematic relation of Garnotia.The maximum likelihood and bayesian method were used for Garnotia and its related genera to construct molecular phylogenetic tree.The results showed that Garnotia was clustered in the large branch of the Panicoideae,closely related to Arundella and Andropogoneae.It was not supported that Garnotia to be part of Pooideae,Eragrostoideae,Andropogoneae and Arundinelleae.Combined with morphological analysis,support established Garnotieae.