Study On The Comparative Anatomy Of Leaves And Roots Of Drepanostachyum And Ampelocalamus

Drepanostachyum Keng f. and Ampelocalamus S. L. Chen et al. belong to Arundinarieae Nees, Bambusoideae Nees, Poaceae. They altogether have 22 species and there are 18 species distributing in Taiwan,Hainan and the three provinces in Southweast of China. Most of species of the two genara have similar morphology and distribute in valley or steep slope of limestone areas. we have not found the flowers of some species, such as, D.saxatile (Hsueh et Yi) Keng f. ex Yi, D.yongshanense (Hsueh et D.Z. Li.) Yi, D. mianningense (Q. Ii et X. Jiang) Yi. So some scholars attribute the three species into Ampelocalamus and others play them into Drepanostachyum. Considering the difficulty of morphological taxonomy, we study the anatomy of roots and leaves of 13 species of the two genara. On these ground, we analyze the anatomical relationship of the two genara and definite the systymatic position of D.saxatile, D.yongshanense and D. mianningense.Our main results as followed:(1) The anatomy of 10 species'roots was done. Their exodermises, endodermises, pericycles and the layers of fiber near exodeermise are very similar. All these morphologies are more close to those of scattered bamboos. Therefore, the relationship of the two genera is very close and they are more advanced than other clustered bamboos. The instability of the vessels of Metaxylem, air cavities and the piths in the cross section of roots shows all these are varying in the couse of root growing. in a word, the anatomical structures of theroots can not provide with the taxonomic proofs of Drepanostachyum and Ampelocalamus.(2) In the cross section, the mesophyll cells of 13 species is similar and all look like arm-cells. The number of vascular vundle of the midrib in one species is not the same.The shape and the number of the bulliform cells vary much. For example, in some species such as, D.scandens and D.microphyllum, there are only 2 to 3 near to the midrib, while there are 5 even more than 7 ones on the side of leaf verge. Except that the mesophyll cells of A.actinotrichus and A. menglaensis only have two layers, that of other eleven species often have three layers. Of the A.actinotrichus and A. menglaensis, the percent of the air cavities to the mesophyll cells is larger than that of other eleven species and the air cavities are often longer than 128μm and wider than 10μm, while in other eleven species the air cavities wider than 10μm.appear only near the midris and the width of the air cavities near lateral veins are all less than 10μm. It is obvious that the air cavities of D. fractiflexum looks much smaller. Its length is no more than 56μm and even there are absent beside some lateral veins near the leaf verge.