Leaf ecoanatomy of three Gramineae species in different communities in Xiangshan Mountain,Huaibei,China

The results of eco-anatomic observation on leaf blades of 3 Gramineae species in early successional communities in Xiangshan Mountain,Huaibei,China,indicated that Arthraxon hispidus and Themeda japonica(C4 plants),share characteristics of thicker epidermis and homomorphism mesophyll cells with stomata mostly distributed in the upper epidermis and with Kranz-type vascular bundle sheaths.Achnatherum extremiorientale(C3 plant) on the other hand,is characterized by a thinner epidermis,mesophyll cells near the epidermis that are palisade-like,stomata are mostly distributed in the lower epidermis,and the vascular bundle sheath consists of one layer of parenchyma cells and one layer of sclerenchyma cells.In different successional communities,the lamina of 3 Gramineae species showed great anatomical plasticity in the order: A.extremiorientale(0.24)T.japonica(0.19)A.hispidus(0.17).Compared with mixed forest,the leaves collected in the shrub and shrub-herb tend to have more xeromorphic features such as thicker leaf and epidermis,mesophyll,and vascular bundles,and smaller stomata.The result of stepwise multiple regressions indicated that lamina structure is commonly influenced by many environment factors,of which soil water content(SWC) and wind velocity(WV) are the principle factors.With an increase of SWC,thickness of upper and lower epidermis,leaf and mesophyll thickness of A.hispidus,leaf and mesophyll thickness of A.extremiorientale,thickness of upper epidermis and vascular bundle of T.japonica are all reduced.With the increase of WV,the stomatal length in the lower epidermis of A.hispidus,and in the upper epidermis of T.japonica were reduced,but the thickness of the vascular bundle of A.extremiorientale increased.The stomatal length in the lower epidermis of A.extremiorientale decreased with the degree of coverage.