The leaf epidermal micromorphology of the seven species of Potentilla

The epidermal micromorphology characters of the seven species of Potentilla from Liaoning were examined with the light microscope(LM).The results showed that the cells of both surfaces had sinuate thick anticlinal walls, the combination of epidermal cells were more closely to enhance the resistance and mechanical support ability. The leaf epidermal micromorphology of the seven species of Potentilla could be divided into three types by the epidermal cell shape：1) Polygon: The shape of the upper epidermal cells of P.flagellaris, P.fragarioides, P. discolor and P.paradoxa, P.freyniana were polygonal.2) Nearly polygon: The shape of the upper epidermal cells of P.multicaulis, P.kleiniana and the lower epidermal cells of P.paradoxa were nearly polygonal.3) Irregular: The shape of the lower epidermal cells of P.flagellaris, P.fragarioides,P.discolor, P.multicaulis and P.kleiniana were irregular. There was no stomata on the upper epidermal cells of P.fragarioides, P.discolor, P.paradoxa, P.freynian. There were rarely fewer stomata on the upper epidermal cells of P.flagella. There were stomatas on the upper epidermal cells of P.multicaulis and P.kalinin, and the lower epidermal cells of P.flagella, P.multicaulis, P.Kalinin, P.fragarioides, P.discolor,P.freyniana, P.paradoxa. The stomata index of the lower epidermal cells of P. fragarioides,P. multicaulis and P. discolor were obviously larger than the lower epidermal cells of P.flagellaris,P.paradoxa,P.freyniana and P.kleiniana. The stomata index of P.flagella,P.multicaulis and P.kleiniana on the upper epidermis was smaller than on the lower. The stomata index study showed that P.flagella, P.paradoxa, P.kalinin, P.freyniana had strong drought resistance.