Photosynthetic and anatomic responses of peanut leaves to cadmium stress

Cadmium ( Cd) treatments caused an inhibition in the net photosynthetic rate ( P-N) of peanut ( Arachis hypogaea) plants, due to the reduction of stomatal conductance ( g(s)) and photosynthetic pigment contents, as well as the alteration in leaf structure. The decrease of the transpiration rate and gs might result from the Cd-induced xerophyte anatomic features of leaves ( i.e. thick lamina, upper epidermis, palisade mesophyll, high palisade to spongy thickness ratio, as well as abundant and small stomata). The decline of P-N was independent of the impairment in photosystem 2.