Effect of drought stress on anatomical structure and photosynthesis of Pugionium cornutum (L.) Gaertn. leaves in seedling

The effect of drought stress on anatomical structrue and photosynthesis of chinese specie,Pugionium cornutum(L.) Gaertn.Leaves in seedling were obeserved by conventional paraffin sectioning and Li-6400 photosynthetic apparatus respectively.Which would help us to find out how to the P.cornutum(L.) Gaertn.dealed with the drought stress and the survival strategy in arid environment in seedling,and which would provide theoretical basis for plant drought resistance.The results showed that: The net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),upper and lower epidermis thickness of P.cornutum(L.) Gaertn.leaves decreased with the soil water content decreasing under drought stress,to the contrary,the carbon dioxide concentration incresed,and the thickness of spongy tissue decresed at first and then incresed,howere,the stomatal limitation(Ls),water use efficiency(WUE),palisade tissue,palisade tissue/spongy tissue and leaf structure closely degrees(CTR) incresed at first and then decresed.There were lillte affect on the anatomical structure and photosynthesis of P.cornutum(L.) Gaertn.Leaves when the soil water content were more than 39% WHC,however,the photosynthesis were restrained and the Leaf blade tightness incresed when the soil water content were less than 39% WHC,and P.cornutum(L.) Gaertn.could faced up the drought stress.The ability of photosynthesis of P.cornutum(L.) Gaertn.leaves in seedling was mainly induced by non-stomatal factors,and the structure change of leaves would affect the photosynthesis,at the same time,the photosynthesis would affect the strcture of leaves by the production of reactive oxygen.P.cornutum(L.) Gaertn.could grow well in morderate even more soil drought stress,and it would grow in serious soil drought stess by changing the strcture of leaves,which possiblely were the one of reasones that P.cornutum(L.) Gaertn.could survived and reproducted in desert.