Abstract: The effects of different sulfate supply level on N and S metabolism and on root vigor of corn were quantitatively studied with Hoagland solution under greenhouse conditions.The results showed that in S-deficient solution,root vigor and leaf nitrate reductase (NR) activity significantly rdduced,top root ratio (T/R) increased,and S and N accumulation in tops and roots decreased.The partition of Sdecreased in roots and incompletely expanded leaves,but increased in senescent leaves and sheaths stems ;while the partition of N increased in roots,but decreased in incompletely and fully expanded leaves.The content of protein,protein N,protein S,and sulfate Ssignificantly reduced, percentage of non protein N increased,inorganic S/total S ratio decreased,and total N/total Sratio increased.The protein N/ protein Sratio in tops had no observable changes.but increased significantly in roots,showing that root was a sensitive organ to S deficiency.There was a close relatioinship between protein content and NR activity in S-deficiency.D eficient or excessive S supply limited Nand Smetabolism of corn plant.N/Sor inorganic S/total Sratio in roots was a sensitive index to indicate the deficiency of Ssupply,which was 10.7 or 0.302 under normal condition,respectively.

Key words: Zea mays L., Sulfate supply, Nitrogen, Metabolism, N-S interaction, Roots vigor, species composition, Minjiang Estuary, diet composition, stable isotope