Effects of different nitrogen forms on the dry matter accumulation and leaf nitrogen metabolism of muskmelon

Effects of four nitrogen forms (NO^-₃-N∶NH⁺₄-N were 100∶0，75∶25，50∶50 and 25∶75, respectively)on the muskmelon (cv. Chunli and Milinglong) plant dry matter accumulation and leaf nitrogen metabolism were investigated. The results showed that different nitrogen forms significantly affected the dry matter accumulation percentage in different plant organs. Leaf nitrate reductase, nitrate content and soluble protein content decreased with the increase of ammonium nitrogen form, whereas the highest leaf free amino content was obtained in the treatment of NO^-₃-N∶NH⁺₄-N(50∶50).