Dry Matter Yield and Nitrogen‐15 Uptake by Tomatoes Under Sodium Chloride Stress

Abstract

Abstract An absorption study was conducted in nutrient solution with seedlings of tomato ( Lycopersicon esculentum Mill.; cv. Columbia) to observe the effects of NaCl on ( 15 N) uptake and distribution in plant roots and shoots. The 14‐d‐old seedlings were grown for 16 d (14 d as group of 6 plants per container and 2 d after the final transfer of 2 plants per container) in complete Hoagland solution no. 1, then salinized (except the controls, −0.03 MPa) to −0.3, −0.6, and −0.9 MPa osmotic potentials with NaCl. Nutrient solutions were sampled daily for N loss after addition of 15 NH 4 15 NO 3 to the pots. The cumulative 15 N loss was considered to be absorbed by plants. Lowering the osmotic potential of the culture solution decreased total N uptake at all salinity levels, and 15 N uptake of the plants at medium (−0.6) and high (−0.9 MPa) salinity levels. A low level of salinity (−0.3 MPa) did not affect 15 N uptake compared with the control (−0.03 MPa). Water uptake and dry matter yield were affected to a greater extent than 15 N absorption. Nitrogen‐15 concentration was slightly higher in roots than in shoots.