Effect of salt stress on dry matter production and nitrogen uptake by tomatoes1

Abstract

Abstract Dry matter yield and nitrogen (total and 15N) uptake of tomato plants (Lycopersicum esculentum Mill., cv. Columbia) subjected to saline stress by NaCl were studied in a greenhouse. The treatments consisted of low (control), medium (4 bars), and high (8 bars) salinity. The saline treatments were prepared by adding NaCl to culture solutions. The plants were 80 days old at the start of the 15N treatments and each was in a pot containing 1.8 kg of quartz sand. The 15N was provided to plants by adding K15NO3 to the pots and the 15N treatment period continued for 30 days. The plants were harvested at each 5‐day interval during the 15N treatment period. Dry matter production and nitrogen (total and 15N) uptake were significantly lower for the saline treatments as compared with the control. The significant difference in the above factors (dry matter production, total‐N, and 15N content of plants) was first noted on day 15 of the 15N treatment, and this difference continued to the end of the study period....