Changes of micronutrients, dry weight and plant development in canola (Brassica napus L.) cultivars under salt stress

This study was carried out to determine the effects of salt stress on the growth, dry weights and micronutrient contents of canola (Brassica napus L.) cultivars grown in greenhouse conditions. 12 canola cultivars (Marinca, Kosa, Spok, Semu DNK207 NA, Tower, Liraspa, Star, Tobin, Helios, Semu 209/81, Regent and Lirawell) were exposed to salinity treatments (150 mM NaCl and control). Shoot, leaf and root dry weights of all the cultivars at 45-day-old plants were determined. Micronutrient contents (Fe, Mn, Cu and Zn) of the leaves, stems and roots were also analyzed. Salinity stress negatively affected the canola cultivars and the extent of effects varied depending on the salt tolerance of the cultivars. Generally, salinity reduced the plant growth and dry weights. Fe, Mn, Cu and Zn concentrations were high in the roots when compared with those in the leaves and shoots in the salt applied samples. It was observed that, micronutrient contents showed some variation in the different plant parts of the canola cultivars as a result of salt applications to the growing media. Iron (Fe), manganese (Mn) and copper (Cu) content increased in all the plant parts with salt applications except for some cultivars. On the other hand, when mean data of the cultivars were considered, it could be said that zinc (Zn) content of the leaves was not significantly affected by the salt stress.Key words: Canola, Brassica napus, dry weight, micronutrient accumulation, salt stress

Effect of salinity stress on plant fresh weight and nutrient composition of some Canola (Brassica napus L.) cultivars

Soil salinity is a major limitation to crop production in many areas of the world. A pot experiment was carried out with rapeseed cultivars in order to investigate the effects of salinity stress on plant development and nutrient composition. For the salinity studies, 150 mM NaCl concentration was applied to12 rapseed cultivars (Marinca, Kosa, Spok, Semu DNK207 NA, Tower, Liraspa, Star, Tobin, Helios, Semu 209/81, Regent and Lirawell) under the greenhouse conditions. All the cultivars were harvested after 45 days from planting. Green plants parts were weighted. Harvested rapeseed plants were separated into root, shoot and leaf parts for nutrient (K+, Na+, K+/Na+, Ca2+ and Cl-) analysis. As shown in this study, salinity stress affected negatively all the canola cultivars investigated. Generally, salinity reduced the green parts’ weight. K+, Ca2+ and K+/Na+ contents in plants decreased by salt stress, but Na+ and Cl- content in the roots, shoots and leaves of all the cultivars significantly increased. In the salt treatment, the K+ and Ca2+ concentrations were the highest in the leaf samples as compared to root and shoot samples. Furthermore, the highest concentration of Na+ and Cl- was observed in the leaf and shoot. Under salinity, Regent and Lirawell cultivars retained the highest K+ and Ca2+ content in leaves, with respect to the K+ content. The effect of NaCl treatment on the canola cultivars’ growth was not considerable.Key words: Canola cultivars, green plant parts, nutrient content, salt stress