Effects of different levels of soil salinization on growth indices and nutrient uptake by Persian clover (Trifolium resupinatum L.) and wheat (Triticum aestivum L. Var Chamran)

Salinity stress is regarded as one of the most important abiotic factors limiting plant growth and agricultural products, particularly in arid and semi-arid regions. This study was conducted to determine the effect of different salinity levels including 0.5 (control), 2.5, 5, 7.5 and 10 dS m-1 (a mixture of NaCl, KCl, CaCl2 and MgCl2 with weight proportional, respectively 2:1:1:1) in three replicates using a completely randomized design on growth indices (including plants height, stem diameter, leaf area, soot and root dry mass and shoot to root ratio), sodium, phosphorous and nitrogen concentrations and Na+/K+ ratio in Persian clover and wheat under greenhouse conditions. Results indicated that all the growth indices of clover and wheat decreased significantly (P<0.001) in response to salinity. Results also showed that salinity had a significant effect on nitrogen percentage in clover shoot (P<0.01), wheat shoot (P<0.001) and clover and wheat root (P<0.01). Salinity also induced significant increases (P<0.001) in sodium concentration and Na+/ K+ ratios in clover and wheat shoot. However, phosphorus concentrations in both plants were significantly (P<0.01) reduced by soil salinization. The results of the current study illustrated that wheat is capable of controlling the accumulation of sodium in its tissues, and can therefore decrease the sodium to potassium ratio when compared with Persian clover. Furthermore, the amount of decreases in phosphorus concentrations in wheat shoot in response to salinity was less than that in Persian clover. As a result, wheat is more tolerant to salinity than clover is.