Effects of paclobutrazol and salt stress on growth and ionic contents in two cultivars of wheat.

The effect ofpaclobutrazol (PBZ) treatment on salinity tolerance of wheat (Triticum aestivum), were investigated for two salt-tolerant and salt-sensitive cultivars. Salinity with PBZ treatment significantly reduced the plant height and length and area of sixth leaf in both cultivars. With increasing salinity, a gradually reduction was observed in roots length, fresh and dry weight of shoot and sixth leaf and relative water content of PBZ-applied plants in both cultivars. The greatest reduction was observed at 225 mM NaCl with 60 or 90 ppm PBZ. Salinity with PBZ treatment increased Na+ content in the sixth leaf and roots of both cultivars and the greatest increase was observed in salt-sensitive cultivar. In PBZ-treated plants, K+, P and N contents increased in line with elevating salinity in both cultivars, except at 90 ppm PBZ in salt-sensitive cultivar. Very similar effects of NaCl and PBZ treatment were observed for both cultivars regardless of their salinity susceptibility. The results suggest that PBZ treatment may be useful to improve the salt tolerance of wheat via reducing the negative effect of salinity on vegetative growth and the Na+ content and increasing the K+, P and N contents.