Effect of NaCl, water stress or both on gas exchange and growth of wheat

Responses of wheat (Triticum aestivum L.) to various concentrations of NaCl and levels of drought were followed. With the rise of NaCl or drought, or NaCl and drought together, growth was retarded. The water content of shoots and roots was mostly unchanged. The chlorophyll and carotenoid contents were increased in plants subjected to salinity or drought or both. Only high salinity level induced a considerable decrease in net photosynthetic rate (P-N) and dark respiration rate (R(D)). P-N and R(D) were decreased with the decrease of soil moisture content. The content of Na+ in the shoots and roots of wheat plants increased with increasing salinity or decreasing soil moisture content or both treatments. Considerable variations in the content of K+, Ca2+ or Mg2+ were induced by the NaCl, drought or both treatments.