Wheat growth as affected by nitrogen type, pH and salinity. II. photosynthesis and transpiration

Abstract

The interactions among the form of N (ammonium or nitrate) supplied, NaCl concentration and pH of the nutrient media were studied with wheat (Triticum aestivum L. cv. Barkai) plants growing hydroponically. The effects of these parameters on mineral content and plant growth were reported in our previous paper (1). Neither photosynthetic or transpiration rates were affected by salinity in the range of NaCl concentrations used. Stomatal conductance, however, decreased with increasing NaCl concentrations in the medium. Chlorophyll content of the leaves of ammonium‐fed plants decreased with increasing pH. This response is more moderate in nitrate‐grown plants. Consequently, a difference is observed between photosynthesis rates expressed on the basis of leaf area or of chlorophyll content. The relative content of K and Na, and its possible effect on photosynthesis and transpiration are discussed.

Notes

Pesent address: C.I.D.A. Las Torres (DGIEA), Apartado Oficial, E‐41200 Alcala del Rio, Sevilla, Spain.