MORPHOLOGICAL AND ANATOMICAL ROOT RESPONSES OF SALT-STRESSED WHEAT PLANTS GROWN UNDER DIFFERENT POLYPHOSPHATE FERTILIZERS FORMS AND PHOSPHORUS DOSES

Understanding the role of nutrients in the alleviation of salt stress effects and the unrevealed significance of root system architecture for plant adaptation is one of the major research axes in the actual context of agriculture. Indeed, root anatomy is considered also a valuable parameter to be considered to understand how the roots system counter soil salinity effects on plant growth. Although the P-fertilizer use efficiency of plants under salt stress differs depending on plant species and the severity of salinity in the rhizosphere, optimising phosphorus (P) nutrition seems to bring positive results. This study was planned to investigate the combined effect of salinity and P-availability on root morphology and anatomy as well as nutrient uptake of wheat plants. A pot experiment was performed in open-field conditions using a Moroccan variety of wheat. A special emphasis focused on how polyphosphate fertilizers forms and phosphorus doses alter root morphology and its anatomy under salt stress. Three soluble fertilizers were used: two Orthophosphates (Ortho-A & Ortho-B) and one polyphosphate (Poly-B) were applied at four P levels (0, 30, 45 and 60 ppm of P). The plant growth was analysed on some root parameters (root morphology, root mass density root anatomical analysis, and root and soil nutrient analysis. The results showed that salt stress induced, at both, anatomical and morphological levels, a series of modifications in roots such as a decrease in cell expansion, perturbed cell division and root elongation. Compared to control plants, P-fertilizers significantly increased root length, root surface, root diameters, and other root morphological parameters. The increased root anatomical parameters (root and stele diameter, cortex thickness, central metaxylem vessels area, central metaxylem, and Protoxylem number observed under P-treatments, could determine the root performance and efficiency to acquire water and nutrients and their transport to the aboveground organs of wheat plants under salinity.