Abstract
a Water Studies Center, King Faisal Univ., Al-Hassa, Saudi Arabia
aprince{at}kfu.edu.sa
Basic information is needed to estimate P status of Salicornia bigelovii Torr. with increased precision if progress is to be made in adapting this halophyte as a conventional oilseed crop for direct seawater irrigation in coastal areas of arid regions. The P nutrition of salicornia was studied by using the nutrient solution technique in the greenhouse. The culture solutions were seawater, enriched to 1/2-strength modified Hoagland's solution [pH = 6.2 ± 0.2; electrical conductivity (EC) = 54 ± 2 dSm -1 ], and P treatments ranging from 0 to adequate amounts of P for full growth. All stages of deficiency symptoms were observed at harvest, ranging from stunted growth, necroses, purplish coloration, chlorosis, and dark bluish-green coloration to no symptoms. Dry and fresh weight of the tops were plotted against soluble P and total P values to give plant nutrient calibration curves that were fitted to the composite growth model by the least squares procedure. On the basis of the curve sharpness coefficient and range parameter output values and ease of sampling, semiwoody internodes, matured internodes and soluble P concentration were selected from the five plant parts sampled and the two forms of P determined as the best combination to diagnose the P status of Salicornia. About 480 mg kg -1 of soluble P in semiwoody internode tissue was tentatively set as the critical concentration for growth of the salicornia. The corresponding value for total P was set at 780 mg kg -1 .
Abbreviations: EC, electrical conductivity • SRS, sum of residual squares • WOM, Ware–Ohki–Moon model