Salinity affects phosphorus uptake and partitioning in zucchini

Zucchini plants (Cucurbita pepo L. cv. Moschata) were grown in artificial s oil in 1-m(3) containers under greenhouse conditions in order to determine how to improve the performance of this crop in an salinity-affected agricul tural area where there can be an enormous economic return with correction. Eight weeks after planting, four salinity treatments were initiated by the addition of 0, 20, 40, or 80 mM sodium chloride (NaCl) to the irrigation wa ter. The leaves and fruits were collected and both total phosphorus (P) and inorganic P concentrations were measured. As salinity increased, total and inorganic P concentration in the leaf increased significantly. With the sa linity increase, total and inorganic P concentration in the fruit was not a ffected. Total P content decreased in the skin and then returned to levels close to the control. In the fleshy part as well as in the whole fruit, how ever, increased salinity increased total P accumulation. Inorganic P conten t in the pulp increased significantly, while in skin and whole fruit, inorg anic P content was not affected by the NaCl treatment. In our study, these P forms in the fruit showed that increased salinity augmented P accumulatio n, especially in the fleshy part where the accumulation of both P forms was not only more pronounced, but was also more directly related to increases in soil salinity. Thus, it is necessary to know what responses occur under such salinity conditions in order to improve the fertilizer management, and therefore crop performance, when dealing with this high ionic contaminatio n.