*3.7. Phosphorus Accumulation in Plant Fractions*

Phosphorus accumulation in plant fractions was significantly affected by the main factors and their interaction (Table 7). Passing from As− to As+ treatment, Proot increased mostly in self-grafted "Proteo" (from 3527 to 31,390 mg kg−<sup>1</sup> DW, +790%), followed by "Dinero" (from 3566 to 17,059 mg kg−<sup>1</sup> DW, +378%), "Magnus" (from 14,362 to 22,938 mg kg−<sup>1</sup> DW, +60%), and "Shintoza" (from 12,535 to 19,210 mg kg−<sup>1</sup> DW, +53%) (Table 7). Conversely, the As+ treatment significantly reduced Pshoot as compared to the standard nutrient solution, with the highest drop recorded in "Proteo" grafted onto "Dinero" and "Magnus" (from 7001 to 4923 mg kg−<sup>1</sup> DW, on average, <sup>−</sup>30%) (Table 7). Passing from As− to As+, Ppulp significantly increased in "Proteo" grafted onto "Dinero", "Magnus", and 'Strong Tosa' (by 4472, 1334, and 1203 mg kg−<sup>1</sup> DW, respectively, corresponding to +758%, +35%, and +30%), whereas did not show any significant variation in the other graft combinations (Table 7).


**Table 7.** Phosphorus accumulation (mg kg−<sup>1</sup> DW) in different organs of melon plants as affected by As concentration in the nutrient solution and rootstock. Different letters within main factors indicate significance at Fisher's LSD test (*p* = 0.05).
