*3.1. Aboveground Plant Biomass and Partitioning*

Whole plant biomass was affected by the main factors and their interaction (Table 1). In As− treatment this variable was higher in "Proteo" grafted onto "Strong Tosa" and "RS841" (309 g plant<sup>−</sup>1, on average), whereas in response to As+ treatment it significantly decreased in "Proteo" grafted onto "Dinero" (from 251.7 to 198.7 g plant<sup>−</sup>1, <sup>−</sup>21%) and "Strong Tosa" (from 317.0 to 239.3 g plant<sup>−</sup>1, <sup>−</sup>25%) (Table 1). Among the plant components, stem biomass resulted 30 and 24 g plant−<sup>1</sup> in As<sup>−</sup> and As+, respectively (−20%) (Table 1). Passing from As− to As+, there was a general decrease of the leaf biomass too. This response was more marked in "Proteo" grafted onto "Dinero" (from 66.4 to 42.0 g plant−1, <sup>−</sup>37%), 'Magnus' (from 56.7 to 44.5 g plant−1, <sup>−</sup>22%), 'RS841' (from 66.3 to 52.1 g plant−1, <sup>−</sup>21%), and "Strong Tosa" (from 58.0 to 44.4 g plant<sup>−</sup>1, <sup>−</sup>23%), whereas no significant difference was recorded when "Proteo" was self-grafted or grafted onto "Shintoza" (Table 1). When grown in the As+, fruit biomass showed a significant variation in "Proteo" grafted onto 'Magnus' and "Strong Tosa", where it varied by +33% (from 119.9 to 159.1 g plant−1) and <sup>−</sup>26% (from 231.1 to 170.9 g plant−1), respectively (Table 1).

**Table 1.** Aboveground biomass production and partitioning (g dry weight plant<sup>−</sup>1) in melon plant as affected by As concentration in the nutrient solution and rootstock. Different letters within main factors indicate significance at Fisher's protected least significant difference (LSD) test (*p* = 0.05). NS—not significant.

