Ricerche sui portinnesti degli agrumi: influenza sullo stato nutrizionale delle foglie

This paper reports some results concerning the influence of different citrus rootstocks on leaf nutritional status of the scion varieties. Two rootstocks (sour orange and «Troyer» citrange) have been compared for « Hamlin » and «Frost Navel» sweet oranges, and «Frost Eureka» lemon. Five rootstocks (sour orange, «Troyer» citrange, «Rubidoux») trifoliate orange, «Orlando» tangelo, and «Palestine» sweet lime) were also compared for «Marsh seedless» grapefruit. The results showed that rootstocks appear to exert a strong influence on the leaf mineral levels of the grafted varieties. Particularly it has been observed that sour orange decreases N, P, K and Mg uptake, while increases leaf Ca content. « Troyer» citrange induces higher Mg and Cu levels, and reduces leaf Ca content. « Rubidoux » trifoliate orange, on the other hand, exerts a positive influence on N and Mg uptake, and a negative influence on Ca, Na, Zn, and Cu leaf content. «Orlando» tangelo shows a marked aptitude in increasing N, P, K, Ca and Na leaf levels, while decreases Cu leaf content. Finally, «Palestine» sweet lime induces on the scion leaves higher contents of N, K, Ca, Na, and Mn, and lower Mg and Cu levels.