Abstract:

【Objective】To clarify the influence of boron (B) treatments on utilization ability of B in Newhall navel orange(Citrus sinensis Osbeck ‘Newhall’)grafted on citrange [C. sinensis (L.) Osb.× Poncirus trifoliata (L.) Raf.] or trifoliate orange [Poncirus trifoliata(L.)Raf.] at cellular level.【Method】Nutrient solution culture method was used in this study. The difference of leaf B forms between the two rootstocks was analyzed according to the concentration of B forms and their relative relationship.【Result】The results showed that the free B concentration of citrange was relatively lower and the sime-bound B concentration was relatively higher in the treatments of B deficiency (B0, B 0 mg?L-1), normal B (B05, B 0.5 mg?L-1) and high B (B50, B 5.0 mg?L-1), on the contrary, in trifoliate orange. R value of citrange was 2.31, 1.23, and 1.06 in the treatments of B0, B05, B50,respectively, which was much higher than that (1.80, 0.57, 0.82) of trifoliate orange in the same treatment. The free B and semi-bound B concentrations of citrange (16.39,17.38 mg?kg-1) were more higher than that of trifoliate orange (8.60 and 7.02 mg?kg-1) in the treatment of B50. Under the conditions of normal or high B, the bound B concentration of citrange was 7.34 and 7.43 mg?kg-1, respectively, there was no significant difference, while the bound B concentration of trifoliate orange was the highest (9.20 mg?kg-1) under the condition of high boron.【Conclusion】B transmembrane transport was easier in citrange-grafted plants compared to that in trifoliate orange, so B utilization ability of Newhall navel orange grafted on citrange was higher. Furthermore, B could fully bind the cell wall in citrange-grafted plants at relatively low B supply.

Key words: citrange, trifoliate orange, Newhall navel orange, boron forms, utilization ability