We used 8-month-old navel orange plants (Citrus sinensis
cv. Newhall) grafted on Carrizo citrange (Citrus sinensis (L.)
Osb. × Poncirus trifoliata (L.) Raf.) rootstock with uniform stem
diameter (6–7 mm), height (18–22 cm) and total fresh weight
(20–25 g). The selected plants all consisted of only one main shoot
of the scion and had 12–15 leaves, which were not fully expanded
at the beginning of the experiment.