The study aimed to evaluate the effects of different concentrations of putrescine (Put: 0, 2.5, 5, and 7.5 mg L⁻¹) and forchlorfenuron (CPPU: 0, 0.4, and 0.8 mg L⁻¹) on the in vitro growth and multiplication of shoots in Japanese orange (Citrus japonica). Explants cultured on a Murashige and Skoog (MS) medium received supplements of 2 mg L⁻¹ BA (benzyl adenine) and 0.1 mg L⁻¹ NAA (1-naphthaleneacetic acid) for four weeks. Results revealed that increasing Put concentration in the multiplication medium significantly improved stem length, the number of leaves, fresh weight, and plant survival. The highest values were notable at Put (7.5 mg L⁻¹) for stem length (2.127 cm), leaves/explant (8.268), and 0.7944 mg and 85.6% survival, respectively, compared with the control. The latter recorded the lowest values (0.843 cm, 5.911, 0.7333 mg, and 67.8%, respectively). Similarly, increasing the CPPU concentration (0.8 mg⁻¹) revealed the highest values for shoots/explant (CPPU: 4.025), shoot length (2.090 cm), leaves/explant (8.687), fresh weight (0.8975 mg), dry weight (0.2192 mg), and survival (91.7%). The interaction between CPPU (0.8 mg L⁻¹) and Put (7.5 mg L⁻¹) concentrations recorded the topmost average stem length (2.750 cm), leaf number (9.533 leaves/explant), and survival percentage (100.0%).
Kumquat (Citrus japonica), plant tissue culture, putrescine (Put), CPPU, NAA, BA
The interaction between CPPU (0.8 mg L⁻¹) and Put (7.5 mg L⁻¹) concentrations recorded the highest average stem length (2.750 cm), leaf number (9.533 leaves/explant), and survival percentage (100.0%) in the Japanese orange.