Effect of Growth Regulators on Micropropagation of Japanese Orange

Abstract

  The study was conducted in the Plant Tissue Culture Laboratory of the Department of Horticulture and Landscape gardening, College of Agriculture, Al-Qasim Green University, during the period from November 2022 to June 2023 as a factorial experiment using a completely randomized design (CRD) with two factors and ten replicates, the first factor being Putrescine (PUT) at four concentrations (0 , 2.5, 5 and 7.5 mg L^-1) and the second factor (CPPU) at three concentrations (0, 4 and 8 mg L^-1) added to the nutrient medium to determine their effect on the growth of multiplying kumquat (Japanese orange) plants in vitro. The results can be summarized as follows:

1- The results showed that there were significant differences between the concentrations of Putrescine (PUT) added to the nutrient medium in most of the vegetative and chemical growth traits at the concentration (7.5 mg L^-1), which was significantly excelled on the other concentrations as it recorded the highest average in branch length, number of leaves, and fresh weight. And the survival of the crops and the content of the shoots of chlorophyll and carotenoids, and the content of the shoots of total soluble sugars, nitrogen, phosphorus, potassium, auxin, and cytokinins (2.0011 mg 100 g^-1, 1.9267 mg 100 g^-1, 10.0956 mg g^-1, 13.5811 µg kg. ^-1, 24.2344 µg kg^-1) respectively, compared to the lowest results with the control treatment (0(While the concentration (5 mg L^-1) showed a significantly excelled on the other concentrations, as it recorded the highest rates in gibberellin, reaching (31.820 µg kg^-1), respectively, compared to the control treatment (0(.

2- The results showed that there were significant differences between the concentrations of CPPU added to the nutrient medium in most of the vegetative growth traits and chemical traits, especially at the concentration (0.8 mg L^-1), which was significantly excelled on the other concentrations as it recorded the highest rates in the shoots’ content of chlorophyll and carotenoids. The content of the shoots of total soluble sugars, auxin, and cytokinins reached (2.1383 mg.100g^-1, 1.9908 mg.100g^-1, 10.1792 mg.L^-1, 13.7992 µg kg^-1, 24.4975 µg kg^-1), respectively compared to By transaction (0). Adding a concentration (0.4 mg L-1) showed significantly excelled on the other concentrations, as the highest rate was recorded in gibberellin, reaching (32.249 µg kg^-1) compared to the control treatment (0(The bi- interaction between the two experimental factors, (PUT) and CPPU, had a similar significant effect on most of the studied traits, especially with the interaction treatments. There was a significant difference for the interaction (PUTx0.8CPPU7.5) in its chlorophyll content, the carotene content of the shoots, and the shoots’ content of Sugars, the auxin content of the shoots, and the shoots’ content of cytokinins were recorded (2.5133 mg 100 g^-1, 2.3367 mg 100 g^-1, 10.5700 mg L^-1, 14.3633 µg kg-1, 25.3733 µg kg^-1) respectively compared with the interaction ( PUT 0 x CPPU 0 (