Accelerating the growth of araucaria heterophylla seedlings through different gibberellic acid concentrations and nitrogen

A study was conducted to see whether the growth of Araucaria heterophylla seedlings could be hastened with the use of different gibberellic acid concentrations and nitrogen levels. The gibberellic acid (GA) concentrations used were 0ppm (control), 100 ppm, 200 ppm and 300 ppm, while nitrogen (N) levels were 0g N pot-1 (control), 1.0g N pot-1 and 2.0g N pot-1. The effect both the GA and N was substantial for all the growth parameters studied. Maximum plant height (42.4 cm), stem thickness (1.43 cm), lateral branch length (22.7 cm), internode length (8.6 cm), root length (30.9 cm), root thickness (1.18 cm), number of roots (15.3) and plant survival (97.8%) were observed in plants treated with 300 ppm GA, while minimum values for all the mentioned parameters were recorded in control. In case of nitrogen dose, maximum plant height (36.1 cm), stem thickness (1.05 cm), lateral branch length (19.4 cm), internode length (6.2 cm), root length (25.5 cm), root thickness (0.89 cm), number of roots (11.8) and plant survival (98.3%) were observed for plants supplied with 2.0g N per plant, while the minimum for all the above parameters were found in control. The interaction between different gibberellic acid concentrations and nitrogen levels was non significant in case of all the parameters studied