Morphological and physiological plasticity of tomato in response to Azolla fern, a novel organic fertilizer of environmentally friendliness

Tomatoes are highly valued vegetable crops due to their excellent nutritional content. However, production remained low due to an incorrect combination of organic and inorganic soil nutrition. A pot experiment was conducted under shaded conditions with Azolla and inorganic nitrogen fertilization to determine the morphological and physiological plasticity of tomatoes. The study used a factorial combination of four levels of Azolla (0, 25, 50, and 75 g per pot) and four levels of nitrogen (0, 0.23, 0.46, and 0.69 g per pot) in a complete randomized design with three replications. We collected data on chlorophyll content (Chl a, Chl b, TChl), photosynthetic rate, water use efficiency, transpiration rate, stomata number, branch number (primary and secondary), plant height, leaf area, stomata conductance, relative water content, and number of leaves. Analysis of variance was employed to analyze the data, and the means were separated using the least significant differences test at a 5 % significance level. The results showed that primary and secondary branches, stomata number, transpiration rate, and water use efficiency were highly plastic due to the higher nitrogen levels and Azolla alone. The interaction effect of Azolla and nitrogen had a significant influence on chlorophyll content, photosynthesis rate, stomatal conductance, relative water content, number of leaves, plant height, and leaf area. It can be concluded that a balanced combination of organic and inorganic fertilizers remains essential for optimal tomato growth and physiology, emphasizing that the exclusive use of organic farming methods may not be the ideal solution.