Chlorophyll-a fluorescence analysis of ipil (Intsia bijuga) leaves under different biofertilizer treatments

Abstract

The photosynthetic activity of various plants can be evaluated through chlorophyll a fluorescence imaging. The photosynthetic activity of ipil (Intsia bijuga) treated with varying combinations of Rhizobium, vesicular arbuscular mycorrhiza (VAM), and chemical fertilizers, namely urea, ammonium phosphate, and nitrogen-phosphorus-potassium (NPK) fertilizer, was investigated. One leaf from each plant was exposed to blue light, after which an image of the red fluorescence from the leaf was captured. The obtained image was used to calculate the ratio of fluorescence decrease (Rfd) value of each plant. The Rfd values of the plant samples were analyzed using two-way analysis of variance. There were no significant differences between the mean Rfd values of the plant treatment groups, except for those treated with 20 g Rhizobium and 0.5 g urea which yielded a significantly greater mean Rfd than that of the control group, with no Rhizobium, VAM, or chemical fertilizer. On the other hand, mean Rfd values for the three plant age groups – 30, 90, and 120 days (1.649, 1.607, and 1.994, respectively) – were proved to be significantly different from each other (for α = 0.05). The interaction between the two factors considered, the plant age and the treatment group, was found out to be insignificant (f_computed = 0.847, f_critical = 1.78, for α = 0.05).