Effect of soil nutrient concentrations on the quantity of tannin and flavonoid deposited in Gmelina arborea fruit located in different locations

Abstract

This research was geared towards the study on the effect of soil nutrient concentrations on the quantity of tannin and flavonoid deposited in Gmelina arborea fruit located in Onigambari forest reserve within latitude 7o 23’ N and longitude 3o 33’ E and environs of Ijebu-Ife  which lies within latitude 6o 47’ N and longitude 4o 2’ E. Soil samples and 50 Gmelina arborea fresh fruits were collected from each  location, the pulps and seeds were air dried for 15 days at room temperature to reduce its moisture content, and then grinded into  powdery forms before being subjected to Trease and Evans technique to screen for the Tannin and Flavonoid quantity. The results were subjected to both t-test and analysis of variance using Statistical Analysis System (SAS) 9.0 version. Means were separated using Duncan’s Multiple Range Test (DMRT) at 5% probability. The seed (0.54 g) and pulp (0.45 g) harvested from Ijebu-Ife have higher concentration of tannin compared with Onigambari seed (0.06 g) and pulp (0.12 g), also flavonoid concentration of seed (0.11 g) and pulp (0.24 g) of Onigambari is lower than that of Ijebu Ife seed (0.35 g) and pulp (0.40 g). The study shows that variations in soil nutrient concentration levels, soil pH and soil textural class of different locations will influence the quantity of Tannin and Flavonoid of Gmelina arborea fruit. The study further revealed that soil nutrient at concentrations levels that are high and tending towards toxicity will reduce deposits of plant phytochemicals which is a quality parameter in plant nutrition.