Abstract

Biological metabolites released by plants have regulatory effects on seed germination, growth and some other physiological functions of plants found at rhizospere of such plants. Hence, this study investigated inhibitory influence of Azadirachta indica. Juss.,Senna siameaLam and Mangifera indica L. leaf cold extracts on Zea mays. Phytochemical contents of leaves of the three plants were determined. Five viable Z. mays seeds were planted in thirty perforated buckets filled with loamy soil and arranged using completely randomized design with five replicates. Z. mays seedlings in each pot were treated with 20 ML, 40 ML, 60 ML, 80 ML and 100 ML A. indica, S. siamea, and M. indica leaf cold extracts. Water served as control. Growth parameters of Z. mays were measured at 4, 6, 8 and 10 weeks after planting. Also nutritional contents of grains of the Z. mays were evaluated. Data were analyzed using Statistical Analysis System (SAS, 2013). Means were calculated using Analysis of Variance and separated using Duncan’s Multiple Range Test at p < 0.05. Results revealed that cyanogenic glycolside (3.69 gmg/kg) and flanonoids (14.27 mg/kg) were significantly higher (p < 0.05) in A. Indica leaves, phenol (8.13 mg/kg) in M. indica while saponins (3.44 mg/kg) were observed in S. siamea leaves. The growth parameters showed significant decrease with inclusion of the extracts. Highest number of leaf (8.51), root length (9.97 cm) and plant height (115.13 cm) were recorded in Z. mays controlled. Highest vitamin A (1.31 mg/kg) was recorded in Z, mays treated with 20 m ML A. indica leaf cold extract, Vitamin B1 (5.257 mg/kg) in Z. mays treated with 20 ML. siamea leaf cold extract. Also, Vitamin B2 (1.473 mg/kg) and Vitamin C (5.683 mg/kg) were significantly higher in control. Sodium (164.60 mg/kg), potassium (50.79 mg/kg), calcium (374.64 mg/kg), iron (325.87 mg/kg), zinc (3.81 mg/kg) and magnesium (2.92 mg/kg) were significantly higher in controlled Z .mays. Crude protein (4.83 mg/kg) and moisture (3.81 mg/kg), crude fibre (14.54 mg/kg) and carbohydrate (9.27 mg/kg) and ash (10.54 mg/kg) were relatively higher in control compared with leaf cold extracts of A. indica, S. siamea and M. Indica. In conclusion, A. indica, S. siamea and M. indica leaves contained appreciable amount of allelopathic contents capable of inhibiting growth and reduced nutritional contents of grains Z. mays studied. Also, 100ML leaf cold extracts of the three plants produced highest inhibitory effects on the germination and growth of Z. mays

Keywords: Inhibition, Nutritional contents, Forest plants, Germination, Phytochemical contents, Azadirachta indicaa, and Senna siamea