Evaluation of the allelopathic effect of an aqueous extract of the leavesoffour plant speceices on the germination of seeds and growth of some economic plants seedlings

Abstract

The research included a study of the effect of the biological activities of the aqueous extract of the leaves of four plant species (pine, cypress, camphor, walnut) on the germination of seeds of four economic plant species (wheat, barley, corn, tomato) and the growth of their roots and seedlings. 1 kg of adult leaves of each species were collected and after drying in the laboratory away from light, they were ground and the extracts were prepared at concentrations of 50 and 100 g/l of each type and mixtures of different concentrations from the four plant species; 10 seeds were planted in each pot at a rate of 3 replications for each condition, and the extract was irrigated with the extract twice a week for six weeks. The readings were taken at each watering. The results showed that the beginning of germination in some treatments was identical to the control in wheat and barley, while others accelerated the start of germination and actually started a week before the control in wheat, corn and barley, and among the treatments delayed the beginning of germination and extended its duration, the delay in the start of germination reached 10 days for wheat, 5 -25 days for maize, 6-7 days for barley and 4-15 days for tomatoes. There are some treatments that completely inhibited germination in all species, and all treatments reduced the number of germinated seeds, the speed of germination and its percentage, whichWhich ranged between 40-66.7%, 13-70%, 13-66.7%, 86.7-93.3%, in wheat, corn, barley and tomatoes, respectively. As for the period of reaching its peak germination, it varied greatly according to the treatments within the same species as well as between species. Some treatments increased the average length of seedlings compared to the control, and others decreased their length, and the matter is different from one treatment to another and from one type to another; As for the longest roots, in only three treatments, the length of the roots increased in wheat and barley, while the rest of the treatments were inhibited by different degrees of root growth, and the percentage of decrease in the length of the roots compared to the control ranged: between 2-69.5% in wheat, 7-56% in maize, 7.5-62% in Barley, 41-55% in tomatoes, the extracts that stimulated the growth of roots and seedlings were in different concentrations, often weak.

The results had confirmed that the effect of the extracts differed significantly according to the powder, its concentration, the composition of the mixture, its concentration and the type of target plant, and this was confirmed by the statistical study