Allelopathic Effects of Persian silk tree (Albizia julibrissin) on Seedling Biomass Attributes of Tree of Heaven (Ailanthus altissima)

The current study evaluated the allelopathic potential of the Persian silk tree (Albizia julibrissin) leaf residues on seed germination and biomass attributes of the Tree of heaven (Ailanthus altissima) seedlings. An experiment was conducted based on a completely randomized design by eight replications. Experimental treatments consisted of different levels of leaf residues at concentrations of 0%, 2.5%, 5%,and 7.5%.Germination index was used in order to investigate the effect of allelochemicals on seeds germination. In addition, the effect of allelopathic materials on seedling biomass was measured by calculating the parameters of collar diameter, fresh and dry weight of seedlings, root dry weight, number of leaves, seedling weight vigor index and percentages of seedling water content index. The results revealed that seed germination index, seedling dry weight, seedling fresh and dry root weight and seedling weight vigor index significantly decreased at different concentrations of leaf residues compared to control, but the increase in concentration had no significant effect on these attributes. But higher concentrations of leaf residues had stronger inhibitory effects on seedling collar diameter, fresh seedling weight and the number of leaves per seedling. The present study clearly proved the allelopathic effects of the Persian silk tree (Albizia julibrissin) leaf residues on biomass attributes of the Tree of heaven (Ailanthus altissima) seedlings. In addition, the Persian silk tree (Albizia julibrissin) leaf residues can be used to control the irregular growth of Tree of heaven seed as an invasive species, as well as weed management in agroforestry systems which require further studies.