**14. Allelochemical effects of** *P. juliflora*

Analysis of chemical extracts showed that allopathic compounds are phenolic or antioxidant capability in nature. Sluggish in breakdown and heavy buildup of leaf litter below *P. juliflora* may result in the increase of toxic substances in the soil layers, hindering the growth of other plant species [102, 103]. For instance, report by Kaur et al. [104] shows that there was a noticeable accrual of litter beneath the thicket of *P. juliflora* compared with *P. juliflora cineraria* in the hyper-arid habitats. Studies by El-Keblawy and Al-Rawai [103] reveal that lower species richness, evenness, and frequency of native species in plots under shades of *P. juliflora*. However, it had no allopathic effect on its seedlings growing below its canopies. But, Muturi et al. [70] show *P. juliflora* canopy hindered regeneration of other native species. Findings by Samuel et al. [105] depict that leaves of *P. juliflora* have greater inhibitory effects than its roots and barks. Muturi et al. [70] also indicated that bark contained the least inhibitory composites. But, shoot and root growth introverted by leaf and root extracts at higher application and concentrations. *P. juliflora* had both positive and negative interactions with plant communities in naturalized areas [2, 13, 23, 24, 50, 105]. Several studies carried out in many parts of the world show that problems of *P. juliflora* were outweighing positive ones ecologically, socioeconomically, and in all health aspects. However, some studies indicate that above-ground biomass, frequency, and cover of understory plant species were significantly higher under non-invaded grazing lands than under the shades of *P. juliflora* [71].
