Phenotypic plasticity of four invasive species in north-eastern section of the Nile Delta coast, Egypt
One of the essential mechanisms through which plants can adapt to prevailing environmental conditions is phenotypic plasticity. To explain the invasive success across the invaded new areas, the phenological pattern and vegetative features of the exotic species are investigated. The four exotic weeds included in this study are Xanthium strumarium L., Bassia indica (Wight) A. J. Scott, Atriplex lindleyi Moq., and Trianthema portulacastrum L.
Results indicated that shoot length was greatest in X. strumarium, followed by B. indica and A. lindleyi but least in T. portuiaeustrum. Fresh weight of the foliage was comparable in X. strumarium and A. lindleyi, being higher in both than in B. indica and T. portulacastrum. Dry wight of the foliage was highest in X. strumarium, followed by A. Lindleyi, but it was least with comparable values of B. indica and T. portulacastrum. Water content of shoots was higher in T. portulacastrum and B. indica, slightly lower in X. strumarium and least in A. lindleyi.
The highest concentrations of P (0.620.02), K (0.060.001), and Mg (24.763.79) were found in site 2 of T. portulacastrum. The highest levels of N (6.070.30), Na (0.200.009), and moisture content (44.320.40) were found in site 3 for B. indica. The components with the lowest concentrations were P (0.100.01), K(0.010.0003), Mg (0.370.01), and Na (0.040.003) in A. Lindleyi at site 4, whereas N (2.171.00) and moisture content (17.215.10) were the lowest in X. strumarium at site 1.Analysis of variance revealed significant (P<0.05) to very highly significant (P<0.001) variation in growth parameter among the studied plant species. Based on the magnitude of the F ratio, the variability was most evident in shoot dry weight, followed by shoot fresh weight and water content but was relatively low in number of leaves, number of branches and water content of shoot
Based on the obtained results, it can be concluded that the four exotic weeds can successfully invade new areas by changing their phenological plasticity. The optimal management and control measures of these exotic weeds will benefit from this.
Keywords: Biological invasion, environmental factors, exotic weeds, growth parameters, phenotypic traits