Ecological studies on the macrohydrophytes in Egypt II. Ludwigia stolonifera (Guill. and Perr.) P.H. Raven.

The present study contributes information about the environmental factors controlling the distribution, variation in standing crop phytomass and chemical compositional change of Ludwigia stolonifera. Also, treatment with cattle manure, as source of organic waste, was made to evaluate the response of the plant to the environmental pollution. The sandy textured bottom sediments of Ludwigia habitat at Damira irrigating canal had higher percentages of organic carbon and total soluble salts in spring than in the other seasons while the overlying water was characterized by low total soluble salts. The phytomass and assimilating surface area were increased in spring and summer months and appeared to decline in winter. The phytochemical constituents were highly concentrated during August. As common in hydrophyte, the plant organs of L. stolonifera are characterized by abundance of aerenchyma, absence of cork cells and reduction of vascular tissues. Addition of cattle manure to the aquatic habitat of Ludwigia plant resulted in an increase of organic carbon, salinity, chloronity and in a decrease of pH value of hydrosoil and water. Heavy metals accumulation showed considerable increase due to application of cattle manure and this appeared to be a reflection to the increased concentrations of these metals in the environment.