Eco-genetic study on water hyacinth, Eichhornia crassipes (Mart.) Solms, the world's most invasive aquatic plant

Tarek Abd El-Ghafar El-Shahawy

Abstract


Water hyacinth is a complicated, multifaceted problem disturbs all interested and concerned entities in aquatic weed management. Water hyacinth, which is the world's most aggressive and destructive aquatic freshwater species, extends over vast areas of the world creating serious ecological and cultural problems. So far, water quality does not represent a dilemma against water hyacinth growth. The objective of the current work is to study the potential genetic differences between water hyacinth populations growing under different aquatic ecosystems in Egypt. Water and plant samples were collected from three different sites namely irrigation water, drainage water and sewage water at Al-Buhayrah Governorate, Damanhour District. The physicochemical properties and heavy metal content of selected waters were estimated. Heavy metals in roots and shoots coupled with the patterns of genetic structure within each type were also evaluated. Poor quality of sewage water was prominent with relatively small concentrations of trace elements. Plants from the different regions absorbed and accumulated heavy metals to varying degrees. Relatively high concentrations were estimated in sewage water plants if compared with the plants of the other sources. Root and shoot tissues of the same plant also exhibited various degrees of heavy metal accumulation. Overall, roots showed a high affinity for the different elements, an exception is Zn. The genetic variation between plants was expected. DNA analysis of the plants using ISSR–PCR technique showed different genetic regions with an increasing number of molecular markers in sewage water plants. This fact surely indicates that water hyacinth has an innate ability to tolerate harsh growth conditions with high genetic potential which enables it to live sustainably.


Keywords


Aquatic weeds; Aquatic ecosystems; genetic variation; heavy metals; invasive plants; water quality

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