Impact of Gibberellin Treatment on the Growth and Nutrient Condition of Vallisneria natans (Lour.) Hara in Substrate with Various Fertility

摘要

Vallisneria natans (Lour.) Hara is a typical macrophyte engineering plant frequently applied in water restoration projects. This study treated V. natans with Gibberellin (GA), and measured its growth features and nutrient element allocation as it grew in high, medium, and low fertility substrates. With GA treatment, V. natans leaf length, leaf bio-mass, and total biomass increased significantly (p＜0.05), while total concentrations of nitrogen, phosphorus, and soluble sugar in the roots and leaves increased in all substrates, except root total phosphorus values which notably (p＜0.05) decreased in low-phosphorus substrate. Moreover, GA treatment significantly (p ＜ 0.05) decreased the number of ramets while increasing their total biomass, which indicates that this plant hormone substantially affected V. natans asexual reproduction. Substrate available phosphorous (AP) concentrations positively impacted plant growth in a significant manner (p＜0.05), and substrate NO_3~- concentrations decreased significantly (p＜0.05) as the plant grew. V. natans growth increased substrate Eh while significantly (p＜0.05) decreasing substrate NO_3~- concentrations. It can be concluded that GA might be applied effectively to waterbody restoration projects by improving the growth status of the plant, and that substrate fertility is critical to enhancing both the growth and nutrient conditions of any plant treated with GA.