ABSTRACT

Azolla is a free-floating hydrophyte fern grown in temperate and tropical regions. The specialized dorsal leaves of the fern possess cavity that harbors cyanobacteria capable of fixing atmospheric nitrogen (N) through biological processes. It is either incorporated into the soil before rice transplantation or grown as an inter-crop with rice crop. Its intercropping also improves efficiency of applied N fertilizer. The recovery of heavy metals from aqueous environment is another key feature of Azolla as bioremediator of flooded soils. In general, Azolla efficiently absorbs heavy metals from aqueous medium containing lower concentrations (<20 mg L^-1); however, filiculoides species were found to absorb higher metal content (0.40% Ni) from Ni rich solution (500 mg L^-1). Biosorption involves biological processes for recovery of metals and hence is considered as eco-friendly and cost-effective procedure to remove contaminants from wastewater. The utilization of Azolla has remained limited in agriculture due to its sensitivity to high temperatures, light intensity, composition of growth medium and difficult production technology. The use of Azolla is beneficial due to its reliance on natural resources and utility for flooded rice production as well as phytoremediation potential in agro-environment.

摘要

Azolla是一种生长在温带和热带地区的自由漂浮的水生蕨类植物。蕨类植物特殊的背叶有一个腔，里面有蓝藻，能够通过生物过程固定大气中的氮 (N)。它要么在水稻移植前掺入土壤中，要么作为与水稻作物的间作种植。它的间作也提高了施氮肥的效率。从水环境中回收重金属是Azolla作为淹水土壤生物修复剂的另一个关键特征。一般来说，Azolla 能有效地从含有较低浓度 (<20 mg L ^-1 ) 的水性介质中吸收重金属；然而，丝状发现物种从富 Ni 溶液 (500 mg L ^-1 ) 中吸收更高的金属含量 (0.40% Ni )。生物吸附涉及回收金属的生物过程，因此被认为是从废水中去除污染物的环保且具有成本效益的程序。的利用率满江红一直限于在农业，由于其在高温下，光强，生长培养基和困难的生产工艺的组合物的敏感性。使用Azolla是有益的，因为它依赖自然资源和水淹水稻生产的效用以及在农业环境中的植物修复潜力。