In this study, the Aquatic and semi Aquatic of Dez River were studied during 2010-2011. In this area 68 species belonging to 43 genera and 28 families were identified. Phragmites australis and Juncus effusus were the most dominant marginal species that constituted vast populations in the waters of this area. Polygonum cespitosum was the most frequent emersed species in the area. Potamogeton spp. the most dominant submersed species of this region. According to results, families of Juncaceae, Potamogetonaceae, Polygonaceae, Cyperaceae and Poaceae, were the largest families, respectively. The most of plants chorotype with 42% is related to Irano –Turanian. Studying of plants life forms by Raunkiaar method showed that hydrophyte and Trophyte with 17 percent of species are the most frequent life forms.

In this study, the Aquatic and semi Aquatic plants of Khuzestan province were studied during 2009-2010. In the studied area 50 species belonging to 32 genera and 24 families were identified.Ceratophyllum demersum, Najas marina and Potamogeton crispuswere the most dominant submerged species that constituted vast populations in the waters of this area.Typha laxmanni, Polygonum cespitosum, Phragmites australisand Cyperus pygmaeus made huge populations in the margins of the area. Potamogetonaceae, Polygonaceae and Juncaceae were the largest families, respectively. In Dezful, genera of Potamogeton were the largest genus of sub-merged plants in this area. In Shush – Ahvaz, genera ofPolygonum hydropiperwas the largest genus of marginal plants in this area.In Ahvaz, genera ofPhragmites australis were the largest genus of emersed plants in this area. In Shadegan wetland, genera of Phragmites australis, Cyperus pygmaeus, Scripus lariaceae and Juncuswere the largest genus in this area. Chorologically, 24% of species were Iran-Turanin. The largest of biotic spectrum of this area consisted of Hydrophyte (13%).

Due to the lack of fresh water, the purification of polluted water is of utmost importance and places a significant financial burden on countries. The effect of Myriophyllum spicatum and Lemna gibba on nitrate absorption in an area of the Tigris River has been investigated in the light of the low cost and ease of application of Aquatic plants in purifying water pollution. Aquarium experiments were designed with three treatments, three replicates, and a closed flow. In the aquarium, the biological requirements for the growth of the studied plants were met. The residence time was determined to be 36 days, and nitrate changes were recorded every three days, 12 times. Except for periods 3 and 4, there were significant differences in the rate of nitrate absorption between the studied plants in all treatments (P < 0.05). At the end of the 12th period, M. spicatum and L. gibba had contaminant removal efficiency of 83.31% and 86.27%, respectively. L. gibba ability to utilize nitrate as a nutrient was demonstrated by its significantly increased dry weight at the end of the experiment (P < 0.05). In the current study, the significant difference between the average levels of nitrate in the samples and the control sample indicates the presence of a factor other than bacterial decomposition, namely the presence of plants. According to the findings, these macrophytes are viable for reducing nitrate and organic matter loads in polluted waters. Controlling these macrophytes, so that the nutrients in their tissues do not return to the environment during decomposition is necessary to improve water quality and maintain the achieved quality.

Disposal of waste products and residuals into the natural water bodies can have fatal consequences for Aquatic ecosystems, posing severe threats to natural habitats and human health. Natural treatment systems are the most suitable treatment technologies for various types of wastewaters, which has attracted much attention in recent years. Phytoremediation is a plant-based technique used to eliminate or recover surplus nutrients in contaminated environments. The use of Aquatic plants in wastewater phytoremediation is very efficient due to they have a very significant ability for assimilating and degrading contaminants (e. g., nitrates, phosphates, and heavy metals). Phytoremediation is a relatively new technology that is considered as an operational, efficient, new, and environmentally friendly technology that is still in the early stages of development and optimization. Its application on a large scale is still limited. It should also be noted that a clear vision of this innovation should be taken into account and, accurate data should be made available to the public as it will enhance its efficiency as a manageable solution in the worldwide. Additionally, phytoremediation has been evaluated as a separate low-tech and environmentally friendly green option compared to the existing technologies. The present study attempts to review the recently published literature to explain phytoremediation technology and its advantages in purifying water and wastewater.

The objective of this study was to determine the biomass of dominant Aquatic plants at Hashilan wetland in Kermanshah Province, western Iran. Systematic sampling was used by placing 454 square plots (1×1m) on 15 transects laid out on the area. Canopy cover was estimated in each plot and converted to biomass. Calculations for all plots (454) showed that two species, Carexdistans and Caladium mariscus, with 0.402 and 0.005kg per\square meter, were the most and least notable species, respectively. The average plant biomass increased and dominant species changed when only plots containing the species were included in calculations. In this case, 1Yphadomingensiswith 1.912 (S.E=0125) and Juncus articulates with 0.614 (S.E=0.086) kg per square meter had the highest and lowest biomass respectively.

In this study, the Aquatic and semi Aquatic plants in channels of agriculture and aquaculture of Khuzestan province were identified during 2008-2009. In the area, 55 species belonging to 36 genera and 26 families were identified. In total channels of agriculture and aquaculture of Khuzestan Province Ceratophyllum demersum and Najas minor (submerged species) were observed. In North Khuzestan, Dezful-Shush, Ceratophyllum and Potamogeton were the largest genus. Between Shush–Ahvaz Polygonum hydropiper and Phragmites australis were the highest diversity in this area. The South of Khuzestan, Phragmites australis, Cyperus pygmaeus and Typha australis, three emerged Aquatic plans, were the most dominant species though related to the international wetland of Shadegan. In East-South Khuzestan (Mahshahr Port-Hendijan), Phragmites australis and Lemna gibba were the largest genus. Chorologically, 29% of species were Iran-Turanin. The largest of biotic spectrum of this area was consisted of Hydrophyte (24%).

In this study, the Aquatic and semi-Aquatic plants of Parishan wetland were studied during 2008 to 2009. In this area 54 species belonging to 48 genera and 28 families were identified. Najas marina and Ceratophyllum demersum were the most dominant submerged species that constituted vast populations in the waters of this area. Phragmites australis, Typha laxmanni and Scirpus wardianus were also the most frequent helophytic species that form vast and attractive populations in the margins of the area. The other dominant t helophytic and semi-Aquatic species of the coasts of this wetland were Lycopus europaeus, Carex pachystylis, Cyperus pygmaeus, Juncus maritimus‚ J. rigidus and Mentha longifoli. Asteraceae (with 6 species), Papilionaceae (with 6 species), Scrophulariaceae (with 4 species) and Poaceae (with 4 species) were the largest families respectively. Juncus (with 3 species) was also the largest genus in this area. Chorologically, 50% of species were Iran-Turanin, 12/96% were Iran-Turanin and Sahara-Syndian, 7/40% were Iran–Turanin and Mediterranean and 14/81% were Cosmopolites. The biotic spectrum of this area consisted of Therophytes, Cryptophytes, Hemicryptophytes, Chamaephytes and Phanerophytes (59/25%, 33/33%, 3/70%, 1/85% and 1/85% respectively).

In this research the composition and diversity of hydrophytes of irrigation canals in Ahvaz and suburbs were surveyed in a one-year period. Biological type and species of the Aquatic and semi Aquatic plants were recorded.23 species of 15 families in 22genera had been recognized from the mentioned areas. After sampling, they were cleaned and transported to the Lab and the identification procedure was carried out by the botanical keys. Finally the medicinal Aquatic plants had been identified according to the Aquatic plants encyclopedia and the other references. Poaceae, Hydrocharitaceae, Ranunculaceae, Scrophulariaceae, Cyperaceae, Typhaceae, Ceratophyllaceae, Amaranthaceae and Asteraceae were the families which these medicinal plants belonged to.