Kandali, R.Supriya, Yenkokpam2020-11-032020-11-032019-07https://krishikosh.egranth.ac.in/handle/1/5810154293Because of the enormous diversity in flora & fauna, the north eastern region of India has long been recognized as the biodiversity hotspot. A great diversity has also been observed in aquatic plants growing in this region. These plants are widespread in natural and man-made wetlands. Although a number of studies have reported several of them as being useful, but many of them are still unexplored. Neptunia oleracea Lour. commonly known as water mimosa or water sensitive plant is a wild aquatic legume. In India, the plant is distributed in Assam, Manipur and Tripura in North-East India. In Manipur, this plant is used as a vegetable by the Meiteis, the valley inhabitants and is considered as a local delicacy. Moreover, the ability of this plant to accumulate heavy metal can be explored for its use in phytoremediation of soil. The present investigation was intended to study the morpho-phenological as well as biochemical characteristics of Neptunia oleracea Lour. and evaluation of its phytoremediation potentiality on arsenic contaminated water. The plant materials were collected from West Imphal district, Manipur. The study of plant morphology revealed that the stem length at the maturity was 1.47m. Mature leaves were green in color with length and breadth of 7.06 cm and 4.9 cm, respectively. The roots were adventitious and fibrous with average number of root nodules to the extent of 20.66 per plant. The phenological characteristic showed that flower developed during July-September in rainy season. The flowers were bright yellow in color, silky and bloomed for about 7-11 days. The inflorescence type was spike where it was a type of raceme with flowers that were absence of pedicel and erect. The mean length of inflorescence was 11.1 cm with peduncle length of 9 cm. The fruit occurred in October-November with mean length of 6.16 cm. An average of 32 seeds/fruit was observed where as in each pod 5 seeds with mean seed weight of 12.9 mg were recorded. The percent moisture content in shoot and root was found to be 79.200% and 71.033%, respectively which significantly varied (C.D P>0.05=5.732). The crude protein content in the shoot was 6.410 g/100g and in the root 7.933 g/100g. There was a significant difference (C.D P>0.05=0.586) in the crude protein content in shoot and root of Neptunia oleracea Lour. In this investigation the crude fat content in shoot was 0.403g/100g and in root it was recorded to be 0.173g/100g. The amount of vitamin C in the shoot was found to be 1.698 mg/100g and in root it was recorded to be 1.357mg/100g on fresh weight basis. Statistically, there was a significant difference (C.D P>0.05=0.272) in the shoot and root vitamin C content. Soluble protein recorded in the shoot of Neptunia oleracea Lour. was 2.560g/100g and in root it was 1.377g/100g on a dry weight basis. Statistically, there was a significant difference in the shoot and root content of soluble protein in Neptunia oleracea Lour (C.D P>0.05=0.316). In this investigation the starch content in shoot was 1.355g/100g and in root was 1.177g/100g on dry weight basis while the total soluble sugar found in the shoot was 0.572g/100g and in root it was 0.320g/100g on dry weight basis. There was a significant difference found in the total soluble sugar content in shoot and root (C.D P>0.05= 0.0874). The ash content obtained in this investigation was 1.390g/100g and 0.940g/100g in shoot and root respectively with a significant difference (C.D P>0.05=0.0642). The mean calcium content recorded in the shoot was 344.960 mg/100g and in root was 358.830 mg/100g on dry weight basis which varied significantly (C.D P>0.05=7.321). The sodium content in shoot was 224.100 mg/100g and in root was 197.660 mg/100g on dry weight basis which significantly varied (C.D P>0.05=7.542). There was high potassium content in shoot of about 622.330 mg/100g and in root it had a value of 530.033 mg/100g on dry weight basis. The zinc content was recorded to be 10.310 mg/100g in shoot and 9.960 mg/100g in root on dry weight basis. The experiment on phytoremediation of arsenic contaminated water using Neptunia oleracea Lour revealed that the plant tissue with the treatment T3 (2.5mg/L) showed an arsenic accumulation to the tune of 1472 ppb which was about 60% of the initial arsenic content in water thus making it a strong candidate for phytoremediation of arsenic contaminated water. From the present investigation it can be concluded that Neptunia olercea Lour. had high crude protein, potassium, calcium and ash content. Further, a low crude fat was advantageous. The high content of some important minerals, such as potassium and calcium makes it nutritionally superior. The plant also displayed a strong phytoremediation potentiality by removing as much as sixty per cent of the arsenic present in water which might be useful to develop suitable technology to remove excess arsenic in freshwater systems as well as underground water in north east India where arsenic is a major contaminant.EnglishThesis