Sucheta Sharma

Selenium Accumulation and Antioxidant Status of Rice Plants Grown on Seleniferous Soil from Northwestern India

Abstract Greenhouse experiment was conducted to investigate selenium accumulation and its antioxidant response in two rice varieties (PR116 and Pusa Basmati 1121) grown on normal and seleniferous soils. The plant growth was reduced at early developmental stages and flowering was delayed by a period of 10 d on seleniferous soil. Selenium accumulation increased by 3–20 and 13–14 folds in leaves, 18 and 3 folds in grains from Pusa Basmati 1121 and PR116 varieties, respectively. Selenium accumulation in leaves from rice plants grown on seleniferous soil resulted in significant increase in chlorophyll content, hydrogen peroxide, proline, free amino acids, total phenol and tannin contents. Lipid peroxidation levels and peroxidase activities in leaves increased whereas catalase activity showed a reverse trend. It is concluded that selenium accumulation decreased dry matter content in rice during crop development but these plants were able to combat selenium toxicity by inducing alterations in their defense system.

Changes in biochemical components of wheat and rapeseed grown on selenium-contaminated soil

To study changes in some biochemical parameters in relation to selenium accumulation in wheat and rapeseed, plant samples at different growth stages of the crops were collected from the normal and selenium-contaminated region of Punjab. Plants grown in seleniferous soils accumulated 220–242 folds Se in wheat (Triticum aestivum L.var PBW 343) and 51–67 folds in rapeseed (Brassica napus L.var GSL-1) leaves; and 16–17 folds in grains of both the crops. Due to selenium accumulation, lipid and protein contents remained significantly low in leaves at both the stages of growth as well as grains of both the crops. Distinct differences were noticed in both the crops with respect to changes in total soluble sugars, reducing sugars and starch contents. In seleniferous soils, wheat leaves at stage I (55-day-growth) contained significantly higher amounts of total soluble sugars, reducing sugars and starch and thereafter these parameters recorded significantly low values in leaves at stage II (ear initiation) as well as in grains. On the other hand, a significant decrease in total soluble sugars and reducing sugars was recorded due to Se accumulation in rapeseed leaves at both growth stages. Quality of rapeseed grains harvested from seleniferous soil was not affected by Se accumulation except decrease in lipid content. Se accumulation did not influence the proportion of different lipid classes like phospholipids, glycolipids and sterols but reduced the proportion of unsaturated fatty acids.

The effect of some pesticides in conjunction with nitrogen sources on growth and carbohydrate and nitrogen constituents of sugarcane during formative phase

SummaryThe effect of gamma isomer of benzene hexachloride and Telodrin both in absence and presence of ammonium and nitrate nitrogen carriers on shoot and root growth and carboydrate and nitrogen constituents of sugarcane was studied. The pesticides induced shoot emergence and development of tillers and roots. Shoot growth, nitrogen intake and insoluble nitrogen content invariably increased by pesticide application while soluble carbohydrate and soluble nitrogen content of the shoot decreased. Pesticides also increased the water-soluble nitrate content of the soil.The effect of pesticides was not confined to ammonical source of nitrogen rather the pesticides proved equally effective under nitrate source of nitrogen and also in absence of additional nitrogen. Beneficial effect of pesticides on growth and development of sugarcane appears largely on account of more efficient utilisation of soil and fertilizer nitrogen. The results raise an interesting possibility of using these pesticides as growth stimulators to increase the efficiency of sugarcane plants growing under sub-optimal conditions of nitrogen

Selenium Accumulation and Biochemical Composition of Brassica Grains Grown in Selenate- or Selenite-Treated Alkaline Sandy Loam Soil

In a greenhouse experiment, Brassica plants were grown in an alkaline sandy loam soil treated with different levels of selenate selenium (Se) or selenite Se ranging from 0 to 4 mg Se kg−1. Plants grown in Se-treated soil were stressed at an early stage of pod setting and produced fewer pods per plant. Selenium accumulation increased by 2- to 35-fold in shoots, 3- to 19-fold in roots, and 2- to 57-fold in grains. Selenium accumulation in grains resulted in significant increases in contents of reducing sugars, starch, glucosinolate, and free and sulfur-containing amino acids and a decrease in lipid content. Selenium accumulation significantly increased the proportions of different lipid classes such as glycolipids, sterols, and free fatty acids whereas triacylglyceride content showed the reverse trend. Oil extracted from Brassica grains grown in the seleniferous region contained Se within safe limits and thus is safe for human consumption.

Effects of biocontrol agents on lipid and protein composition of Indian mustard seeds from plants infected with Alternaria species

Field experiments were carried out with Indian mustard (Brassica juncea L. Cv RLM 1359) to investigate the influence of biocontrol agents on seeds from plants infected with Alternaria blight. The biocontrol agents viz, Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis were applied as seed treatment/seed treatment coupled with spray on 30 and 60 days after sowing of seeds in experimental fields. The plants treated with different biocontrol agents were more developed than non-treated plants throughout the experiment. Biochemical analysis revealed that application of biocontrol agents resulted in increase in lipid and protein content in seeds from treated plants. The proportion of various lipidic fractions i.e. phospholipids, glycolipids and sterol content in seeds increased with a corresponding decrease in total glycerides. The proportion of 18:3, 20:1 and 22:1 fatty acids increased while that of 18:1 and 18:2 fatty acids decreased in seeds with application of biocontrol agents. There were both qualitative and quantitative differences in the banding patterns of albumin and globulin proteins after application of biocontrol agents. The data suggested that biochemical alterations in the host induced by treatment with biocontrol agents could be associated with defence mechanisms and enhanced growth of the plant.

Variation in Selenium Tolerance, Accumulation, and Growth Parameters of Different Wheat Cultivars

ABSTRACT In a greenhouse experiment, wheat cultivars PDW 291, PBW 550, and TL 2908 were grown in alkaline sandy-loam soil treated with sodium selenate at 0, 2, and 4 mg selenium (Se) kg−1 soil. Selenate-treated wheat plants accumulated greater Se in roots, stems, leaves, and grains and showed growth retardation, snow-white chlorosis, decreased shoot length and chlorophyll, and reduced leaf area and produced less number of grains as compared to control plants. Maximum reduction in these parameters was observed in selenate-treated TL 2908 plants and most of the plants died before maturity with almost no grain formation with 4 mg Se kg−1 soil. Selenium accumulation resulted in decreased reducing sugar, starch, and protein contents in grains whereas total free amino acids increased significantly in all the three cultivars. Selenium accumulation in wheat showed metabolic disturbances and its accumulation in grains was beyond toxic levels, thus making it unfit for consumption.

Biochemical changes associated with application of biocontrol agents on Indian mustard leaves from plants infected with Alternaria blight

The present investigation reports the biochemical changes associated with application of biocontrol agents on Indian mustard (Brassica juncea L Cv RLM 1359) leaves from plants infected with Alternaria blight. Indian mustard seeds were treated separately with three biocontrol agents, viz. Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis and grown in experimental fields; followed by spraying on 30 and 60 days after sowing (DAS). The use of biocontrol agents showed enhanced growth in comparison to control, decreased disease index on the leaves as well as the pod wall of Indian mustard. These biocontrol agents enhanced the content of dry matter, total phenol, ortho-dihydroxyphenols, starch, total soluble sugars, reducing sugars, total lipids and different membrane lipids in the leaves. The total protein content decreased after treatment with biocontrol agents at 30 and 60 days after sowing. The data suggested that treatment with biocontrol agents initiated in the plants a number of biochemical changes which can be considered to be a part of plant defense response.

A REVIEW ON ADVANCES OF SUSTAINED RELEASE DRUG DELIVERY SYSTEM

Sustained release matrix tablets facilitate prolonged and cont inuous drug release and improve the b ioavailability of drugs while avoiding unwanted side effects. Ofloxacin is a broad spectrum antibacterial agent used for treating wide range of gram positive and gram negative in fections. The goal in designing sustained or controlled delivery systems is to reduce frequency of dosing or to increase the effectiveness of the drug by localization at the site of action, reducing the dose required, providing uniform drug delivery. Sustained release drug administration means not only prolongatio n of duration of dr ug delivery, but the term also implies the predictability and reproducibility of drug release kinetics. The controlled release of drug sub stances and their effective transport to sites of action can be exploited to maximize the beneficial clinical response and to minimize the incidence of unbeneficial adverse reactions and side effects. Oral ingestion has long been the most convenient and commonly employed route of drug delivery. Indeed, for sustained release systems, oral route of administration has receiv ed most of the attention with respect to research on physiological and drug constraints as well as design and testing of prod ucts.

Influence of Growing Environment on Antinutrients/Bioactive Compounds in Soybean, Glycine max (L.) Merill Genotypes

Seed quality of soybean, Glycine max (L.) Merrill at harvest is dependent upon the environmental conditions during its development and maturation. Stability of performance of genotypes across the environment is considered essential for the release of soybean cultivars with improved nutritional quality. The objective of the present study was to compare the contents of anti-nutrients and bioactive compounds of twenty soybean genotypes grown at two locations (Ludhiana and Gurdaspur) and two planting times (June and July) in Punjab state of India. Averaged over both, the locations and planting times, genotype ‘SL 313’ showed the least trypsin inhibitor activity while ‘SL 992’ exhibited minimum phytate and saponin contents. Genotypes ‘SL 989’ and ‘DS 2614 contained minimum contents of phenols and tannins respectively. Minimum trypsin inhibitor activity in all the genotypes was observed at Ludhiana in June planting and phytate and saponins at Gurdaspur during July planting. Averaged over 20 genotypes, the maximum mean values for phytate was observed at Ludhiana in June planting. All the genotypes expressed maximum saponin content at Ludhiana except ‘Sel P’. Averaged over 20 genotypes, minimum phenol and tannin contents were observed at Ludhiana during June planting. It is important to identify genotypes with variable concentrations of these anti-nutrients so as to develop cultivars depending upon their further utilization in food industry or for medicinal applications.

Influence of selenite and selenate on growth, leaf physiology and antioxidant defense system in wheat (Triticum aestivum L.): Selenium toxicity in wheat

BACKGROUND Selenium (Se) induced oxidative stress as well as synthesis of non-specific selenoproteins has been attributed to its toxicity in plants. Selenium toxicity can affect growth, chlorophyll and protein synthesis and crop yield. This study reveals the effects of different sources (sodium selenite and sodium selenate) and levels (2 and 4 mg Se kg-1 soil) of Se on its uptake, leaf physiology, antioxidant defense system, isoenzymic patterns and mitochondrial activity in wheat cultivar PBW621 at tillering and ear-initiation stages. RESULTS Higher Se accumulation in leaves of wheat plants was observed in selenate than control and selenite treatments. Selenium tolerance index, chlorophyll, photosynthetic efficiency, mitochondrial reduction test, electron transport system activity, lipid peroxidation, proline and glutathione in Se-treated wheat plants decreased significantly as compared to control. Significant increase in hydrogen peroxide and activities of antioxidant enzymes, namely catalase, peroxidase, superoxide dismutase, glutathione reductase in leaves was due to the presence of Se-induced oxidative stress in wheat plants. CONCLUSION Wheat cultivar PBW621 could adapt to applied selenite concentrations by developing antioxidant defense system but selenate treated plants could exhibit toxicity tolerance up to 2 mg kg-1 and died at high concentrations due to damage to tissue development and function.