Dynamic Changes in Fermentation Quality and Structure and Function of the Microbiome during Mixed Silage of Sesbania cannabina and Sweet Sorghum Grown on Saline-Alkaline Land.

Protein-rich Sesbania cannabina and sugar-rich sweet sorghum [Sorghum dochna (Forssk.) Snowden] are characterized by their higher tolerance to saline-alkaline stresses and simultaneous harvests. They could be utilized for coensiling because of their nutritional advantages, which are crucial to compensate protein-rich forage in saline-alkaline regions. The current study investigated the fermentation quality, microbial community succession, and predicted microbial functions of Sesbania cannabina and sweet sorghum in mixed silage during the fermentation process. Before ensiling, the mixtures were treated with compound lactic acid bacteria (LAB) inoculants followed by 3, 7, 14, 30, and 60 days of fermentation. The results revealed that the inoculated homofermentative species Lactobacillus plantarum and Lactobacillus farciminis dominated the early phase of fermentation, and these shifted to the heterofermentative species Lactobacillus buchneri and Lactobacillus hilgardii in the later phase of fermentation. As a result, the pH of the mixed silages decreased significantly, accompanied by the growth of acid-producing microorganisms, especially L. buchneri and L. hilgardii, which actively influenced the bacterial community structure and metabolic pathways. Moreover, the contents of lactic acid, acetic acid, 1,2-propanediol, and water-soluble carbohydrates increased, while the contents of ammonia-N and fiber were decreased, with increasing ratios of sweet sorghum in the mixed silage. Overall, coensiling Sesbania cannabina with >30% sweet sorghum is feasible to attain high-quality silage, and the relay action between homofermentative and heterofermentative LAB species could enhance fermentation quality and conserve the nutrients of the mixed silage. IMPORTANCE The coensiling of Sesbania cannabina and sweet sorghum is of great practical importance in order to alleviate the protein-rich forage deficiency in saline-alkaline regions. Furthermore, understanding the microbial community's dynamic changes, interactions, and metabolic pathways during ensiling will provide the theoretical basis to effectively regulate silage fermentation. Here, we established that coensiling Sesbania cannabina with >30% sweet sorghum was effective at ensuring better fermentation quality and preservation of nutrients. Moreover, the different fermentation types of LAB strains played a relay role during the fermentation process. The homofermentative species L. plantarum and L. farciminis dominated in the early phase of fermentation, while the heterofermentative species L. buchneri and L. hilgardii dominated in the later phase of fermentation. Their relay action in Sesbania cannabina-sweet sorghum mixed silage may help to improve fermentation quality and nutrient preservation.

Mechanistic elucidation of germination potential and growth of Sesbania sesban seedlings with Bacillus anthracis PM21 under heavy metals stress: An in vitro study.

Soils contaminated with heavy metals such as Chromium (Cr) and Cadmium (Cd) severely impede plant growth. Several rhizospheric microorganisms support plant growth under heavy metal stress. In this study, Cr and Cd stress was applied to in vitro germinating seedlings of a Legume plant species, Sesbania sesban, and investigated the plant growth potential in presence and absence of Bacillus anthracis PM21 bacterial strain under heavy metal stress. The seedlings were exposed to different concentrations of Cr (25-75 mg/L) and Cd (100-200 mg/L) in Petri plates. Growth curve analysis of B. anthracis PM21 revealed its potential to adapt Cr and Cd stress. The bacteria supported plant growth by exhibiting ACC-deaminase activity (1.57-1.75 µM of α-ketobutyrate/h/mg protein), producing Indole-3-acetic acid (99-119 µM/mL) and exopolysaccharides (2.74-2.98 mg/mL), under heavy metal stress condition. Analysis of variance revealed significant differences in growth parameters between the seedlings with and without bacterial inoculation in metal stress condition. The combined Cr+Cd stress (75 + 200 mg/L) significantly reduced root length (70%), shoot length (24%), dry weight (54%) and fresh weight (57%) as compared to control. Conversely, B. anthracis PM21 inoculation to seedlings significantly increased (p ≤ 0.05) seed germination percentage (5%), root length (31%), shoot length (23%) and photosynthetic pigments (Chlorophyll a: 20%; Chlorophyll b: 16% and total chlorophyll: 18%), as compared to control seedlings without B. anthracis PM21 inoculation. The B. anthracis PM21 inoculation also enhanced activities of antioxidant enzymes, including superoxide dismutase (52%), peroxidase (66%), and catalase (21%), and decreased proline content (56%), electrolyte leakage (50%), and malondialdehyde concentration (46%) in seedlings. The B. anthracis PM21 inoculated seedlings of S. sesban exhibited significantly high (p ≤ 0.05) tissue deposition of Cr (17%) and Cd (16%) as compared to their control counterparts. Findings of the study suggested that B. anthracis PM21 endured metal stress through homeostasis of antioxidant activities, and positively impacted S. sesban growth and biomass. Further experiments in controlled conditions are necessary for investigating phytoremediation potential of S. sesban in metal-contaminated soils in presence of B. anthracis PM21 bacterial strain.

Mechanism and application of Sesbania root-nodulating bacteria: an alternative for chemical fertilizers and sustainable development.

Chemical fertilizers are used in large-scale throughout the globe to satisfy the food and feed requirement of the world. Demanding cropping with the enhanced application of chemical fertilizers, linked with a decline in the recycling of natural or other waste materials, has led to a decrease in the organic carbon levels in soils, impaired soil physical properties and shrinking soil microbial biodiversity. Sustenance and improvement of soil fertility are fundamental for comprehensive food security and ecological sustainability. To feed the large-scale growing population, the role of biofertilizers and their study tends to be an essential aspect globally. In this review, we have emphasized the nitrogen-fixing plants of Sesbania species. It is a plant that is able to accumulate nitrogen-rich biomass and used as a green manure, which help in soil amelioration. Problems of soil infertility due to salinity, alkalinity and waterlogging could be alleviated through the use of biologically fixed nitrogen by Sesbania plants leading to the conversion of futile land into a fertile one. A group of plant growth-promoting rhizobacteria termed as "rhizobia" are able to nodulate a variety of legumes including Sesbania. The host-specific rhizobial strains can be used as potential alternative for nitrogenous fertilizers as they help the host plant in growth and development and enhance their endurance under stressed conditions. The review gives the depth understanding of how the agriculturally important microorganisms can be used for the reduction of broad-scale application of chemical fertilizers with special attention to Sesbania-nodulating rhizobia.

Analysis of host protein interactions in plant viruses: an in silico study using Sesbania mosaic virus.

The dynamics of interactions of viral proteins with their host are pivotal in establishing a successful infection and ensuring systemic spread. To uncover these, an in silico analysis of the interactions between the coat protein (CP) of Sesbania mosaic virus (SeMV), a group IV virus with single-stranded positive-sense RNA genome was carried out with the known crystal structures of proteins belonging to the Fabaceae family, which is its natural host. SeMV is an isometric plant virus which infects Sesbania grandiflora, a member of Fabaceae, and causes mosaic symptoms. Earlier results have indicated that the assembly and disassembly events of SeMV favor the formation of CP dimers. Hence, the ability and strength of interactions of CP dimer with the host proteins were assessed using in silico protein-protein docking approaches. A set of 61 unique crystal structures of native proteins belonging to Fabaceae were downloaded from the Protein Data Bank (PDB) and docked with the CP dimer of SeMV. From the docking scores and interaction analysis, the host proteins were ranked according to their strength and significance of interactions with the CP dimers. The leads that were identified present themselves as strong candidates for developing antivirals against not only SeMV but also other related viruses that infect Fabaceae. The study is a prototype to understand host protein interactions in viruses and hosts.

Ohr and OhrR Are Critical for Organic Peroxide Resistance and Symbiosis in Azorhizobium caulinodans ORS571.

Azorhizobium caulinodans is a symbiotic nitrogen-fixing bacterium that forms both root and stem nodules on Sesbania rostrata. During nodule formation, bacteria have to withstand organic peroxides that are produced by plant. Previous studies have elaborated on resistance to these oxygen radicals in several bacteria; however, to the best of our knowledge, none have investigated this process in A. caulinodans. In this study, we identified and characterised the organic hydroperoxide resistance gene ohr (AZC_2977) and its regulator ohrR (AZC_3555) in A. caulinodans ORS571. Hypersensitivity to organic hydroperoxide was observed in an ohr mutant. While using a lacZ-based reporter system, we revealed that OhrR repressed the expression of ohr. Moreover, electrophoretic mobility shift assays demonstrated that OhrR regulated ohr by direct binding to its promoter region. We showed that this binding was prevented by OhrR oxidation under aerobic conditions, which promoted OhrR dimerization and the activation of ohr. Furthermore, we showed that one of the two conserved cysteine residues in OhrR, Cys11, was critical for the sensitivity to organic hydroperoxides. Plant assays revealed that the inactivation of Ohr decreased the number of stem nodules and nitrogenase activity. Our data demonstrated that Ohr and OhrR are required for protecting A. caulinodans from organic hydroperoxide stress and play an important role in the interaction of the bacterium with plants. The results that were obtained in our study suggested that a thiol-based switch in A. caulinodans might sense host organic peroxide signals and enhance symbiosis.

Biochemical and Anatomical Investigation of Sesbania herbacea (Mill.) McVaugh Nodules Grown under Flooded and Non-Flooded Conditions.

Sesbania herbacea, a native North American fast-growing legume, thrives in wet and waterlogged conditions. This legume enters into symbiotic association with rhizobia, resulting in the formation of nitrogen-fixing nodules on the roots. A flooding-induced anaerobic environment imposes a challenge for the survival of rhizobia and negatively impacts nodulation. Very little information is available on how S. herbacea is able to thrive and efficiently fix N2 in flooded conditions. In this study, we found that Sesbania plants grown under flooded conditions were significantly taller, produced more biomass, and formed more nodules when compared to plants grown on dry land. Transmission electron microscopy of Sesbania nodules revealed bacteroids from flooded nodules contained prominent polyhydroxybutyrate crystals, which were absent in non-flooded nodules. Gas and ion chromatography mass spectrometry analysis of nodule metabolites revealed a marked decrease in asparagine and an increase in the levels of gamma aminobutyric acid in flooded nodules. 2-D gel electrophoresis of nodule bacteroid proteins revealed flooding-induced changes in their protein profiles. Several of the bacteroid proteins that were prominent in flooded nodules were identified by mass spectrometry to be members of the ABC transporter family. The activities of several key enzymes involved in nitrogen metabolism was altered in Sesbania flooded nodules. Aspartate aminotransferase (AspAT), an enzyme with a vital role in the assimilation of reduced nitrogen, was dramatically elevated in flooded nodules. The results of our study highlight the potential of S. herbacea as a green manure and sheds light on the morphological, structural, and biochemical adaptations that enable S. herbacea to thrive and efficiently fix N2 in flooded conditions.

Autotoxicity of root exudates varies with species identity and soil phosphorus.

Root exudate autotoxicity (i.e. root exudates from a given plant have toxic effects on itself) has been recognized to be widespread. Here we examined how plant species identity and soil phosphorus (P) availability influenced this autotoxicity and the possible stoichiometric mechanisms. We conducted an experiment with three species (Luctuca sativa, Sesbania cannabina, and Solidago canadensis), which were subject to four treatments consisting of activated carbon (AC) and soil P. AC addition increased the whole-plant biomass of each species under high P conditions and this AC effect varied strongly with species identity. For Solidago, the relative increase in whole-plant biomass due to AC addition was larger in the low P than in the high P. Root exudate autotoxicity differed between roots and shoots. AC addition decreased root N:P ratios but failed to influence shoot N:P ratios in three species. These findings suggest that soil P enrichment might mediate root exudate autotoxicity and that this P-mediated autotoxicity might be related to root N and P stoichiometry. These patterns and their implications need to be addressed in the context of plant communities.

Enhanced phytoremediation of uranium-contaminated soils by arbuscular mycorrhiza and rhizobium.

Uranium phytoextraction is a promising technology, however, facing difficult that limited plant biomass due to nutrient deficiency in the contaminated sites. The aim of this study is to evaluate the potential of a symbiotic associations of a legume Sesbania rostrata, rhizobia and arbuscular mycorrhiza fungi (AMF) for reclamation of uranium contaminated soils. Results showed AMF and rhizobia had a mutual beneficial relations in the triple symbiosis, which significantly increased plant biomass and uranium accumulation in S. rostrata plant. The highest uranium removal rates was observed in plant-AMF-rhizobia treated soils, in which 50.5-73.2% had been extracted, whereas 7.2-23.3% had been extracted in plant-treated soil. Also, the S. rostrata phytochelatin synthase (PCS) genes expression were increased in AMF and rhizobia plants compared with the plants. Meantime, content of malic acid, succinic acid and citric acid were elevated in S. rostrata root exudates of AMF and rhizobia inoculated plants. The facts suggest that the mutual interactions in the triple symbiosis help to improve phytoremediation efficiency of uranium by S. rostrata.

Elucidation of the molecular responses to waterlogging in Sesbania cannabina roots by transcriptome profiling.

Sesbania cannabina, a multipurpose leguminous crop, is highly resistant to waterlogging stress. However, the scant genomic resources in the genus Sesbania have greatly hindered further exploration of the mechanisms underlying its waterlogging tolerance. Here, the genetic basis of flooding tolerance in S. cannabina was examined by transcriptome-wide gene expression changes using RNA-Seq in seedlings exposed to short-term (3 h) and long-term (27 h) waterlogging. After de- novo assembly, 213990 unigenes were identified, of which 145162 (79.6%) were annotated. Gene Ontology and pathway enrichment analyses revealed that the glycolysis and fermentation pathways were stimulated to produce ATP under hypoxic stress conditions. Energy-consuming biosynthetic processes were dramatically repressed by short and long term waterlogging, while amino acid metabolism was greatly induced to maintain ATP levels. The expression pattern of 10 unigenes involved in phenylpropanoid biosynthesis, glycolysis, and amino acid metabolism revealed by qRT-PCR confirmed the RNA-Seq data. The present study is a large-scale assessment of genomic resources of Sesbania and provides guidelines for probing the molecular mechanisms underlying S. cannabina waterlogging tolerance.

Identification of Sesbania sesban (L.) Merr. as an Efficient and Well Adapted Phytoremediation Tool for Cd Polluted Soils.

A pot experiment was carried out to assess Cd uptake and accumulation efficiency of Sesbania sesban. Plants were grown in soil spiked with 25, 50, 100, 150, 200, 250, and 300 mg/kg Cd. After 120 days, plants were harvested and analyzed for Cd content. A steady increase in Cd accumulation with increasing metal concentration in soil was observed for all treatments. Accumulation of Cd was greatest in roots (86.7 ± 6.3 mg/kg), followed by stem (18.59 ± 1.9 mg/kg), and leaf (3.16 ± 1.1 mg/kg). Chlorophyll content declined with increasing Cd concentration, while proline and protein content increased as compared to control. At higher Cd levels, root, shoot length, and biomass were all significantly reduced (p ≤ 0.001). An increase in total protein along with greater A250/A280 value suggested an increase in metal-protein complexes. Considering the rapid growth, high biomass, accumulation efficiency, and adaptive properties, this plant could be used as a valuable tool for the phytoremediation of Cd contaminated soils.

Restoration of red mud deposits by naturally growing vegetation.

Disposal of red mud (RM) poses serious environmental problems such as wind erosion, air and water pollution. To overcome these problems, effective restoration of the disposal land through naturally growing vegetation is a sustainable and economical approach. The present study involved estimation of frequency (F), density (D), abundance (Ab), and important value index (IVI) of natural flora on abandoned RM sites in order to assess their metal toxicity tolerance capacity. Based on visual observations and highest IVI, S. Asper and S. punicea were identified as effective ecological tools for the restoration of barren RM sites. From the study, remarkable differences were observed between non-rhizospheric and rhizospheric RM of both species. These rhizospheric RM analyses confirm the ability of S. asper and S. punicea for enhancing the biological activities of abandoned RM. Translocation factor (TF) of iron was maximum (2.58) in S. asper, and bioconcentration factor (BCF) was found maximum (1.25) in S. punicea, but both TF (2.58) and BCF (1.35) were high in S. asper. Therefore, this plant could be reported as an iron hyperaccumulator plant. These results suggest that these plant species can be exploited for effective restoration of RM deposited land without any inputs or maintenance.

EFFECT OF WATERLOGGING STRESS ON MEIOTIC COURSE, TETRAD FORMATION AND POLLEN FERTILITY OF SESBANIA PEA.

Sesbania cannabina a multipurpose leguminous crop of family Fabaceae, is widely adaptable to adverse climatic conditions such as waterlogging, drought and high salinity. Flooding and water logging are very common phenomena and there may be possibility to become more serious alarms for environment, which is progressively deteriorated by human beings by their anthropogenic activities, polluting the atmosphere. Flooding provides a case of natural selection to the nature which selects the plants which are more adaptable to this condition and renders themselves to survive due to this tolerance or resistance behavior. Present study envisages the effect of waterlogging stress on chromosomal biology of Sesbania pea. To study the effect of waterlogging stress on microsporogensis of Sesbania cannabina, presoaked seeds were sown in experimental pots. Permanent waterlogged condition is created by shifting pots in water filled tanks. Cytological studies showed various types of chromosomal aberrations induced by waterlogging stress and reduction in pollen fertility was also encountered.

Characterization of cadmium-resistant bacteria for its potential in promoting plant growth and cadmium accumulation in Sesbania bispinosa root.

The cadmium (Cd) resistant bacteria were isolated from soils of Damanganga river, Vapi, and identified 11 potential Cd resistant bacteria based on 16S rDNA sequences. The Cd resistant bacteria belonged to four different genera: Providencia spp., Morganella sp., Stenotrophomonas sp., and Bacillus spp. The assessment of plant growth-promoting (PGP) parameters revealed that the Cd tolerant bacteria showed one or more PGP properties. Further, a pot experiment was conducted to elucidate the effects of Cd resistant bacteria on the plant growth and the uptake of Cd by Sesbania bispinosa. The bacterized seedlings recorded 36.0-74.8% and 21.2-32.9% higher root and shoot lengths, respectively, in Cd amended soil compared with control. The Cd mobilization in the root of S. bispinosa by microbial inoculants ranged from 0.02 ± 0.01 to 1.11 ± 0.06 ppm. The enhanced concentrations of Cd accumulation in S. bispinosa roots correspond to the effect of the bacterial strains on metal mobilization in soil. The present observations showed that the Cd resistant strains protect the plants against the inhibitory effects of Cd, probably due to the production of PGP properties. The present results provided a new insight into the phytoremediation of Cd contaminated soil.

Natural dye sensitized TiO2 nanorods assembly of broccoli shape based solar cells.

TiO2 nanorods based thin films with rutile phase have been synthesized using template free low temperature hydrothermal method. The scanning electron microscope images showed that the prepared TiO2 samples were made of TiO2 nanorods and the nanorods had arranged by itself to form a broccoli like shape. The X-ray diffraction studies revealed that the prepared TiO2 samples exhibit rutile phase. The grown TiO2 nanorods had been sensitized using the flowers of Sesbania (S) grandiflora, leaves of Camellia (C) sinensis and roots of Rubia (R) tinctorum. Dye sensitized solar cells had been fabricated using the natural dye sensitized TiO2 nanorods based thin film photoelectrode and the open circuit voltage and short circuit current density were found to lie in the range of 0.45-0.6 V and 5.6-6.4 mA/cm(2) respectively. The photovoltaic performance of all the fabricated natural dye sensitized TiO2 solar cells indicate that natural dyes have the potential to be used as effective sensitizer in dye sensitized solar cells.

Chromium translocation, concentration and its phytotoxic impacts in in vivo grown seedlings of Sesbania sesban L. Merrill.

The present in vivo pot culture study showed hexavalent chromium (Cr+6) induced phytotoxic impacts and its translocation potential in 21 days old sesban (Sesbania sesban L. Merrill.) seedlings. Cr+6 showed significant growth retardation in 21 days old sesban (Sesbania sesban L. Merrill.) seedlings. Germination of seeds at 10,000 mg L-1 of Cr+6 exhibit 80% inhibition in germination. Seedling survival was 67% after 7 days of seedling exposure to 300 mg kg-1 of Cr+6. Shoot phytotoxicity was enhanced from 6% to 31% with elevated supply of Cr+6 from 10 mg kg-1 to 300 mg kg-1. Elevated supply of Cr+6 exhibited increasing and decreasing trends in % phytotoxicity and seedling tolerance index, respectively. Elevated supply of chromium showed decreased chlorophyll and catalase activities. Peroxidase activities in roots and leaves were significantly higher at increased supply of Cr+6. Cr bioconcentration in roots was nearly 10 times more than stems whereas leaves showed nearly double accumulation than stems. Tissue specific chromium bioaccumulation showed 53 and 12 times more in roots and shoots respectively at 300 mg kg-1 Cr+6 than control. The present study reveals potential of sesban for effective Cr translocation from roots to shoots as evident from their translocation factor and Total Accumulation Rate values.

Enzymatic and chemical oxidation of polygalactomannans from the seeds of a few species of leguminous plants and characterization of the oxidized products.

Plant polysaccharides are used in a growing number of applications, in their native or in chemically and/or biochemically modified forms. In the present work, we compare TEMPO-mediated oxidation with laccase of polygalactomannans (PGM) from different species of plant leguminous to chemical oxidation with NaClO/NaBr/TEMPO. We have investigated the gums from: locust bean (Ceratonia siliqua), tara (Caesalpinia spinosa), guar (Cyamopsis tetragonolobus), sesbania (Sesbania bispinosa) and fenugreek (Trigonella foenum-graecum). Upon laccase/TEMPO oxidation, PGM viscosity and concentration of reducing groups increased up to five-fold and structured, elastic, stable gels were formed, which could be degraded by hydrolysis with ß-mannanase. Conversely, chemical oxidation with NaClO/NaBr/TEMPO caused a rapid, intermediate transition of the gum solutions to compact gels, that immediately reverted to liquid, with a lower viscosity than at the start and an increased concentration of reducing groups, similar to the reaction with laccase. We interpret the above as due to, in the case of laccase, oxidation of primary hydroxyl groups to aldehydes, able to form stable hemiacetalic bonds with free hydroxyl groups. While upon chemical oxidation, primary OH's are only transiently oxidized to aldehydes, followed by rapid oxidation of all carbonyl groups to carboxylates. In either cases, TEMPO appeared to cause a limited splitting of glycosidic bonds of PGM. Native and oxidized PGM were further characterized by 1D and 2D NMR spectroscopy and by rheology.

Restoration of sodic soils involving chemical and biological amendments and phytoremediation by Eucalyptus camaldulensis in a semiarid region.

Salt-affected soils in semiarid regions impede the agricultural productivity and degrade the ecosystem health. In South India, several hectares of land are salt-affected, where the evapotranspiration exceeds the annual precipitation. This study is an attempt to ameliorate sodic soils, by an experiment involving chemical treatment (addition of gypsum), organic amendments (decomposed bagasse pith and green manuring with Sesbania rostrata) and phytoremediation by plantation of Eucalyptus camaldulensis. The prime focus is to minimize the use of gypsum and improve the soil health in terms of nutrients, microbial population and enzyme activity in addition to sodicity reclamation. At the end of the third year, a reduction of 10 % in soil pH, 33 % in electrical conductivity and 20 % in exchangeable sodium percentage was achieved compared to the initial values. Three- to fourfold increases in organic carbon content were observed. Significant improvement in the available major and micronutrients of soil, microbial growth and enzyme activity was observed, suggesting phytoremediation by E. camaldulensis as a sustainable option for restoration of similar kind of degraded lands.

Effect of lead on phytotoxicity, growth, biochemical alterations and its role on genomic template stability in Sesbania grandiflora: a potential plant for phytoremediation.

The present study was aimed at evaluating phytotoxicity of various concentrations of lead nitrate (0, 100, 200, 400, 600, 800 and 1000mgL(-1)) in Sesbania grandiflora. The seedling growth was significantly affected (46%) at 1000mgL(-1) lead (Pb) treatment. Accumulation of Pb content was high in root (118mgg(-1) dry weight) than in shoot (23mgg(-1) dry weight). The level of photosynthetic pigment contents was gradually increased with increasing concentrations of Pb. Malondialdehyde (MDA) content increased in both the leaves as well as roots at 600mgL(-1) Pb treatment and decreased at higher concentrations. The activity of antioxidative enzymes such as superoxide dismutase and peroxidase were positively correlated with Pb treatment while catalase and ascorbate peroxidase activities increased up to 600mgL(-1) Pb treatment and then slightly decreased at higher concentrations. Isozyme banding pattern revealed the appearance of additional isoforms of superoxide dismutase and peroxidase in Pb treated leaf tissues. Isozyme band intensity was more consistent with the respective changes in antioxidative enzyme activities. Random amplified polymorphic DNA results indicated that genomic template stability (GTS) was significantly affected based on Pb concentrations. The present results suggest that higher concentrations of Pb enhanced the oxidative damage by over production of ROS in S. grandiflora that had potential tolerance mechanism to Pb as evidenced by increased level of photosynthetic pigments, MDA content, and the level of antioxidative enzymes. Retention of high levels of Pb in root indicated that S. grandiflora has potential for phytoextracting heavy metals by rhizofiltration.

Effect of substitution of concentrate mix with Sesbania sesban on feed intake, digestibility, body weight change, and carcass parameters of Arsi-Bale sheep fed a basal diet of native grass hay.

An experiment was conducted to assess the effect of substitution of concentrate mix with Sesbania sesban on feed intake, digestibility, average daily gain (ADG), and carcass parameters of Arsi-Bale sheep. The experiment employed 25 male sheep with mean (±standard error) initial body live weight (BLW) of 19.1 ± 0.09 kg. The experiment consisted of 7 days of digestibility and 90 days of feeding trials followed by carcass evaluation. The experiment employed a randomized complete block design with five treatments and five blocks. Treatments comprised of grass hay alone fed ad libitum (GHA; control), GHA + 100 % concentrate mix (CM) consisting of wheat bran and noug seed cake at a ratio of 2:1 (0 S. sesban), GHA + 67 % CM + 33 % S. sesban (33 S. sesban), GHA + 33 % CM + 67 % S. sesban (67 S. sesban), and GHA + 100 % S. sesban (100 S. sesban). Total dry matter intake (DMI) was higher (p < 0.001) for sheep in 0 S. sesban-100 S. sesban (800-821 g/day) compared to sheep in control (611 g/day). However, the effect of S. sesban inclusion (0 S. sesban-100 S. sesban) on total DMI was quadratic, and DMI declined after 67 S. sesban. Digestibility of DM, organic matter (p < 0.01), and crude protein were higher (p < 0.001) in supplemented group compared to the control. ADG, feed conversion efficiency (ADG/DMI), slaughter BLW, hot carcass weight, and total edible offals were higher (p < 0.05-0.001) for sheep in 0 S. sesban-100 S. sesban than those in control. Increased level of S. sesban inclusion, in general, reduced growth and carcass parameters in this study. However, there was no difference between 0 S. sesban and 33 S. sesban in most parameters studied. Thus, it can be concluded that S. sesban could substitute a concentrate when it accounted for up to 33 % of the mix.

Rhizodegradation of petroleum hydrocarbons by Sesbania cannabina in bioaugmented soil with free and immobilized consortium.

The present study reports the effect of bioaugmentation by free and immobilized bacterial culture on the rhizodegradation of petroleum-polluted soil using Sesbania cannabina plant. Total petroleum hydrocarbon (TPH), hydrocarbon-degrading bacterial counts, microbial activity and root morphology were assessed during 120 days of plant growth. TPH concentration analyzed by GC-MS showed that bioaugmentation did not improve the TPH degradation. TPH concentration decreased from 2541 mg kg(-1) to 673 mg kg(-1) and 867 mg kg(-1) in the rhizosphere of free (FR) and immobilized bacterial inoculated (IR) soil, respectively at the 120th day while in the rhizosphere of uninoculated soil (CR) concentration decreased to 679 mg kg(-1) only at the 90th day, showing higher and rapid rhizodegradation with indigenous bacteria than bioaugmented bacterial cultures. Various predominant bacterial groups responsible for higher TPH degradation in the rhizosphere of S. cannabina were identified by PCR-DGGE analysis. It is concluded that natural plant-microbe interaction in the rhizosphere of S. cannabina was efficient enough to degrade TPH and plant rhizosphere keeps bacterial community in its surrounding therefore immobilized culture had no obvious effect on petroleum degradation.