Patterns of litterfall and return of nutrients across anthropogenic disturbance gradients in three subalpine forests of west Himalaya, India     

Sanjay Gairola  Ranbeer S. Rawal  U. Dhar 《Journal of Forest Research》2009,14(2):73-80

The study was conducted to improve our understanding of the effects of forest disturbance on litterfall and patterns of nutrient return in three subalpine forest ecosystems (i.e. Betula utilis-dominated, Abies pindrow-dominated, and Acer mixed broadleaf) of Indian west Himalaya. Total litterfall (t ha⁻¹ yr⁻¹) ranged between 2.6–3.6 and 2.1–2.6 for pristine and degraded stands, respectively. Whereas total litterfall decrease from pristine to degraded stand was about 25–30% in B. utilis and Acer mixed-broadleaf forests, the level of disturbance did not affect total litterfall in A. pindrow (coniferous) forest. Nutrient (N, P, and K) concentrations in litter components of the forests studied also varied across forest types and disturbance intensities. For pristine stands, among all the forests, return of total nutrients via litterfall was higher. The study revealed that patterns of litterfall and nutrient return in the forests studied were sensitive to intensity of disturbance, although sensitivity varied among forest types and nutrient contents. Increased intensity of disturbance greatly affected the total annual amount of nutrient return in broadleaf forests. Maximum impact was recorded in B. utilis forest with a significant decline in nutrient return from pristine to degraded stands (i.e. 64% for N, 38% for P, and 67% for K). Corresponding values for decline in Acer mixed forest were 17, 13, and 33% for N, P, and K, respectively, whereas in A. Pindrow forest N return was 15% higher and P return was 33% lower. This study indicates that the litterfall and litter nutrient concentrations in these forests are sensitive to the intensity of disturbance, which affects the amount of nutrient return. This will have a strong bearing on forest nutrient cycling.  相似文献   

Defluoridation of Drinking Water Using PURAL® MG-20 Mixed Hydroxide Adsorbent     

Patankar  Gaurang V.  Tambe  Amruta S.  Kulkarni  Bhaskar D.  Malyshew  Alexander  Kamble  Sanjay P. 《Water, air, and soil pollution》2013,224(9):1-13

Water, Air, &; Soil Pollution - High applications of P fertilizers and manure are general practice in intensive agriculture and may cause eutrophication in adjacent streams. Bioavailability of P...  相似文献   

Dietary pyridoxine promotes growth and cellular metabolic plasticity of Chanos chanos fingerlings exposed to endosulfan induced stress          下载免费PDF全文

Neeraj Kumar  Kondusamy Ambasankar  Kishore Kumar Krishnani  Sanjay Kumar Gupta  Paramjit Singh Minhas 《Aquaculture Research》2017,48(5):2074-2087

An attempt was made to assess the effect of dietary pyridoxine supplementation on growth performance and cellular metabolic enzymes of Chanos chanos fingerlings under endosulfan induced stress. Two‐hundred and twenty‐five fish were randomly distributed into five treatments, each with three replicates and fed four isocaloric and isonitrogenous diets with graded levels of pyridoxine for 45 days. Endosulfan concentration in the water was maintained at sublethal level of 1/40th of 96 h LC₅₀ (0.52 ppb). Dietary pyridoxine supplementation significantly enhanced growth performance viz. weight gain (%), specific growth rate, feed conversion ratio and protein efficiency ratio of fish compared to control diet fed group. The results of this experiment revealed that the activities of digestive and metabolic enzymes were significantly improved after feeding with dietary pyridoxine supplementation in C. chanos. Significantly increased muscle and brain ascorbic acid content was observed in fish fed diets containing pyridoxine. Histological studies on liver of fish fed pyridoxine‐supplemented diet showed the normal architecture of hepatocytes compared to non‐pyridoxine fed group. The results obtained in this study revealed that the inclusion of pyridoxine in diet has a protective effect against endosulfan induced stress in C. chanos fingerlings through metabolic enzyme activities and vitamin C content. This study has a potential in ameliorating the toxic effect of endosulfan induced stress using dietary supplementation of pyridoxine.  相似文献   

Role of Thiol Metabolism in Arsenic Detoxification in Hydrilla verticillata (L.f.) Royle     

Sudhakar Srivastava  Seema Mishra  Sanjay Dwivedi  R. D. Tripathi 《Water, air, and soil pollution》2010,212(1-4):155-165

Arsenic (As) contamination of the environment has emerged as a concerning issue recently for which phytoremediation has been suggested as a viable solution. Hydrilla verticillata (L.f.) Royle is a widely distributed rapidly growing aquatic weed possessing significant potential to accumulate As and is thus a potential candidate for the purpose of As phytoremediation. In the present study, an investigation of thiol metabolism was conducted in H. verticillata, which revealed differential effects upon exposure to arsenite [As(III)] and arsenate [As(V)]. The accumulation of arsenic was found to be higher upon exposure to As(III) than to As(V). Besides, As(III) was found to induce the activities of enzymes, such as cysteine synthase and γ-glutamylcysteine synthetase and the amounts of cysteine and glutathione (GSH) to higher levels than that observed with As(V). The activity of glutathione-S-transferase was, however, stimulated to a higher level upon exposure to As(V) than As(III). The activity of arsenate reductase was found to increase upon As(V) exposure at all concentrations and durations. In addition, a significant stimulation in the activity of phytochelatin synthase was noticed in vitro with an increase in As/GSH concentration and time of incubation. Arsenic detoxification in H. verticillata thus appeared to involve an induction of thiol synthesis and consumption in a coordinated manner, though differentially upon exposure to As(III) and As(V). The information gained through this study would help in better designing of the pilot experiment at the field level depending on the chemical composition of the contaminated water.  相似文献   

Effect of macrophage secretory products on elaboration of virulence factors by planktonic and biofilm cells of Pseudomonas aeruginosa     

Mittal R  Sharma S  Chhibber S  Harjai K 《Comparative immunology, microbiology and infectious diseases》2006,29(1):12-26

Macrophages, which constitute the first line of defense, pour their secretions in the mileu following stimulation with pathogens. These secretory products, referred to as macrophage secretory products (MSPs), can influence ultimate outcome of an infection. In the present investigation, it was observed that different strains of Pseudomonas aeruginosa vary in their ability to stimulate macrophages leading to variability in generation of macrophage secretory products. Cytokine levels, reactive nitrogen intermediates and protein content of macrophage secretory products generated with biofilm cells of P. aeruginosa was found to be more as compared to their planktonic counterparts. The effect of macrophage secretory products produced in response to interaction of macrophages with P. aeruginosa on elaboration of virulence factors produced by planktonic and biofilm cell forms of this pathogen was assessed. Significant enhancement in growth and elaboration of all the virulence determinants by both the cell forms was observed when P. aeruginosa was grown in presence of supernatants with macrophage secretory products. Implications of these findings in relation to urinary tract infections induced by P. aeruginosa have been discussed.  相似文献   

Extinction risk and conservation priorities     

Miller RM  Rodríguez JP  Aniskowicz-Fowler T  Bambaradeniya C  Boles R  Eaton MA  Gärdenfors U  Keller V  Molur S  Walker S  Pollock C 《Science (New York, N.Y.)》2006,313(5786):441

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Identification and characterization of SNPs in released,landrace and wild accessions of mungbean (Vigna radiata (L.) Wilczek) using whole genome re-sequencing     

Bangar  Pooja  Tyagi  Neetu  Tiwari  Bhavana  Kumar  Sanjay  Barman  Paramananda  Kumari  Ratna  Gaikwad  Ambika  Bhat  K. V.  Chaudhury  Ashok 《Journal of Crop Science and Biotechnology》2021,24(2):153-165

Journal of Crop Science and Biotechnology - Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] is vital grain legume having nutritional and socio-economic importance, especially in the...  相似文献   

Phenylpropanoids of Alpinia galanga as efflux pump inhibitors in Mycobacterium smegmatis mc(2) 155     

Roy SK  Pahwa S  Nandanwar H  Jachak SM 《Fitoterapia》2012,83(7):1248-1255

The first and second line drugs used for the treatment of tuberculosis are now becoming ineffective due to emergence of resistant strains. Efflux pump provokes resistance in mycobacterium and hence could be explored as a new target for the discovery of anti-TB agents. In search of efflux pump inhibitors, MIC and modulation factor of phenylpropanoids isolated from A. galanga rhizome were determined prior to the accumulation and efflux assay. Phenylpropanoid compounds viz. 1'-S-1'-Acetoxychavicol acetate, trans-p-coumaryl diacetate and 1'-S-1'-acetoxyeugenol acetate were found to be potent modulators and decreased the MIC of ethidium bromide by 64 fold at the concentration of 2.5, 6.25 and 5.0mg/L respectively. 1'-S-1'-Acetoxyeugenol acetate enhanced the accumulation and inhibited the efflux of EtBr in Mycobacterium smegmatis mc(2) 155 cells.  相似文献   

Investigations on the role of acid invertase and UDP-glucose pyrophosphorylase in potato clones with varying resistance to cold-induced sweetening     

Marian J. McKenzie  Joseph R. Sowokinos  Irene M. Shea  Sanjay K. Gupta  Rebecca R. Lindlauf  John A. D. Anderson 《American Journal of Potato Research》2005,82(3):231-239

Fifteen potato (Solanum tuberosum L.) clones with varying resistance to cold-induced sweetening were analysed for vacuolar acid invertase (AcInv, EC 3.2.1.26) and UDP-Glc pyrophosphorylase (UGPase; EC 2.7.7.9) activities related to their ability to accumulate sugars following cold storage (4 C). The UGPase isozyme profiles for each clone were also determined. Immunoblot analysis demonstrated a 55 kD protein, in seven of the 15 clones, that reacted with UGPase antisera in addition to the 53 kD UGPase subunit previously reported. The UGPase activity of these clones was significantly lower than that of the “single subunit” clones. Basal AcInv activity showed a positive correlation to the Glc:Suc ratio across the clones that was moderately significant before and after cold temperature storage. The activity of UGPase, which limits the rate of Suc formation, was of secondary importance in limiting the rate of hexogenesis when vacuolar AcInv activity was excessive. It is suggested that with the potato clones from this breeding program that AcInv (and its inhibitor) plays a dominant role in the hexogenic pathway by regulating the hexose:Suc ratio. The finding of a new protein that is reactive with UGPase antisera may prove to play an important function in the regulation of Suc formation in potatoes.  相似文献   

Estimation of potential recharge through direct seeded and transplanted rice fields in semi-arid regions of Punjab using HYDRUS-1D     

Gulati  Dinesh  Satpute  Sanjay  Kaur  Samanpreet  Aggarwal  Rajan 《Paddy and Water Environment》2022,20(1):79-92

Paddy and Water Environment - The present study utilizes soil water balance and HYDRUS-1D for estimating and predicting potential recharge in groundwater declining region of central Punjab,...  相似文献