Effect of Barleria acanthoides Vahl., on root knot nematode infection and growth of infected okra and brinjal plants

Abstract Barleria acanthoides Vahl. is a xerophytic herb found in Karachi. In the present study B. acanthoides was used against root-knot nematode, Meloidogyne javanica (Treub) Chitwood, In vitro and greenhouse experiments. Its effects on root-knot infection, growth, chlorophylls and protein contents in leaves of okra (Abelmoschus esculentus (L.) Moench. var. Arka anamika) and brinjal (Solanum melongena L. var. Black beauty) plants were observed. Aqueous extracts of B. acanthoides significantly inhibited egg hatching of root-knot nematode and caused appreciable mortality of second stage juveniles of M. javanica In vitro. Soil amendment with shoot material of B. acanthoides at 1% and 2% w/w significantly suppressed nematode galling in okra and brinjal roots. B. acanthoides amendment resulted in enhanced growth, chlorophyll and total protein contents in okra and brinjal compared to unamended M. javanica inoculated plants

Soil amendment with halophytes induces physiological changes and reduces root-knot infection in eggplant and okra

Root-knot nematode, Meloidogyne javanica (Treub) Chitwood is a soil-borne plant pathogen of roots. Nematode infection results in altered plant growth and physicochemical processes due to gall formation. Many plants contain unique biochemicals that have biocidal properties and offer a potential novel approach to suppress the nematode populations in soil and improve growth of crop plants. In the present study effect of some indigenous halophytic plant species (Tamarix indica Willd, Suaeda fruticosa Forssk and Salsola imbricata (Schultz) Dandy) were tested against M. javanica. Tested halophytes significantly (P<0.001) reduced egg hatching and caused mortality of second stage juveniles (J2) in vitro. These halophytes when incorporated in soil (0.3, 0.5 and 1% w/w) markedly increased growth of eggplant (Solanum melongena L. cv. Black beauty) and okra (Abelmoschus esculentus [L.] Moench. cv. Arka anamika) and provided control of root-knot infection at higher doses (0.5 and 1%). Amended eggplants and okra showed significant (P<0.001) increase in chlorophylls and decrease in chlorophyll a/b ratio. Protein concentration in leaves of both the plants were increased with 1% amendment of S. fruticosa and S. imbricata. While nucleic acid concentrations were varied with different treatments. &nbsp

Effect of Heavy Metal Pollution on Leaf Litter Decomposition of Two Species of Mangroves, Avicennia marina and Rhizophora mucronata

Decomposition of litter is influenced by physicochemical characteristics of the habitat which is affected by pollution. In this study the effect of heavy metals on leaf litter decomposition of two mangrove species, Avicennia marina and Rhizophora mucronata is investigated. An experiment was conducted in which litter bags were half-buried in mangrove soil in earthen pots in a greenhouse in which close to natural conditions were maintained and they were treated with 0, 5 and 10 ppm Ni and Pb as a solution of sea water for 16 weeks. Periodic observations were taken on the dry weight remaining and the four factor ANOVA was performed. All four factors (species, heavy metals, concentrations, time) were found to be significant (P at the most 0.05) while some of the interactions were also significant. Half-life and rate of decomposition, k were calculated on the basis of 12 periodic weight loss observations. The litter decomposition followed an exponential decay curve in all cases. The highest rate of decomposition (0.0155 gDWd-1) and the shortest half life (7.44 days) were found for the control of Avicennia marina. In general, decomposition rate of A. marina was more rapid compared to that of R. mucronata. Whereas, the decomposition in treatments with heavy metals were found to be slower than in the controls, the minimum of which (0.0105 gDWd-1) and the longest half life (18.17 days) were found in Rhizophora mucronata leaves treated with 10 ppm Pb. Lead appears to be more inhibitory to the process of litter decomposition compared to nickel. The two mangrove species responded differentially to the heavy metal concentrations. The influence of heavy metals in the decomposition process is discussed

Effect of Heavy Metal Pollution on Leaf Litter Decomposition of Two Species of Mangroves, Avicennia marina and Rhizophora mucronata

Decomposition of litter is influenced by physicochemical characteristics of the habitat which is affected by pollution. In this study the effect of heavy metals on leaf litter decomposition of two mangrove species, Avicennia marina and Rhizophora mucronata is investigated. An experiment was conducted in which litter bags were half-buried in mangrove soil in earthen pots in a greenhouse in which close to natural conditions were maintained and they were treated with 0, 5 and 10 ppm Ni and Pb as a solution of sea water for 16 weeks. Periodic observations were taken on the dry weight remaining and the four factor ANOVA was performed. All four factors (species, heavy metals, concentrations, time) were found to be significant (P at the most 0.05) while some of the interactions were also significant. Half-life and rate of decomposition, k were calculated on the basis of 12 periodic weight loss observations. The litter decomposition followed an exponential decay curve in all cases. The highest rate of decomposition (0.0155 gDWd-1) and the shortest half life (7.44 days) were found for the control of Avicennia marina. In general, decomposition rate of A. marina was more rapid compared to that of R. mucronata. Whereas, the decomposition in treatments with heavy metals were found to be slower than in the controls, the minimum of which (0.0105 gDWd-1) and the longest half life (18.17 days) were found in Rhizophora mucronata leaves treated with 10 ppm Pb. Lead appears to be more inhibitory to the process of litter decomposition compared to nickel. The two mangrove species responded differentially to the heavy metal concentrations. The influence of heavy metals in the decomposition process is discussed

Impact of sample size on principal component analysis ordination of an environmental data set: effects on eigenstructure

In this study, we used bootstrap simulation of a real data set to investigate the impact of sample size (N = 20, 30, 40 and 50) on the eigenvalues and eigenvectors resulting from principal component analysis (PCA). For each sample size, 100 bootstrap samples were drawn from environmental data matrix pertaining to water quality variables (p = 22) of a small data set comprising of 55 samples (stations from where water samples were collected). Because in ecology and environmental sciences the data sets are invariably small owing to high cost of collection and analysis of samples, we restricted our study to relatively small sample sizes. We focused attention on comparison of first 6 eigenvectors and first 10 eigenvalues. Data sets were compared using agglomerative cluster analysis using Ward’s method that does not require any stringent distributional assumptions

Acute pancreatitis due to hypertriglyceridemia

Apart from other interventions, surveillance remains a major focus of the national response to HIV/AIDS. However, with a shift in the epidemic pattern, the existing surveillance strategies are barely insufficient and long­term structural changes are desirable. This article provides a conceptual framework for developing a scientific system for HIV surveillance in Pakistan. Second generation surveillance system including repeated cross­sectional surveys in high risk population groups are suggested to collect behavioral and serological data at regular intervals on an annual basis to monitor the epidemic trend as well as the associated behaviors. In addition, multiple data resources have been highlighted, which could be coordinated to describe the epidemic pattern in the country. This information should form the basis for national prevention planning and ought to be used for making sensible choices through which prevention efforts are most likely to reduce new infections

Impact of indiscriminate disposal of untreated effluents in Korangi creek, Karachi, Pakistan

Abstract Korangi creek is one of the major creek of Indus delta which receives both untreated industrial and domestic effluents. It provides an important waterway to approach Port Qasim. A survey of water quality and the sediments along with biodiversity of benthic fauna was conducted. A total of 24 water and 14 sediment samples were collected from February to November 2014. The mean pH of seawater and sediment samples was 7.41 and 7.5, respectively. The mean salinity of seawater was 36‰. The mean BOD5 of seawater and sediments was 288 mg/l and 1645 mg/kg, respectively, while COD was 1231.9 mg/l and 1645.3 mg/kg, respectively. Cyanide content was low in seawater but slightly higher in sediment. Mean phenol level of seawater and sediment was 0.61 mg/l and 8.11 mg/kg. Heavy metals in the seawater was established to be in the order Pb > Cu > Cr > Ni > Zn > As. The trend in sediment was slightly different and followed the following pattern Pb > As > Ni > Cu > Cr > Zn. The distribution pattern of the estimated variables for seawater and sediments was examined using the principal component analysis and cluster analysis. Annelida and Arthropoda were the dominant components of biodiversity. Taxa diversity was measured and Shannon index (H) ranged between 1.364 and 1.969 while equitability (J) ranged between 0.549 and 0.862. Dominance (D) was in the range of 0.156–0.436