Influence of the root endophyte Piriformospora indica on the plant water relations,gas exchange and growth of Chenopodium quinoa at limited water availability

This study aimed to evaluate the ability of Piriformospora indica to colonize the root of Chenopodium quinoa and to verify whether this endosymbiont can improve the growth, performance and drought resistance of this species. The study delivered, for the first time, evidence for successful colonization of P. indica in quinoa. Hence, pot experiment was conducted in the greenhouse, where inoculated and non‐inoculated plants were subjected to ample (40%–50% WHC) and deficit (15%–20%WHC) irrigation treatments. Drought adversely influenced the plant growth, leading to decline the total plant biomass by 74%. This was linked to an impaired photosynthetic activity (caused by lower g_s and C_i/C_a ratio; stomatal limitation of photosynthesis) and a higher risk of ROS production (enhanced ETR/A_gross ratio). P. indica colonization improved quinoa plant growth, with total biomass increased by 8% (controls) and 76% (drought‐stressed plants), confirming the growth‐promoting activity of P. indica. Fungal colonization seems to diminish drought‐induced growth hindrance, likely, through an improved water balance, reflected by the higher leaf ψ_w and g_s. Additionally, stomatal limitation of photosynthesis was alleviated (indicated by enhanced C_i/C_a ratio and A_net), so that the threat of oxidative stress was minimized (decreased ETR/A_gross). These results infer that symbiosis with P. indica could negate some of the detrimental effects of drought on quinoa growth, a highly desired feature, in particular at low water availability.     

Development of an appropriate procedure for estimation of RUSLE EI30 index and preparation of erosivity maps for Pulau Penang in Peninsular Malaysia

Pluviographic data at 15 min interval from 6 stations in Pulau Penang of Peninsular Malaysia were used to compute rainfall erosivity factor (R) for the revised universal soil loss equation (RUSLE). Three different modelling procedures were applied for the estimation of monthly rainfall erosivity (EI₃₀) values. While storm rainfall (P) and duration (D) data were used in the first approach, the second approach used monthly rainfall for days with rainfall ≥ 10 mm (rain₁₀) and monthly number of days with rainfall ≥ 10 (days₁₀). The third approach however used the Fournier index as the independent variable. Based on the root mean squared error (RMSE) and the percentage error (PE) criteria, models developed using the Fournier index approach was adjudged the best with an average PE value of 0.92 and an average RMSE value of 164.6. Further, this approach was extended to the development of a regional model. Using data from additional sixteen stations and the Fournier index based regional model, EI₃₀ values were computed for each month. ArcView GIS was used to generate monthly maps of EI₃₀ values and also annual rainfall erosivity (R). The rainfall erosivity factor (R) in the region was estimated to vary from 9000 to 14,000 MJ mm ha^− 1 h^− 1 year^− 1.     

Chitosan-filled polypropylene composites: The effect of filler loading and organosolv lignin on mechanical,morphological and thermal properties

In this work, the effect of organosolv lignin on properties of polypropylene (PP)/chitosan composites was investigated. Mechanical and thermal properties of the composites were analyzed by means of ASTM D 638-91, ASTM D 256, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Tensile strength and elongation at break of the PP composites decreased upon the presence of chitosan filler, but Young’s modulus improved. Impact strength was found to increase with the maximum value at 30 php of filler loading. At a similar loading, treated PP/chitosan composites were found to have higher tensile strength, elongation at break, Young’s modulus as well as impact strength than untreated composites. Furthermore, the presence of organosolv lignin imparted a plasticizing effect. Thermal properties of the treated PP/chitosan composites were better as compared with the untreated PP/chitosan composites; although the chemical treatment did not alter the thermal degradation mechanism. In addition, the obtained results were comparable to results from previous studies. This finding implied that the organosolv lignin could be a potential reagent to replace its synthetic counterpart.     

Metabolism, uptake and translocation of 14C-paraquat in resistant and susceptible biotypes of Crassocephalum crepidioides (Benth.) S. Moore

The metabolism, uptake and translocation of paraquat in resistant (R) and susceptible (S) biotypes of Crassocephalum crepidioides (Benth.) S. Moore (redflower ragleaf) at the 10-leaf stage was investigated. A study on the properties of leaf surface was carried out to examine the relationship between leaf surface characters and paraquat absorption. The extractable paraquat was not metabolized by the leaf tissue of either the resistant or susceptible biotypes. Differential metabolism, therefore, does not appear to play a role in the mechanism of resistance. Both biotypes did not show any significant difference in the amount of cuticle and trichome densities. Furthermore, both biotypes are identical in the structure of stomata, trichomes and epicuticular wax. The results of the leaf surface studies are in agreement with the findings of the uptake study. Both biotypes demonstrated no significant difference in absorption between the resistant and susceptible biotypes. However, 10% of the absorbed ¹⁴C-paraquat into the S biotype was translocated basipetally, but not in the R biotype. The results of this study suggest that in C. crepidioides , differential translocation may contribute to the mechanism of resistance at the 10-leaf stage.     

Sulfur uptake and translocation in maize (zea mays) grown in a high pH soil treated with elemental sulfur

A glasshouse experiment was conducted to elucidate the influence of elemental sulfur (S) application rates (0, 0.5, 1.0, and 2.0 g S kg^?1 soil) on the release and uptake of S at 0, 20, and 40 days after incubation. Results showed that there was a progressive upward trend in maize leaves, stem, and root S content with application of elemental S. However, maize production followed a nonlinear model. Plants grown in untreated soils suffer from S deficiency and addition of elemental S at a rate of 0.5 g S kg^?1 soil alleviated S deficiency. The decrease in maize performance due to the highest S application rate was not related to S toxicity. The greatest leave, stem, and root productions were obtained at S concentrations of 0.41, 0.58, and 0.2%, respectively. Overall, application of elemental S at a rate of 0.5 g S kg^?1 soil is recommended for maize performance improvement.     

2种昆虫病原真菌对草地贪夜蛾体表侵染模式的扫描电镜观察

【目的】在前期筛选获得对草地贪夜蛾高效致病真菌球孢白僵菌（Beauveria bassiana）菌株GZSL-1和玫烟色虫草（Cordyceps fumosorosea）菌株IFCF01的基础上,进一步明确2株菌株在草地贪夜蛾体表的侵染模式,为阐明菌株致病机理,提高昆虫病原真菌对草地贪夜蛾的防效提供理论依据。【方法】利用扫描电镜观察草地贪夜蛾2龄幼虫分别接种菌株GZSL-1和IFCF01（孢子悬浮液浓度为1.0×107孢子/mL）后分生孢子在幼虫体表附着、萌发、穿透和增殖的过程。【结果】菌株GZSL-1和IFCF01萌发后均可形成附着胞,草地贪夜蛾幼虫体表结构对2株菌株分生孢子萌发、附着和穿透芽管长度有不同程度的影响。2株菌株在各结构区均有较高的萌发率（> 90.00%）和附着胞率（> 80.00%）,在平缓结构区比瘤状突起结构区观察到更短的穿透芽管。在各结构区,菌株GZSL-1形成的穿透芽管长度均短于菌株IF-CF01相应的芽管长度,在平缓结构区,菌株GZSL-1的穿透芽管长度显著短于菌株IFCF01（P<0.05）。菌株GZSL-1和IFCF01分生孢子接种后分别在16和8 h内萌发,在24和32 h内普遍出现穿透结构穿透草地贪夜蛾幼虫体壁。2株菌株的初级和次级分生孢子分别在接种后72和96 h内出现。【结论】扫描电镜观察证实球孢白僵菌菌株GZSL-1和玫烟色虫草菌株IFCF01对草地贪夜蛾具有高致病性,揭示了病原真菌分生孢子在草地贪夜蛾虫体上的侵染过程,结果为后续2株菌株的改良及田间应用打下理论基础。     

Allometric equations for estimating the above-ground biomass in tropical lowland Dipterocarp forests

Allometric equations can be used to estimate the biomass and carbon stock of forests. However, so far the equations for Dipterocarp forests have not been developed in sufficient detail. In this research, allometric equations are presented based on the genera of commercial species and mixed species. Separate equations are developed for the Dipterocarpus, Hopea, Palaquium and Shorea genera, and an equation of a mix of these genera represents commercial species. The mixed species is constructed from commercial and non-commercial species. The data were collected in lowland mixed Dipterocarp forests in East Kalimantan, Indonesia. The number of trees sampled in this research was 122, with diameters (1.30 m or above buttresses) ranging from 6 to 200 cm. Destructive sampling was used to collect the samples where diameter at breast height (DBH), commercial bole height (CBH), and wood density were used as predictors for dry weight of total above-ground biomass (TAGB). Model comparison and selection were based on Akaike Information Criterion (AIC), slope coefficient of the regression, average deviation, confidence interval (CI) of the mean, paired t-test. Based on these statistical indicators, the most suitable model is ln(TAGB) = c + αln(DBH). This model uses only a single predictor of DBH and produces a range of prediction values closer to the upper and lower limits of the observed mean. Model 1 is reliable for forest managers to estimate above-ground biomass, so the research findings can be extrapolated for managing forests related to carbon balance. Additional explanatory variables such as CBH do not really increase the indicators’ goodness of fit for the equation. An alternative model to incorporate wood density must be considered for estimating the above-ground biomass for mixed species. Comparing the presented equations to previously published data shows that these local species-specific and generic equations differ substantially from previously published equations and that site specific equations must be considered to get a better estimation of biomass. Based on the average deviation and the range of CI, the generalized equations are not sufficient to estimate the biomass for a certain type of forests, such as lowland Dipterocarp forests. The research findings are new for Dipterocarp forests, so they complement the previous research as well as the methodology of the Good Practice Guidance for Land Use and Land Use Change and Forestry (GPG-LULUCF).     

Comparative efficacy sensitivity and specificity of the tests used for the Diagnosis of Helicobacter pylori

Abstract: A total number of 157 samples were examined by 4 different tests-In-house rapid urease (iRUT), Culture, Histopathology and Immunochromatography (Immuno CardSTAT) for the detection of Helicobacter pylori from the patients reported to Hospital Kuala Lumpur, Malaysia during 2007 to 2008. Out of the samples examined 47 (29.9%) were positive for H. pylori by the tests used in the laboratory. Efficacy of detection of the bacteria by the tests- In-house rapid urease, Culture, Histopathology and Immuno CardSTAT were 31.8, 13.9, 30.3 and 32.8%, respectively. However, sensitivity and specificity of the iRUT were 91.5 and 93.6%, respectively and the Positive Predictive Value (PPV) was 86% and the Negative Predictive Value (NPV) was 96.3%. The sensitivity for Immuno CardSTAT rapid test was 100% and the specificity was 79.3%. The PPV was 50% and the NPV was 100%. Convenient methods to the authors were 'In house rapid urease test and Immunochromatography though variability of specificities were observed.