Studies on in vitro degradability of mixed crude enzyme extracts produced from Pleurotus spp

A preliminary investigation was conducted to assess lignocellulolytic efficiency of crude extracts from three white-rot fungi, Pleurotus florida PF05 (PF), Pleurotus sajor-caju PS07 (PS) and Pleurotus eryngii PE08 (PE). The activities of CMC-ase, xylanase, beta-glucosidase, beta-xylosidase, laccase and Mn peroxidase in extracts were evaluated. PF produced its highest CMC-ase (317 UL(-1)'), beta-glucosidase (62 UL(-1)), beta-xylosidase (37 UL(-1)) and laccase (347 UL(-1)) activities while, PS produced highest xylanase (269 UL-(1)) and Mn peroxidase (69 UL(-1)) activities. In addition, crude extracts extracted were employed for their in vitro degradability assessment; and were evaluated with mono and mixed extracts separately to corn cob substrate. The losses in cell wall components and dry matter during 5 and 10 days incubations were analyzed after treatments of extracts. Maximum 8.2, 4.4 and 2.8% loss were found respectivelyin hemicellulose (HC), cellulose (C) and lignin (L) with mono extract of PF within 10 days. The influence of mono extract of each strain (PF PS and PE) and their mixed extracts (PF+PS, PF+PE, PS+PE and PF+PS+PE) on degradation of cell wall constituents were remarkably differed. The mixed extract treatment proved maximum 13.6% HC loss by PF+PS+PE extract, 9.2% loss in C by PF+PS extract and 5.2% loss of L by the PF+PS+PE extract treatment. The highest dry matter loss (8.2%) was recorded with PF+PS+PE mixed extract combination.     

Effect of sulphur and phosphorus on yield, quality and nutrient status of pigeonpea (Cajanus cajan)

A field experiment was conducted to study the impact of Sulphur(S) and Phosphorus (P) on yield, nutrient status of soil and their contents in pigeonpea (Cajanus cajan) during the year 2008-2009. Seven treatments were studied in Factorial Randomized Block Design with three replications. The treatment combinations were derived from three levels of sulphur (0, 20 and 40 kg S ha(-1)) and four levels of phosphorus (0, 25, 50 and 75 kg ha(-1)). The experimental soil was medium black, slightly calcareous, clay in texture and slightly alkaline in reaction. The results indicated a significant increase in grain yield (14.81 q ha(-1)) and straw yield (41.26 q ha(-1)) of pigeonpea after 20 kg S ha(-1) and 50 kg P2O5 ha(-1) treatment with common dose of nitrogen @ 30 kg ha(-1). The increase in grain and straw yield was 102.77 and 52.87% as compare to higher over control. Maximum number of pods plant(-1), maximum number of grains pod and test weight by this treatment was also observed as compared to control. Application of S and P improved soil fertility status and S alone did not influence P availability. Hence, in order to maintain the fertility status of the soil at high level, combine application of 20 kg S ha(-1) with 50 kg P2O5 ha(-1) is essential. The residual fertility status of soil is advocated for rainfed pigeonpea crop grown on vertisol in Vidarbha region.     

The optimal extinction of a renewable natural resource

This paper examines conditions for extinction when the net benefits from a renewable resource are a nonlinear function of the harvest rate. As in the linear case, extinction depends on the size of the interest rate relative to the growth potential of the species. Here, however, the size of the initial resource stock is also crucial. It is shown that extinction is optimal if the interest rate is greater than the growth potential of the species, but only for small initial stocks. Indeed, if the initial stock is sufficiently high, extinction need not be optimal even if the interest rate is infinite.     

Comparative study on the effect of chemicals on Alternaria blight in Indian mustard--a multi-location study in India

High severity of Altemaria blight disease is a major constraint in production of rapeseed-mustard in India. The aim of this study was to investigate the suppressive potential of chemicals viz., zinc sulphate, borax, sulphur, potash and calcium sulphate, aqueous extracts viz., Eucalyptus globosus (50 g l-1) leaf extract and garlic (Allium sativum) bulb (20 g l-1) extract, cow urine and bio-agents Trichoderma harzianum, Pseudomonas fluorescence in comparison with the recommended chemical fungicide (mancozeb), against foliar disease Alternaria blight of Indian mustard [Brassica juncea (L.) Czern. and Coss] under five different geographical locations of India. Mancozeb recorded the lowest mean severity (leaf: 33.1%; pod: 26.3%) of Alternaria blight with efficacy of garlic bulb extract alone (leaf = 34.4%; pod = 27.3%) or in combination with cow urine (leaf = 34.2%; pod = 28.6%) being statistically at par with the recommended chemical fungicide. Chemicals also proved effective in reducing Alternaria blight severity on leaves and pods of Indian mustard (leaf = 36.3-37.9%; pod = 27.5-30.1%). The effective treatments besides providing significant reduction in disease severity also enabled increase in dry seed yield of the crop (mancozeb = 2052 kg ha-1; garlic = 2006 kg ha-1; control = 1561 kg ha-1).