Rice-residue biochar influences phosphorus availability in soil with contrasting P status

ABSTRACT

Thermo-chemical conversion of crop residues to produce biochar is an emerging strategy in the context of sustainable phosphorous (P) use and residue management. An incubation study for 90 d was conducted to investigate the effects of rice-residue biochar (0, 10, 20 and 40 g kg^?1) in combination with inorganic-P (KH₂PO₄) (0, 25 and 50 mg kg^?1) on phosphorous availability in medium- and high-P status soils. Increasing biochar addition rates alone or in combination with inorganic-P resulted in a significant increase in P pools, i.e. plant available P or Olsen-P (from 8 to 132 mg kg^?1 in medium-P and 15 to 160 mg kg^?1 in high-P soils), microbial biomass P and various mineral-bound inorganic-P fractions in the order (Ca-P > organic-P > Al-P > loosely held/soluble-P > Fe-P > reductant soluble-P). Further, lower phosphatase activity (19–50%) with increasing rates of biochar addition in both soils elucidates the ability of biochar to act as a long-term source of available P in the experimental soils. The results demonstrate that rice-residue biochar can directly or indirectly enhance the status of available P in soils and hence can be used as a beneficial amendment to meet the crop P demand.     

Differences between tight and loose cultures: a 33-nation study

With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.     

Generation of interspecific hybrids between <Emphasis Type="Italic">Trifolium vesiculosum</Emphasis> and <Emphasis Type="Italic">T. alexandrinum</Emphasis> using embryo rescue

Interspecific hybrids were developed between Trifolium alexandrinum cultivar Wardan × Trifolium vesiculosum and T. alexandrinum cultivar BL1 × T. vesiculosum through embryo rescue, as the crosses failed to set seed under natural conditions. Trifolium vesiculosum was used as a donor/male parent in this study as it is reported to possess tolerance to stem rot and high forage yield. Fertilization in crossed florets of the crosses was manifested from the recovery of swollen ovaries (< 7.80%) and confirmed from the presence of one degenerated ovule in most (> 93.00%) of the swollen ovaries. The hybrid embryos at various developmental stages (heart, torpedo and cotyledonary) were rescued at a frequency of 2.56% from Wardan × T. vesiculosum and 6.12% from BL1 × T. vesiculosum. Differentiation occurred only in the cotyledonary stage embryos, resulting in 17 putative interspecific hybrid plantlets. The assessment of plantlet hybridity through SSR markers (for the alleles inherited from the donor parent), micromorphological leaf traits (leaf texture and stomata) and morphological characters (plant height, leaflet length and width) confirmed production of two interspecific hybrids designated as AV1 and BV3 representing both the crosses. AV1 displayed moderate resistance and BV3 was resistant to stem rot.     

Stimulatory effect of phosphate-solubilizing fungal strains (Aspergillus awamori and Penicillium citrinum) on the yield of chickpea (Cicer arietinum L. cv. GPF2)

The effect of six phosphate-solubilizing fungi (PSF, two strains of Aspergillus awamori, and four of Penicillium citrinum) isolated from rhizosphere of various crops, was observed on the growth and seed production of chickpea plants (Cicer arietinum L. cv. GPF2) in pot experiments. The phosphate (P) solubilizing activity of PSF in liquid varied from 38 to 760 μg ml^?1 for tricalcium phosphate (TCP) and 28–248 μg ml^?1 for mussoorie rock phosphate (MRP). All PSF isolates were biocompatible and produced growth-promoting hormone, Indole acetic acid (IAA), varying in concentration from 2.5 to 9.8 μg ml^?1. Of the various pot experiments carried out in green house, maximum stimulatory effect on chickpea plants growth was observed by inoculation of two A. awamori strains. This treatment resulted in 7–12% increase in shoot height, nearly three-fold increase in seed number and two-fold increase in seeds weight as compared to the control (un-inoculated) plants. Inoculation of four strains of P. citrinum exhibited lesser stimulatory effect. It showed 7% increase in shoot height, two-fold increase in seed number and 87% increase in seeds weight as compared to the control plants. However, a consortium of all the six fungal isolates showed no stimulatory effect on chickpea plants growth.     

Genomic analysis of local isolate of Mycobacterium avium subspecies paratuberculosis

Mycobacterium avium subspecies paratuberculosis (MAP) causes Johne's disease (JD or paratuberculosis) in animals and has also been implicated in Crohn's disease of humans. It has been shown that MAP is endemic in animal population of India. Understanding of heterogeneity among MAP strains is important both for diagnosis and design control measures. Genotyping and epidemiological investigations revealed that MAP 'Bison type' was the predominant strain infecting domestic ruminant population in India. MAP 'Bison type' has also been reported from USA. A number of comparative genomics studies have been conducted to understand 'Cattle type' and 'Sheep type' strains. However, present study was the first attempt to characterize MAP 'Bison type' S5 using different markers including IS900, ISMAP02, IS1311, LSPs and SSRs. Study showed that MAP S5 is similar to MAP K10 in terms of number of IS900, IS1311 and ISMAP02 elements. There was high sequence similarity for IS900 and ISMAP02 between MAP K10 and MAP S5. However, this study also reported genetic differences between two strains. In some IS1311 loci, TG gap at 64th and 65th position was observed in MAP S5. Further sequencing of few more MAP isolates confirmed that this gap was specific to indigenous MAP 'Bison type' and can be further used as molecular signature. ISMAP02 locus 1 was observed at polymorphic position in MAP S5 compared to MAP K10. MAP 'Bison type' S5 also showed polymorphic profile for LSP(P)4. Polymorphism was also observed in SSRs. This pilot study may form the basis for future epidemiological investigations.     

Trichoderma sp. endochitinase and β-1,3-glucanase impede Rhizoctonia solani growth independently,and their combined use does not enhance impediment

Rhizoctonia solani causing rice sheath blight is responsible for significant crop yield losses. Trichoderma spp., biological control agents, have been reported to antagonize R. solani through coordinated action of several cell wall-degrading enzymes including endochitinase and β-1,3-glucanase. In this study two antifungal genes, encoding endochitinase and β-1,3-glucanase, isolated from Trichoderma sp. antagonistic to R. solani, were cloned individually in His-tagged expression vectors and mobilized in Escherichia coli for protein expression. The purified proteins assayed in vitro with R. solani impeded pathogen growth independently by causing hyphal distortions revealed through scanning electron microscopy. The combined use of endochitinase and β-1,3-glucanase did not enhance the inhibition. The distortions caused by endochitinase were due to catalytic activity of Glu172 and Asp241 residues on glycosidic linkages in chitin polymers, whereas Glu628, Tyr631, and Asp569 in β-1,3-glucanase targeted glucan polymers. The distinctions of this study from earlier reports are (a) chitin polymers in the R. solani cell wall are exposed and not embedded within the β-glucan matrix; (b) chitin and β-1,3-glucan are vital polymers in the R. solani cell wall, rather than chitin as the only main polymer; and (c) hyphal tips of R. solani remain unaffected after an antifungal assay with endochitinase and β-1,3-glucanase, instead of exhibiting distortion.     

Abundance and diversity of arthropods in transgenic Bt and non-Bt cotton fields under Indian conditions

Phytoparasitica - Two-year field studies during Kharif 2015 and 2016 were conducted to assess the abundance and diversity of arthropod communities of Bt cotton carrying Cry1Ac and Cry2Ab proteins...