Technique for visual demonstration of germinating arbuscular mycorrhizal spores and their multiplication in pots

We describe a simple technique for the germination of arbuscular mycorrhizal (AM)–fungal spores and their multiplication in pots. Glomus fasciculatum, G. mosseae, and Gigaspora margarita were used. A single wheat seedling was tied to a glass slide, previously covered with filter paper with the help of thread. One single surface‐sterilized AM‐fungal spore was placed on the middle portion of the root of the wheat seedling using a sterilized syringe. The slide was placed vertically in a 100 mL glass beaker filled with 25 mL of root exudates–water (1:4, v/v) solution, which was collected by growing twenty wheat seedlings in a 150 mL beaker filled with 100 mL sterilized distilled water for 7 d. The slide was observed daily using a compound microscope to follow the time course of germination. In this technique, the spore is directly in contact with the host root, and a visualization of spore germination, hyphal development, and appressorium formation is possible without disrupting fungal growth or the establishment of the symbiosis. The method allows to document the germination events and to assess hyphal‐elongation rates by photographing the same spore on consecutive days. The inoculated seedling was used to initiate single‐spore multiplication in a sterilized (autoclave on 3 alternate days at 120°C for 120 min at 1.05 kg cm^–2 pressure) potted sandy soil (150 mL volume) into which the slide with the inoculated seedling was inserted carefully through a previously made slit. The wheat seedlings in all pots (4 treatments and 15 replications) became colonized by mycorrhiza, confirming that the establishment of the AM‐fungal symbiosis is highly reproducible. Our technique permits the relatively undisturbed growth of the symbiotic partners, the visualization of germinating AM‐fungal spores, and their multiplication in pots. This simple and low‐cost method facilitates the production of pure lines of AM fungi from single spores, allowing for the study of intraspecific variation and potentiality for cytological, biochemical, physiological, and taxonomical studies.     

Fodder production and soil health with conjunctive use of saline and good quality water in ustipsamments of a semi‐arid region

Food and fodder shortage in arid and semi‐arid regions force farmers to use marginal quality water for meeting the water requirement of crops which result in low quality, reduced production and an adverse impact on soil properties. A field study on loamy‐sand (Hyperthermic Typic Ustipsamments) saline soil was conducted during 1999–2001 at Central Institute for Research on Buffaloes, Hisar. This involved assessment of effects of conjunctive use of saline water, EC = 4·6–7·4 dSm⁻¹, SAR = 14–22 ((mmol⁻¹)^½ with good quality water on five fodder crop rotations: oat‐sorghum (Avena sativa‐–Sorghum bicolor), rye grass–sorghum (Loleum rigidum—Sorghum bicolor), Egyptian clover—sorghum (Trifoleum alexandrinum—Sorghum bicolor), Persian clover—sorghum (Trifoleum resupinatum—Sorghum bicolor) and Indian clover–sorghum (Melilotus indica—Sorghum bicolor) and certain soil properties associated with it. Leguminous winter fodder crops were more sensitive to poor quality water use. Reductions in fodder yield with use of saline water alone throughout season were 85, 68, 54, 42, 36 and 26 per cent in Indian clover, Egyptian clover, Persian clover, oat, rye grass and sorghum respectively as compared to good quality water. Leguminous fodder crops produced protein rich (12–14 per cent) and low fibre (18–20 per cent) fodder as compared to poor quality grassy fodder under good quality water irrigation but their quality deteriorated when saline water was used. These leguminous crops accumulated proportionately higher Na⁺ (1·58 per cent) resulting in adverse impact on their growth as compared to grassy fodder crops. Higher soil salinity (12·2 dSm⁻¹), SAR = 20 (mmol⁻¹)^½ was recorded with saline water irrigation; and slight adverse impact was noticed on infiltration rate and contents of water dispersible clay. Alternate cyclic use of canal and saline water could be an option for fodder production under such conditions. Copyright © 2006 John Wiley & Sons, Ltd.     

Foliar fertilization of nickel affects growth,yield component and micronutrient status of barley (Hordeum vulgare L.) grown on low nickel soil

Foliar application of nickel (Ni) has higher use efficiencies and is preferred over soil application in view of its very low requirement. Pot experiments were conducted during winter season of 2012-2013 and repeated during 2013-2014. Treatments consisted of twelve Ni levels applied as nickel sulphate (NiSO4.7H₂O) spray (T₁-Ni_0%, T₂-Ni_0.05%, T₃-Ni_0.1%, T₄-Ni_0.2%, T₅-Ni_0.3%, T₆-Ni_0.4%, T₇-Ni_0.5%, T₈-Ni_0.6%, T₉-Ni_0.7%, T₁₀-Ni_0.8%, T₁₁-Ni_0.9%,and T₁₂-Ni_1.0%,) with recommended doses of fertilizers (RDF) applied in all pots. The result showed that growth and yield attributes viz. plant height, leaf greenness index, number of tillers, number of ears pot^-1, number of grains ear^-1, straw yield, grain yield and weight of 1000 grains of barley was the maximum with three foliar application of 0.2% of NiSO4.7H₂O (T₄-Ni_0.2%) at 20, 40, and 60 days after sowing (DAS) during both the years. The concentration of Fe, Mn and Zn in grain increased significantly up to T₄-Ni_0.2% and after this level, a significant decline was recorded during both the years. As regards to the concentration of Ni is concerned, it increased significantly both in grain and straw with increasing levels of Ni spray and the maximum concentration was at T₁₂-Ni_1.0%, during both the years. The uptake of Fe, Mn, Cu and Zn in grain of barley increased significantly during both the years up to T₄-Ni_0.2%,thereafter, it declined significantly with successive increase in dose of Ni spray. Thus 0.2% foliar spray of NiSO4.7H₂O significantly increased growth, yield and Fe, Cu, Mn, Zn (micronutrients) status in barley.     

Isolation, purification, and identification of protein associated with corn fiber gum

Corn fiber gum (CFG), an alkaline hydrogen peroxide extract of the corn kernel milling byproduct "corn fiber", is a proteinaceous arabinoxylan with protein content ranging from ca. 2 to 9% by weight for CFG samples isolated from different corn milling fiber sources. Several studies have suggested that protein associated with CFG could be partly responsible for its excellent emulsifying properties in oil-in-water emulsion systems. Nevertheless, the composition and identity of the protein component has never been determined. In the present study, CFG was deglycosylated by treating with trifluoromethanesulfonic acid, and the resulting proteins were purified by passage through C18 solid phase extraction cartridges. The proteins were then separated and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein band from the gel was treated with a proteolytic enzyme, chymotrypsin, and the resulting peptides were cleaned using C18 Zip Tip pipet tips and analyzed using matrix-assisted laser desorption/ionization with automated tandem time-of-flight mass spectrometry. The partial sequences derived from the mass spectrometry analyses of the resulting chymotryptic peptides were found to be similar to the 22-kDa alpha-zein Z1 (az22z1) protein (a major storage protein in corn endosperm) when queried against the primary sequences from the National Center for Biotechnology Information database. This is the first report that this hydrophobic protein is associated with CFG and may explain why CFG is an excellent emulsifier for oil-in-water emulsion systems.     

An Overview of Biodegradation of LNAPLs in Coastal (Semi)-arid Environment

Contamination of soil and water due to the release of light non-aqueous phase liquids (LNAPLs) is a ubiquitous problem. The problem is more severe in arid and semi-arid coastal regions where most of the petroleum production and related refinery industries are located. Biological treatment of these organic contaminated resources is receiving increasing interests and where applicable, can serve as a cost-effective remediation alternative. The success of bioremediation greatly depends on the prevailing environmental variables, and their remediation favoring customization requires a sound understanding of their integrated behavior on fate and transport of LNAPLs under site-specific conditions. The arid and semi-arid coastal sites are characterized by specific environmental extremes; primarily, varying low and high temperatures, high salinity, water table dynamics, and fluctuating soil moisture content. An understanding of the behavior of these environmental variables on biological interactions with LNAPLs would be helpful in customizing the bioremediation for restoring problematic sites in these regions. Therefore, this paper reviews the microbial degradation of LNAPLs in soil-water, considering the influences of prevailing environmental parameters of arid and semi-arid coastal regions. First, the mechanism of biodegradation of LNAPLs is discussed briefly, followed by a summary of popular kinetic models used by researchers for describing the degradation rate of these hydrocarbons. Next, the impact of soil moisture content, water table dynamics, and soil-water temperature on the fate and transport of LNAPLs are discussed, including an overview of the studies conducted so far. Finally, based on the reviewed information, a general conclusion is presented with recommendations for future research subjects on optimizing the bioremediation technique in the field under the aforesaid environmental conditions. The present review will be useful to better understand the feasibility of bioremediation technology, in general, and its applicability for remediating LNAPLs polluted lands under aforesaid environments, in particular.     

Protein and oil rich wild horsegram

Protein and oil content were analysed for the seeds of the wild horsegram (IC 212722) belonging to the new species Macrotyloma sar-garhwalensis Gaur and Dangwal. Seed contains 38.37 ± 1.03% crude protein. More than 95% of the total nitrogen belongs to protein nitrogen. Contribution of albumin-globulin, glutelin and residual protein fraction to the total seed protein accounts for 75.27%, 17.52% and 7.19% respectively. The combined albumin-globulin protein (Lowrys protein) fraction of the IC 212722 seed protein contains 16.82% nitrogen, in comparison to 18.19%, 15.82%, 16.81% and 16.42% nitrogen found in a similar part of three cultivated lines of SK-2001, VLG-1, Raipur Local and standard protein (Bovine Albumin Fraction V, Sigma Chemical Co.), respectively studied in the present experiment. The true seed protein (34.88%) content of IC-212722 line was about two times higher than the other three-horsegram lines.IC 212722 line also contains 10.85 ± 0.16% ether extracted materials, in comparison to 0.80–1.47% materials found in the other three-horsegram lines.     

Why grain yield of transplanted rice on permanent raised beds declines with time?

Permanent raised beds are being promoted as a resource conservation technology for rice–wheat systems in Indo-Gangetic plains (IGP) to improve the water productivity of rice and wheat in addition to other benefits, as furrow irrigation can be more efficient than flood irrigation. However, several studies carried out in the NW IGP have shown rice grain yields to decrease with the increasing age of the beds. The present study was conducted on a deep alluvial loam (Ustochrept) in a farmer's field at Phillaur, Punjab, India, to identify possible reasons for the declining grain yield of rice on the permanent raised beds (37.5 cm wide alternating with 30 cm wide furrows 15 cm deep) in comparison to fresh raised beds. The beds were formed with a bed planter drawn by a 35-hp 4-wheel tractor, which was also used to direct drill wheat on the permanent beds each year, and to reshape the beds prior to each rice crop. This paper reports a study of rice root distribution and mass at the end of the vegetative stage, and soil bulk density after harvest, for transplanted rice on permanent beds (4th rice crop, 8th crop) in comparison with transplanted rice on fresh beds (1st crop).Rice grain yield declined linearly with increasing age of the permanent beds. It decreased by 19% in 2004, 45% in 2005 and 59% in 2006 from 4.64 t ha⁻¹ in 2003. In situ exposure of root profiles on permanent and fresh beds revealed that the horizontal spread of roots on permanent beds (6 cm from the base of the plant at 18 cm depth and 12 cm at 27 cm depth) was much less than on fresh beds (12 cm at 18 cm depth and 18 cm at 27 cm depth). The root mass density in at 0–15 cm the middle of the fresh beds was 59% higher than on the permanent beds. Bulk density was significantly higher under the shoulder and side of the permanent beds to the depth of sampling (0–15 cm) than under the fresh beds at the same positions across the furrow. The decline in performance of rice on beds as the beds aged was at least partly due to compaction of the permanent beds by the tractor tyres, which had width similar to that of the top of the furrow. This hindered the spread of the roots particularly towards the beds.     

Stem and leaf rust resistance in wild relatives of wheat with D genome (Aegilops spp.)

Resistance to stem rust and leaf rust in five D genome species of wheat viz., 267 accessions of Aegilops tauschii Coss., 39 of Ae. cylindrica Host, 17 of Ae. ventricosa Tausch, 4 of Ae. crassa Boiss. and 8 of Ae. juvenalis (Thell.) Eig were evaluated at adult plant stage. Two hundred and thirty nine (90 %) accessions of Ae. tauschii, 30 (77 %) of Ae. cylindrica, 16 (94 %) of Ae. ventricosa, 3 (75 %) of Ae. crassa Boiss. and 5 (62.5 %) of Ae. juvenalis were resistant to stem rust pathotypes prevalent in South India at Wellington under field condition. Invariably, all the accessions of the five species were resistant to leaf rust pathotypes. Quantitative measurement of disease using area under the disease progress curve revealed the slow progress of disease in the resistant accessions compared to susceptible check (Agra Local). Since all the five species have D genome, it could be concluded that the genes present in D genome might play a vital role in leaf rust resistance, but in case of stem rust resistance wide range of differential response was noticed. Among the species evaluated, Ae. tauschii was exploited to a larger extent, followed by Ae. ventricosa and Ae. cylindrica for leaf and stem rust resistance because of the homology of D genome with hexaploid bread wheat. While, Ae. crassa and Ae. juvenalis could not be utilized so far, possibly due to partial homology which makes the transfer of traits difficult. So, these species have considerable potential as a source of rust resistance and may enhance the existing gene pool of resistance to stem and leaf rusts.     

Assessing soil properties and nutrient availability under conservation agriculture practices in a reclaimed sodic soil in cereal-based systems of North-West India

Soil quality degradation associated with resources scarcity is the major concern for the sustainability of conventional rice-wheat system in South Asia. Replacement of conventional management practices with conservation agriculture (CA) is required to improve soil quality. A field experiment was conducted to assess the effect of CA on soil physical (bulk density, penetration resistance, infiltration) and chemical (N, P, K, S, micronutrients) properties after 4 years in North-West India. There were four scenarios (Sc) namely conventional rice-wheat cropping system (Sc1); partial CA-based rice-wheat-mungbean system (RWMS) (Sc2); CA-based RWMS (Sc3); and CA-based maize-wheat-mungbean (Sc4) system. Sc2 (1.52 Mg m^?3) showed significantly lower soil bulk density (BD). In Sc3 and Sc4, soil penetration resistance (SPR) was reduced and infiltration was improved compared to Sc1. Soil organic C was significantly higher in Sc4 than Sc1. Available N was 33% and 68% higher at 0–15 cm depth in Sc3 and Sc4, respectively, than Sc1. DTPA extractable Zn and Mn were significantly higher under Sc3 and Sc4 compared to Sc1. Omission study showed 30% saving in N and 50% in K in wheat after four years. Therefore, CA improved soil properties and nutrient availability and have potential to reduce external fertilizer inputs in long run.