Physiological Analysis of Yield Variation in Mungbean (Vigna radiata [Roxb.] Wilczek)

Two mungbean varieties, Guj-1 and PIMS-1 differing in their productivity potential, were examined to investigate their photosynthetic system at various stages of growth in relation to yield with two different dates of sowing. Vertical leaves were found to be beneficial. On the other hand, excessive leaf area during the later stages of growth may be detrimental to yield. Lower LAD at seedling stage and overall high NAR values may be reflected in higher grain yield. NAR declined as season progressed and this, in turn, may be related with increase in LAI. The grain yield was considerably more at the first date of sowing as compared to second date of sowing, the effect was being more pronounced in var. PIMS-1 . Various environmental factors recorded at two different dates of sowing and at various stages of growth indicated that these factors may have influenced the yield potential at two different dates of sowing.     

Ultrastructure of sarcocysts from water buffalo in India

The ultrastructure of sarcocysts of macro- and microscopic species of Sarcocystis was compared from naturally infected water buffalo from India. Grossly visible sarcocysts had walls consisting of cauliflower-like villar protrusions, typical of S. fusiformis. The sarcocyst wall of the microscopic species of Sarcocystis was 6.4 microns thick and consisted of tightly packed conical villar protrusions that were 9.6 microns long and 3.7 microns wide at the base. At approximately 3 microns above the base, the distal two-thirds of the villar protrusion became conical shaped and was bent laterally at an angle of 45 degrees to the sarcocyst surface. The granular layer beneath the villar protrusions was 0.9 microns thick. In S. levinei the granular layer was 1.9 microns thick, the villar protrusions were narrow and it had a highly undulating primary cyst wall. Whether the microscopic S. levinei-like sarcocysts of Indian and Malaysian water buffalo are distinct species of Sarcocystis will require further investigation.     

Primary sulfates in atmospheric sulfates: estimation by oxygen isotope ratio measurements

The relative amounts of primary and secondary sulfates in atmospheric aerosols and precipitation can be estimated from measurements of the stable oxygen isotope ratios. The oxygen-18 content of sulfates formed in power plant stack gases before emission into the atmosphere is significantly higher than that of sulfates formed from sulfur dioxide after emission. Results show that 20 to 30 percent of the sulfates in rain and snow at Argonne, Illinois, are of primary origin.     

The uptake,distribution, and accumulation of 15N-labelled ammonium and nitrate nitrogen top-dressed at different growth stages of rice

A pot experiment with soil culture was carried out to trace ¹⁵N-labelled nitrogen top-dressed at different growth stages of rice. The study involves the use of a modified vacuum system for determining total nitrogen by gu volumetric measurement, and the N₂ gas sampled in the discharge tube was analysed for nitrogen-15 by the optical spectrographic technique.

The plants took up more nitrogen from (¹⁵NH₄)₂SO₄ than from Na¹⁵NO₃, irrespective of the stage of dressing, and the uptake of both forms was much higher when the planta were top-dressed at the young panicle formation stage as compared with the later dressings. At full maturity the plants had the highest accumulation of labelled nitrogen from both ammonium and nitrate sources when they are top-dressed at the young panicle formation stage. More than 80% ot the labelled nitrogen taken up by the plants waa distributed in the brown rice and this trend was more remarkable when top-dressing was carried out at the milk stage. The distribution patterns of ammonium and nitrate nitrogen were similar in brown rice but differed in leaves and stem.

Nitrogen transported from other parts to the panicle was utilized for the formation ot the husk until the booting stage, and then for brown rice development. With the completeness of husk formation, at the milk stage, nitrogen transported to the grain might have been utilized for brown rice development more rapidly. In the brown rice, nitrogen from ammonium was translocated maximally to the inner part of the endosperm from dressing at the booting stage, and to the embryo from that at the milk stage, whereas that from nitrate was translocated maximally to the embryo from the dressings at both stages.     

RAPD and ISSR fingerprinting in cultivated chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.) and its wild progenitor <Emphasis Type="Italic">Cicer reticulatum</Emphasis> Ladizinsky

Detection of genetic relationships between 19 chickpea cultivars and five accessions of its wild progenitor Cicer reticulatum Ladizinsky were investigated by using RAPD and ISSR markers. On an average, six bands per primer were observed in RAPD analysis and 11 bands per primer in ISSR analysis. In RAPD, the wild accessions shared 77.8% polymorphic bands with chickpea cultivars, whereas they shared 79.6% polymorphic bands in ISSR analysis. In RAPD analysis 51.7% and 50.5% polymorphic bands were observed among wild accessions and chickpea cultivars, respectively. Similarly, 65.63% and 56.25% polymorphic bands were found in ISSR analysis. The dendrogram developed by pooling the data of RAPD and ISSR analysis revealed that the wild accessions and the ICCV lines showed similar pattern with the dendrogram of RAPD analysis. The ISSR analysis clearly indicated that even with six polymorphic primers, reliable estimation of genetic diversity could be obtained, while nearly 30 primers are required for RAPD. Moreover, RAPD can cause genotyping errors due to competition in the amplification of all RAPD fragments. The markers generated by ISSR and RAPD assays can provide practical information for the management of genetic resources. For the selection of good parental material in breeding programs the genetic data produced through ISSR can be used to correlate with the relationship measures based on pedigree data and morphological traits to minimize the individual inaccuracies in chickpea.     

Accumulation of bioactive compounds during growth and development of mango ginger (Curcuma amada Roxb.) rhizomes

Accumulation of bioactive compounds and storage components during developmental stages of mango ginger ( Curcuma amada Roxb.) rhizome was investigated from 60 to 240 days, as a function of physiological maturity. Four distinct developmental phases were defined, namely, vegetative phase (up to 60 days from planting), initiation and development phase (60-150 days), maturation phase (150-180 days), and senescence phase (180 days). Difurocumenonol, a bioactive terpenoid compound and phenolics were identified as biomarkers, to determine the optimum physiological maturity to harvest mango ginger rhizome. Accumulation of phenolics was observed in newly initiated rhizomes (after 60 days from planting). The phenolic content was high in mango ginger pulp compared to its juice. Newly initiated rhizome contained no difurocumenonol, and it was observed after 120 days after planting. Peak accumulation of phenolics, difurocumenonol, and total protein were noticed in 180 day old rhizome. Accordingly, the abundance of these components on 180 days was set as an optimum maturity standard for harvest of mango ginger rhizome, compared with a conventional harvest period that ranges from 200 to 240 days.     

Differentiation of chloride and sulphate salinity on the basis of ionic distribution in genetically diverse cultivars of wheat

Sulphate (SO₄) salinity, in general, was found to be more injurious than chloride (Cl) salinity in all the four genetically diverse wheat cultivars—Triticum monococcum (Cl), T. aestivum cv. Chinese spring (C2), T. turgidum cv. langdon (C3) and amphidiploid (C4) obtained by a cross between T. aestivum cv. Chinese spring x Thinopyrum bessarabicum grown in hydroponic cultures containing iso‐osmotic saline treatments T1 (90 mM NaCl), T2 (45 mM NaCl+22.5 mM Na₂SO₄), T3 (15 mM NaCl + 37.5 mM Na₂SO₄), and T4 (45 mM Na₂SO₄). Among the cultivars, C4 followed by C2 and C3 appeared to be more salt resistant and Cl the most salt sensitive as far as various observations on osmotic potential and internal ion accumulation were concerned. Salt resistance could be ascribed to more exclusion of Na and Cl ions. Sulphate injury might be due to less effective sequestration or mobility of this ion towards some innocuous centres of plant tissues. Most of the interactive effects of cultivar versus salinity were prominently higher in cultivar C4 in treatment T1.     

Yield components,light interception and marker compound accumulation of stevia (Stevia rebaudiana Bertoni) affected by planting material and plant density under western Himalayan conditions

A field experiment was conducted to study the effect of planting material and plant density on stevia (Stevia rebaudiana Bertoni) under western Himalayan conditions during 2011 and 2012. The experiment conducted in a split plot design consisted of two types of planting material (rooted slips and fresh seedlings) in the main plot and five inter- and intra-row spacing in subplots with three replications. Yield attributes and dry leaf biomass yield of stevia were not affected by the type of planting material; however, plant density significantly influenced the yield attributes and leaf and stem dry biomass. Although the wider spacing (60 × 45 cm) gave more leaves, higher leaf area index, higher leaf dry mass per plant as compared to closer spacing, it resulted in lower values of these attributes per unit area. Plants spaced in 30 × 30 cm accumulated 41.2% and 42.8% more total biomass than 60 × 45 cm. Steviol glycoside content did not change due to different planting materials and plant densities; however, closer plant spacing (30 × 30 cm) recorded 114.8% and 70.0% higher steviol glycoside accumulation compared to wider row spacing (60 × 45 cm) in 2011 and 2012, respectively.     

Effects of surface fire on litter decomposition and occurrence of microfungi in a Cymbopogon polyneuros dominated grassland

Abstract

Litter decomposition rate, changes in macronutrients such as nitrogen (N), phosphorus (P) and potassium (K) from different grades of litter decomposition and occurrence of soil microfungi were investigated in a Cymbopogon polyneuros-dominated tall grass ecosystem from a burned and an unburned site in southern India. The litter decomposition rate was higher at the burned site than at the unburned site. This rate was also higher when the litter was mixed with the mineral soil material than leaving the litter unaffected on the soil surface. The concentrations of N, P, and K in the litter decreased as a result of progressed litter decomposition. Occurrence of microfungi identified from the different decomposition grades of the Cymbopogon polyneuros litter was higher at the burned site compared to the unburned site. Microfungal species present at both sites showed only minor differences.     

Curcumin nanoparticles: preparation, characterization, and antimicrobial study

Curcumin is a highly potent, nontoxic, bioactive agent found in turmeric and has been known for centuries as a household remedy to many ailments. The only disadvantage that it suffers is of low aqueous solubility and poor bioavailability. The aim of the present study was to develop a method for the preparation of nanoparticles of curcumin with a view to improve its aqueous-phase solubility and examine the effect on its antimicrobial properties. Nanoparticles of curcumin (nanocurcumin) were prepared by a process based on a wet-milling technique and were found to have a narrow particle size distribution in the range of 2-40 nm. Unlike curcumin, nanocurcumin was found to be freely dispersible in water in the absence of any surfactants. The chemical structure of nanocurcumin was the same as that of curcumin, and there was no modification during nanoparticle preparation. A minimum inhibitory concentration of nanocurcumin was determined for a variety of bacterial and fungal strains and was compared to that of curcumin. It was found that the aqueous dispersion of nanocurcumin was much more effective than curcumin against Staphylococcus aureus , Bacillus subtilis , Escherichia coli , Pseudomonas aeruginosa , Penicillium notatum , and Aspergillus niger . The results demonstrated that the water solubility and antimicrobial activity of curcumin markedly improved by particle size reduction up to the nano range. For the selected microorganisms, the activity of nanocurcumin was more pronounced against Gram-positive bacteria than Gram-negative bacteria. Furthermore, its antibacterial activity was much better than antifungal activity. The mechanism of antibacterial action of curcumin nanoparticles was investigated by transmission electron micrograph (TEM) analysis, which revealed that these particles entered inside the bacterial cell by completely breaking the cell wall, leading to cell death.