Papaya (Carica papaya L.) Leaf Powder: Novel Adsorbent for Removal of Methylene Blue from Aqueous Solution

Batch sorption experiments were carried out to investigate the potentiality of papaya leaf powder (PLP) for the removal of methylene blue (MB) from aqueous solution. The effects of various experimental parameters, such as adsorbent dose, initial solution concentration, contact time, and solution pH were also studied. The amount of dye adsorbed was found to increase with increase in initial dye concentrations. Papaya leaf adsorbs MB better in basic medium. The adsorption equilibrium data fitted well in the Langmuir isotherm equation with a monolayer sorption capacity of 512.55?mg?g^?1. The kinetics of MB adsorption onto papaya leaf was examined using the pseudo-first and pseudo-second order and unified approach kinetic models. The adsorption kinetics followed the pseudo-second order kinetic model, but the rate constant was found to depend on initial dye concentration. The unified approach model described the equilibrium and kinetics well. The forward and backward rate constants were determined from the unified approach model.     

Allelopathic Effect of Eucalyptus globulus Labill. on Cyperus rotundus L. and Cynodon dactylon L. Pers.

The allelopathic potential of Eucalyptus globulus Labill. (gum tree) fresh and dried leaf leachates was studied using two perennial weeds, viz. purple nutsedge (Cyperus rotundus L.) and bermuda grass (Cynodon dactylon L. Pers) as test weeds. Aqueous leachate of fresh leaves of eucalyptus significantly suppressed the establishment of vegetative propagules and early seedling growth of the weeds. Leachate of fresh leaf cuttings had growth inhibitory effect on bermuda grass but showed growth promotion effect on purple nutsedge. Similarly the leachate of dried leaves of eucalyptus had differential influence on the growth of the two weeds. There is a possibility to harness the allelochemicals of eucalyptus leaves as herbicides for the management of these perennial weeds.     

Effect of kilning on the antioxidant and pro-oxidant activities of pale malts

Pale malts were prepared using standard and rapid kilning regimes that differed in the temperature and moisture profiles in the kiln. Samples were taken over the last 9 h of kilning, that is, at 18, 20, 22, 25, and 27 h. Antioxidant activity, assessed by redox potential, scavenging of the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS*+), and ferric reducing/antioxidant power (FRAP), increased at moisture levels below 6.7% for both regimes. The 27 h malt exposed to the rapid regime (moisture content of 4.8%) had a higher activity than the 27 h standard regime sample (moisture content of 4.8%). None of the malts scavenged oxygen. Pro-oxidant activity profiles were different for the malts obtained using each regime and, at 27 h, the rapid procedure gave malt with higher activity. Levels of (+)-catechin and ferulic acid (the most abundant phenolic compounds identified) generally increased as the moisture content of malt fell below 6.7%. Differences in antioxidant and pro-oxidant activities of the 27 h malts are partly attributed to the Maillard reaction, as evidenced by lower L* and higher b* values and higher levels of Maillard-derived flavor compounds, in the sample obtained by the rapid procedure. Levels of lipid-derived flavor compounds were significantly higher after 27 h of kilning using the rapid procedure.     

High Performance Thin Layer Chromatography (HPTLC) profile of an insecticidal compound of <Emphasis Type="Italic">Trochus radiatus</Emphasis> and assessment of mucus-associated bacterial extracts

The current study is based on the screening of novel insecticides from new sources that have not being exploited hitherto. The major objectives of this research work were to extract marine molluscs, Lambis lambis, Trochus radiatus and Chicoreus ramosus, from Tuticorin coastal waters using different solvents to test their insecticidal properties and partially purify the active components. The ethyl acetate extracts of L. lambis and T. radiatus showed 100% mortality of Sitophilus oryzae, at a concentration of 200 μg ml⁻¹. The LC₅₀ values for ethyl acetate extracts of L. lambis, T. radiatus and C. ramosus were found to be 67.08, 348.86 and 571.42 μg ml⁻¹, respectively. With regard to bacterial metabolites, at a concentration of 200 μg ml⁻¹ the ethyl acetate extract of A3 was able to elicit an activity of 40% and that of strain A1 – 20%. The LC₅₀ values of the bacterial metabolites were also investigated. Upon chromatographic separation of active ethyl acetate extracts of T. radiatus, the 100% methanol column-purified fraction was found to have an activity of 30% at a concentration of 10 μg against S. oryzae. The purity of the partially pure active compound was observed to be 72.78% on analysis with high pressure thin layer chromatography.     

Reverse phase passive haemagglutination test for the detection of rinderpest antigen

Reverse phase passive haemagglutination [RPHA] test was applied for the detection of rinderpest antigen in various organs of rinderpest infected cattle. The results of RPHA were compared with counter immunoelectrophoresis [CIE] and single radial haemolysis [SRH] test. RPHA was as sensitive as CIE and SRH in detecting rinderpest antigen.     

Alternate Selection Indices for Leaf Photosynthetic Rate in Greengram (Vigna radiata [L.] Wilczek) Cultivars

Significant differences were observed for leaf net photosynthetic rate, chlorophyll content, soluble protein content, nitrate reductase activity, stomatal frequency and specific leaf mass among ten greengram cultivars. Leaf net photosynthetic rate had significant positive correlation with soluble protein, nitrate reductase activity, stomatal frequency and specific leaf mass. Leaf net photosynthetic rate had no relationship with leaf chlorophyll content in greengram.     

An Analysis of Grain Development in Oryza sativa L. Cultivars

A field study was conducted to determine if differences in grain filling rate and duration existed in two early cultivars of rice. There is no cultivar difference in duration of grain filling and grain matured in about 30 days from anthesis in both the cultivars. The effective grain filling period in rice is only 10 days between 3rd and 13th day from anthesis. There is significant difference in grain filling rate and is positively related to grain weight. Grain filling rate is more important than duration of filling for achieving higher grain size and thus yield in rice.     

Functional Growth Model for Pod Development in Greengram and Blackgram

Identification of readily measured traits that are associated with higher productivity of field crops is important to breeders. The objective of this study was to find out whether pod filling rate or duration of pod filling greatly decide final pod weight in greengram and blackgram. The effective pod filling duration is only 16 days in both the crops. Pod filling rate is more important than duration of pod development. Richards function is found to more closely fit the data on pod development from anthesis to maturity in both the species.