Determination of calcium responsiveness towards exogenous application in two genotypes of Eleusine coracana L. differing in their grain calcium content

In order to investigate the influence of exogenous application of calcium (Ca) on its accumulation in finger millet, two genotypes (GPHCPB-1 and GPHCPB-45), which posses low and high grain Ca contents, respectively, were subjected to regular fertigation of varying levels of Ca in Hoagland’s nutrient medium. The responsiveness of both the genotypes towards increasing exogenous application of Ca (0.1, 5.0, 10 and 20) was determined in terms of changes in tissue Ca levels, agro-morpho-physio-biochemical parameters. Sharp increase of Ca content in root, stem and spike was observed up to excess level of Ca (10 mM) in GPHCPB-1 while in case of GPHCPB-45 an increase in Ca content was observed only up to sufficient level of Ca (5 mM) and above that its accumulation remained constant or declined in both the genotypes. In case of leaf the level of Ca increased linearly at all concentrations of supplied Ca in both the genotypes. Both the genotypes behave differentially as GPHCPB-45 genotype accumulated more Ca and was also superior in root length, root dry matter accumulation, plant height and relative water content at Ca deficient condition (0.1 mM) as compared to GPHCPB-1 genotype. The continuous rise in stem diameter, biomass, seed yield, chlorophyll content, SPAD value, seed oxalic acid and phytic acid content were recorded in both the genotypes up to excess or toxic levels of supplied Ca. On the basis of present study it was concluded that Ca accumulation in plant is determined by both genetic (genotype dependent) as well as environmental factors (availability of Ca in rhizosphere).     

Effects of water stress, nitrogen stress and certain sensory stimuli on infestation and damage by Chilo partellus (Swinhoe) to maize

Foliar, stalk and dead heart damage caused by Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) to several maize genotypes (Inbred A, MBR 8637, Poza Rica 7832, ER-29SVR, Across 7844, Bulk CG 4141, MMV 600 and ICZ2-CM) subjected to water stress were significantly lower than those observed when plants were grown in the absence of water stress. Resistance of maize genotypes to C. partellus was distinguished clearly when there was no water stress to the plants. Resistance/susceptibility of maize genotypes Inbred A, MMV 400, MBR 8637 and Poza Rica 7832 to C. partellus was the same at 0, 60, 90 and 120 kg of N per hectare. At each nitrogen level, the genotypes MMV 400, MBR 8637 and Poza Rica 7832 suffered significantly lower damage than the susceptible Inbred A. The humidity stimuli from maize plants and the olfactory/hygro stimuli from the plants infested with larvae were the most important factors affecting host plant selection by ovipositing C. partellus females.     

The structure of the conglobate gland in Dictyoptera

An account is given of the structure and occurrence of the conglobate gland in Mantodea and Blattaria.     

Morphology of the alimentary and reproductive organs of Luciola discicollis Cast. (Coleoptera: Lampyridae)

The morphology of the alimentary and reproductive organs of L. discicollis (Coleoptera: Lampyridae) was studied in detail. The alimentary canal possesses a pouch-like proventriculus. It is suggested that this structure was once functional in ancestral Lampyridae. The details of the reproductive organs are given and it appears that they might be of value in determining the inter-relationships of the families included in the superfamily Cantharoidea. Male and female specimens of L. discicollis have been found to exhibit sexual dimorphism particularly marked in respect of the gut and the size of the eyes.     

Maturation and Ripening of Fruit ofAmelanchier alnifoliaNutt. are Accompanied by Increasing Oxidative Stress

The extent of oxidative stress during ripening of saskatoon(AmelanchieralnifoliaNutt.) fruit was examined. Lipid peroxidation duringfruit development from the mature green to the fully ripe (purple)stage was evidenced by the accumulation of ethane and 2-thiobarbituricacid reactive substances. Fruit polar lipid and free fatty acidconcentrations also declined during ripening. Moreover, thedouble bond index of fatty acids in the polar lipid fractionfell during ripening, reflecting a progressive increase in thesaturation of membrane lipids. This increase in saturation waspartly due to a 65% decline in the concentration of linolenicacid. Activities of superoxide dismutase (SOD) and catalase(CAT) fell about 4-fold and 18-fold, respectively, during development,indicating higher potential for the accumulation of cytotoxicH₂O₂. Peroxidase activity remained relatively low and constantfrom the mature green to the dark red stage of development,then increased towards the end of ripening as fruits turnedpurple. Lipoxygenase (LOX) activity increased 2.5-fold fromthe mature green to the fully ripe stage. Tissue prints showedLOX to be present throughout fruit development and Western analysisrevealed that the increase in activity during ripening was dueto increased synthesis of the enzyme. Collectively, these resultsprovide evidence that ripening of this climacteric fruit isaccompanied by a substantial increase in free-radical-mediatedperoxidation of membrane lipids, probably as a direct consequenceof a progressive decline in the enzymatic systems responsiblefor catabolism of active oxygen species. The role of glutathione-mediatedfree-radical scavenging was also examined as a potential systemfor coping with this increased oxidative stress. Concentrationsof reduced and oxidized glutathione (GSSG) increased 2-foldand GSSG increased as a percentage of total glutathione, reflectingthe increase in oxidative status of fruits during ripening.Tissue prints of glutathione reductase (GRase) and transferase(GTase) showed these enzymes to be distributed throughout thepericarp at all stages of fruit development. GRase and GTaseactivities rose sharply during the later stages of fruit ripening,correlating well with substantial increases in the levels ofboth enzymes. Hence, the glutathione-mediated free-radical scavengingsystem was up-regulated towards the end of ripening, perhapsin response to the increasing oxidative stress resulting fromthe accumulation of lipid hydroperoxides from increased LOXactivity, in conjunction with a decline in SOD/CAT activities.Copyright1998 Annals of Botany Company Amelanchier alnifoliaNutt.; saskatoon fruit; ripening; oxidative stress.