Phytochrome mediated induction of nitrate reductase activity in etiolated maize leaves

The effects of red and far-red light on the enhancement of in vitro nitrate reductase activity and on nitrate accumulation in etiolated excised maize leaves were examined. Illumination for 5 min with red light followed by a 4-h dark period caused a marked increase in nitrate reductase activity, whereas a 5-min illumination with far-red light had no effect on the enzyme activity. The effect of red light was completely reversed by a subsequent illumination with the same period of far-red light. Continuous far-red light also enhanced nitrate reductase activity. Both photoreversibility by red and far-red light and the operation of high intensity reaction under continuous far-red light indicated that the induction of nitrate reductase was mediated by phytochrome. Though nitrate accumulation was slightly enhanced by red and continuous far-red light treatments by 17% and 26% respectively, this is unlikely to account for the entire increase of nitrate reductase activity. The far-red light treatments given in water, to leaves preincubated in nitrate, enhanced nitrate reductase activity considerably over the dark control. The presence of a lag phase and inhibition of increase in enzyme activity under continuous far-red light-by tungstate and inhibitors of RNA synthesis and protein synthesis-rules out the possibility of activation of nitrate reductase and suggests de novo synthesis of the enzyme affected by phytochrome.     

FUZZY MULTIATTRIBUTE DECISION MAKING APPROACH FOR DEVELOPMENT AND COMPARISON OF SOY FORTIFIED PANEER

Soyfortified paneer (SFP) samples prepared from blends containing different proportions of buffalo milk of varying fat content and soy milk (7.5 °B) were evaluated organoleptically for assessing the quality attributes like body and texture, flavor and taste, color and appearance and the overall acceptability. Sensory data were analyzed using fuzzy logic approach, which addresses the problem of data classification in a unified qualitative and quantitative manner. Results of the study indicated that the fuzzy multiattribute decision making approach provide an adequate and reliable system for product formulation and comparison, based on sensory data. The developed fuzzy mathematical model performed remarkably well in the evaluation and ranking of various SFP samples. The SFP sample made from blend of buffalo milk (4.5% fat) and soy milk (7.5 °B) in the proportion of 90:10 was found to be the most acceptable one for different classes of consumers irrespective of their preferences for a particular sensory quality attribute.     

Gene actions for yield and its attributes and their implications in the inheritance pattern over three generations in opium poppy (<Emphasis Type="Italic">Papaver somniferum</Emphasis> L.)

The gene actions for yield and its attributes and their inheritance pattern based on five parameter model have been explored in four single crosses (NBIHT-5 × NBIHT-6, NBIHT-5 × NBMHT-1, NBMHT-1 × NBIHT-6 and NBMHT-2 × NBMHT-1) obtained using thebaine rich pure lines of opium poppy (Papaver somniferum L.) for three consecutive generations. All the traits showed nonallelic mode of interaction, however, dominance effect (h) was more pronounced for all the traits except thebaine and papaverine. The dominance × dominance (l) effects were predominant over additive × additive (i) for all traits in all the four crosses except for papaverine. The seed and opium yield, and its contributing traits inherited quantitatively. The fixable gene effects (d) and (i) were lower in magnitude than nonfixable (h) and (l) gene effects. The estimates of heterosis were also higher in comparison to the respective parents which suggested preponderance of dominance gene action for controlling most of the traits. The phenotypic coefficient of variation was marginally higher than those of genotypic coefficient of variation for all the traits. The traits thebaine, narcotine, morphine and opium yield had high heritability coupled with high genetic advance. The leaf number, branches per plant and stem diameter showed positive correlation with opium and seed yields. The selection of plants having large number of leaves, branches and capsules with bigger size would be advantageous to enhance the yield potential.     

Effect of Ammonium, Sucrose and Light on the Regulation of Nitrate Reductase Level in Pisum sativum

In shoot apices of 7-day-old dark-grown peas the addition of ammonium along with the inducer nitrate resulted in a more than two-fold increase in nitrate reductase activity. Individual amino acids, amides and amino-acid mixture could not replace the ammonium effect. Ammonium also stimulated NADH-glutamate dehydrogenase but not glucose-6-phosphate dehydrogenase. Sucrose caused a marked stimulation of nitrate reductase induction and showed synergistic effect with light. In presence of cordycepin and cycloheximide, induction of nitrate reductase was inhibited more if ammonium or sucrose was supplied along with the inducer. With actinomycin D, α-amanitin or chloramphenicol, no differential inhibition took place in presence of ammonium. The inhibition of enzyme activity by chloramphenicol and 3-(3,4-dichlorophenyl)-l,dimethyl urea was completely relieved by sucrose. Incorporation of ¹⁴C-lysine was markedly stimulated by sucrose, but was not affected by ammonium. The effect of sucrose and light on ¹⁴C-lysine incorporation was additive. Cordycepin and cycloheximide did not have any differential effect on ¹⁴C-lysine incorporation in the presence of ammonium as well as sucrose. The inhibition of ¹⁴C-lysine incorporation caused by chloramphenicol was relieved by sucrose. Sucrose also caused a marked increase in ³H-uridine incorporation but ammonium had no effect. Actinomycin D and cordycepin blocked the sucrose dependent increase in ³H-uridine incorporation. The results suggest that ammonium mediated stimulation may depend on a regulatory protein(s) synthesized in response to ammonium, whereas sucrose acts mainly by an overall increase in RNA and protein synthesis. The effect of light does not seem to be dependent on photosynthetic light reactions.     

Development of Pollen Embryoids in Anther Cultures of Datura innoxia: II. EFFECTS OF GROWTH HORMONES

In anther cultures of Datura innoxia the addition of growthhormones, such as auxins, gibberellins, and cytokinins, to theculture medium enhanced the production of pollen embryoids.Cytokinins appeared to be the most effective and, among thefour cytokinins tested, zeatin and kinetin gave the best results.Generally speaking, combinations of hormones did not improvethe response over that of an individual hormone. The numberof embryoids per anther varied in the same medium and did notstrictly correlate with the percentage of responding anthers.     

Expression of a Neurospora crassa zinc transporter gene in transgenic Nicotiana tabacum enhances plant zinc accumulation without co‐transport of cadmium

Zinc (Zn) is an essential micronutrient required for growth and development of all organisms. Deficiency of Zn in humans is widespread, affecting 25% of world population and efforts are underway to develop crop plants with high levels of Zn in their edible parts. When strategies for enhancing Zn in crop plants are designed, it is essential to exclude cadmium (Cd), a toxic analogue of Zn. In the present work, a high affinity and high specificity zinc transporter gene (tzn1) from Neurospora crassa was cloned and introduced into Nicotiana tabacum with the objective of enhancing the potential of plants for zinc acquisition. When grown in hydroponic medium spiked with ⁶⁵Zn, transgenic plants showed enhanced accumulation of Zn (up to 11 times) compared to control plants, which was confirmed further by environmental scanning electron microscopy coupled with Energy Dispersive X‐ray analysis. More importantly, no significant difference in uptake of Cd²⁺, Fe²⁺, Ni²⁺, Cu²⁺, Mn²⁺ and Pb²⁺ between the transgenic and control plants was observed. The present studies have shown that Neurospora crassa tzn1 is a potential candidate gene for developing transgenic plants for improving Zn uptake, without co‐transport of Cd and may have implications in Zn phytofortification and phytoremediation.     

The Effects of {delta}-Aminolevulinic Acid and Inhibitors of RNA and Protein Synthesis on Phytochrome Mediated Chlorophyll Accumulation in Sorghum bicolor

In 5-d-old etiolated seedlings of Sorghum bicolor, 12 h of darknessafter 5 min in red light eliminated a lag before the accumulationof chlorophylls in subsequent continuous white light. Increasingthe dark period to 24 h and 36 h, increased the rate of chlorophyllaccumulation in the later stages of greening. Exogenous -aminolevulinicacid neither completely removed the lag, nor increased the rateof chlorophyll accumulation. Cycloheximide (25 µg ml^–1)and 6-methyl purine (5.0 µg ml^–1), given continuouslyor only until the 12 h dark period following the red light irradiation,restored the lag and decreased the rate of chlorophyll accumulation.D-threo-chloramphenicol (400µg ml^–1) also decreasedthe rate of chlorophyll accumulation but did not restore thelag. Addition of these inhibitors even 12 h after red lightirradiation decreased the rate of chlorophyll accumulation.Rifampicin (Rifamycin SV, 400 µg ml^–1) did not havesuch effects. Key words: Chlorophylls, Phytochrome, -Aminolevulinic acid, Sorghum bicolor