Physiology of Senescence and Postharvest Handling in Some Select Ornamental Flowers of Caryophyllaceae

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Effect of Ethylene Antagonist Silver Thiosulphate on the Flower Longevity of Clarkia pulchella Pursh.

An experiment was conducted to study the effect of different concentrations of silver thiosulphate (STS) on flower longevity of Clarkia pulchella Pursh. The buds were subjected to 0.1, 0.25, 0.5, 0.75 and 1 mM of STS for 1 h pulse treatment. A separate set of flowers kept in distilled water was designated the control group. STS treatment resulted in improved flower longevity besides maintaining higher fresh and dry mass, water content and floral diameter. Conversely, total phenols, lipid peroxidation and lipoxygenase (LOX) activity decreased. The flowers treated with STS showed a significant increase in the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). Amongst various grades used, 0.5 mM STS was found to be most effective in enhancing the flower longevity by 1.5 days. The present study reveals that STS maintains lower LOX activity, thereby increased membrane stability index by improving the activity of antioxidant enzymes

Working with pastoral communities to conserve threatened wild mammals

In India, most of the conservation sites have local community and the policy makers as the major stake holders. However, they have been rarely involved in conservation. The alpine and subalpine meadows of Hirpora Wildlife Sanctuary are overstocked with about 300 livestock/sq km, which seems to be more than the carrying capacity. The pastures have started exhibiting a degraded look because of overgrazing and wild ungulates such as markhor Capra falconeri and musk deer Moschus crysogaster have started decimating. At the same time, we have the herders who are mainly dependent on the livestock for their survival. And the large carnivores such as Tibetan wolf and Himalayan Brown bear attack the livestock resulting in the loss for herders and retaliatory killings of these carnivores. Therefore it is important to understand the social and ecological issues and consult with the herders - the major stake holders to save the alpine pastures, rare wild ungulates and also provide relevant incentives and alternatives to the herders. The present study is a step towards it. We studied the changing traditional livestock grazing practices and the increase in grazing pressure as a result. We also looked at the problem of livestock depredation by the large carnivores like wolf and brown bear and its impact on the attitudes of livestock herders and the conservation of these carnivores. We engaged with the herders to encourage them to leave the non-traditional practices and discussed about the relevant incentives to help them. We interviewed the livestock herders to record the livestock numbers, change in traditional practices to understand the grazing pressure on the pastures. We also recorded the number of livestock killed by the carnivores and the attitude of herders towards these carnivores. We conducted Focused Group Discussions and Participatory Rural Appraisals with the livestock herders to discuss the changing grazing practices, its negative impacts, and its conservation implications along with the incentives for the herders. We found that the changing herding practices have doubled the livestock numbers. Livestock herders, who were traditionally grazing their own livestock, bring livestock of landlords now along with them to earn cash. Some of the traditional herders even sublet their pastures to non-traditional herders for the season to earn money. About 2% of livestock is being killed by carnivores and herders hate Tibetan wolf more than the brown bear because Tibetan wolf is too smart to deceive herders to attack the livestock. Herders agreed to leave the non-traditional practices and continue with the traditional livestock grazing practices to conserve these pastures, herbivores and improve the quality of livestock. They outlined the incentives such as solar lights, cooking gases and the school bags and books and school fees for their children to give them proper education. Herders also pledged not to go for retaliatory killings of carnivores.peerReviewe

Polarographic Determination and Antimicrobial Activity of Cu(II) Complex with 4-Chlorobenzylidene-4-aminoacetanilide

The electrochemical behaviour of the complex of Cu(II) with 4-chlorobenzylidene-4-aminoacetanilide (CAA) was studied. It was observed that CAA forms 1:1 complex with Cu(II) in between pH 6.5 to 7.1. It was found that the reduction process of Cu(II)- CAA complex is two electron reversible reduction process at D.M.E. The logarithm value of stability constant of Cu(II)-4-Chlorobenzylidene-4-aminoacetanilide (CAA) complex has been found to be 4.85.The redox properties of the complex was extensively investigated by electrochemical method using cyclic voltammetry (CV).The Cu(II) complexes exhibited quasi-reversible single electron transfer process.The Schiff base and its complex has been screened for their in-vitro antibacterial (Escherichiacoli, Staphylococcus aureus, Vibrio cholerae and Bacillus subtilis) and antifungal (Aspergillus niger and Penicillium liliacinum) activities by minimum inhibitory concentration (MIC) method

Physiological and biochemical aspects of flower development and senescence in Nicotiana plumbaginifolia Viv.

Healthy buds of Nicotiana plumbaginifolia growing in the Kashmir University Botanic Garden were selected for the present study. Flower development and senescence was divided into seven stages, viz., tight bud stage (I), mature bud stage (II), pencil stage (III), partially open stage (IV), open stage (V), partially senescent stage (VI) and senescent stage (VII). Various physiological and biochemical changes were recorded at each stage of flower development and senescence. Floral diameter, fresh mass, dry mass and water content showed an increase up to flower opening (stage V) and thereafter a significant decrease was recorded as the flower development progressed towards senescence through stages VI and VII. An increase in α-amino acids, total phenols and sugars was registered towards anthesis (stage V) and a decrease in these parameters was recorded with senescence. Protease activity showed a significant increase towards senescence with a concomitant decrease in soluble proteins. Based on the quantitative analysis of various biochemical parameters, the flower opening in N. plumbaginifolia seems to be accompanied by an increase in the water content, soluble proteins, α‑amino acids and phenols. A decrease in these parameters, besides an increase in protease activity induces senescence in the beautiful flowers of N. plumbaginifolia. Understanding flower senescence may help in improving the postharvest performance of this beautiful ornamental flower to make it a potential material for the floriculture industry

Adsorptive stripping voltammetric study of vitamin B1 at multi-walled carbon nanotube paste electrode

The electrochemical response of vitamin B1 at different types of carbon electrodes viz: glassy carbon electrode (GCE), carbon paste electrode (CPE), single walled carbon nanotube paste electrode (SWCNTPE) and multi walled carbon nanotube paste electrode (MWCNTPE) has been investigated using cyclic voltammetric (CV) and differential pulse adsorptive stripping voltammetric (DPAdSV) methods. A simple and selective differential pulse adsorptive stripping voltammetric method has been developed for the determination of vitamin B1 in pure form and in pharmaceutical preparations. Various parameters that can influence the peak signal (effect of buffer, accumulation time, pH, scan rate, accumulation potential, and pulse amplitude) have been scrutinized. The best results were obtained in acetate buffer (pH 6.3) using multi-walled carbon nanotube paste electrode at a deposition time of 80 s, deposition potential of 0.0 V, scan rate of 50 mV s−1 and pulse amplitude of 50 mV. The reduction peak current varies linearly with the concentration of vitamin B1 over the range of 1.0 × 10−7–1.0 × 10−6 M. The limits of detection and quantification of the pure drug are 1.1 × 10−10 M and 2.0 × 10−9 M, with the correlation coefficient, r = 0.997 and the relative standard deviation, RSD = 1.2% (n = 5). Experimental results reveal that the MWCNTPE has advantages of small background current, high signal to background current ratio and good reproducibility

Voltammetric interaction of vitamin B1 with DNA at multiwalled carbon nanotube paste electrode

The interaction between vitamin B1 and DNA was studied with differential pulse voltammetry (DPV) at the bare and DNA modified MWCNTPE. The differential pulse voltammograms of vitamin B1 showed that peak potentials shifted to a more negative value and peak currents decreased with the addition of DNA, indicating the dominance of electrostatic interactions. The combining constant (β) and combining number (m) of DNA–mVB1 were determined too. The work has been supplemented by an UV spectral study

Indirect Electrochemical Analysis of Crocin in Phytochemical Sample

A new electroanalytical method has been developed for the quantitative determination of crocin in a sample of stigmas of saffron (Crocus sativus L.). Crocin is polarographically inactive. However, cysteine in 0.02 M NaCl, pH=5.2±0.01 produces a well defined wave/peak with E1/2/Ep= –0.47/–0.45 V vs. Ag/AgCl. On recording polarograms of a set of solution containing a fixed concentration of cysteine and varying concentrations of crocin under aforesaid experimental conditions a gradual decrease in peak height/diffusion current and a negative shift in peak potential was observed. Thus, indicating cysteine-crocin interaction. Amperometric titration indicated crocin to cysteine ratio of 1:2. The above amperometric titration procedure has been used to determine the concentration of crocin in a sample of saffron. Crystallization process was carried out for the extraction of crocin from dried powder of saffron stigmas. The crystallized crocin was identified by UV-Visible spectrophotometry(at 255 nm and 442 nm) and the quantitative analysis by the developed amperometric method. The concentration of crocin in saffron was found to be 2.13% and purity of isolated crocin 96.81%. The percent recovery varied from 98.56–100.31% and RSD (n=5) of 2.17%.The validation of the proposed procedure for the quantitative assay of crocin was examined via an evaluation of the repeatability, recovery, selectivity and relative standard deviation