3,334 research outputs found
Effectiveness of plant based insecticides as a sustainable means of control of cucumber mosaic virus
Cucumber (Cucumis sativus) is an important crop in Pakistan. It is affected by many biotic and abiotic factors. Among these, Cucumber mosaic virus is the important disease with economic losses. The purpose of this study was to evaluate the effectiveness of plant based insecticides as a sustainable means to control the Cucumber Mosaic Virus. Sustainable means are economical, environmental friendly and socially acceptable. For this purpose, cucumber varieties /lines were evaluated against cucumber mosaic virus (CMV) under natural field conditions conducive for development of disease and aphid population. All varieties/lines were in the range of moderately susceptible to susceptible except Beet alpha and Nandini-732 which were moderately resistant with 16.26% disease incidence and highly susceptible with 50.11% disease incidence respectively. Relative humidity and rainfall had a positive relationship with the disease (CMV) development while temperature had a negative relation with disease development. Aphid population increased with the increase of relative humidity and rainfall and decreased as the humidity and rainfall decreased. With the increase in temperature, there was a gradual decrease in aphid population build up. For economical and environmentally safe management of the disease, one pesticide and different bio-pesticides were evaluated under natural field conditions against insect vector and disease. In order to manage CMV and aphid population, the pesticide Imidacloprid and three plant extracts of neem (Azadirachta indica), garlic (Calotropis gigantea) and aak (Allium sativum) were used. All the applied treatments gave significant results. Among them, imidacloprid was proved the best in reduction of disease incidence/severity and aphid population. It was followed by neem, garlic and aak extract respectively. Aak was found to be the least effective treatment even though it led to a significant reduction in disease incidence and aphid population compared to the untreated control where maximum plant infection and aphid population was found on plants
The monetary policy during shocks: an analysis of large Asian economies’ response to COVID-19
The economies all over the world that have been adversely
affected by the COVID-19 pandemic have recently started to
devise different strategies to mitigate its consequences. Therefore,
in order to dwell deeper into the measures taken by the policy
makers around the world, this paper specifically analyzes how the
monetary policies have been devised, in response to COVID-19.
For this purpose, this paper has taken into consideration a panel
of 8 Asian economies that have been affected the most acutely
by the virus, have faced multiple lockdowns, and have also experienced other economic restraints, due to this very phenomenon.
In order to compare the possible monetary policy options, and
their outcomes during the COVID-19 pandemic, this paper refers
to the global recession shock, as a valid point of reference. In
addition to this, in order to gain access to the empirical evidence,
the ARDL methodology has been applied on the quarterly data
from 2005Q3 to 2020Q3. The results of the study have indicated
that various plans have been taken into consideration, so as to
lessen the consequences of these shocks that have trickled down
into the respective economies of these countries. That is to put
forth that, in the incidence of global recession, the monetary
authorities have resorted to a less prudent stance. Whereas, more
flexibility, through a persistent decrease in the policy rate has
been observed since the pandemic first hit the world. In this
regard, our results imply that a successful, efficient and effective
response to the economic consequences of COVID-19, would
ideally entail a set of remedial policies and structural reforms
Detection of somaclonal variation by random amplified polymorphic DNA analysis during micropropagation of Phalaenopsis bellina (Rchb.f.) Christenson
Phalaenopsis bellina (Rchb.f.) Christenson orchid species are known for their beautiful flower shape, graceful inflorescence and fragrance. Protocorm-like bodies (PLBs) of P. bellina were induced from leaf segments. The PLBs were then subjected to proliferation using ½ strength Murashige and Skoog (MS) media with two subcultures at three months intervals. Twelve decamer random amplified polymorphic DNA (RAPD) primers were used to study somaclonal variation among the mother plant, the initially induced PLBs and proliferated PLBs after 3 and 6 months in culture. Eight out of twelve primers produced 172 bands with 18 polymorphic bands in all the treatments. The amplified products varied between 125 to 8000 bp. Among the primers used, P 16 produced the highest number of bands (29), while primer OPU 10 produced the lowest number (15). The range of similarity coefficient was from 0.83 to 1.0 among the different sub-cultures and mother plant (MP). It was found that minimal or no changes occurred between the MP and the PLBs produced after 3 months of induction. The induced PLBs were then subcultured for six months for proliferation and this resulted in about 17% dissimilarity with MP. It is reported that micropropagation of P. bellina can be carried out successfully using ½ strength MS media for 6 months but further proliferation may result in somaclonal variation which might change the prolific characteristic of this orchids.Key word: Moth orchid, somaclonal variation, random amplified polymorphic DNA, protocorm-like bodies
Phylogeny of Artemisia L.: Recent developments
In this review, classification and phylogeny of genus Artemisia L. is discussed. Its centers of diversity lie in the temperate and cold temperate regions of the Eurasia, North America and Asia. Artemisia has two basic chromosome numbers, with ploidy levels x=9 and x=8. Chromosome number in diploid is most often 2n=18 or 16. The genus is divided into five large groups Absinthium DC., Artemisia L., Dracunculus Besser, Seriphidium Besser and Tridantatae (Rydb.) McArthur. Its phylogeny was based on the two hypothesized evolutionary trends, loss of fertility in the disc florets and loss of ray florets. Recently its molecular phylogeny based on internally transcribed spacer (ITS), externally transcribed spacer (ETS) regions of the DNA and chloroplast DNA suggested that the genus Artemisia is a monophyletic but it could not resolve the problem of infra-generic classification. This study revealed that there is need to search new genome regions to establish a natural classification based on modern molecular techniques
Foliar epidermal anatomy and its systematic implication within the genus Sida L. (malvaceae)
Micro morphological investigations of the foliar epidermal anatomy, particularly the diversity and distribution of glandular and eglandular trichomes on leaves of Sida alba L., S. alii S. Abedin var. alii, S.cordata (Burm. F.) Brss, S. mysorensis Wight and Arn, S. ovata Forssk. S. spinosa L and S.yunnanensis S.Y.Hu have been carried out to assess the systematic relevance of epidermal features and trichome diversity within the genus Sida L. Configuration of epidermal cells is polygonal to irregular with smooth or undulating outline. Leaves are amphistomatic and amphitrichomic. Six diverse morphological types of glandular and eglandular foliar trichomes are described. Stellate and peltate types of trichomes are characteristically found in all taxa studied. S. alii and S.spinosa are distinct in having long-stalked and short-stalked capitate trichomes. S. mysorensis is characterized by multicellular uniseriate trichomes, but these are not observed in other taxa of genus Sida. The results of foliar epidermal anatomy, especially type, distribution and structure of foliar trichomes are of high systematic value in this genus of family Malvaceae
Effect of growing degree days on autumn planted sunflower
Sunflower (Helianthus annus L.) having high degree of adaptability under wide range of climatic conditions, allow the crop to be productive in broad range of environments. Field experiments in autumn were laid out at Pir Mehr Ali Shah, Arid Agriculture University Rawalpindi, Pakistan for two years (2007 and 2008), to document the effect of growing degree days (GDD) on the performance of sunflower hybrids. Four sunflower hybrids, Alisson-RM, Parasio-24, MG-2 and S-278 were planted in randomized complete block design with four replications during autumn season. The data on growing degree days accumulation during autumn and their effect on achene, oil yield and yield components of sunflower like number of achenes per head, hundred achenes weight, biological and achene yield was recorded. All these agronomic characters as well as oil characteristics were influenced by prevailing temperature. GDD collected during autumn season was the same for both years of study. Amongst hybrids, the hybrid MG-2 showed the maximum values for all the agronomic as well as oil parameters during the autumn season. At the late planting of sunflower during autumn season, crop completes its life cycle in short duration and accumulates less heat units, thus, achene and oil yield along with yield attributes are affected accordingly.Key words: Growing degree days (GDD), yield and yield components, sunflower
Development and in-vitro Evaluation of Once Daily Tablet Dosage Form of Loxoprofen Sodium
Purpose: To formulate and characterize once daily controlled release tablet of loxoprofen sodium.Methods: Eudragit RS-100, hydroxylpropyl methylcellulose (HPMC) and pectin were used as release retarding polymers. All the formulations were prepared by direct compression method. Various precompression studies were carried out to determine Hausner’s ratio, Carr’s index, angle of repose, bulk density and tapped density Differential scanning calorimetry (DSC) studies and also post-compression studies to evaluate hardness, friability, weight variation, drug content, in-vitro drug release were conducted on the tablets. The drug release data were subjected to kinetic models, including zero order, first order, Hixon Crowell, Higuchi and Korsmeyer-Peppas.Results: Compressibility index (7.6 ± 1.32 - 12.5 ± 1.43%), Hausner’s ratio (1.08 ± 0.04 - 1.14 ± 0.03), angle of repose (27.78 ± 0.47 - 30.49 ± 0.46°), hardness (6.25 ± 0.27 - 7.21±0.21 kg/cm2), friability (0.14 ± 0.06 - 0.28 ± 0.0 %), weight variation (249.5 ± 2.09 - 251.35 ± 2.41 mg) and drug content (97.30 ± 0.28 - 103.70 ± 0.31 %) were within generally accepted limits for the pre-and post-compression formulations, respectively. The tablets having the maximum amount of among the three polymers tested as matrix materials, HPMC, represented by F3 tablets, exerted better sustained release properties after 12 h. Release pattern was more of Fickian diffusion followed by Higuchi mechanism.Conclusion: The release of the loxoprofen sodium was optimized up to 12 h.Keywords: Loxoprofen, Sustained release, hydroxypropyl methylcelluose, Pectin, Eudragit, Matrix tablet
Effect of β-Glucuronidase on Extraction Efficiency of Silymarin from Human Plasma Samples Using Validated HPLC-UV Analysis
Purpose: To investigate the effect of β-glucuronidase on the extraction efficiency of silymarin (mainly as silybin) from spiked human plasma using a sensitive and reproducible high performance liquid chromatography (HPLC) method.Methods: The importance of β-glucuronidase was evaluated by comparing the extraction efficiency of silymarin in β-glucuronidase-treated and untreated plasma samples. Isocratic HPLC with simple UV detection (288 nm) was applied to analyze the major silymarin components using Thermo-Electron C18 column (200 mm, 4.6 mm I.D., 5μm particle size). The mobile phase, consisting of methanol and 20 mM potassium dihydrogen phosphate buffer (50:50 v/v pH 2.8), was pumped at 1 ml/min.Results: The mean extraction efficiency was 98.97 % (CV = 1.69 %) for treated and 40.88 % (CV = 2.77 %) for untreated plasma samples, compared with nominal concentrations.Conclusion: The studied method showed 60 % reduced extraction efficiency of untreated samples compared to treated samples.Keywords: Silymarin, Silybin, Extraction Efficiency, β-glucuronidase, HPL
Comparison of particle bombardment-transformation parameters between stem and calli explants of Aglaonema simplex
Aquatic plant posses a very interesting stress tolerance mechanism compared to terrestrial plants. However, lack of aquatic mutants available is a hindrance to explore the cellular mechanism that governs various adaptations between these two types of plants. Therefore, the aim of this study is to provide the optimum parameters for the genetic transformation of native aquatic plant in tropical country, Aglaonema simplex, by using stem and callus tissue. Explants were bombarded with various sizes of gold particles coated with 35 sec promoter constructed into 35 sec-sGFP-TYG-nos (puc18) plasmid harbouring green fluorescent protein. High transient expression was obtained when the tissues were bombarded twice by gold particles coated with spermidine under acceleration pressure of 1100-1350 psi and with the vacuum pressure set to 24 Hg. The calli were found susceptible to high pressure impact, showing better result at a longer bombardment distance (12 cm) of stopping screen to explants by the use of gold particle of smaller size (1 μm). In contrast, the optimal bombardment distance shown by stem tissues was achieved at a 6 cm distance by the use of gold particle of 1.6 μm. PCR and PCR-southern blot analyses exhibited that the gene was integrated into the genome of transformants and this indicates that the protocol can be used for genetic engineering purpose in the future
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