G. Sarwar

Salt tolerance potential in some members of Brassicaceae physiological studies on water relations and mineral contents

Salt tolerance potential of six cultivars of different brassica species and Eruca sativa was assessed in a field experiment conducted at Biosaline Research Station-II of NIAB, Faisalabad, Pakistan. Experiment consisted of four salinity treatments (i.e. 3.3, 11, 20, 27 dS/m). Cultivars Sheiaralle (B. napus), Peela Raya (B. carinata) and Chakwali Raya and RL-18 (B.juncea) produced significantly greater plant height, number of pods on main branch and yield per plot than others under all salinity treatments. These plants have potential to grow under saline condition and produced more than 50% seed yield up to 11 dS/m and approximately 50% up to 20 dS/m salt treatment. Experiment was repeated next year with two salt tolerant (RL-18 and Sheiaralle) and two salt sensitive cultivars (Brown Raya and Raya Anmol) under above mentioned conditions. Result showed that tolerant varieties have less Na+ content, water potential, osmotic potential while they have greater K+, Ca++ Mg++ content and turgor potential than sensitive ones. Effect of salinity on P content was not much pronounced in all brassica varieties.

Salinity induced changes in α-amylase and protease activities and associated metabolism in cotton varieties during germination and early seedling growth stages

The increase in salinity of the medium resulted in the decrease α-amylase and protease activities in all cotton varieties tested, however it was more pronounced in NIAB-86. Decrease in concentration of reducing and non-reducing sugars, slower mobilization of reserve protein and reduced amino acidslevels were observed with increase in salinity levels. However, varieties K-115 showed better performance than others. The variety K-115 also had a capacity to mobilization and had higher levels of sugars, total free amino acids and reserve protein during germination and early seedling growth stages. However, varieties K-115 showed better performance than others. Variety K-115 showed highest germination followed by NIAB-Karishma and NIAB-86. The variety K-115 also had a capacity to mobilization and had higher levels of total free amino acids and less reserve protein during germination and early seedling growth stages.

Field Evaluation of Mungbean Recombinant Inbred Lines against Mungbean Yellow Mosaic Disease Using New Disease Scale in Thailand

Studies were conducted to identify the sources of resistance in mungbean recombinant inbred lines (RILs) in Thailand against mungbean yellow mosaic disease (MYMD). 146 mungbean RILs in series were evaluated in a field including resistant parent NM-10-12-1 and susceptible parent KPS 2 during summer 2008 under high inoculum pressure. The RILs were subsequently scored for disease symptom severity ratings (DSSR) using a new scale. Observations regarding DSSR and % disease index (%DI) showed that the tested RILs responded differently to the disease. A large number of RILs (132) were found highly susceptible, 12 were susceptible, 3 were tolerant and one was resistant. Overall screening results showed that three RILs, viz. line no. 30, 100 and 101 had minimum DSSR and % disease index thus they are good source of resistance to MYMD in spite of high disease pressure and can therefore be used directly as varieties to manage the disease in Thailand.

Mungbean phyllody disease in Pakistan: symptomatology, transmission, varietal response and effects on yield characteristics

Mungbean plants showing typical symptoms of infection by a phytoplasma that causes phyllody disease (transformation of floral parts into green, leaf-like structures) were examined in field crops in both spring and summer seasons. The most common symptoms were floral virescence, phyllody, reduction in leaf size, extensive proliferation of branches and stunting of plants. Sometimes these symptoms were accompanied by longitudinal splitting of green pods followed by germination of green (physiologically mature) seeds, producing small plants. Phyllody disease pathogen was successfully transmitted from diseased to healthy mungbean plants using either grafting and the leafhopper Orosius albicinctus under laboratory conditions. Transmission via seeds and by insects that included leafhopper Amrasca devastans, pea aphid Acyrthosiphon pisum, beetles Brumoides suturalis, Hippodamia variegata, Menochilus sexmaculatus, and the whitefly Bemisia tabaci failed to produce disease under laboratory conditions. During the spring and summer seasons of 2009, a field trial of 162 exotic and indigenous mungbean genotypes obtained from 8 different geographical regions was conducted, aiming to shed light on the causes of susceptibility to phyllody disease. Sixty-one genotypes showed infection, ranging from 1.00% to 4.35%. Significant variation in all yield and morphological characteristics due to phyllody disease on mungbean plants depending on growth stages was also recorded. Comparison between healthy and diseased plants showed significant percentage reduction at all growth stages. Maximum reduction in all the tested charcateristics was recorded when plants were infected before flowering followed by infection at the flowering and pod-setting stages. The most severely affected plant variables at all infection stages were the number of seeds per plant, the number of normal seeds per plant and yield per plant. Severely infected plants produced no seeds but some partially infected plants produced very small, sickle-shaped, upright and leathery pods with degenerate seeds.

Comparative simulation of silicon, PDMS, PGA and PMMA actuator for piezoelectric micropump

Microelectromechanical system (MEMS), a technology of miniature devices comprises micropumps that are also crucial components in microfluidic analysis systems. This article provides comparative study that focused on numerical simulation of silicon, Polydimethylsiloxane (PDMS), Polymethyl methacrylate (PMMA) and Polyglycolic acid (PGA) actuator for piezoelectric micropump in order to determine which one is better. The aim and objectives of this study is to exhibit the usefulness of finite element analysis (FEA) and simulation techniques for selecting a better material for membrane attached on an actuator in a piezoelectric micropump. The piezoelectric micropump consists of actuator having piezoelectric disk coupled on membrane that can be made of different materials like silicon, PDMS, PMMA and PGA. The behavior of actuator like deflection and stress for different materials has been analyzed by applying voltage from 50 V to 150 V for varying frequency 50 Hz to 150 Hz. The maximum deflection at 150 V has been found for PGA that is 67 μm and minimum deflection comes out for silicon that is 16 μm while others PDMS has deflection of 25.2 μm and PMMA has deflection of 25.8 μm. This research work offers helpful information for piezoelectric micropump design.

Growth performance and nutritional value of salt tolerant plants growing under saline environments

Salinity is a serious problem of agriculture worldwide, particularly in arid and semiarid regions. Most of Pakistan is arid to semi-arid with low annual precipitation and 6.3 million hectares (mha) land is affected to varying degree of salinity [1]. As a result of this, heavy losses in crop yields and plant productivity have been recorded [2]. Lands with high salinity are not cultivated and are changing into wasteland, and farmers owning these lands are migrating towards cities or towns as a result of which population load on cities is increasing day by day and deficiencies in food, feed, fodder and industrial materials are being faced. So, there is an urgent need to utilize these lands for plant production [3].

Level of Knowledge and Causes of Dental Disease among the Students of Selected Secondary Schools in Dhaka City

To assess the level of knowledge and causes of dental disease among the urban school children a cross-sectional study was conducted in two secondary schools of Dhaka city. 20 students each of class 6, 7 & 8 from each school were randomly selected. List of the students was obtained from the teacher & from the list 20 were selected. Regarding the level of knowledge 54% were found to have average knowledge and 25.8% had good knowledge about causes of dental disease. People should be made more aware about the maintenance of oral hygiene for ensuring better oral health. DOI: http://dx.doi.org/10.3329/bjdre.v3i1.16589 Bangladesh Journal of Dental Research & Education Vol.3(1) 2013: 12-15