Physiological and biochemical changes in desiccation sensitive curry leaf (Murraya koenigii (L.) Sprengel) seeds

Curry leaf (Murraya koenigii (L.) Sprengel) is an important spice tree propagated by seeds. However, the seeds are sensitive to desiccation and considered as recalcitrant. Therefore, an experiment was conducted to analyze its level of desiccation and changes takes place during water loss. The results indicated that the reduction in seed moisture from 47.4 per cent leads to loss in viability. In which, the initial seed germination (100 %) declines slowly during desiccation and at the seed moisture content of 33.1 per cent it recorded 69 per cent germination at six days of exposure under ambient temperature (30±20C). Further moisture loss leads to drastic reduction in germination and hence, this could be the critical or lowest safe moisture content. In addition, the reduction in seedling vigour and enzymatic activity and increase in seed leachate were noticed during desiccation of the curry leaf seeds

Aquaporins and their implications on seeds: A brief review

Aquaporins (AQPs) are water channel proteins. They play a key role in maintaining water balance and homeostasis in cells under stress conditions in living organisms. AQPs are pore forming transmembrane proteins that facilitate water movement and various small neutral solutes across cellular membranes. Aquaporin expression and transport functions are modulated by various phytohormones mediated signalling in plants. Transcriptome analysis revealed the role of aquaporins in regulating hydraulic conductance in plant roots and leaves. Different AQPs found in the seed system have individual functions that are more time and tissue specific, ultimately helping in the seed imbibition process to complete seed germination. Seed specific TIP3s aquaporin helps to maintain seed longevity under expressional control of ABI3 during seed maturation and heat shock proteins and late embryogenic abundant proteins. Under stress circumstances, the major significance of aquaporin expression in seeds is to maintain water influx and efflux rates, as well as protein modification, post translational alterations, nutritional acquisition and allocation, subcellular trafficking and CO2 transport. The present review mainly focused on aquaporin structure, classification, role and functional activity during solute transport, reproductive organs development, plant growth development, abiotic stress response and also various roles in seeds such as seed biology, seed development and maturation, seed dormancy, seed germination and longevity

Volatile organic compound analysis as advanced technology to detect seed quality in groundnut

An experiment was conducted to profiling the volatile organic compounds emitted from groundnut seeds during storage and also to assess the volatiles emission level during seed deterioration. Volatile organic compounds profiling of stored groundnut seeds was done through GC-MS at monthly intervals. The results showed that several volatile compounds were released from stored groundnut seeds and all the compounds are falling into eight major groups viz., alcohols, aldehydes, acids, esters, alkanes, alkenes, ketones and ethers. The study clearly demonstrated the influence of volatile organic compounds emission level on physiological and biochemical properties during storage. There was a significant decrease in physiological and biochemical quality attributes noted due to an increase in the strength of volatiles released during ageing. When the release of total volatile strength reached more than 50%, a significant reduction in physiological attributes such as germination, root and shoot length, dry matter production and vigour index were observed. With respect to biochemical properties, a significant increase in electrical conductivity of seed leachate, lipid peroxidation and lipoxygenase activity, and a decrease in dehydrogenase, catalase and peroxidase activities were observed. However, the highest reduction in all these properties was recorded when the total volatile strength reached 92.72%. The study concluded that the volatiles released during seed deterioration could be considered the signature components for detecting the seed quality during storage

Assessment of rice (Co 51) seed ageing through volatile organic compound analysis using Headspace-Solid Phase Micro Extraction/ Gas Chromatography-Mass Spectrometry (HS-SPME/GCMS)

Seed ageing is an inevitable process that reduces seed quality during storage. When seeds deteriorate as a result of the lipid peroxidation process, it leads to produce toxic volatile organic compounds. These volatiles served as an indicator for the viability of stored seeds. With this background, the study was conducted to profile the volatile organic compounds emitted from rice seeds during storage. Volatile profiling of stored rice var. Co 51 seeds was done through Headspace-Solid phase microextraction/ Gas chromatography-mass spectrometry (HS-SPME/GCMS). The study clearly demonstrated that the significant decrease in physiological and biochemical quality attributes was noted due to an increase in the strength of volatiles released during ageing. When the release of total volatile strength reached more than 40%, a significant reduction in physiological attributes such as germination, root and shoot length, dry matter production and vigour index were observed. With respect to biochemical properties, a significant increase in electrical conductivity of seed leachate, lipid peroxidation and lipoxygenase activity, and decrease in dehydrogenase, catalase and peroxidase activities were observed. However, the highest reduction in all these properties were recorded when the total volatile strength reached to 54.90%. Finally, the study concluded that, among all the volatiles, 1-hexanol, 1-butanol, ethanol, hexanal, acetic acid, hexanoic acid and methyl ester were the most closely associated volatiles with seed deterioration. It indicates that these components could be considered the signature components for assessing the seed quality in rice during storage.

Importance of trmE for Growth of the Psychrophile Pseudomonas syringae at Low Temperatures▿ †

Transposon mutagenesis of Pseudomonas syringae Lz4W, a psychrophilic bacterium capable of growing at temperatures between 2 and 30°C, yielded 30 cold-sensitive mutants, and CSM1, one of these cold-sensitive mutants, was characterized. Growth of CSM1 was retarded when it was cultured at 4°C but not when it was cultured at 22°C and 28°C compared to the growth of wild-type cells, indicating that CSM1 is a cold-sensitive mutant of P. syringae Lz4W. The mutated gene in CSM1 was identified as trmE (coding for tRNA modification GTPase), and evidence is provided that this gene is induced at low temperatures. Further, the cold-inducible nature of the trmE promoter was demonstrated. In addition, the transcription start site and the various regulatory elements of the trmE promoter, such as the −10 region, −35 region, UP element, cold box, and DEAD box, were identified, and the importance of these regulatory elements in promoter activity were confirmed. The importance of trmE in rapid adaptation to growth at low temperatures was further highlighted by plasmid-mediated complementation that alleviated the cold-sensitive phenotype of CSM1

Switching angles computations using pso in selective harmonics minimization pwm

The preprogrammed pulse width modulation (PWM) method for operating power converters ensures minimum switching loss and at the same time better quality waveform at the output. The Fourier series analysis of the predefined output waveform with the removal of certain low order harmonics yields a set of trigonometric equations in which switching angles are treated as variables. It results in removal of preselected harmonics from the output and control on the fundamental component. The main challenge in implementation of selective harmonics minimization is in solving of these system of highly non linear equations which have different number of solutions for different range of modulation index. The particle swarm optimization technique can be used to obtain switching angles from the system of highly non linear equations by properly formulating an objective function which need to be minimized. The requirement of symmetry constraints on the output waveform can be implemented using penalty function approach. The main advantage of the PSO approach over algebraic and numerical based techniques is that it can be used for computation of large number of switching angles with less dependency on the initial guess of the solution.Scopu