House flies are one of the major public health pests in urban settings. People usually use insecticides containing pyrethroids for the management of house flies; however, there is a lack of information on pyrethroid resistance in house flies from urban areas. In the present study, resistance to four pyrethroids (beta-cyfluthrin, deltamethrin, permethrin, transfluthrin) was assessed in house flies collected from urban areas of Punjab, Pakistan. Significant levels of resistance to all the pyrethroids were found in different strains of house flies. The resistance ratios (RRs) at the median lethal dose (LD) level were in the range of 5.25- to 11.02-fold for beta-cyfluthrin, 7.22- to 19.31-fold for deltamethrin, 5.36- to 16.04-fold for permethrin, and 9.05- to 35.50-fold for transfluthrin. Pairwise comparison of the log LDs revealed a highly significant correlation (p < 0.01) between deltamethrin and permethrin, suggesting the possibility of a cross-resistance mechanism. The results revealed the occurrence of pyrethroid resistance in house flies from urban areas of Punjab. Regular resistance monitoring surveys and integrated approaches for the management of house flies are needed to retain the efficacy of these insecticides for a longer period of time.
Plant hormones are considered to play an important role in plant adaptation to drought and salt stress. The objective of the study was to investigate the changes in endogenous jasmonic acid (JA) in relation to differences in the salt resistance of maize genotypes. Two maize genotypes (SR 03 and Across 8023) were compared for changes in water relations, growth and tissue JA levels in response to 100 mM NaCl. Salt stress significantly reduced the shoot growth of both genotypes; however, SR 03 exhibited significantly less reduction in relative shoot fresh weight than Across 8023. Both genotypes showed an identical response to salt stress regarding plant water relations; therefore, genotypic differences in the salt resistance could not be attributed to changes in shoot turgor and these results were further confirmed by the response of both genotypes under equiosmotic stress (À0.49 MPa) of either 100 mM NaCl or PEG-6000. GC-MS/MS analysis showed that salt stress did not alter shoot JA levels of both genotypes, however significantly increased the root JA levels of Across 8023. In contrast, root JA levels of salt-resistant SR 03 did not change by salt stress. Increase in root JA levels in response to stress treatments does not coincide with the growth inhibition of shoot in Across 8023. In contrast, both PEG and NaCl did not change the JA concentrations in both root and shoot tissues of SR 03. Growth assays with maize seedlings showed that JA supply in root medium inhibits shoot extension growth and both maize genotypes were sensitive to the inhibitory effects of JA. These results suggest that maize genotypes differ in JA accumulation during the first phase of salt stress and JA may indirectly be involved in leaf growth inhibition of the salt-sensitive genotype. In addition, our results also showed that treatment of salt-stressed plants with exogenous JA improved the Na + exclusion by decreasing the Na + uptake at the root surface.
Reproductive success in cereals is determined primarily by grain setting and grain filling. The kernel abortion in maize during pre-anthesis drought has been widely studied, but the reasons behind this abortion are still largely unknown. The present study investigated the impact of drought stress (control and drought) around pollination and foliar sprays of potassium (K; 0, 1, 2 and 5% K2SO4) on leaf K concentrations and yield determinants of maize under greenhouse and field conditions. Results of both experiments revealed that drought stress before pollination strongly reduced the cob fresh weights, number of grains per cob and hence grain yields. While cob length, cob diameter and grain weights were only slightly affected by drought. Potassium concentrations in cob leaves of drought stressed plants were slightly below the critical threshold values. Foliar spray of 2 and 5% K significantly increased the leaf K concentration, number of grains per cob and grain yield in drought treatments of both experiments. Foliar application of K had little or no significant effect on growth and yield determinants of control plants. It is concluded that potassium deficiency could be one factor associated with poor kernel setting under drought stress. Foliar application of 2 and 5% K2SO4 before silking can significantly improve grain number and grain yield in droughtstressed maize.
Arable soils are frequently subjected to contamination with copper as the consequence of imbalanced fertilization with manure and organic fertilizers and/or extensive use of copper-containing fungicides. In the present study, the exposure of stone-head cabbage (Brassica oleracea var. capitata) to elevated Cu2+ levels resulted in leaf chlorosis and lesser biomass yield at ≥2 µ M. Root nitrate content was not statistically affected by Cu2+ levels, although it was substantially decreased at ≥5 µ M Cu2+ in the shoot. The decrease in nitrate contents can be related to lower nitrate uptake rates because of growth inhibition by Cu-toxicity. Shoot sulfate content increased strongly at ≥2 µ M Cu2+ indicating an increase in demand for sulfur under Cu stress. Furthermore, at ≥2 µM concentration, concentration of water-soluble non-protein thiol increased markedly in the roots and to a smaller level in the shoot. When exposed to elevated concentrations of Cu2+ the improved sulfate and water-soluble non-protein thiols need further studies for the evaluation of their direct relation with the synthesis of metal-chelating compounds (i.e., phytochelatins).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.