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Spatio-temporal changes in the six major glaciers of the Chitral River basin(Hindukush Region of Pakistan)between 2001 and 2018

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Journal of Mountain Science 2020年第3期17卷 572-587页

作者： Jawaria GUL Sher MUHAMMAD LIU Shi-yin Siddique ULLAH shakeel ahmad Huma HAYAT Adnan ahmad TAHIR Department of Environmental Sciences COMSATS University Islamabad(CUI)Abbottabad Campus22060AbbottabadPakistan International Center for Integrated Mountain Development(ICIMOD) KathmanduNepal Institute of International Rivers and Eco-Security Yunnan UniversityKunmingChina Division of Environmental System Analysis School of EnvironmentTsinghua UniversityBeijing 100084 China

Glaciers in the northern Pakistan are a distinctive source of freshwater for the irrigation,drinking and industrial water supplies of the people living in those regions and downstream. These glaciers are under a direct global warming impact as indicated in many previous studies. In this study, we estimated the glacier dynamics in terms of Equilibrium Line Altitude(ELA), mass balance and the snout position variation using remote sensing data between 2001 and 2018. Six glaciers, having area≥ 20 km2 each, situated in the Chitral region(Hindukush Mountains) were investigated in this study. Digital Elevation Model(DEM) and available cloud-free continuous series of Landsat and Sentinel satellite images from minimum snow cover season were used to monitor the variability in the studied glaciers by keeping the status of glaciers in year 2001 as a reference. The annual climatic trends of mean temperature and total precipitation from Chitral weather station were detected using the nonparametric Mann-Kendall’s test. Results revealed a general increase in the ELA, decrease in the glacier mass balance and the retreat of snout *** upward shift in the ELA for the entire study area and data period was ~345 ± 93 m at a rate of^13 m.a-1 from the reference year’s position i.e.~4803 m asl. Estimated mean mass balance for the entire study area indicated a decline of-0.106 ± 0.295 m w.e. a-1. Periods of snout retreat and advance in different glaciers were found but the mean value over the entire study area was a retreat of-231 ± 140 *** obvious relationship was found between the glacier variation trends and the available gauged climatic data possibly due to the presence of debris cover in ablation zones of all the studied glaciers which provides insulation and reduces the immediate climatic effects.

关键词： Glacier dynamics Hindukush region Sentinel Landsat Mass balance Equilibrium Line Altitude Snout position

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Effects of uniconazole with or without micronutrient on the lignin biosynthesis,lodging resistance,and winter wheat production in semiarid regions

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Journal of Integrative Agriculture 2020年第1期19卷 62-77页

作者： Irshad ahmad MENG Xiang-ping Muhammad KAMRAN Shahzad ALI shakeel ahmad LIU Tie-ning CAI Tie HAN Qing-fang Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau Ministry of Agriculture/College of AgronomyNorthwest A&F UniversityYangling 712100P.R.China Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of Education/Institute of Water Saving Agriculture in Arid Areas of ChinaNorthwest A&F UniversityYangling 712100P.R.China

Lodging stress results in grain yield and quality reduction in wheat. Uniconazole, a potential plant growth regulator significantly enhances lignin biosynthesis and thus provides mechanical strength to plants in order to cope with lodging stress. A field study was conducted during the 2015–2016 and 2016–2017 growing seasons, to investigate the effects of uniconazole sole application or with micronutrient on the lignin biosynthesis, lodging resistance, and production of winter wheat. In the first experiment, uniconazole at concentrations of 0(CK), 15(US1), 30(US2), and 45(US3) mg L^-1 was applied as sole seed soaking, while in the second experiment with manganese(Mn) at concentration of 0.06 g L^-1 Mn, 0.06 g L^-1 Mn+ 15 mg L^-1 uniconazole(UMS1), 0.06 g L^-1 Mn+30 mg L^-1 uniconazole(UMS2), and 0.06 g L^-1 Mn+45 mg L^-1 uniconazole(UMS3), respectively. Uniconazole sole application or with micronutrient significantly increased the lignin content by improving the lignin-related enzyme activities of phenylalanine ammonia-lyase, cinnamyl alcohol dehydrogenase, tyrosine ammonialyase, and peroxidase, ameliorating basal internode characteristics, and breaking strength. The spike length, spike diameter, spikes/plant, weight/spike, yield/spike, and grain yield increased and then decreased with uniconazole application at a higher concentration, where their maximum values were recorded with UMS2 and US2 treatments. The lignin accumulation was positively correlated with lignin-related enzyme activities and breaking strength while, negatively correlated with lodging rate. Uniconazole significantly improved the lignin biosynthesis, lodging resistance, and grain yield of winter wheat and the treatments which showed the greatest effects were uniconazole seed soaking with micronutrient at a concentration of 30 mg L^-1 and 0.06 g L^-1 , and uniconazole sole seed soaking at a concentration of 30 mg L^-1 .

关键词： lignin biosynthesis lodging resistance semi-arid regions manganese uniconazole wheat

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欧姆加热纳米流体中具有热跳现象移动表面的Falkner-Skan流分析

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Journal of Central South University 2023年第3期30卷 834-843页

作者： ahmad shakeel Farooq HINA Farooq MUHAMMAD Department of Mathematics and Statistics Riphah International UniversityIslamabad 44000Pakistan Department of Pure and Applied Mathematics The University of HaripurHaripur 22600Pakistan

边界层假设下的Falkner-Skan流分析因其在渗流、导热垫、热交换器、油层检测和地热分析等许多工业领域和过程中的广泛应用引起了越来越多的关注。本文主要研究了氧化石墨烯-水纳米流体的Falkner-Skan磁楔流。通过对驻点附近进行分析,研... 详细信息

边界层假设下的Falkner-Skan流分析因其在渗流、导热垫、热交换器、油层检测和地热分析等许多工业领域和过程中的广泛应用引起了越来越多的关注。本文主要研究了氧化石墨烯-水纳米流体的Falkner-Skan磁楔流。通过对驻点附近进行分析,研究了可拉伸壁面的速度和热滑现象,以及黏性耗散和欧姆加热对热传输的影响。利用同伦算法说明了相关参数与速度和热传输机理的关系,阐述了Nusselt数和表面摩擦因数的影响。结果表明:温度随着Brinkman数的增长而升高,进一步的热跳则使温度场减小;Hartmann数的增加使热场厚度增大,动量谱厚度减小。该研究对医疗、高温设施、热交换器和机械结构有极大意义。

关键词： Falkner-Skan流纳米流体磁流体动力驻点速度滑移热滑黏性耗散欧姆加热

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Nitrogen management improves lodging resistance and production in maize(Zea mays L.)at a high plant density

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Journal of Integrative Agriculture 2023年第2期22卷 417-433页

作者： Irshad ahmad Maksat BATYRBEK Khushnuma IKRAM shakeel ahmad Muhammad KAMRAN Misbah Raham Sher KHAN HOU Fu-jiang HAN Qing-fang Key Laboratory of Crop Physio-Ecology and Tillage Science in North-Western Loess Plateau Ministry of Agriculture/College of AgronomyNorthwest A&F UniversityYangling 712100P.R.China State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems/Key Laboratory of Grassland Livestock Industry Innovation Ministry of Agriculture and Rural Affairs/Engineering Research Center of Grassland IndustryMinistry of Education/College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730020P.R.China Department of Biotechnology Abdul Wali Khan University MardanMardan 23200Pakistan

Lodging in maize leads to yield losses *** this study,we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics,culm mechanical strength,lignin content,root growth,lodging percentage and production in maize at a high plant *** compared a traditional nitrogen(N)application rate of 300 kg ha–1(R)and an optimized N application rate of 225 kg ha^(–1)(O)under four N application modes:50%of N applied at sowing and 50%at the 10th-leaf stage(N1);100%of N applied at sowing(N2);40%of N applied at sowing,40%at the 10th-leaf stage and 20%at tasseling stage(N3);and 30%of N applied at sowing,30%at the 10th-leaf stage,20%at the tasseling stage,and 20%at the silking stage(N4).The optimized N rate(225 kg ha^(–1))significantly reduced internode lengths,plant height,ear height,center of gravity height and lodging *** optimized N rate significantly increased internode diameters,filling degrees,culm mechanical strength,root growth and lignin *** application of N in four split doses(N4)significantly improved culm morphological characteristics,culm mechanical strength,lignin content,and root growth,while it reduced internode lengths,plant height,ear height,center of gravity height and lodging *** diameters,filling degrees,culm mechanical strength,lignin content,number and diameter of brace roots,root volume,root dry weight,bleeding safe and grain yield were significantly negatively correlated with plant height,ear height,center of gravity height,internode lengths and lodging *** conclusion,treatment ON4 significantly reduced the lodging percentage by improving the culm morphological characteristics,culm mechanical strength,lignin content,and root growth,so it improved the production of the maize crop at a high plant density.

关键词： high plant density lodging resistance maize nitrogen rates nitrogen application modes

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Phyto-Toxicity of Chromium in Maize： Oxidative Damage, Osmolyte Accumulation, Anti-Oxidative Defense and Chromium Uptake

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Pedosphere 2017年第2期27卷 262-273页

作者： shakeel ahmad ANJUM Umair ASHRAF Imran KHAN Mohsin TANVEER Muhammad SHAHID Abdul SHAKOOR WANG Longchang College of Agronomy and Biotechnology Southwest University/Engineering Research Center of South Upland Agriculture Ministry of Education Chongqing 400716 (China) Department of Agronomy University of Agriculture Faisalabad 38040 (Pakistan) Department of Crop Science and Technology College of Agriculture South China Agricultural University Guangzhou 510642 (China) Scientific Observing and Experimental Station of Crop Cultivation in South China Ministry of Agriculture Guangzhou 510642 (China) School of Land and Food University of Tasmania Hobart 7005 (Australia)

Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium （Cr） stress levels, i.e., O, 30, 60, 90, 120, and 150 μmol L^-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation of reactive oxygen species （ROS）, and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots 〉 leaves 〉 stem ~ seeds in both genotypes. The increased Cr toxicity resulted in higher free proline, soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide （H2O2） and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution.

关键词： agronomic characteristics anti-oxidative enzyme activity Cr accumulation Cr translocation heavy metal stress reactiveoxygen species

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