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Physiological m.chanism.of Nitrogen m.diating Cotton (<i>Gossypium.hirsutum.lt;/i>L.) Seedlings Growth under Water-Stress Conditions

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Am.rican Journal of Plant Sciences 2012年第6期3卷 721-730页

作者： Zhigou Zhou derrick m. oosterhuis Departm.nt of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA. Key Laboratory of Crop Physiology & Ecology in Southern China of m.nistry of Agriculture Nanjing Agricultural University Nanjing China

The objective of this investigation was to study the effects of nitrogen on tolerance to water-stress in cotton (Gossypium.hirsutum.L.) seedlings. Growth cham.er studies with pots of washed sand were carried out in Fayetteville, USA, and Nanjing, Chinawith three water conditions (well-watered, drought-stressed, and waterlogging), and three nitrogen rates, low nitrogen (16 m., approxim.tely 224 m. N·l–1 water), m.dium.nitrogen (24 m., approxim.tely 448 m. N·l–1 water) and high nitrogen (32 m., approxim.tely 672 m. N·l–1 water), respectively. The results showed that water-stress treatm.nts reduced plant biom.ss, C/N ratio, root vigor and leaf photosynthesis (Pn). The plant response to water-stress resistance was affected by nitrogen, and was correlated with the activities of antioxidant enzym.s. The changes of anti-oxidant enzym.s was the highest in the low nitrogen rate in the drought-stressed and waterlogged cotton seedlings. m.londialdehyde (m.A) content increased significantly in the water-stress treatm.nts, and was the lowest in the low nitrogen rate. There was a significant reduction of N accum.lation under water stress. Low-nitrogen treatm.ntincreased C accum.lation, while high-nitrogen treatm.nt decreased N accum.lation. Root vigor was decreased by water stress, and was highest in the low-nitrogen rate. After term.nating the water stress, N application prom.ted root vigor, especially in waterlogged seedlings. The trends of Pn weresim.larto that of root vigor. These results suggested that low N application m.y contribute to cotton drought tolerance by enhancing the activity of antioxidant enzym.s and conse-quently decreasing lipid peroxidation, and enhancing root vigor. However, higher N should be applied to waterlog- ging-stressed cotton seedlings after term.nating waterlogging.

关键词： Cotton Seedling Nitrogen Water Deficit Drought Stress Waterlogging Antioxidant Enzym. Activity Photosynthesis Root Vigor

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Effect of 1-m.P on Gas Exchange and Carbohydrate Concentrations of the Cotton Flower and Subtending Leaf under Water-Deficit Stress

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Am.rican Journal of Plant Sciences 2013年第1期4卷 142-152页

作者： Dim.tra A. Loka derrick m. oosterhuis Departm.nt of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA

Ethylene is an endogenous plant horm.ne that increases under adverse environm.ntal conditions, resulting in leaf and fruit abscission and ultim.tely yield reduction. In cotton, however, the effects of water-deficit stress on ethylene production have been uncertain. In this study it was hypothesized that application of an ethylene inhibitor 1-m.thylcyclo- propene (1-m.P) would prevent ethylene production and result in alleviation of water-deficit stress consequences on the physiology and m.tabolism.of the cotton flower and subtending leaf. To test this hypothesis, growth cham.er experim.nts were conducted in 2009-2010 with treatm.nts consisting of (C) untreated well-watered control, (C + 1m.P) well-watered plus 1-m.P, (WS) untreated water-stressed control, and (WS + 1m.P) water-stressed plus 1-m.P. The plants were subjected to two consecutive drying cycles during flowering, approxim.tely 8 weeks after planting, and 1-m.P was foliar applied at a rate of 10g. ai/ha at the beginning of each drying cycle. The results showed that 1-m.P application had no significant effect on gas exchange functions and did not prevent reductions from.water stress in leaf photosynthesis, respiration and stom.tal conductance. However, application of 1-m.P resulted in a decrease in sucrose content of water-stressed pistils com.ared to the control indicating that 1-m.P has the potential to interfere in carbohydrate m.tabolism.of reproductive units.

关键词： Cotton 1-m.thylcyclopropene Ethylene Water-Deficit Stress Carbohydrates Gas Exchange

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Endogenous Levels of Polyam.nes under Water-Deficit Stress during Cotton’s Reproductive Developm.nt

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Am.rican Journal of Plant Sciences 2015年第2期6卷 344-354页

作者： Dim.tra A. Loka derrick m. oosterhuis Cristiane Pilon Altheim.r Laboratory Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville AR USA

Polyam.nes, putrescine (PUT), sperm.dine (SPD) and sperm.ne (SPm. are im.licated in plants’ responses under conditions of abiotic stress. Previous research in other crops has indicated that polyam.nes and changes in their concentrations are associated with drought tolerance under conditions of water-deficit stress;however, no inform.tion exists on cotton (Gossypium.hirsutum.L.). Growth cham.er experim.nts were conducted with two cotton cultivars differing in drought tolerance, ST5288B2F (drought-sensitive) and Siokra L23 (drought-tolerant) in order to investigate the distribution of free polyam.nes, the effect of water-deficit stress on the polyam.ne m.tabolism.of cotton reproductive units and their subtending leaves as well as the possible relationship between polyam.nes and drought tolerance in cotton. Our results showed that cotton ovaries contained significantly higher levels of total free polyam.nes com.ared to their subtending leaves under both control and water stress conditions. Water-deficit stress significantly increased PUT concentrations in ST5288B2F, while SPm.levels significantly decreased in Siokra L23. The results indicated that water-deficit stress significantly affected cotton polyam.ne m.tabolism.in reproductive structures and their subtending leaves;however, no clear relationship between drought-tolerance and changes in polyam.ne accum.lation was established. Further research is needed to elucidate the m.chanism.according to which water-deficit stress affects polyam.ne m.tabolism.

关键词： Cotton Gas Exchange Polyam.ne Levels Reproductive Units Water-Deficit Stress

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Changes in the Ovarian Polyam.ne Content and Seed Set Efficiency of Cotton by the Plant Growth Regulator Bm.6

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Am.rican Journal of Plant Sciences 2012年第9期3卷 1328-1335页

作者： Androniki C. Bibi derrick m. oosterhuis Evangelos D. Gonias Departm.nt of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA

Naturally occurring polyam.nes in plants have been im.licated in floral initiation, and fruit developm.nt. The plant growth regulator Bm.6 was form.lated to stim.late seed production and fruit growth by enhancing polyam.ne synthe-sis. The objectives of this study were to determ.ne the effect of Bm.6 on free polyam.ne content in cotton (Gos-sypium.hirsutum.L.) ovaries and on seed set efficiency, and also to investigate genotypic differences in ovarian polyam.ne content. Bm.6 was applied at the first flower stage and two weeks later at 2.34 m./ha. This study showed that application of Bm.6 had a significant positive effect on ovarian polyam.ne content of cotton. Putrescine and sper-m.dine one week after the 1st Bm.6 application and putrescine two week after the 1st Bm.6 application, were significantly increased com.ared to the untreated control. Higher seed set efficiency with the Bm.6 application was observed when the total num.er of seeds was used for the calculation. However, when the num.er of harvestable seeds was used to calculate seed set efficiency Bm.6 had no significant effect. In addition, application of Bm.6 did not significantly alter seedcotton yield of the crop. Only sm.ll differences in ovarian polyam.ne content were detected am.ng the genotypes tested, possibly due to the narrow genetic pool of the com.ercial cotton genotypes used. Application of Bm.6 can significantly increase cotton seed num.er by enhancing polyam.nes biosynthesis, but further research is needed to determ.ne how to capitalize on the increased potential num.er of harvestable seeds.

关键词： Putrescine Sperm.dine Sperm.ne Bm.6 Gossypium hirusutm L. Ovaries

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Radiation Use Efficiency of Cotton in Contrasting Environm.nts

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Am.rican Journal of Plant Sciences 2012年第5期3卷 649-654页

作者： Evangelos D. Gonias derrick m. oosterhuis Androniki C. Bibi Bruce A. Roberts Departm.nt of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA Plant Science Departm.nt California State University Fresno USA

Crop growth and yield varies am.ng locations due to differences in environm.ntal param.ters, such as tem.erature, relative hum.dity, solar radiation and vapor pressure deficit. Previous research has shown that increasing vapor pressure deficit has a negative effect on radiation use efficiency of m.ny crops. In this study, the radiation use efficiency of cot-ton (Gossypium.hirsutum.L.) grown in two contrasting production environm.nts, Arkansas and California, was evaluated for two years, in 2006 and 2007. Tem.erature, relative hum.dity, vapor pressure deficit and photosyntheti-cally active radiation were recorded at both locations. Although the crop in California accum.lated m.re dry m.tter during the period of the study, the radiation use efficiency was found to be lower com.ared to Arkansas. Radiation use efficiency for the Arkansas and California locations was estim.ted at 2.060 and 1.518 g?m.–1 of intercepted photosynthetically active radiation, respectively. The higher productivity observed in California can be attributed to larger am.unts of incident and intercepted radiation in this location. Radiation use efficiency of cotton was estim.ted to decrease with increasing vapor pressure deficit by a slope of –0.47 g?m.–1?kPa–1.

关键词： Dry m.tter Environm.nt Gossypium hirsutum L. Light Interception Radiation Use Efficiency Vapor Pressure Deficit

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Response of Two Inexpensive Com.ercially Produced Soil m.isture Sensors to Changes in Water Content and Soil Texture

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Agricultural Sciences 2015年第10期6卷 1148-1163页

作者： Tyson B. Raper Christopher G. Henry Leo Espinoza m.kham.adzakhrab Ism.nov derrick m. oosterhuis Departm.nt of Plant Sciences University of Tennessee Jackson TN USA Departm.nt of Biological and Agricultural Engineering University of Arkansas Stuttgart AR USA Departm.nt of Crop Soil and Environmental Sciences University of Arkansas Little Rock AR USA Departm.nt of Crop Soil and Environmental Sciences University of Arkansas Fayetteville AR USA

The use of low-cost (<200 USD) soil m.isture sensors in crop production system. has the potential to give inference on plant water status and therein drive irrigation events. However, com.ercially available sensors in... 详细信息

The use of low-cost (m.isture sensors in crop production system. has the potential to give inference on plant water status and therein drive irrigation events. However, com.ercially available sensors in this price range vary in sensing m.thodologies and lim.ted inform.tion on sensor to sensor relationship is available. The objective of this research was to test the response of the Waterm.rk 200SS and Decagon 10HS sensors to changes in water content of three dissim.lar soils representing com.on soils in Arkansas row-crop production in nine plastic, 19 L containers under variable environm.ntal conditions. Both sensors were influenced by changes in soil tem.erature but the m.gnitudes of the tem.erature responses were sm.ll relative to the m.isture responses. Furtherm.re, the 10HS sensor did not indicate a significant im.act of soil texture on estim.ted volum.tric water contents (VWCs). The sm.ll sphere of influence on the tested soil m.isture param.ters coupled with the substantial evaporative dem.nds and tem.eratures under which this experim.nt was conducted resulted in suspected non-uniform.drying and wetting of the tested containers. Subsequently, non-linear relationships were noted between 10HS estim.ted VWCs and actual container VWCs and the 200SS predicted lower water potentials than calculated by converting container VWC to soil water potential. The failure of the sensors to accurately predict container VWC highlights the im.ortance of understanding the relatively sm.ll quantity of soil on which these sensors rely as well as the potential variability in soil m.isture within a very lim.ted volum.. The authors caution users of sensors that soil variability m.y be one of the m.st im.ortant considerations in sensor deploym.nt.

关键词： Soil m.isture Sensor 10HS Waterm.rk 200SS Decagon Com.arison Soil Texture

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Feeding the Children Chinese assistance nourishes Uganda’s next generation

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ChinAfrica 2025年第1期17卷 42-43页

作者： derrick SILIm.NA 不详

Adriano Kanyesigye and his friends walk up to 5 m.les each day to attend a school where they are served a free ***’s a journey that pupils in Karam.ja in northeast Uganda willingly m.ke to avoid starvation.“I’m.really grateful that m. kids have at least one m.al a day when they go to school,rather than staying hom. where food is scarce,”Anisha Kanyesigye told ChinAfrica.“At hom.,we have nothing to *** we boil sorghum.or eat adaka-a residue from.locally brewed alcohol.”The 30-year-old resident of Karam.ja explained that the region is struggling with hunger,as the local population is severely im.acted by a food crisis caused by drought and pests.

关键词： nothing northeast really

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Potential Association between Soil and Leaf Chem.cal Properties, and Soybean Seed Com.osition

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Agricultural Sciences 2014年第6期5卷 560-570页

作者： Luciano m. Jaureguy Pengyin Chen Kristofor Brye derrick oosterhuis Andy m.urom.ustakos John R. Clark Agricultural Statistics Laboratory University of Arkansas Fayetteville USA Departm.nt of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA

m.xim.zing the expression of seed quality traits by understanding how they are affected by environm.ntal variables m.y help develop high quality nutritious soybeans. Eight specialty soybean breeding lines were grown at two Arkansas locations differing by soil texture, with three replications in 2011. Before the reproductive period, soil and leaf sam.les were collected from.each plot. Soil sam.les were analyzed for particle size distribution, electrical conductivity, pH, and a set of extractable nutrients from.the top 12.5 cm. while leaf sam.les were analyzed for the sam. set of nutrients as the soil sam.les. At m.turity, seed sam.les were analyzed for the sam. set of nutrients as were leaf and soil sam.les, plus protein, oil, fatty acids, and sugars. All leaf elem.nts were within the adequate levels for soybean production at both locations. Overall, seed com.osition of breeding lines did not differ am.ng locations and no significant changes in breeding line ranking am.ng locations were observed. Attem.ting to m.dify seed com.osition by nutrient fertilization m.y not be profitable, as no direct relationships were observed between leaf or soil chem.cal properties, and seed com.osition. These findings m.y provide a starting point for future studies on fertilization and m.nagem.nt practices that im.rove soybean seed quality.

关键词： Soybean Seed Com.osition Soil Properties

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Realising the Potential of Genom.cs for m. tuberculosis: A Silver Lining to the Pandem.c?

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China CDC weekly 2022年第20期4卷 437-439页

作者： Tim.thy m.Walker derrick W Crook Oxford University Clinical Research Unit Ho Chi Minh CityVietnam Nuffield Departm.nt of m.dicine University of Oxford OxfordUK

The im.act of the severe acute respiratory syndrom. coronavirus 2(SARS-CoV-2)pandem.c on tuberculosis has been ***,there were 1.4 m.llion fewer patients receiving tuberculosis treatm.nt in 2020,representing not a fall in the global case load but a failure to serve m.llions of patients with the disease(1–2).m.rbidity,m.rtality,and onward transm.ssion are inevitable outcom.s of such failure,setting the world back a decade of progress.

关键词： tuberculosis m.rtality acute

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High Tem.erature and the Ethylene Antagonist 1-m.thylcyclopropene Alter Ethylene Evolution Patterns,Antioxidant Responses,and Boll Growth in Gossypium.hirsutum

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Am.rican Journal of Plant Sciences 2013年第7期4卷 1400-1408页

作者： Eduardo m.Kawakam. derrick m.oosterhuis John L.Snider Toby R.FitzSim.ns Av.Antonio Teixeira dos Santos RondonópolisBrazil Departm.nt of Crop Soiland Environmental SciencesUniversity of Ar-kansasFayettevilleUSA Departm.nt of Crop and Soil Sciences University of GeorgiaTiftonUSA

The cotton (Gossypium.hirsutum.L.) crop experiences high tem.eratures during flowering and boll developm.nt, but inform.tion regarding the im.act of ethylene inhibition and high tem.erature on early boll developm.nt is lim.ted. The objective of this study was to determ.ne the effects of high tem.erature and the anti-ethylene com.ound 1-m.thylcy-cloprone (1-m.P) on G. hirsutum.boll developm.nt. Treatm.nts consisted of tem.erature regim. (38/20?C and 30/ 20?C), 1-m.P treatm.nt, and days past anthesis (DPA). High tem.erature decreased ethylene synthesis by 61% at 2 DPA, and 1-m.P caused a 40% decrease in ethylene production at 1 DPA. Glutathione reductase activity increased under high tem.erature, whereas superoxide dism.tase activity (SOD) and m.m.rane peroxidation (m.londialdehyde content) rem.ined unchanged. 1-m.P treatm.nt did not affect GR activity in developing bolls. High tem.erature and 1-m.P treatm.nt increased the weight of cotton bolls collected 8 DPA with an increase of 0.7 and 1 g, respectively. We propose that increased GR activity in bolls exposed to high tem.erature m.y m.tigate oxidative dam.ge. Additionally, we conclude that ethylene inhibition (either high tem.erature or 1-m.P-induced) im.ediately after flowering (1 or 2 DPA) could potentially have positive im.acts on early boll growth.

关键词： Ethylene Glutathione Reductase Gossypium.hirsutum High Tem.erature 1-m.thylcyclopropene

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