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American Journal of Plant Sciences 2013年第7期4卷 1400-1408页

作者： Eduardo m.Kawakami derrick m.oosterhuis John L.Snider Toby R.FitzSimons Av.Antonio Teixeira dos Santos RondonópolisBrazil Department of Crop Soiland Environmental SciencesUniversity of Ar-kansasFayettevilleUSA Department of Crop and Soil Sciences University of GeorgiaTiftonUSA

The cotton (Gossypium hirsutum L.) crop experiences high temperatures during flowering and boll development, but information regarding the impact of ethylene inhibition and high temperature on early boll development is limited. The objective of this study was to determine the effects of high temperature and the anti-ethylene compound 1-methylcy-cloprone (1-mCP) on G. hirsutum boll development. Treatments consisted of temperature regime (38/20?C and 30/ 20?C), 1-mCP treatment, and days past anthesis (DPA). High temperature decreased ethylene synthesis by 61% at 2 DPA, and 1-mCP caused a 40% decrease in ethylene production at 1 DPA. Glutathione reductase activity increased under high temperature, whereas superoxide dismutase activity (SOD) and membrane peroxidation (malondialdehyde content) remained unchanged. 1-mCP treatment did not affect GR activity in developing bolls. High temperature and 1-mCP treatment 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 temperature may mitigate oxidative damage. Additionally, we conclude that ethylene inhibition (either high temperature or 1-mCP-induced) immediately after flowering (1 or 2 DPA) could potentially have positive impacts on early boll growth.

关键词： Ethylene Glutathione Reductase Gossypium hirsutum High Temperature 1-methylcyclopropene

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 SILImINA 不详

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

关键词： nothing northeast really

Physiological mechanism of Nitrogen mediating Cotton (<i>Gossypium hirsutum</i>L.) Seedlings Growth under Water-Stress Conditions

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American Journal of Plant Sciences 2012年第6期3卷 721-730页

作者： Zhigou Zhou derrick m. oosterhuis Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA. Key Laboratory of Crop Physiology & Ecology in Southern China of ministry 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 chamber 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 mm, approximately 224 mg N·l–1 water), medium nitrogen (24 mm, approximately 448 mg N·l–1 water) and high nitrogen (32 mm, approximately 672 mg N·l–1 water), respectively. The results showed that water-stress treatments reduced plant biomass, 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 enzymes. The changes of anti-oxidant enzymes was the highest in the low nitrogen rate in the drought-stressed and waterlogged cotton seedlings. malondialdehyde (mDA) content increased significantly in the water-stress treatments, and was the lowest in the low nitrogen rate. There was a significant reduction of N accumulation under water stress. Low-nitrogen treatmentincreased C accumulation, while high-nitrogen treatment decreased N accumulation. Root vigor was decreased by water stress, and was highest in the low-nitrogen rate. After terminating the water stress, N application promoted root vigor, especially in waterlogged seedlings. The trends of Pn weresimilarto that of root vigor. These results suggested that low N application may contribute to cotton drought tolerance by enhancing the activity of antioxidant enzymes and conse-quently decreasing lipid peroxidation, and enhancing root vigor. However, higher N should be applied to waterlog- ging-stressed cotton seedlings after terminating waterlogging.

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

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

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American Journal of Plant Sciences 2013年第1期4卷 142-152页

作者： Dimitra A. Loka derrick m. oosterhuis Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA

Ethylene is an endogenous plant hormone that increases under adverse environmental conditions, resulting in leaf and fruit abscission and ultimately 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-methylcyclo- propene (1-mCP) would prevent ethylene production and result in alleviation of water-deficit stress consequences on the physiology and metabolism of the cotton flower and subtending leaf. To test this hypothesis, growth chamber experiments were conducted in 2009-2010 with treatments consisting of (C) untreated well-watered control, (C + 1mCP) well-watered plus 1-mCP, (WS) untreated water-stressed control, and (WS + 1mCP) water-stressed plus 1-mCP. The plants were subjected to two consecutive drying cycles during flowering, approximately 8 weeks after planting, and 1-mCP was foliar applied at a rate of 10g. ai/ha at the beginning of each drying cycle. The results showed that 1-mCP application had no significant effect on gas exchange functions and did not prevent reductions from water stress in leaf photosynthesis, respiration and stomatal conductance. However, application of 1-mCP resulted in a decrease in sucrose content of water-stressed pistils compared to the control indicating that 1-mCP has the potential to interfere in carbohydrate metabolism of reproductive units.

关键词： Cotton 1-methylcyclopropene Ethylene Water-Deficit Stress Carbohydrates Gas Exchange

Endogenous Levels of Polyamines under Water-Deficit Stress during Cotton’s Reproductive Development

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American Journal of Plant Sciences 2015年第2期6卷 344-354页

作者： Dimitra A. Loka derrick m. oosterhuis Cristiane Pilon Altheimer Laboratory Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville AR USA

Polyamines, putrescine (PUT), spermidine (SPD) and spermine (SPm) are implicated in plants’ responses under conditions of abiotic stress. Previous research in other crops has indicated that polyamines and changes in their concentrations are associated with drought tolerance under conditions of water-deficit stress;however, no information exists on cotton (Gossypium hirsutum L.). Growth chamber experiments 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 polyamines, the effect of water-deficit stress on the polyamine metabolism of cotton reproductive units and their subtending leaves as well as the possible relationship between polyamines and drought tolerance in cotton. Our results showed that cotton ovaries contained significantly higher levels of total free polyamines compared 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 polyamine metabolism in reproductive structures and their subtending leaves;however, no clear relationship between drought-tolerance and changes in polyamine accumulation was established. Further research is needed to elucidate the mechanism according to which water-deficit stress affects polyamine metabolism.

关键词： Cotton Gas Exchange Polyamine Levels Reproductive Units Water-Deficit Stress

Changes in the Ovarian Polyamine Content and Seed Set Efficiency of Cotton by the Plant Growth Regulator Bm86

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American 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 Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA

Naturally occurring polyamines in plants have been implicated in floral initiation, and fruit development. The plant growth regulator Bm86 was formulated to stimulate seed production and fruit growth by enhancing polyamine synthe-sis. The objectives of this study were to determine the effect of Bm86 on free polyamine content in cotton (Gos-sypium hirsutum L.) ovaries and on seed set efficiency, and also to investigate genotypic differences in ovarian polyamine content. Bm86 was applied at the first flower stage and two weeks later at 2.34 mL/ha. This study showed that application of Bm86 had a significant positive effect on ovarian polyamine content of cotton. Putrescine and sper-midine one week after the 1st Bm86 application and putrescine two week after the 1st Bm86 application, were significantly increased compared to the untreated control. Higher seed set efficiency with the Bm86 application was observed when the total number of seeds was used for the calculation. However, when the number of harvestable seeds was used to calculate seed set efficiency Bm86 had no significant effect. In addition, application of Bm86 did not significantly alter seedcotton yield of the crop. Only small differences in ovarian polyamine content were detected among the genotypes tested, possibly due to the narrow genetic pool of the commercial cotton genotypes used. Application of Bm86 can significantly increase cotton seed number by enhancing polyamines biosynthesis, but further research is needed to determine how to capitalize on the increased potential number of harvestable seeds.

关键词： Putrescine Spermidine Spermine Bm86 Gossypium hirusutm L. Ovaries

Realising the Potential of Genomics for m. tuberculosis: A Silver Lining to the Pandemic?

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China CDC weekly 2022年第20期4卷 437-439页

作者： Timothy m Walker derrick W Crook Oxford University Clinical Research Unit Ho Chi Minh CityVietnam Nuffield Department of medicine University of Oxford OxfordUK

The impact of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)pandemic on tuberculosis has been ***,there were 1.4 million fewer patients receiving tuberculosis treatment in 2020,representing not a fall in the global case load but a failure to serve millions of patients with the disease(1–2).morbidity,mortality,and onward transmission are inevitable outcomes of such failure,setting the world back a decade of progress.

关键词： tuberculosis mortality acute

Radiation Use Efficiency of Cotton in Contrasting Environments

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American 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 Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA Plant Science Department California State University Fresno USA

Crop growth and yield varies among locations due to differences in environmental parameters, such as temperature, relative humidity, solar radiation and vapor pressure deficit. Previous research has shown that increasing vapor pressure deficit has a negative effect on radiation use efficiency of many crops. In this study, the radiation use efficiency of cot-ton (Gossypium hirsutum L.) grown in two contrasting production environments, Arkansas and California, was evaluated for two years, in 2006 and 2007. Temperature, relative humidity, vapor pressure deficit and photosyntheti-cally active radiation were recorded at both locations. Although the crop in California accumulated more dry matter during the period of the study, the radiation use efficiency was found to be lower compared to Arkansas. Radiation use efficiency for the Arkansas and California locations was estimated at 2.060 and 1.518 g?mJ–1 of intercepted photosynthetically active radiation, respectively. The higher productivity observed in California can be attributed to larger amounts of incident and intercepted radiation in this location. Radiation use efficiency of cotton was estimated to decrease with increasing vapor pressure deficit by a slope of –0.47 g?mJ–1?kPa–1.

关键词： Dry matter Environment Gossypium hirsutum L. Light Interception Radiation Use Efficiency Vapor Pressure Deficit

Potential Association between Soil and Leaf Chemical Properties, and Soybean Seed Composition

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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 mauromoustakos John R. Clark Agricultural Statistics Laboratory University of Arkansas Fayetteville USA Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville USA

maximizing the expression of seed quality traits by understanding how they are affected by environmental variables may 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 samples were collected from each plot. Soil samples were analyzed for particle size distribution, electrical conductivity, pH, and a set of extractable nutrients from the top 12.5 cm, while leaf samples were analyzed for the same set of nutrients as the soil samples. At maturity, seed samples were analyzed for the same set of nutrients as were leaf and soil samples, plus protein, oil, fatty acids, and sugars. All leaf elements were within the adequate levels for soybean production at both locations. Overall, seed composition of breeding lines did not differ among locations and no significant changes in breeding line ranking among locations were observed. Attempting to modify seed composition by nutrient fertilization may not be profitable, as no direct relationships were observed between leaf or soil chemical properties, and seed composition. These findings may provide a starting point for future studies on fertilization and management practices that improve soybean seed quality.

关键词： Soybean Seed Composition Soil Properties

Response of Two Inexpensive Commercially Produced Soil moisture 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 mukhammadzakhrab Ismanov derrick m. oosterhuis Department of Plant Sciences University of Tennessee Jackson TN USA Department of Biological and Agricultural Engineering University of Arkansas Stuttgart AR USA Department of Crop Soil and Environmental Sciences University of Arkansas Little Rock AR USA Department of Crop Soil and Environmental Sciences University of Arkansas Fayetteville AR USA

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

The use of low-cost (moisture sensors in crop production systems has the potential to give inference on plant water status and therein drive irrigation events. However, commercially available sensors in this price range vary in sensing methodologies and limited information on sensor to sensor relationship is available. The objective of this research was to test the response of the Watermark 200SS and Decagon 10HS sensors to changes in water content of three dissimilar soils representing common soils in Arkansas row-crop production in nine plastic, 19 L containers under variable environmental conditions. Both sensors were influenced by changes in soil temperature but the magnitudes of the temperature responses were small relative to the moisture responses. Furthermore, the 10HS sensor did not indicate a significant impact of soil texture on estimated volumetric water contents (VWCs). The small sphere of influence on the tested soil moisture parameters coupled with the substantial evaporative demands and temperatures under which this experiment was conducted resulted in suspected non-uniform drying and wetting of the tested containers. Subsequently, non-linear relationships were noted between 10HS estimated 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 importance of understanding the relatively small quantity of soil on which these sensors rely as well as the potential variability in soil moisture within a very limited volume. The authors caution users of sensors that soil variability may be one of the most important considerations in sensor deployment.

关键词： Soil moisture Sensor 10HS Watermark 200SS Decagon Comparison Soil Texture