SA对水分胁迫下红小豆叶片过氧化物酶活性的影响   总被引：3，自引：0，他引：3  

杨剑平  金文林  徐红梅  王文平  陈莹玉 《北京农学院学报》2002,17(4):11-14

水杨酸(SA)处理红小豆叶片3d后,处理叶片及未接受处理叶片内的POD活性增加,并且不同浓度的SA对叶片内POD活性影响不同.通过测定渗透胁迫14d的红小豆植株叶片发现,SA处理能显著增加渗透胁迫下叶片中的POD活性.  相似文献   

Evidence for increased somatic cell mutations at the glycophorin A locus in atomic bomb survivors   总被引：16，自引：0，他引：16  

R G Langlois  W L Bigbee  S Kyoizumi  N Nakamura  M A Bean  M Akiyama  R H Jensen 《Science (New York, N.Y.)》1987,236(4800):445-448

A recently developed assay for somatic cell mutations was used to study survivors of the atomic bomb at Hiroshima. This assay measures the frequency of variant erythrocytes produced by erythroid precursor cells with mutations that result in a loss of gene expression at the polymorphic glycophorin A (GPA) locus. Significant linear relations between variant frequency (VF) and radiation exposure were observed for three different variant cell phenotypes. The spontaneous and induced VFs agree with previous measurements of radiation-induced mutagenesis in other systems; this evidence supports a mutational origin for variant cells characterized by a loss of GPA expression and suggests that the GPA assay system may provide a cumulative dosimeter of past radiation exposures. VFs for some survivors differ dramatically from the calculated dose response, and these deviations appear to result primarily from statistical fluctuations in the number of mutations in the stem-cell pool. These fluctuations allow one to estimate the number of long-lived hemopoietic stem cells in humans.  相似文献   

Impact of in-season split application of nitrogen on intra-panicle grain dynamics,grain quality,and vegetative indices that govern nitrogen use efficiency in sorghum     

Troy J. Ostmeyer  Somayanda M. Impa  Scott R. Bean  Rajveer Dhillon  Chad Hayes  Glen Ritchie  Antonio R. Asebedo  Yves Emendack  S. V. Krishna Jagadish 《植物养料与土壤学杂志》2023,186(6):647-660

Background

The correct rate and timing of nitrogen (N) has the potential to improve sorghum productivity through modified grain yield components and quality. The impacts of in-season split application of N have little documentation.

Aim

An experiment was conducted to determine the optimum rate and timing of N to relate vegetative indices that govern nitrogen use efficiency and to maximize grain yield and quality under different soil types.

Methods

Pioneer 86P20 was grown in three environments on two different soil types following a completely randomized block design with nine N application treatments. Treatments included differing N rates applied at critical developmental stages of sorghum (planting, panicle initiation, and booting), accompanied with high temporal aerial phenotyping.

Results

Opportunities to increase grain protein content while using split N applications were observed, with panicle initiation identified as a critical developmental stage. In-season split application of N enhances grain yield under low soil mineral N. Split application of 31 kg N ha⁻¹ each at the time of planting, panicle initiation, and booting emerged as optimum N treatment to increase protein content in sorghum. Vegetative indices, that is, normalized difference vegetation index and normalized difference red edge index are capable of predicting grain yield and protein content, respectively. Intra-panicle grain numbers and weights were altered significantly at different portions within panicles, with an opportunity to enhance yield potential at the bottom portion. The strong stay-green trait in this hybrid locked a large proportion of nitrogen in the leaves, which warrants the need for balancing stay-green and senescence in sorghum improvement programs.

Conclusions

Findings highlight that in grain sorghum remobilization of residual leaf N into grain is a target to increase yield and grain quality. An optimized stay-green trait balanced with senescence is recommended for enhancing sorghum yield potential.  相似文献   

Fire and Invasive Species Management in Hot Deserts: Resources,Strategies, Tactics,and Response     

Alix Rogstad  Travis M. Bean  Aaryn Olsson  Grant M. Casady 《Herpetological Monographs》2009,31(3):6-13

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Detecting North American signal crayfish (Pacifastacus leniusculus) in riffles     

Z. F. Gladman  W. E. Yeomans  C. E. Adams  C. W. Bean  D. McColl  J. P. Olszewska  C. W. McGillivray  R. McCluskey 《水产资源保护:海洋与淡水生态系统》2010,20(5):588-594

• 1. The spread of the invasive signal crayfish (Pacifastacus leniusculus) outside its natural range is of widespread concern due to the threats posed to native biodiversity. To date, there is no standard protocol for determining signal crayfish presence or absence in a watercourse.
• 2. For the purposes of this investigation, the crayfish detection ability of active sampling methods — hand‐netting, electrofishing (one, two and three runs), kick sampling and Surber sampling — was tested at 30 sites along the River Clyde, southern central Scotland.
• 3. No single technique was successful in detecting crayfish in 100% of the sites known to contain crayfish and so the application of combinations of techniques was considered. The combination of techniques that resulted in a 100% detection rate was electrofishing (three runs) together with kick sampling. These results suggest that three‐run electrofishing and kick sampling are the best candidates for incorporation into a crayfish detection protocol.
• 4. The mean time taken to apply electrofishing (three runs) was significantly greater than the mean time to apply kick sampling. Given the lower effort required for its application, kick sampling is recommended as the preliminary technique: if kick sampling yields a negative result, the application of electrofishing will decrease the chance of recording a false negative presence. If both kick sampling and electrofishing fail to detect crayfish, trapping may further decrease the risk of a false negative result.
• 5. These findings have assisted in the development of a crayfish detection protocol, which will be applied across Scotland to determine the current distribution of signal crayfish. Copyright © 2010 John Wiley & Sons, Ltd.

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Wheat Flour Proteins as Affected by Transglutaminase and Glucose Oxidase     

C. M. Rosell  J. Wang  S. Aja  S. Bean  G. Lookhart 《Cereal Chemistry》2003,80(1):52-55

Enzymes are good tool to modify wheat proteins by creating new bonds between the protein chains. In this study, the effect of the addition of glucose oxidase (GO) and transglutaminase (TG) on the wheat flour proteins is presented. The modification of wheat proteins was determined by analyzing the changes in gluten quality, alveograph parameters, and protein modifications. The amount of wet gluten increased with the addition of GO and TG, but the gluten quality was not improved in any case. Regarding the alveograph parameters, the effect of GO was readily evident obtaining wheat dough with higher tenacity and lower extensibility than the control, while TG led to doughs with lower tenacity and that were also less extensible. The protein modifications were characterized by free‐zone capillary electrophoresis (FZCE). FZCE data indicated that TG polymerizes mainly glutenins and, of those, the high molecular weight glutenin subunits were the most affected.  相似文献   

Evaluation of Novel Precast SDS‐PAGE Gels for Separation of Sorghum Proteins     

S. R. Bean 《Cereal Chemistry》2003,80(5):500-504

Precast polyacrylamide gels using novel buffer chemistry for enhanced resolution and shelf life stability of the gels were evaluated for separating sorghum proteins. Two gels with different acrylamide concentrations, 12 and 4–12%, were tested with two different buffer systems. Gels were evaluated for separation resolution, as well as protein solubility problems such as streaking. High‐resolution separations were obtained for all the major classes of kernel proteins using these gels. Run times were typically 45–60 min, producing relatively rapid separations. Resolution was significantly affected by the buffer system used. The use of precast gradient gels eliminates the need for casting gradient gels for routine analysis of sorghum proteins and avoids handling the toxic acrylamide monomer. This system will be useful for routine separations of sorghum proteins as well as for research programs using SDS‐PAGE to screen sorghum lines for digestibility or for other protein‐related quality factors.  相似文献   

Optimizing Quantitative Reproducibility in High‐Performance Capillary Electrophoresis (HPCE) Separations of Cereal Proteins     

S. R. Bean  G. L. Lookhart 《Cereal Chemistry》2001,78(5):530-537

High‐performance capillary electrophoresis (HPCE) is capable of producing high‐resolution, rapid separations of cereal proteins. Furthermore, HPCE is highly reproducible in terms of migration time. However, little work has focused on the quantitative reproducibility of cereal protein separations. Several factors such as sample matrix, sample evaporation, voltage ramp‐up time, sample injection time, and capillary end‐cut were evaluated for involvement in quantitative reproducibility. These experiments showed that preventing sample evaporation, using optimum injection times, and ensuring a clean, square cut on the capillary all improved the reproducibility of peak areas. Combining these factors into an optimized procedure produced reproducibility with peak areas varying by 1.76% relative standard deviation (RSD). Migration time was also excellent under these conditions, varying by only 0.45% RSD. Other variables such as peak area percent, peak height, and peak height percent also showed good reproducibility with RSD < 4%. Increasing the voltage ramp‐up time from 0.17 to 0.68 increased peak efficiency by ≈150%. This factor had no effect on quantitative reproducibility, however. The gradual buildup of contaminants on the capillary walls occurred over time and decreased both separation efficiency and reproducibility. Rinsing capillaries periodically with appropriate solvents delayed this effect. Peak efficiency was a good marker for capillary performance and lifetime.  相似文献   

Separation of Water‐Soluble Proteins from Cereals by High‐Performance Capillary Electrophoresis (HPCE)     

S. R. Bean  M. Tilley 《Cereal Chemistry》2003,80(5):505-510

Most research concerning grain proteins has concentrated on the gluten storage proteins. The albumins and globulins are the water‐ and salt‐soluble proteins that contain biologically active enzymes and enzyme inhibitors. A free‐zone capillary electrophoresis method was developed to separate these proteins. Optimization included sample extraction method, capillary temperature, buffer composition, and additives. The optimal conditions for separation of these proteins was 50 μm i.d. × 27 cm (20 cm to detector) capillary at 10 kV (with a 0.17 min ramp‐up time) and 25°C. The optimum buffer was 50 mM sodium phosphate, pH 2.5 + 20% acetonitrile (v/v) (ACN) + 0.05% (w/v) hydroxypropylmethyl‐cellulose (HPMC) + 50 mM hexane sulfonic acid (HSA). Sample stability was an issue that was addressed by lyophilizing fresh extracts and redissolving in aqueous 50% ethylene glycol and 10% separation buffer. This method was successfully used in both wheat flour and whole meal samples. Comparisons were made of several wheats of different classes as well as several cereal grains. This methodology could be useful in screening cereal grains for important enzymes and their impact on end‐use quality such as food functionality, food coloration, and malting quality.  相似文献