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1.
回顾了基于CPTU测试成果确定粘土固结屈服应力和超固结比的方法,表明土的固结屈服应力和超固结比与CPTU测试参数之间不存在惟一的相关关系,仅仅针对某一地区的相关关系才是有效的.根据苏北里下河地区泻湖相沉积土的CPTU测试资料,对3种经验方法进行了比较.评价了固结屈服应力与CPTU测试参数现有经验关系的有效性,并且确定出适宜于里下河地区泻湖相沉积土的预测方法.结果表明:基于净锥尖阻力的相关关系比其他经验方法具有较高的精度,可以有效地预测该地区泻湖相沉积土的固结屈服应力和超固结比. 相似文献
2.
以中乐油2号和蓉油11号油菜为材料,通过盆栽试验,研究渍害胁迫及恢复进程中油菜幼苗叶片光系统Ⅱ(PSⅡ)光化学特性的变化.结果表明:随着渍害胁迫的加剧,两品种油菜叶片初始荧光(F0)、非光化学淬灭系数(qN)不断上升,最大荧光(Fm)、PSⅡ最大光化学量子产量(Fv/Fm)、PSⅡ实际光化学量子产量(Yield)、表观光合电子传递速率(ETR)、光化学淬灭系数(qP)不断下降,说明随着渍害胁迫的加剧,PSⅡ部分反应中心受到破坏,光合电子传递受阻,光能转换效率下降,发生明显光抑制;从第13d起进行恢复处理,所有叶绿素荧光参数均有所恢复,但仍未达到对照水平.可见,当渍害胁迫超出了油菜机体自我调节的阈值时,油菜叶片的部分光合机构发生不可逆的破坏,最终影响油菜的正常生长. 相似文献
3.
以青稞幼苗为试材,采用营养液水培法研究了200mmol／L NaCl胁迫对青稞幼苗叶片相对含水量（RWC）、叶绿素、丙二醛（MDA）、脯氨酸含量的影响．结果显示,在200mmol／L NaCl胁迫2,4,6,8d后,青稞幼苗叶片相对含水量、叶绿素含量随胁迫的进行而不断下降,其中叶绿素含量在前4d下降尤其明显;MDA和脯氨酸含量则显著上升．表明200mmol／L NaCl胁迫对青稞幼苗造成了严重的生理伤害． 相似文献
4.
Response to temperature stress of reactive oxygen species scavenging enzymes in the cross-tolerance of barley seed germination 总被引：1，自引：0，他引：1
A number of studies have shown the existence of cross-tolerance in plants, but the physiological mechanism is poorly understood.
In this study, we used the germination of barley seeds as a system to investigate the cross-tolerance of low-temperature pretreatment
to high-temperature stress and the possible involvement of reactive oxygen species (ROS) scavenging enzymes in the cross-tolerance.
After pretreatment at 0 °C for different periods of time, barley seeds were germinated at 35 °C, and the content of malondialdehyde
(MDA) and the activities of ROS scavenging enzymes were measured by a spectrophotometer analysis. The results showed that
barley seed germinated very poorly at 35 °C, and this inhibitive effect could be overcome by pretreatment at 0 °C. The MDA
content varied, depending on the temperature at which seeds germinated, while barley seeds pretreated at 0 °C did not change
the MDA content. Compared with seeds germinated directly at 35 °C, the seeds pretreated first at 0 °C and then germinated
at 35 °C had markedly increased activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and
glutathione reductase (GR). The SOD and APX activities of seeds germinated at 35 °C after 0 °C-pretreatment were even substantially
higher than those at 25 °C, and GR activity was similar to that at 25 °C, at which the highest germination performance of
barley seeds was achieved. These results indicate that low-temperature pretreatment can markedly increase the tolerance of
barley seed to high temperature during germination, this being related to the increase in ROS scavenging enzyme activity.
This may provide a new method for increasing seed germination under stress environments, and may be an excellent model system
for the study of cross-tolerance. 相似文献
5.
INTRODUCTION For critical structures and applications, requiring a given reliability, it is necessary to account for un-certainties and variability in material properties, loads and geometric tolerances. Using various reliability analysis methods, we can determine the reliability of existing structures or systems; or design new structures or systems with certain desired reliability. Manufacturing processes may involve many factors that have inherent uncertainties or random variations in th… 相似文献
6.
Remote sensing techniques have the potential to provide information on agricultural crops quantitatively, instantaneously
and above all nondestructively over large areas. Crop simulation models describe the relationship between physiological processes
in plants and environmental growing conditions. The integration between remote sensing data and crop growth simulation model
is an important trend for yield estimation and prediction, since remote sensing can provide information on the actual status
of the agricultural crop. In this study, a new model (Rice-SRS) was developed based mainly on ORYZA1 model and modified to
accept remote sensing data as input from different sources. The model can accept three kinds of NDVI data: NOAA AVHRR(LAC)-NDVI,
NOAA AVHRR(GAC)-NDVI and radiometric measurements-NDVI. The integration between NOAA AVHRR (LAC) data and simulation model
as applied to Rice-SRS resulted in accurate estimates for rice yield in the Shaoxing area, reduced the estimating error to
1.027%, 0.794% and (−0.787%) for early, single, and late season respectively. Utilizing NDVI data derived from NOAA AVHRR
(GAC) as input in Rice-SRS can yield good estimation for rice yield with the average error (−7.43%). Testing the new model
for radiometric measurements showed that the average estimation error for 10 varieties under early rice conditions was less
than 1%.
Project supported by the National Defense Scientific and Technological Committee of China(No. Y97#14-6-2) 相似文献
7.
研究了NaCl胁迫对5个不同番茄品种的幼苗生长、果实可溶性糖含量及产量的影响.结果表明,盐胁迫抑制了番茄幼苗植株的生长,降低了幼苗的单株鲜重,减少了果实产量,但可以提高果实可溶性糖含量.同一盐胁迫条件下,不同番茄品种性状存在显著差异. 相似文献
8.
Li QY Niu HB Yin J Shao HB Niu JS Ren JP Li YC Wang X 《Journal of Zhejiang University. Science. B》2010,11(11):862-870
A transgenic barley line (LSY-11-1-1) with overexpressed Phalaris coerulescens thioredoxin gene (PTrx) was employed to measure the growth, protein oxidation, cell viability, and antioxidase activity in barley roots during germination
on the presence of 2 mmol/L AlCl3 on filter paper. The results show that (1) compared with the non-transgenic barley, LSY-11-1-1 had enhanced root growth,
although both were seriously inhibited after AlCl3 treatment; (2) the degree of protein oxidation and loss of cell viability in roots of LSY-11-1-1 were much less than those
in roots of non-transgenic barley, as reflected by lower contents of protein carbonyl and Evans blue uptakes in LSY-11-1-1;
(3) activities of catalase (CAT), glutathione peroxidase (GPX), ascorbate peroxidase (APX), and glutathione reductase (GR)
in LSY-11-1-1 root tips were generally higher than those in non-transgenic barley root tips, although these antioxidase activities
gave a rise to different degrees in both LSY-11-1-1 and non-transgenic barley under aluminum stress. These results indicate
that overexpressing PTrx could efficiently protect barley roots from oxidative injury by increasing antioxidase activity, thereby quenching ROS caused
by AlCl3 during germination. These properties raise the possibility that transgenic barley with overexpressed PTrx may be used to reduce the aluminum toxicity in acid soils. 相似文献
9.
INTRODUCTION Soil-borne pathogens, including Pythium spp. and Fusarium spp., cause significant yield losses in horticulture and agriculture crops (Mao et al., 1997). Current practices for controlling plant diseases are based largely on disease resistant crops, cultivation management in fields and application of synthetic pesticides (Elizabeth and Emmert, 1999). Biological control using antagonistic microbes to reduce the use of chemical pesticides in a system of integrated plantdisease … 相似文献
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11.
本文通过对我省四年来大小麦高产攻关试验总结，分析高产大小麦穗粒结构和群体发展特征，提出大小麦667m2产量超350kg的配套栽培技术措施。 相似文献
12.
Zhang Xin Zhang Bing-xin Zhang Zhen Shen Wei-feng Yang Ching-hong Yu Jing-quan Zhao Yu-hua 《Journal of Zhejiang University. Science. B》2005,6(8):770-777
Fusarium head blight (FHB) caused byFusarium graminearum is a devastating disease that results in extensive yield losses to wheat and barley. A green fluorescent protein (GFP) expressing
plasmid pRP22-GFP was constructed for monitoring the colonization of two biocontrol agents,Brevibacillus brevis ZJY-116, on the spikes of barley and their effect on suppression of FHB. Survival and colonization of theBrevibacillus brevis ZJY-1 andBacillus subtilis ZJY-116 strains on spikes of barley were observed by tracking the bacterial transformants with GFP expression. Our field
study revealed that plasmid pRP22-GFP was stably maintained in the bacterial strains without selective pressure. The retrieved
GFP-tagged strains showed that the bacterial population fluctuation accorded with that of the rain events. Furthermore, both
biocontrol strains gave significant protection against FHB on spikes of barley in fields. The greater suppression of barley
FHB disease was resulted from the treatment of barley spikes with biocontrol agents before inoculation withF. graminearum.
Project supported by the National Natural Science Foundation of China (No. 30230250) and Science and Technology Committee
of Zhejiang Province (No. 2003C22029), China 相似文献
13.
14.
Wang JP Raman H Zhang GP Mendham N Zhou MX 《Journal of Zhejiang University. Science. B》2006,7(10):769-787
Aluminium （Al） toxicity is one of the major limiting factors for barley production on acid soils. It inhibits root cell division and elongation, thus reducing water and nutrient uptake, consequently resulting in poor plant growth and yield. Plants tolerate Al either through external resistance mechanisms, by which Al is excluded from plant tissues or internal tolerance mechanisms, conferring the ability of plants to tolerate Al ion in the plant symplasm where Al that has permeated the plas- malemma is sequestered or converted into an innocuous form. Barley is considered to be most sensitive to Al toxicity among cereal species. Al tolerance in barley has been assessed by several methods, such as nutrient solution culture, soil bioassay and field screening. Genetic and molecular mapping research has shown that Al tolerance in barley is controlled by a single locus which is located on chromosome 4H. Molecular markers linked with Al tolerance loci have been identified and validated in a range of diverse populations. This paper reviews the （1） screening methods for evaluating Al tolerance, （2） genetics and （3） mechanisms underlying Al tolerance in barley. 相似文献
15.
Investigation of newly developed added damping and stiffness device with low yield strength steel 总被引：2，自引：0，他引：2
INTRODUCTIONThisresearchfocusedonusingthemechanicalpropertiesoflowyieldstrengthsteel(LYS)tode-velopanewdeviceforaddeddampingandstiffnessandseismicresistanceofrhombiclowyieldstrengthsteelplate.ThemechanicalpropertiesofLYSandtheeffectofthisnewlydevelopeddevicewereinvestigatedbyexperimentalmethod.Ex-pectedly,thisnewdevicecantakeadvantageofplasticenergyabsorbabilitytoabsorbanddissipatetheenergyofearthquakestablyandensurethesafetyofthemainstructure.Ananalyticalmodelisproposedforanalyzingtheh… 相似文献
16.
Energy dissipators, isolated-resistant and specific structural forms for earthquake resistance are popular topics in the research
to improve shock-resistance. In this work, experimental methods were used to investigate the property of low yield strength
steel. Carbon content in LYS material is lower than that in other steels; the ultimate stress is three times the yield stress.
The ultimate elongation rate is about 62% and the ductility is 2–3 times that of A36 steel. In order to overcome some defects
of ordinary use metallic dampers, the mechanical characteristic of low yield strength steel is used to develop added damping
and stiffness for rhombic steel plate absorber. Test of the energy dissipation behavior for this newly developed device indicated
that LYS could stably dissipate or absorb the input energy of earthquake. Then, the analytical model for the hysteretic behavior
of this new device is proposed. Comparison of experimental data and numerical simulation results showed that this analytical
model is suitable for simulating the hysteretic energy behavior of this new device. 相似文献
17.
Assessment of genetic diversity by simple sequence repeat markers among forty elite varieties in the germplasm for malting barley breeding 总被引：1，自引：0，他引：1
Jun-mei Wang Jian-ming Yang Jing-huan Zhu Qiao-jun Jia Yue-zhi Tao 《Journal of Zhejiang University. Science. B》2010,11(10):792-800
The genetic diversity and relationship among 40 elite barley varieties were analyzed based on simple sequence repeat (SSR)
genotyping data. The amplified fragments from SSR primers were highly polymorphic in the barley accessions investigated. A
total of 85 alleles were detected at 35 SSR loci, and allelic variations existed at 29 SSR loci. The allele number per locus
ranged from 1 to 5 with an average of 2.4 alleles per locus detected from the 40 barley accessions. A cluster analysis based
on the genetic similarity coefficients was conducted and the 40 varieties were classified into two groups. Seven malting barley
varieties from China fell into the same subgroup. It was found that the genetic diversity within the Chinese malting barley
varieties was narrower than that in other barley germplasm sources, suggesting the importance and feasibility of introducing
elite genotypes from different origins for malting barley breeding in China. 相似文献
18.
程民生 《开封教育学院学报》2011,31(2):1-4
宋英宗一朝开封气象状况十分复杂,旱涝交加,尤以雨涝灾害最为突出,最严重的一次导致数千人死亡。英宗朝也是北宋开封沙尘天气最多的时期,凡六次。开封异常气象对宋代社会政治经济均产生了一定的影响。 相似文献
19.
Population structure and linkage disequilibrium in elite barley breeding germplasm from the United States 总被引：2，自引：0，他引：2
Hao Zhou Gary Muehlbauer Brian Steffenson 《Journal of Zhejiang University. Science. B》2012,13(6):438-451
Cultivated barley is known to have a complex population structure and extensive linkage disequilibrium (LD). To conduct robust association mapping (AM) studies of economically important traits in US barley breeding germplasm, population structure and LD decay were examined in a complete panel of US barley breeding germplasm (3 840 lines) genotyped with 3 072 single nucleotide polymorphisms (SNPs). Nine subpopulations (sp1‒sp9) were identified by the program STRUCTURE and subsequently confirmed by principle component analysis (PCA). Out of the nine subpopulations, seven were very similar to the respective subpopulations identified by Hamblin et al. (2010) which were based on half of the germplasm and half of the SNP markers, but two subpopulations were found to be new. One subpopulation was dominated by six-rowed spring lines from Utah State University (UT) and the other was composed of six-rowed spring lines from multiple breeding programs (USDA-ARS Aberdeen (AB), Busch Agricultural Resources Inc. (BA), UT, and Washington State University (WA)). LD was found to decay across a range from 4.0 to 19.8 cM. This result indicates that the germplasm genotyped with 3 072 SNPs would be robust for mapping and possibly identifying the causal polymorphisms contributing to disease resistance and perhaps other traits. 相似文献