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蔬菜品种类型多,发生的病害也多达数百种,但其病原主要分为五大类,即病毒病害、细菌病害、真菌病害、线虫病害和非侵染性生理病害。现将这五大类病害田间简易诊断方法介绍如下：1病毒病害该病毒人用肉眼看不到,主要靠昆虫或接触摩擦传播,几乎所有的蔬菜都可感染病毒病害。蔬菜受侵染后,往往出现维管束系统坏死,主输导组织受害后,全株出现受害症状;支输导组织受害后,局部表 相似文献
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由植物病原细菌Ralstonia solanacerum(Pseudomonas solanacearum)引起的青枯病,广泛分布在热带、亚热带和温带地区,是影响番茄、茄、海椒、烟草、马铃薯等茄科作物生产的重要因素之一。此病是通过土壤传播的较难防治的一种病害。土壤一旦被该病原菌污染,采取土壤消毒、轮作等,也很难抑制其发生。选用抗性品种是最有效的防治方法。 对青枯病有抗性的番茄品种,一般果实品质较差。因此,在日本,番茄栽培大多选择抗青枯病的砧 相似文献
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柑桔病毒病和类似病毒病害是指由病毒、类病毒 (Ｖｉｒｏｉｄ)、螺原体 (Ｓｐｉｒｏｐｌａｓｍａ)、植原体 (Ｐｈｙｔｏｐｌａｓ ｍａ)和某些细菌 (这些细菌曾被称为类立克次氏体和类细菌 ,是一些用人工合成培养基难以培养的 ,或尚无法培养的细菌 ,习惯称为难培养菌 )引起的柑桔病害。它们的共同特征是可以通过嫁接传播 ,也就是说 ,已感染病害的苗木和接穗在异地间传送是病害远距离传播的主要途径。除了嫁接传播 ,这类病害有的还通过昆虫传播 ,有的通过污染的刀、剪等工具和人手传播 ,个别的通过种子传播。在世界各国发生的此类病害有病毒引… 相似文献
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据中国果树病虫志记载,在30多种果树上,病害达700多种。病害是由感病的植物、致病的病原和一定的外界环境条件三项因素所构成的。这些病害还分非侵染性病害和侵染性病害。前者主要是气象因素、土壤因素和一些有毒物,所以也称生理性病害;后者亦称传染性病害,引起侵染性病害的病原物有真菌、细菌、病毒、线虫、寄生种子植物等。病原物的传播有三种方式,即自动、自然与人为传播。特别是人为传播,人类在各种农业操作中,如播种、移栽、施肥、修剪、嫁接等常无意识的传播了某些病害。贸易与引种可以造成病害的 相似文献
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葡萄根癌病是一种根部细菌性病害，主要危害根颈、主根、侧根．2年生以上的主蔓近地面处也常受害，苗木则多发生在接穗和砧木愈合的地方。病菌多存在于土壤中，主要通过雨水、灌溉传播，从伤口侵入寄主，地下害虫如蛴螬、蝼蛄和土壤线虫等也可以传播，而苗木带菌则是病害远距离传播的主要途径。5月上中旬开始发病．6～8月为发病盛期。管理粗放．严重受冻，地势低洼．排水不良易发生此病。 相似文献
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1 病毒病的种类 苹果锈果、花叶、衰退 (退绿叶斑、茎沟、茎痘 )、绿皱果病等 ;梨坏死斑点、枝梢粗皮病等 ;葡萄扇叶、卷叶、无味果、黄色花叶、叶脉失绿病等 ;桃斑病 ,李矮化病等。2 病毒侵染途径 病毒是一种专性寄生物 ,只能在活细胞内寄生 ,其传播方式受到很大限制。多数病毒在果园中的传播 ,主要是以刺吸式口器的昆虫为媒介 ,如蚜虫可传播多种病毒 ,一种叶蝉可传播一种黄化病毒 ;偶尔也可通过病、健株的接触摩擦而传播 ;另外 ,虫伤、冻伤、修剪、嫁接等机械伤口也是传播和接种病毒的重要途径。3 病毒病症状特点 病毒病绝大多数是… 相似文献
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AIM: Although endovascular radiotherapy inhibits neointimal hyperplasia, the exact alterations induced by β-particles irradiation remain to be elucidated. The objective of this study was to investigate the ability and the cellular mechanism of local β-particles emission from 188Re to inhibit vascular smooth muscle cells (SMCs). METHODS: The SMCs in vitro were irradiated by 188Re with single doses of 2.6 Gy-25.8 Gy. The effects of β-particles on SMCs, such as effective irradiate doses, the period of inhibition for SMCs proliferation, the changes of cell proliferation rate and DNA synthesis rate, cell cycle progression and related gene expression, were investigated by cell count, [3H]-TdR incorporation, cell cycle progression analysis, cell viability and immunocytochemistry, respectivecy. RESULTS: β-particles irradiation with dose of 5.2 Gy could inhibit significantly SMCs proliferation. At dose of 20.6 Gy DNA synthesis inhibitory rate was 92%, SMCs proliferation rate was only 3%. Renoval of 188Re did not abolish the inhibitory effects of β-particles on SMCs proliferation. The expression of P53 was up regulation and PCNA was down regulation after irradiation. CONCLUSION: β-particles from 188 Re was significantly effective and permanent in inhibiting SMCs proliferation, and inhibitory effect was in dose-dependet manner ED50was 5 Gy, the best dose to inhibit SMCs proliferation was 20 Gy. β-particles irradiation induced SMCs to occur G0/G1 arrest, damaged the ability of SMCs reproliferation and led to cell clonogenic death. P53 and PCNA had regulatiory effects on SMCs proliferation after β-particles irradiation. 相似文献
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AIM:To study the effect of L-Arg on plasma content of endothelin (ET) and the expression of proto-oncogene c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy. METHODS: The level of c-fos mRNA were measured by in situ hybridization. The ET in plasma were measured by radioimmunoassay. RESULTS:After eight weeks of treatment with L-Arg, the expression of c-fos decreased markedly (P＜0.01). The ET content in plasma also decreased significantly by L-Arg(P＜0.01).CONCLUSION: Plasma ET content and the expression of c-fos in the left ventricle of rats with renovascular hypertensive hypertrophy could be decreased by L-Arg administration. 相似文献
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《International Journal of Fruit Science》2013,13(3):101-120
Abstract Saskatoon berry (Amelanchier alnifolia Nutt., Rosaceae) and blueberry (Vaccinium corymbosum L., Ericaceae) are substantially equivalent in all characteristics that are important to the consumer, including fruit color, shape, size, nutrition, texture, and uses. In addition, both fruits are native to North America and they have practically identical historical uses and known health benefits. Their composition, processing, nutritional value and metabolism, intended uses, and levels of undesirable substances are compared. 相似文献
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多效唑对猕猴桃离体试管苗生长及内源激素的影响 总被引：18，自引：0，他引：18
多效唑（ＰＰ３３３）处理猕猴桃试管苗，降低了其生长强度；植株体内的ＧＡ３、ＩＡＡ和ＺＴ含量下降，ＡＢＡ的含量上升，乙烯释放率增加；并且能降低外源的ＧＡ３和ＩＡＡ促进生长的作用，而外源的ＧＡ３和ＩＡＡ又能不同程度地逆转多效唑的抑制作用，使植株恢复生长。 相似文献
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HU Zhi-cheng ZHU Jia-yuan ZHU Bin GUO Dong CHEN Bin ZHANG Kai HU Kun-hua LI Ming-tao TANG Bing 《园艺学报》2011,27(9):1802-1806
AIM: To investigate and screen the sensitive proteins in the formation mechanism of pathological scars by comparing the results of differential proteomic analysis between pathological scars and normal skin.METHODS: Two-dimensional gel electrophoresis was used to detect the protein expression profiles in 8 keloid patients, 8 hypertrophic scar patients and 3 matched normal skin patients.The proteins that showed differential expression of over 4-fold change were cut and analyzed by MALDI-TOF/TOF mass spectrometry.RESULTS: A two-dimensional protein profiling comparison between pathological scars and normal skin was successfully established.On average, 2 978 spots in keloid, 2 975 spots in hypertrophic scar and 3 053 spots in normal skin were identified using gel analysis software.Compared with normal skin, there were totally 36 differentially-expressed proteins in keloid and hypertrophic scar identified from the spots of over 4-fold change, including 16 proteins in both keloid and hypertrophic scar (8 up-regulated and 8 down-regulated), 11 only in keloid (9 up-regulated and 2 down-regulated) and 9 only in hypertrophic scar (4 up-regulated and 5 down-regulated).CONCLUSION: Proteomic analysis can identify the proteins with variance of pathological scars versus normal skin, thus providing probable new clues to reveal the formation mechanism of pathological scars. 相似文献
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The objective of this study was to establish a cryopreservation protocol for hawthorn shoot apices (Crataegus pinnatifida Bge.). Cryopreservation was carried out via encapsulation–dehydration, vitrification, and encapsulation–vitrification on shoot apices excised from in vitro cultures. We began by showing that cold-acclimation enhanced the regrowth of cryopreserved apices from 10.0 to 65.5% in encapsulation–dehydration. We then decided that the encapsulation–dehydration method was an optimal cryopreservation method for hawthorn shoot apices in terms of its high recovery after cryopreservation as well as its ease of use compared with vitrification and encapsulation–vitrification. In encapsulation–dehydration, the protocol leading to optimal regrowth was as follows: after cold-acclimation at 5 °C in the dark for 2 weeks, excised shoot tips were pretreated for 24 h at 25 °C on hormone-free Murashige and Skoog [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant. 15, 473–497] (MS) basal medium with 0.4 mol/L sucrose, then encapsulated and precultured in liquid MS medium with 0.8 mol/L sucrose for 16 h at 25 °C. Precultured beads were dehydrated for 6 h at 25 °C in the dessicator containing 50 g silica gel to a moisture content of 15.3% (fresh-weight basis) before cryostorage for 1 h. In addition, we examined the effect of adding glycerol to both the alginate beads and loading solution to enhance regrowth after cryopreservation in encapsulation–dehydration. In the present study, it was shown that adding 0.5 mol/L glycerol resulted in high regrowth percentages (82.5–90.0%) in four Crataegus species. 相似文献
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AIM:To investigate the effect of metallothionein(MT) on proliferation of rat vascular smooth muscle cells (VSMCs) stimulated by homocysteine and its mechanism. METHODS:VSMCs proliferation was measured by [3-H]-TdR incorporation, mitogen-activated protein kinase(MAPK)activity were determined by immunoprecipitation method, the intracellular contents of MT and malondialdehyde (MDA)were assayed by -hemoglobin saturation method and TBA reaction, respectively, and lactate dehydrogenase (LDH) leakage was measured by NADH oxidation. RESULTS:Hcy(10-6-10-4 mmol/L) stimulated [3-H]-TdR incorporation by the VSMCs in a concentration-dependent manner. Compared with control, [3-H]-TdR incorporation in VSMCs treated with 0.1 mmol/L Hcy was increased by 4.2 fold (P＜0.01). Meanwhile, Hcy enhanced MAPK activity, MDA formation and LDH release (P＜0.01)in a concentration-dependent manner. Treatment of VSMCs with MT alone did not change above parameters, compared with control. However, MT (10-6-10-4 mol/L)attenuated significantly Hcy-stimulated proliferation of VSMCs (P＜0.01)in a concentration-dependent manner. And MT inhibited obviously Hcy-induced activation of MAPK activity, MDA formation and LDH release. Preincubation of VSMCs with 0.5 mmol/L ZnCl2 for 6 h induced an increase cellular MT content by 5.7-fold (P＜0.01). The MT-overexpressed VSMCs resisted Hcy-stimulating action on MAPK activity, MDA formation and LDH leakage (P＜0.01). CONCLUSION:These results show that MT has an inhibitory effect on Hcy-induced VSMCs proliferation, and that MT could inhibit Hcy-stimulated MAPK activity and lipid peroxidation. 相似文献
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Duncan Brean W. Boyle Shannon Breininger David R. Schmalzer Paul A. 《Landscape Ecology》1999,14(3):291-309
Historic landcover dynamics in a scrubby flatwoods (Tel-4) and scrub landscape (Happy Creek) on John F. Kennedy Space Center were measured using aerial images from 1943, 1951, 1958, 1969, 1979, and 1989. Landcover categories were mapped, digitized, geometrically registered, and overlaid in ARC/INFO. Both study sites have been influenced by various land use histories, including periods of range management, fire suppression, and fire management. Several analyses were performed to help understand the effects of past land management on the amount and spatial distribution of landcover within the study sites. A chi-squared analysis showed a significant difference between the frequency of landcover occurrence and management period. Markov chain models were used to project observed changes over a 100-year period; these showed current management practices being effective at Tel-4 (restoring historic landscape structure) and much less effective at Happy Creek. Documenting impacts of past management regimes on landcover has provided important insight into current landscape composition and will provide the basis for improving land management on Kennedy Space Center and elsewhere. 相似文献
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AIM: Previous studies performed with XBP-01 in vitro indicated that XBP-01 could inhibit vascular smooth muscle cells from being transformed into foam cell and could eliminate the atherosclerotic plaque in C57BL/6J mouse. This experiment is to investigate its mechanism of eliminating plaques in vitro. METHODS: The cultured porcine artery smooth muscle cells incubated with XBP-01 of 0.1 mg/L for 24 h after preincubated with oxidized low density lipoprotein of 15 mg/L for 72 h in vitro. The samples were analyzed by fluorescence microscope, confocal microscope system and flow cytometry. RESULTS: Apoptosis was triggered by being incubated with oxidized low density lipoprotein and this process was accelerated additionally by being incubated with XBP-01. CONCLUSION: XBP-01 can be effective in eliminating atherosclerotic plaque by accelerating the process in which oxidized low density lipoprotein induced smooth muscle cell apoptosis. 相似文献
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Species distribution models (SDMs) often use elevation as a surrogate for temperature or utilise elevation sensitive interpolations
from weather stations. These methods may be unsuitable at the landscape scale, especially where there are sparse weather stations,
dramatic variations in exposure or low elevational ranges. The goal of this study was to determine whether radiation, moisture
or a novel estimate of exposure could improve temperature estimates and SDMs for vegetation on the Illawarra Escarpment, near
Sydney, Australia. Forty temperature sensors were placed on the soil surface of an approximately 12,000 ha study site between
November 2004 and August 2006. Linear regression was used to determine the relationship with environmental factors. Elevation
was correlated more with moderate temperatures (winter maximums, summer minimums, spring and autumn averages) than extreme
temperatures (summer maximums, winter minimums). The correlation (r
2) between temperature and environmental factors was improved by up to 0.38 by incorporating exposure, moisture and radiation
in the regressions. Summer maximums and winter minimums were predominately determined by exposure to the NW and coastal influences
respectively, while exposure to the NE and SW was important during other seasons. These directions correspond with the winds
that are most influential in the study area. The improved temperature estimates were used in Generalised Additive Models for
37 plant species. The deviance explained by most models was increased relative to elevation, especially for moist rainforest
species. It was concluded that improving the accuracy of seasonal temperature estimates could improve our ability to explain
the patchy distribution of many species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献