马铃薯病毒病防治和外部症状的鉴别

<正>目前,马铃薯种植户对马铃薯病毒病病害重视程度不够,忽略对病毒病的防治,导致植株变形,生长延迟,严重影响产量。病毒是一种非常小的微生物,病毒可以通过接触机械、衣物与相邻的植株传播,也可以通过传播媒介,如蚜虫、线虫、以及真菌,影响马铃薯病毒传播的因素有:品种的感病性、病毒源和传毒媒介,以及气候也是重要的影响因素之一,蚜虫是病毒传播的最优媒介。病毒入侵可以影响到植株的代谢,导致植株感病并表现出相关的     

蔬菜主要病害种类及诊断

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     

番茄砧木品种对青枯病的抗性机理

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     

推广无病毒苗木，促进柑桔优质丰产

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…     

果树侵染性病害不能忽视

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     

葡萄根癌病如何防治——兼答山西省读者徐建亮

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。     

柑桔黄龙病病株感染衰退病毒情况的鉴定

在我国南部柑桔产区,黄龙病是一种十分严重的病害。此病在我国西南的部分地区亦有发生。此病的病原,陈其爆(1943)通过调查和试验,认为最大的可能是病毒。林孔湘(1956)进一步试验证明病害可以通过嫁接传播,明确了病毒病原。福建的嫁接传病试验亦证实了这一点。 从国内外柑桔病毒病发生情况的分析对比中,以及根据利用指示植物鉴定证明黄龙病树受衰退病毒(tristeza)感染,曾经有人认为黄龙病的病原就是衰退病毒或可能是衰退病     

苹果锈果病防治三要点

苹果锈果病也叫苹果花脸病或裂果病,是由类病毒引起的病毒性病害,近年又发现病株组织中有植原体(类菌原质)存在.该病主要由带病接穗或带病砧木通过嫁接传播,也可通过病、健树根部接触传播,还可通过刀、剪、锯等工具传播.梨树是苹果锈果类病毒的潜隐性寄主,故苹果和梨树混栽或靠近梨树的苹果树发病较多.     

甜瓜褪绿黄化病的发生与传毒介体烟粉虱群体数量关系的调查

为研究瓜类褪绿黄化病毒(Cucurbit chlorotic yellows virus,CCYV)的传播介体烟粉虱对该病害发生的影响及不同甜瓜品种对CCYV的抗性,笔者调查了整个甜瓜生长季节中烟粉虱的发生动态、病害的发生情况、控制烟粉虱对病害发生的影响及不同甜瓜品种的发病情况。结果表明,烟粉虱的发生群体数量是影响甜瓜褪绿黄化病发生的最主要因素,不同品种间也存在明显的抗病性差异。因此,在甜瓜生产中有效地控制烟粉虱是控制该病害的关键。     

果树病毒病及其防治

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…     

Relationship between renal hypertension and cardiac α1-adrenoceptor autoantibodies in rats

AIM: To examine the autoantibody against α₁-adrenoceptor and its biologic activities during the development of renal hypertension. METHODS: Renal hypertension of rat was achieved by clipped renal artery, the titre of autoantibody to α₁-adrenoceptor was detected using ELISA immunoassay. Furthermore, the biological offects of these autoantibodies on cultured cardiomyocytes were also examined. RESULTS: After two weeks of clipping renal arteries, both the frequency of occurrence and the titre of autoantibodies to cardiac α₁-adrenergic receptor were significantly increased as compared with the control of pre-treatment. The increased autoantibodies lasted for several weeks and then automatically decreased gradually to the pre-clipping level at 12 weeks. The biological effects of these autoantibodies displayed an "agonistic-like" activities on the beating frequency of cultured neonatal cardiomyocytes. CONCLUSION: Autoantibodies against α₁-adrenoceptor may play a role in the elevation of peripheral vascular resistance and in the development of cardiac hypertrophy in rats with renal hypertension.     

Influence of Mineral Nutrients on Strawberry Fruit Quality and Their Accumulation in Plant Organs

Abstract

This review is based partly on complete articles and partly on abstracts. Three of the 60 articles deal with the total uptake of elements in strawberry plant organs in two different strawberry production systems, both considered as optimal concerning amount and balance of elements. The effect on fruit quality may be dramatic if the level of a particular element is outside this range, but there may also be effects initiated by differences within the optimal range of elements. Most articles refer to product oriented quality, but some focus on consumer oriented quality, as discussed by Shewfelt (1999). The discussion here is on a general basis, so one should keep in mind that there are cultivar differences and that specification of nutrition ideally should mirror the needs of a single cultivar, or a group of cultivars with similar requirements. Also, to get a complete understanding of the subject future reviews should embrace a broader access of information including the effect on plant development of individual elements, such as the role of calcium in fruit firmness and its importance in cell wall structure. However, the intention here is to narrow the information to results that suggest a direct connection between nutrient uptake and fruit quality.     

Mixed-severity fire regime in a high-elevation forest of Grand Canyon,Arizona, USA

Fire regime characteristics of high-elevation forests on the North Rim of the Grand Canyon, Arizona, were reconstructed from fire scar analysis, remote sensing, tree age, and forest structure measurements, a first attempt at detailed reconstruction of the transition from surface to stand-replacing fire patterns in the Southwest. Tree densities and fire-/non-fire-initiated groups were highly mixed over the landscape, so distinct fire-created stands could not be delineated from satellite imagery or the oldest available aerial photos. Surface fires were common from 1700 to 1879 in the 4,400 ha site, especially on S and W aspects. Fire dates frequently coincided with fire dates measured at study sites at lower elevation, suggesting that pre-1880 fire sizes may have been very large. Large fires, those scarring 25% or more of the sample trees, were relatively infrequent, averaging 31 years between burns. Four of the five major regional fire years occurred in the 1700s, followed by a 94-year gap until 1879. Fires typically occurred in significantly dry years (Palmer Drought Stress Index), with severe drought in major regional fire years. Currently the forest is predominantly spruce-fir, mixed conifer, and aspen. In contrast, dendroecological reconstruction of past forest structure showed that the forest in 1880 was very open, corresponding closely with historical (1910) accounts of severe fires leaving partially denuded landscapes. Age structure and species composition were used to classify sampling points into fire-initiated and non-fire-initiated groups. Tree groups on nearly 60% of the plots were fire-initiated; the oldest such groups appeared to have originated after severe fires in 1782 or 1785. In 1880, all fire-initiated groups were less than 100 years old and nearly 25% of the groups were less than 20 years old. Non-fire-initiated groups were significantly older (oldest 262 years in 1880), dominated by ponderosa pine, Douglas-fir, or white fir, and occurred preferentially on S and W slopes. The mixed-severity fire regime, transitioning from lower-elevation surface fires to mixed surface and stand-replacing fire at higher elevations, appeared not to have been stable over the temporal and spatial scales of this study. Information about historical fire regime and forest structure is valuable for managers but the information is probably less specific and stable for high-elevation forests than for low-elevation ponderosa pine forests.This revised version was published online in May 2005 with corrections to the Cover Date.     

瓜叶绿素降解关键酶基因PPH和PAO cDNA片段的克隆与表达初步分析

 以西双版纳黄瓜和‘华黄5号’黄瓜叶片为试验材料,研究了衰老过程中两种黄瓜叶片叶绿素含量变化及脱镁叶绿素脱镁叶绿酸水解酶基因PPH和脱镁叶绿酸a加氧酶基因PAO的表达。结果表明：随着叶片衰老,叶绿素a和叶绿素b含量显著降低,叶绿素a与叶绿素b的比值在0.5左右,推测叶绿素b的含量可能对黄瓜叶片保绿起到重要作用。荧光定量RT-PCR分析结果显示：PPH和PAO在西双版纳黄瓜叶片生长35 d时表达量最高,分别为5.50和1.86;PPH在‘华黄5号’叶片35 d时表达量最高,为7.14,而PAO在35和45 d表达量都很高,分别为3.90和3.91;PPH和PAO在西双版纳黄瓜叶片中的表达量低于在‘华黄5号’中。     

Effects of simvastatin on PDGF-BB and serum-induced proliferation of vascular smooth muscle cells and on the expression of tumor suppressor gene PTEN

AIM:To observe the effect of simvastatin on the proliferation of vascular smooth muscle cells(VSMCs) induced by serum and growth factor PDGF-BB and the effect of simvastatin on the expression of PTEN,a important regulator of G₁/S cell cycle transition. METHODS:The DNA synthesis was determined by [³H]-TdR incorporation, cell cycle was examined with flow cytometry, the protein level of PTEN was measured by Western blot method. RESULTS: (1)Simvastatin inhibited [³H]-TdR incorporation in a dose dependent manner. (2) Flow cytometric DNA analysis revealed that simvastatin induced significantly enhancement of G₀/G₁ phase and decrease in S phase VSMCs.(3)Simvastatin increased protein level of PTEN and mevalonate, a metabolite of HMG-COA, reversed the effect of simvastatin on PTEN protein expression. CONCLUSION:Simvastatin may inhibit proliferation of VSMCs and retarded cell cycle in G₀/G₁ phase by increasing PTEN expression through inhibiting synthesis of mevalonate.     

Relationships of landscape,prey and agronomic variables to the abundance of generalist predators in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis>) fields

A two-year field study investigated the possible effects of grain sorghum (Sorghum bicolor [L.] Moench) and uncultivated areas on the abundance of generalist predators in commercially-managed cotton (Gossypium hirsutum L.) fields in Texas, USA. From 63 to 70 fields were sampled for pests and predators over nine consecutive weeks during early stages of cotton development. Additional data on agronomic practices and landscape composition at three spatial scales were also collected for each field. Stepwise regression analyses were used to determine the relationships of landscape, agronomic and prey variables to the abundance of generalist predators. Because the variables most closely linked to predator levels could vary over time, separate regressions were conducted for three time periods corresponding to stages of grain sorghum growth (half-bloom, hard-dough, maturity) in each year. Significant relationships between predator abundance and agricultural landscape composition appear in both years and in all three time periods, but the specific relationships of landscape variables to cotton predator levels differed between and within years. At maturity in 2001, predator levels rose as the amount of uncultivated land from 1.6 to 3.2 km distant and the perimeter shared with grain sorghum increased. During 2002, the area of grain sorghum (half-bloom) and uncultivated land (hard-dough) within 1.6 km of cotton fields were both positively related to predator numbers. Cotton planting dates and the abundance of cotton fleahoppers (Pseudatomoscelis seriatus [Reuter]) were also strongly linked to predator numbers during both years. Results suggest that the total amount of grain sorghum or uncultivated land in an area is more important than the presence of these habitats adjacent to cotton fields, and that landscape composition may sometimes be the most important factor in determining predator abundance.     

Influence of lanthanum nitrate on the expression of aquaporin 7 in the testis of rats

AIM: To find out whether different dosage of rare earth element-lanthanum can influence the expression of aquaporin 7(AQP 7) in the testis of rats. METHODS:Rats were fed with lanthanum nitrate[La(NO₃)₃]and killed 6 months later.Testes were then removed immediately to extract total RNA.Northern blot analysis is performed finally. RESULTS:0.1 mg/kg La(NO₃)₃ depressed the expression of AQP 7 in rat testis, while 20 mg/kg La(NO₃)₃ had no significant effect on it. CONCLUSION: AQP 7 expession is found in the rat testis; La(NO₃)₃ can depress the expression of AQP 7 in the rat testis.     

Ergebnisse der Leistungsprüfung von Kirschensorten auf wuchsreduzierenden Unterlagen in Ungarn

Zusammenfassung In Ungarn gibt es ein reges Interesse an intensivem Obstanbau. Der Erfolg dieses Anbaus hängt in sehr großem Maße von den Wechselwirkungen zwischen dem Standort, den Sorten-Unterlagen-Kombinationen und dem Anbauverfahren ab.Um die Wirkung wuchsreduzierender Kirschenunterlagen aus ausländischen Züchtungsinstituten unter ungarischen Klimaverhältnissen untersuchen zu können, wurde im Forschungsinstitut für Obst- und Zierpflanzenbau Budapest-Érd ein Vergleichsversuch durchgeführt. Der Versuch wurde mit Cerasus avium C. 2493, Weiroot 13, Weiroot 53, Weiroot 72, Weiroot 154, Weiroot 158, GiSelA 5 und P-HL-A-Unterlagen 1997 in der Versuchsanstalt des Forschungsinstituts für Obst- und Zierpflanzenbau Budapest-Érd aufgepflanzt. Als Kontrolle diente die Sämlingsunterlage Cerasus mahaleb Cema, deren Anteil im ungarischen Süßkirschenanbau bei 70–80% liegt. Die Unterlagen wurden mit drei Süßkirschensorten (Germersdorfi , Linda, Katalin) und mit einer Sauerkirschensorte (Piramis) veredelt.Nach der Wüchsigkeit bis zum Ende des 8. Standjahres konnten die Unterlagen in drei Gruppen eingeteilt werden: starkwüchsige (Cerasus mahaleb Cema, Cerasus avium C. 2493, Weiroot 13), mittelstarkwüchsige (Weiroot 158, Weiroot 154, P-HL-A) und schwachwüchsige Unterlagen (Weiroot 72, Weiroot 53, GiSelA 5). Die stärkste Neigung, Wurzelschosse zu treiben, zeigten Weiroot 13 und Weiroot 154.Während der Untersuchung der generativen Eigenschaften wurde beobachtet, dass es Unterschiede in der Blütezeit der Sorten-Unterlagen-Kombinationen gibt. Auf GiSelA 5 veredelte Sorten blühten 1 oder 2 Tage früher als die Kontrolle. Es gab nur geringe Unterschiede in der Reifezeit der Kombinationen. Den größten Ertrag hatte die Sorte Linda, gefolgt von Katalin, Germersdorfi 3 und Piramis. Der größte Fruchtdurchmesser wurde bei der Süßkirschensorte Germersdorfi 3 gefunden, der größte Anteil an Früchten größer als 26 mm bei den Bäumen auf Weiroot 72 (23%), der geringste Anteil großer Früchte bei den Bäumen auf GiSelA 5. Bei Piramis wurde der größte Fruchtdurchmesser auf Cerasus avium C. 2493 gemessen.     

Effects of corridors on home range sizes and interpatch movements of three small mammal species

Corridors are predicted to benefit populations in patchy habitats bypromoting movement, which should increase population densities, gene flow, andrecolonization of extinct patch populations. However, few investigators haveconsidered use of the total landscape, particularly the possibility ofinterpatch movement through matrix habitat, by small mammals. This studycompares home range sizes of 3 species of small mammals, the cotton mouse(Peromyscus gossypinus), old-field mouse (P.polionotus) and cotton rat (Sigmodon hispidus)between patches with and without corridors. The study site was in S. Carolina,USA. Corridor presence did not have astatistically significant influence on average home range size. Habitatspecialization and sex influenced the probability of an individual movingbetween 2 patches without corridors. The results of this study suggest thatsmall mammals may be more capable of interpatch movement without corridors thanis frequently assumed.This revised version was published online in May 2005 with corrections to the Cover Date.     

Quercetin regulates Fas expression and induces apoptosis in hepatocellular carcinoma HepG2 cells

AIM: To investigate the role of 1, 4, 5- trisphosphate inositol (IP3) and Fas gene expression in apoptosis of HepG2 cells induced by quercetin. METHODS: HepG2 cells were treated with quercetin at different concentrations (including 20, 40, 60, 80 μmol/ L) for 72 h and treated with 60 μmol/ L quercetin for 6 h, 12 h, 24 h, 48 h and 72 h. IP3, Fas mRNA, Fas protein and apoptosis rate were assayed by IP3 - ［3H］ Birtrak assay, RT-PCR, Western blotting and flow cytometry, respectively. RESULTS: When HepG2 cells were incubated with different concentrations of quercetin for 72 h, the IP3 content was lower than those in control. Fas mRNA expression, Fas protein expression and the apoptosis rate were higher than those in control. When HepG2 cells were incubated with quercetin for 6 h, 12 h, 24 h, 48 h, 72 h, the IP3 contents were lower than those in control incubated with 60 μmol/L quercetin for 12 h. Fas mRNA expression was higher than that in control incubated with 60 μmol/L quercetin for 12 h . Fas protein expression was higher than that in control. The apoptosis rate was significantly higher than that in control incubated with 60 μmol/L quercetin for 24 h (P<0.01). CONCLUSION: Quercetin induces apoptosis of HepG2 cells by reducing IP3 production and upregulating Fas gene expression.