干热处理甜瓜、籽瓜细菌性果斑病种子对幼苗发病的影响

为了筛选出对防治甜瓜、籽瓜细菌性果斑病有效、安全的干热处理方式,对人工接种细菌性果斑病的甜瓜、籽用西瓜种子进行不同温度及不同时间的干热处理,经种植鉴定,观测比较了不同处理的出苗率、果斑病病情指数及防治效果。结果显示:对甜瓜带菌种子有较好的防治效果的处理是60℃处理6、8 d,防治效果为85.6%;65℃处理6 d,防治效果为85.0%。对籽用西瓜带菌种子防治效果较好的处理是60℃处理12 d,防治效果为86.5%;65℃处理12 d,防治效果为83.0%。     

籽用南瓜细菌性果腐病种子带菌检测与消毒处理

以市场销售的5份籽用南瓜种子为试材,采用PCR检测技术对南瓜种子细菌性果腐病菌进行检测,用不同浓度的CuSO_4、HCl、H_2O_2、过氧乙酸和漂白粉等药剂处理带菌种子进行消毒处理。研究了不同药剂处理对南瓜种子果腐病菌消毒效果的影响。结果表明:市场销售的5份南瓜种子均携带细菌性果腐病菌;5种药剂对南瓜种子携带的细菌性果腐病菌均有消毒效果,但HCl、H_2O_2、过氧乙酸对南瓜种子的发芽有抑制作用。1.0% CuSO_4处理30 min和1.5%漂白粉处理30 min对南瓜种子果腐病菌防治效果最好,并且2种药剂处理对种子发芽率和发芽势影响不明显。因此,选用1.0% CuSO_4或1.5%漂白粉对南瓜种子进行消毒处理,可以消除种子表皮所携带的果腐病病菌。     

一种新种子处理剂对瓜类细菌性果斑病的防治效果

为了有效防治西瓜甜瓜细菌性果斑病,研究了新种子处理剂——西亚1号不同处理方法和其他药剂处理对西、甜瓜种子发芽率的影响及对细菌性果斑病的防治效果。结果表明:在不影响发芽率的条件下,西瓜最佳处理浓度为700倍、处理时间为60 min;厚皮甜瓜最佳处理浓度为1 000倍、处理时间为45 min;药剂防治效果表明,西亚1号明显好于浓盐酸、过氧乙酸和Tsunami 100。     

带菌育苗基质对西瓜细菌性果斑病发生的影响和药剂筛选研究

西瓜细菌性果斑病（BFB）是西瓜上的毁灭性病害,研究其侵染途径及防治方法对于西瓜生产具有重要意义。本研究通过对育苗基质人工接种西瓜细菌性果斑病菌,发现基质带菌能够导致西瓜幼苗 BFB 的发生。通过室内试验评估了可杀得叁仟、加瑞农、加收米、注射用硫酸链霉素、90% 新植霉素 5 种药剂对西瓜细菌性果斑病菌的抑菌和杀菌效果,发现 90% 新植霉素（100、200、300 mg.L-1）对西瓜细菌性果斑病菌有较强的抑制效果 ,加瑞农 （600、800 倍液）处理细菌 5 h,对西瓜细菌性果斑病菌的室内杀灭效果达到 100%。在此基础上,研究在基质带菌量为 109cfu.kg-1的情况下,不同药剂消毒育苗基质对西瓜幼苗细菌性果斑病的防治效果。结果表明,每 1 m3基质喷淋 100 kg药剂,播种后的第 15 天,加瑞农 600 倍液和加收米 400 倍液对西瓜幼苗细菌性果斑病的防效分别达到 46.4% 和 30.4%。     

不同药剂处理对西瓜细菌性果斑病带菌种子的影响

采用菌悬浮液浸种方式对西瓜种子接菌,利用6种药剂对带菌种子进行浸种处理,并调查各处理对种子发芽、幼苗生长的影响及对西瓜幼苗细菌性果斑病(BFB)的防治效果。试验结果表明,播种前带菌种子采用40%甲醛100倍液浸种1 h,对西瓜幼苗BFB的防效达到100%,对西瓜种子的发芽和幼苗的生长无不良影响。     

干热处理对西瓜种子活力及抑制细菌性果斑病的影响

以‘黑媚娘’西瓜种子为试验材料,在70、75、80℃温度下分别处理24、48、72 h,研究不同干热处理对西瓜种子活力及细菌性果斑病灭菌效果的影响。结果表明:随着处理温度的升高及处理时间的延长,灭菌效果明显增强,‘黑媚娘’西瓜种子在70℃72 h、75℃72 h和80℃72 h处理对种子表面的灭菌率分别高达90.6%、99.4%和100%。70℃干热处理对西瓜种子发芽特性、发芽势均没有影响,75℃、80℃处理降低了西瓜种子活力,与对照有显著性差异。各干热处理后的种子在老化3 d后,活力大大降低。干热处理温度越高,种子萌发活力会相应地降低。因此综合分析干热处理对种子活力及灭菌效果的影响,70℃72 h处理是适宜于西瓜种子细菌性果斑病干热灭菌处理的最佳组合。     

西瓜种子带菌对幼苗细菌性果斑病发生和侵染途径的影响

以西瓜品种"绿之秀"的种子为试材,采用人工接种的方法,研究了细菌性果斑病(bacterial fruit blotch,BFB)病原菌燕麦嗜酸菌西瓜亚种(Acidovorax avenae ssp.citrulli,Aac)的流行因素、种传方式及其在西瓜幼苗的定植情况,并调查了西瓜病果种子不同部位带菌情况。结果表明:发生BFB的西瓜病果采得的种子不完全带菌,种壳和种仁均可带菌,而且种壳带菌率明显高于种仁带菌率;接种菌液量和空气相对湿度是影响BFB发生的重要因素;Aac在西瓜幼苗生长过程中先侵染幼苗子叶,随后沿叶脉侵入下胚轴,侵染过程中有一定的潜伏期,最终引起幼苗下胚轴发病,但不侵染西瓜幼苗的根部。     

十大技术之七(五) 西瓜甜瓜种传细菌性果斑病综合防控技术

<正>细菌性果斑病(BFB)是当前西瓜和甜瓜上最重要的毁灭性病害,其病原菌为西瓜嗜酸菌(Acidovorax citrulli,Ac),在我国西瓜、甜瓜生产及制种地均有发生,并呈上升趋势,给西甜瓜生产及制种带来巨大损失。为了加强西甜瓜细菌性果斑病防控技术,特整理总结西甜瓜种传细菌性果斑病综合防控技术,供参考。1种子消毒处理种子处理是关键。直播的西瓜、甜瓜种子或用于培育嫁接苗的砧木和接穗的种子都要进行药剂消毒处理,具体方法     

带菌嫁接工具对西瓜嫁接苗BFB发生的影响及防治方法

细菌性果斑病（BFB）是西瓜上的毁灭性病害,西瓜嫁接苗集约化生产过程中容易感染该病害 ,研究嫁接过程中 BFB 的侵染途径及防治方法对于西瓜健康种苗生产具有重要意义。本研究通过人工模拟接种西瓜细菌性果斑病菌 pslbtw20,分析了用带菌竹签嫁接对西瓜嫁接苗 BFB 发生的影响,同时研究了不同消毒技术的效果。结果表明,高浓度菌源污染的竹签嫁接能够导致嫁接苗 BFB 的发生,嫁接前采用 40% 甲醛 50 倍液和 75% 酒精浸泡带菌嫁接用具 15 min,防效可达到 100%。     

新疆西瓜甜瓜杂交制种丑菌性果斑病的发生与防治

细菌性果斑病是近几年出现的一种检疫性病害,同时也是一种毁灭性病害,对新疆西瓜甜瓜生产造成严重影响。新疆是我国西瓜甜瓜杂交制种最主要的区域之一．每年西瓜甜瓜制种面积达0．4万hm^2．是新疆农业产业的重要组成部分．生产的杂交种子籽粒饱满,产量高,不仅满足本地区的种植需求,同时向国内其他地区及国外销售^[1]。然而。近年在新疆出现了一种检疫性病害——细菌性果斑病．该病是一种毁灭性病害,对西瓜甜瓜栽培产生很大影响,经济损失较大,并有上升趋势^[2]。西瓜甜瓜杂交制种若发生该病害．不仅严重影响制种公司与制种农户的经济效益．而且该病害主要通过种子带菌传播．若处理不当将导致该病害广泛传播,扩大了危害范围。积极防治细菌性果斑病,生产健康种子意义重大。     

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.     

Effects of radiation from 188Re on smooth muscle cell proliferation

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.     

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.     

Effect of L-Arg on plasma content of endothelin and expression of c-fos mRNA in the left ventricle of rats with renovascular hypertensive hypertrophy

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.     

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.     

Compositional and Functional Properties of Saskatoon Berry and Blueberry

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.     

Cryopreservation of shoot apices of hawthorn in vitro cultures originating from East Asia

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.     

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.