白菜与甜菜间作的生长与资源利用效果

通过设置不同的白菜与甜菜间作密度,监测了复合群体的叶面积指数、漏光率以及各作物产量,研究复合群体的生长动态,光资源分布以及产量产值效应。结果表明:在间作群体中,白菜依其速生优势而表现偏利效应,间作甜菜前期受白菜遮蔽胁迫,其生育期叶面积指数始终低于单作;白菜收获后甜菜通过叶层自动空间散布提高光能截获率,促进了后期光合补偿性生产;白菜2行∶甜菜1行间作(BT1)处理,白菜的实际产量比"预期"产量极显著增高26.7个百分点,甜菜比"预期"产量增高34.0个百分点;白菜2行∶甜菜2行间作(BT2)处理,白菜、甜菜的实际产量比"预期"产量分别极显著增高59.3、53.0个百分点;BT1、BT2间作群体较白菜单作经济效益分别提高10.2、23.7个百分点,较甜菜单作经济效益分别提高91.5、115.1个百分点。分析表明,间作种植显著提高了地气资源的利用效率,BT1间作LER为1.29;BT2间作LER高达1.56。     

河北省太行山苹果产区土壤肥力与施肥现状评价

为综合评价河北省太行山地区苹果园土壤肥力与施肥现状,通过实地调查该地苹果园不同养分投入量、投入类型以及各养分在0~60 cm土层分布状况,并进一步采用产量差法探究最佳养分投入量。结果表明,河北省太行山地区苹果园有机肥平均施入量为5934.72 kg/hm^2,以鸡粪、羊粪、牛粪为主;无机肥N、P2O5、K2O投入量分别为777.63 kg/hm^2、421.86 kg/hm^2、543.39 kg/hm^2。土壤养分随土层加深呈降低趋势,其中0~20 cm土层有机质、有效磷、速效钾、有效铁含量均达到了丰富水平,但有效锰含量处于较低水平,有效铜、有效锌处于适量水平。产量差模型分析显示,河北省太行山苹果园最高产量N、P2O5、K2O投入量分别为821.87 kg/hm^2、580.73 kg/hm^2、676.99 kg/hm^2。建议在实际生产中应降低氮、钾肥投入,适当补充磷、锰肥,同时搭配有机肥。     

不同磷肥施用量对紫菀产量及有效成分含量的影响

以紫菀为试材,采用HPLC法,研究磷肥的不同施肥量(35、40、45kg/667m2)对紫菀的产量、有效成分(紫菀酮)含量的影响。结果表明:当磷肥施用量为40kg/667m2时,其对紫菀的农艺性状及有效成分含量影响显著;当施用量为45kg/667m2时,紫菀产量最高,但与40kg/667m2不存在显著差异,因此确定40kg/667m2为紫菀磷肥的最佳施用量。     

不同间作模式下半夏产量及品质的综合评价

以半夏、魔芋、大豆及辣椒为试材,采用随机区组设计大田试验,研究单作半夏及半夏间作魔芋(半夏‖魔芋)、半夏间作辣椒(半夏‖辣椒)、半夏间作大豆(半夏‖大豆)3种间作处理对半夏产量及品质的影响。结果表明:在产量方面,与大豆间作半夏总产量最高,与辣椒间作半夏一级种产量最高,一级种与四级种呈此消彼长的态势,再加之变异系数较大,所以通过间作提高半夏一级种产出是提高半夏产量的有效途径;在品质方面,与魔芋间作半夏的可溶性蛋白质及浸出物含量最高,与辣椒间作半夏的可溶性糖、还原糖、琥珀酸及鸟苷含量最高,与大豆间作半夏的生物碱含量最高,但品质方面变异系数较小。通过主成分对产量及品质分析综合评分得出半夏‖大豆最高,半夏‖辣椒次之,可作为半夏高产优质栽培的理想间作搭配,为半夏产业化种植提供重要的理论依据。     

磷肥和钾肥配合施用对防风有效成分含量的影响

为了研究不同配比的磷钾肥对1 a生、2 a生有效成分含量的影响,采用田间试验测定1 a生、2 a生防风根干重,以HPLC测定防风有效成分升麻素苷和5-O-甲基维斯阿米醇苷的含量。结果表明,当1 a生和2 a生防风施肥处理分别为P2O5124 kg/hm2和K2O 46 kg/hm2、P2O5186 kg/hm2和K2O 92 kg/hm2时,防风根干重均达到最大值。当1 a生、2 a生防风分别施用P2O5124 kg/hm2和K2O 46 kg/hm2、P2O5124 kg/hm2和K2O 92 kg/hm2时,防风中升麻素苷和5-O-甲基维斯阿米醇苷总含量最高。钾肥对1 a生、2 a生防风根干重均有显著影响。最适于防风有效成分积累的磷肥量为P2O5124 kg/hm2。一定范围内配合施用磷钾肥促进防风生长,有利于升麻素苷和5-O-甲基维斯阿米醇苷含量积累。综合考虑产量与品质,在田间氮素补至一致条件下,即每公顷含氮量为72 kg时,1 a生、2 a生防风肥料施用量分别为P2O5124 kg/hm2和K2O 46 kg/hm2、P2O5124 kg/hm2和K2O 92 kg/hm2,可获得成本低、优质高产防风,对于农业生产实践具有指导意义。     

河北承德中南部地区磷肥不同施用量对地膜马铃薯产量的影响

以马铃薯‘荷兰15’一级种为试验种植材料,探讨马铃薯‘荷兰15’磷肥4种施用量的鲜薯产量、商品薯产量与经济效益。结果表明,适当增加磷肥(P2O5)施用量,可以提高出苗率,增加鲜薯产量、商品薯产量与经济效益。磷肥(P2O5)施用量8 kg/667 m2的鲜薯产量、商品薯产量最高,每667 m2分别为2 513.3 kg和2 254.5 kg,极显著高于不施磷肥鲜薯产量与商品薯产量,显著高于磷肥(P2O5)施用量12 kg/667 m2的鲜薯产量与商品薯产量。磷肥(P2O5)施用量8 kg/667 m2的经济效益最高,为2 965.9元,比不施磷、磷肥(P2O5)施用量4、12 kg/667 m2分别增效1 175.4、805.3和646.4元。综合考虑,承德中南部区域种植马铃薯‘荷兰15’,磷肥(P2O5)施用量8 kg/667 m2最适宜。此水平磷肥(P2O5)施用量的鲜薯产量、商品薯产量及经济效益均最高。     

不同组合药剂对马铃薯晚疫病的防治效果

马铃薯晚疫病是一种毁灭性病害,会严重降低马铃薯的产量和品质。为提高马铃薯晚疫病的防治效果,作者以甘肃省徽县马铃薯主栽品种费乌瑞它为试验材料,开展了不同组合药剂对马铃薯晚疫病的防治效果试验。试验结果表明,“72%甲霜·锰锌可湿性粉剂1.5 kg/hm^(2)+68.75%氟吡菌胺·霜霉威悬浮剂1 L/hm^(2)”处理马铃薯晚疫病的防效最好(92.18%)、产量最高(39 400 kg/hm^(2))、商品薯率最高(85.4%);其次为“72%霜脲·锰锌可湿性粉剂1.2 kg/hm^(2)+68.75%氟吡菌胺·霜霉威1 L/hm^(2)”处理,马铃薯晚疫病的防效为90.13%,产量为38 500 kg/hm^(2),商品薯率为83.2%。上述两种药剂组合可用于防治马铃薯晚疫病,建议在马铃薯生产上推广应用。     

巨峰葡萄氮磷钾肥效及其适宜用量研究

利用“3414”试验设计,开展福安市巨峰葡萄氮磷钾肥效田间试验,结果表明：施用氮磷钾肥分别增产33.9％、28.0％和31.1％.在试验条件下,每667 m2最高产量施肥量为N 16.95 kg,N∶P2O5∶K2O =1∶0.78∶1.22,最高产量为1 476.7 kg;每667 m2最佳经济施肥量为N 16.08 kg,N∶P2O5∶K2O=1∶0.78∶1.23,经济产量为1 475.4 kg.     

生姜的营养特性及钾对生姜产量和土壤肥力的影响

以安丘生姜为试材,研究了生姜不同生长期的养分吸收特性,以及不同钾水平对生姜产量和土壤肥力的影响。结果表明：姜对钾素的需求最多,每生产1 000 kg姜需要从土壤中吸收6.1 kg N、2.36 kg P2O5、9.4 kg K2O。K3处理〔K2O 70 kg?（667 m2）-1〕的生姜产量最高,但与K2处理〔K2O 50 kg?（667 m2）-1〕之间差异不显著。通过产量和施肥量的拟合曲线获得最高产量的钾肥施用量为60 kg?（667 m2）-1,综合考虑不同钾水平对生姜养分吸收和土壤肥力的影响,得出本试验条件下生姜周年生产的钾肥（K2O）投入量为667 m2 50～60 kg比较适宜,同时适宜的氮钾比例为4∶5～4∶6。     

菜豆新品种连农无筋2号的选育

连农无筋2号利用杂交育种，后代经过系统选育而成。它涉及4个亲本：82-3长菜豆、85-1、Cornell49-242、87B。植株蔓生 ，商品荚绿色，扁形，荚长22 cm，荚宽1.5~2.0 cm，荚厚1.2~1.7 cm，荚形指数1.36，单荚质量23.0 g左右。抗锈病，中抗炭疽病 。春、秋露地栽培每667 m²产量分别为3 076、2 243 kg，春季大棚栽培平均每667 m²产量2 500 kg左右，冬季温室栽培平均产量3 200 kg，适合北方地区春秋大棚、春秋露地及冬季温室栽培。     

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.     

辣椒素积累生理研究的最新进展

辣椒素的积累主要受到遗传、环境、竞争物质、酶的影响.在遗传方面,辣椒的基因型以及决定辣椒素含量的特定基因对辣椒素的积累起着决定作用,环境中的光照、温度、CO2、肥料起辅助作用,竞争物质,如木质素、类黄酮、蛋白质、单宁、生物碱、香豆素等物质与辣椒素的积累相互抑制,辣椒素的合成酶和降解酶同样影响辣椒素的积累.     

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.     

微波消解ICP—MS法测定香菇中重金属含量

采用密闭微波消解法消解香菇样品,在优化微波消解条件的基础上,建立微波消解ICP—MS法同时测定千香菇中As、PI）、Cd、Cr、Cu、Zn、Mn、Fe和Mg九种重金属元素的方法,在最佳试验条件下,加标收率为92．0％～104．6％,RSD为2．2％-5．3％。该方法简便、快速、准确：     

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.     

Inferring the effects of landscape structure on roe deer (Capreolus capreolus) movements using a step selection function

In this study, we sought to understand how landscape structure affects roe deer movements within their home-range in a heterogeneous and fragmented agricultural system of south-western France. We analysed the movements of 20 roe deer fitted with GPS collars which recorded their locations every 2–6 h over several months (mean = 9 months). Based on empirical observations and previous studies of roe deer habitat use, we hypothesised that roe deer should avoid buildings and roads, move preferentially along valley bottoms and through the more wooded areas of the landscape. To test these hypotheses we paired each observed movement step with 10 random ones. Using conditional logistic regression, we modelled a step selection function, which represents the probability of selecting a given step as a function of these landscape variables. The selected model indicated that movements were influenced by all the tested landscape features, but not always in the predicted direction: our results suggested that roe deer tend to avoid buildings, roads, valley bottoms and possibly the more wooded areas (although the latter result should be interpreted with caution, as it may be influenced by a bias in the rate of GPS fix acquisition in woods). The distances to buildings and to roads were the most influential variables in the model, suggesting that the avoidance of potential sources of disturbance may be a key factor in determining ranging behaviour of roe deer in human dominated landscapes.     

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.     

Inoculation of growing media with the rhizobacterium Variovorax paradoxus 5C-2 reduces unwanted stress responses in hardy ornamental species

Inoculation of growing media with plant growth promoting rhizobacteria (PGPR) has a number of potential benefits for the production of ornamental plants. Certain rhizobacteria synthesise the enzyme ACC deaminase, which cleaves ACC, the precursor of the plant hormone ethylene. Bacterial metabolism is now known to lead to a reduction in [ACC] in the plant transpiration stream and bacteria are hypothesised to act on ACC exuded from roots. This in turn reduces the ethylene generated in plants growing in growing media inoculated with these bacteria. Here we tested if applications of the ACC deaminase containing rhizobacteria Variovorax paradoxus⁵C–²could be of benefit to ornamental growers by reducing ethylene generation in stressed plants. Ethylene is produced at levels that are inhibitory to growth and development under a number of abiotic stresses. The propagation and production of hardy ornamentals is deleteriously affected by abiotic stresses that involve ethylene signalling, including drought and physical wounding. Inoculation of growing media with V. paradoxus 5C-2 lowered ethylene emission from mature leaves of Cytisus × praecox experiencing drought stress. In addition, bacterial inoculation of the growing media resulted in significantly reduced abscission of the mature leaves under drought treatment. Beneficial effects of inoculation where also found in the wounding response of Fargesia murielae following divisional propagation and late season senescence in Aquilegia × hybrida in response to drought stress. Together these results demonstrate that V. paradoxus⁵C–²has real potential for use on ornamental nurseries in situations where plant stresses are unavoidable.