柑桔营养诊断指导施肥的实践

近１０余年来，对福建南亚热带柑桔主栽品种叶片养分含量和桔园土壤有效态含量进行了研究，提出了叶片和土壤的营养诊断标准，并应用这些诊断标准指导合理施肥，取得了显著的经济效益。     

金柑叶片矿质营养研究简报

为使柑桔生产获得丰产优质,国内外广泛开展了柑桔营养与施肥的研究,但有关金柑的营养与施肥研究尚未见报道。我们拟通过尤溪金柑(金弹)的叶片分析与土壤分析,探讨叶片矿质营养含量与产量的相关性,旨在为合理施肥和进一步开展叶片营养诊断提供科学依据。     

柑桔叶片氮磷钾营养全量速测研究初报

应用叶片营养诊断指导施肥,是夺取柑桔高产稳产与优质的重要手段.近几年国内也日益重视营养诊断的研究和应用.我们于1982年开始应用全量速测法(系江西省赣州地区农科所丘星初同志研究制定的),对温州蜜柑、芦柑的叶片氮磷钾营养进行诊断研究.现将三年初步结果整理于下:     

柑桔叶片营养元素适宜含量的研究

本文综述对柑桔品种(宽皮柑枯类、柚类、甜橙类)叶片营养元素含量适宜范围的研究。研究结果表明:1、各品种不同地点、年份的叶片元素含量存在明显差异,故建立叶片适宜指标时,应采用多点、多株、多年的叶片分析。2、本研究中的三个甜橙品种间叶片元素含量未见稳定差异,故可建立通用的叶片营养元素含量适宜标准。3、各品种叶片元素含量变异系数大小的趋势大致相近。本文初步提出柑桔叶片元素含量适宜标准,可供营养诊断指导施肥之参考。     

甜橙氮素营养的初步探讨

氮素是柑桔营养中的重要元素。它比其他营养元素对柑桔生长发育、开花结实的影响都更为密切,在很大程度上控制着果树的生长和产量。随着果树叶片分析营养诊断技术的发展,当前在一些国家.叶片分析指导施肥已进入生产应用阶段。但是,由于影响柑桔营养的因素是多方面的,尤对氮素来说,至今虽为研究最多的一种元素,但却无定论。现在很多国家对氮肥的合理施用问题,仍在不断的研究改进中。为此,我们于1977年开始,应用叶片分析研究甜橙氮素营养的年周期变化动态,探讨在不同施肥标准下的树体氮素营养状况及其与生长结果的关系,以期为经济有效地施肥提供依据。     

早熟砂梨矿质营养适宜值研究

通过对翠冠、蜜雪梨2个早熟砂梨(Pyrus pyrifolia)主栽品种高产果园大样本群体叶片(翠冠n=115、蜜雪梨n=62)、土壤(n=277)矿质营养因子的统计分布,以及"产量等级"与元素相关性研究,建立了亚热带季风红壤地区,并以豆梨(Pyrus calleryana)为砧木条件下的2个品种的10项叶片矿质营养适宜指标,以及13项砂梨的土壤有效态营养适宜指标。并经叶片营养适宜值差异显著性检验与高接比对验证,翠冠叶片N、K适宜范围显著高于蜜雪梨。另外,经高接比对试验逆向推理,若同砧高接的不同品种营养差异显著,则它们的营养适宜范围差异也显著,否则一致。据此,蜜雪梨叶片营养诊断标准可供黄花梨参考应用。此外,所建立的土壤诊断标准可供亚热带季风红壤地区,与砧木为豆梨等背景条件相似的砂梨产区应用。     

柑桔营养诊断初步研究(1977—1978)

果树营养诊断是研究果树营养规律及提供施肥理论指导的重要手段。数十年来,许多国家很重视果树营养研究,并致力于通过营养诊断达到果树高产、稳产、优质、低消耗,取得了不少进展。1966年,在美国营养生理学家Chapman主持下,归纳汇编了全世界始于三十年代后,以果树为主及其他植物的营养诊断标准。近二、三十年,一些柑桔主产国家,采用植株分析(以叶片分析为主),并结合施肥等方面的研究,以确定柑桔各营养元素的含量     

应用叶片营养诊断指导脐橙园合理化、标准化施肥

我县是脐橙栽植的最适宜区域 ,由于受传统栽培模式的影响 ,现代化果树叶片营养诊断设备欠缺的制约 ,广大果农无法掌握树体营养的盈亏状况 ,仅凭经验法、常规法、目测法指导施肥 ,造成盲目施肥的多、流失浪费的多 ,元素间产生拮抗也不少 ,造成生产成本高、树体营养失调 ,导致低产劣质果园。如何把叶片营养诊断成为果树生产管理中的一项常规措施 ,指导果园合理施肥浅谈一些见解。1　叶片营养诊断作用正确的施肥是保证果树高产、优质的重要措施之一 ,果树的矿质营养原理是指导果树施肥的理论基础 ,果树营养诊断是果树矿质营养原理应用到施肥措…     

南丰蜜桔营养诊断与施肥

柑桔科学施肥是获得优质、稳产、低成本的极其重要的措施,而通过营养诊断能确切估计桔树的营养状况,使柑桔施肥合理化、指标化。到目前,营养诊断已成为现代桔园管理中的一项常规措施。1987年￣2005年,我们对南丰蜜桔进行了叶片营养诊断、果实营养诊断、土壤分析、缺素营养液砂培试验以及施肥对比试验等,对南丰蜜桔营养诊断与施肥作了较为系统的研究,为南丰蜜桔科学施肥提供了依据。     

木瓜叶片矿质元素含量分析

果树叶片营养诊断能指导科学、合理地施肥,这在许多果树上已有研究报道[1,2],但在木瓜栽培上尚未见报道.我们对木瓜叶片中氮、磷、钾、钙、镁、铁、锌、铜、锰、硼10种元素的动态变化进行了研究,旨在为木瓜的矿质营养诊断提供一个合理可靠的采样依据,为木瓜的矿质营养特点研究及生产施肥提供科学依据.     

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.