世界西瓜甜瓜生产与贸易经济分析

本文利用1978—2013年的FAO数据,从西瓜甜瓜种植面积、产量、单产、生产和贸易区域分布等多方面分析了36年来世界西瓜甜瓜产业发展变化情况。分析结果显示,世界西瓜甜瓜种植面积增长缓慢,产量持续增加。亚洲种植面积和产量居首但出口率最低,欧洲和美洲的西瓜甜瓜贸易最为活跃。今后,发展中国家的需求增长将成为世界西瓜甜瓜产业发展的主要驱动因素。     

提高西瓜杂交制种产量和纯度的技术措施

西瓜作为我国主要经济作物,是人们喜爱的水果之一。在社会经济发展影响下,我国农业结构做出适当调整,西瓜种植面积逐年增加,对种子的需求量也日益加大。为了在有限的种植面积增加产量,杂交种子成为提高产量的重要途径。然而,杂交种纯度不高造成的减产令农民十分困惑。本文将对提高西瓜杂交制种产量及纯度技术方法进行分析和研究。     

不同减水增糖措施对大棚西瓜品质及产量的影响

江苏省东台地区西甜瓜种植面积大,近年来大力推进瓜菜西进,在堤西地区大面积推广种植西瓜。但堤西地区多为高水位耕地,早春栽培西瓜,果实膨大期正遇梅雨季节,土壤黏重、湿度大,西瓜果实糖分含量低,降低了西瓜品质。为此作者开展了不同减水增糖措施对大棚西瓜生长、品质、产量和商品性影响的试验。试验结果表明,高畦栽培西瓜有助于促进瓜蔓生长、增加产量、提高西瓜含糖量、提高商品率,但由于试验期间未出现高水位和受渍处理不到位,减水增糖效果不明显;超甜精叶面肥也具有增加西瓜产量和提高商品率的作用,但效果也不明显。生产中如采用高畦栽培西瓜,应适当喷施化学药剂来抑制生育前期根系生长和生物学产量的积累,以取得减水增糖效果。     

西瓜蔬菜优质高效多元复合种植技术

如东县常年种植西瓜面积4000hm^2以上，主要分布于本县的东部沿海区域，种植模式为棉田套种西瓜，常年连作，在西瓜果实膨大期常遇梅雨，导致西瓜病害的大发生，致使西瓜减产，甚至失收。加之西瓜与棉花的共生期长，棉花治虫用药，与西瓜产品质量安全矛盾突出，难以兼顾，消费者心存困惑，影响了销售。这种模式，产量不高不稳，效益低下，逐年萎缩。为了稳定西瓜面积，     

三白西瓜品种资源圃建设及开发

<正>三白西瓜是我市地方名优特农产品之一,栽培历史悠久,自明朝至今,已有400余年种植历史。三白西瓜白皮、白瓤、白籽,多汁、清爽,体大、耐贮藏、产量高。但是由于栽培技术滞后,三白西瓜品种特性逐渐退化,品质下降、产量低,种植面积逐年缩     

大棚草莓—西瓜周年高效栽培模式

为充分利用大棚设施资源优势,提高单位面积产量和种植效益,增加农产品有效供给和满足市场消费新需求,张家港市农业技术推广部门近年来不断探索新的高产高效种植模式,在张家港市金鑫家庭农场种植基地示范推广了大棚设施草莓—西瓜周年高效栽培模式.该模式不仅可以有效提高大棚设施利用率、增加单位面积产量,提高种植效益,而且通过夏季高温闷棚,解决了设施大棚蔬菜种植的连作障碍、病虫害严重等问题,实现了周年生态高效栽培,促进设施蔬菜产业生态、高效、健康、可持续发展.本文主要介绍大棚草莓—西瓜周年高效栽培模式,栽培要点如下.     

提高西瓜杂交制种产量与质量的技术措施

近年来,我国西瓜年播种面积一直保持3330万亩左右,占世界首位。我国西瓜生产需要杂交种子数量很大,需要制种面积近百万亩。西瓜制种田主要集中西北,受自然因素影响大,加强其生产技术研究和应用推广对促进种子产业发展意义重大。1提高西瓜杂交制种产量技术措施1.1母本种植密度西瓜制种田适宜密度有关制种产量,其母本种植密度制约有效种瓜数。     

黑龙江三江平原西瓜双膜覆盖栽培技术

黑龙江省富锦市位于松花江南岸，地处三江平原腹地，全年种植西瓜面积达1600hm^2左右，西瓜除供应本市外，远销哈尔滨、沈阳、天津等地。为满足消费者和市场变化的需求，笔者引导当地瓜农推广种植西瓜双膜覆盖栽培技术，取得了较好的效果。西瓜产量达到2433—3000kg/667m^2，产值2433—3000元／667m^2，西瓜品质好，产量高，上市早，经济效益高。现将三江平原西瓜双膜覆盖栽培技术介绍如下：     

我国西瓜进出口贸易现状及发展趋势研究

通过对农业部信息中心我国西瓜进出口的月度数据进行整理和计算,分析了2010—2016年我国西瓜国际贸易的发展趋势、主要进出口地区的贸易情况,以及主要进出口市场的现状,以对此期间我国西瓜对外贸易的发展进行综合分析。分析结果表明,(1)我国西瓜进出口规模都呈波动增长趋势,具有明显的季节特征,出口规模的季节波动与国内产量变化相符,7—9月为旺季;与进口规模季节波动相反,西瓜进口1—4月为旺季,与国内生产形成互补,以满足国内市场需要。(2)我国西瓜出口总量的90%以上来源于广东、广西和内蒙古,云南出口价格较高;进口总量的70%以上来源于北京、云南和广西,天津和河北进口价格较高。(3)我国西瓜主要出口至中国香港、越南和中国澳门,其中香港占出口总量的69.54%,出口至俄罗斯的价格较高;进口主要源自越南和缅甸,价格偏低,其中超过70%进口自越南。(4)我国西瓜国内市场价格和进口价格呈下降趋势,出口价格逐年上涨。     

不同播期与种植方式对旱地西瓜产量及土壤水分利用的影响

以西瓜品种"金陇5号"为试材,在宁夏中部干旱带开展了旱地地膜西瓜不同播期、种植方式研究,分析了不同播期与种植方式对旱地西瓜产量及土壤水分利用的影响。结果表明:4月15日采用暗窝播种方式西瓜生长状况、产量、产值、纯收入及土壤水分利用效率方面均优于其它处理,较4月25日、5月10日播种的产量分别增产4.8%和28.0%,纯收入增加6 700.02元/hm2和19 604.31元/hm2,水分利用效率提高23.1%、54.4%,抗旱节水、增产增收的效果明显;说明当地旱地西瓜适宜的播种时期为4月中旬,种植方式采用先播种后覆膜的暗窝播种。     

Effect of moisture stress on the ethephon response in tomatoes

Potted plants (cultivar ‘Napoli’) were maintained at 3 levels of moisture (continuously moist, moderate moisture stress and severe moisture stress) and sprayed to run-off with 3 levels of ethephon (0, 250 and 500 p.p.m.) in factorial combination, in order to examine the effect of moisture status on the ethephon-accelerated ripening-response in tomatoes. The largest increases in ripening-rate occurred where plants were moderately stressed and sprayed with 250 p.p.m. ethephon, or where plants were kept continuously moist and sprayed with 500 p.p.m. ethephon. No substantial increase in ripening-rate occurred at higher levels of either ethephon or moisture stress. Leaf senescence was rapid in all treatments other than the moderately stressed and continuously moist controls. In some of the water-stressed treatments a partial recovery of plant water potential occurred as a result of reduced transpiration due to rapid and extensive leaf loss.     

Effects of root architecture on response to melon vine decline

Summary

Melon vine decline (MVD) is a complex disease for which only a few genotypes of Cucumis melo have been described as being tolerant. These genotypes were selected under different inoculum conditions, and little is known about the morphological or biochemical mechanisms of their tolerance to MVD. In order to study the tolerance mechanisms acting in different resistant sources, we conducted a comparative analysis of three tolerant (‘Doublon’, ‘Deltex’, and ‘Pat 81’) and two susceptible (‘Piel de Sapo’ and ‘Amarillo Canario’) melon cultivars. Their responses to non-infested soils, naturally infested soils, and soils artificially inoculated with the principal causal agents of MVD – Monosporascus cannonballus and Acremonium cucurbitacearum – were studied in pots in a greenhouse, and the results were compared with their field responses. We performed a combined study on lesions, root architecture, and root:vine balance. A combination of all of these traits can predict the level of MVD tolerance in infested fields better than the severity of root lesions alone. These features should be taken into account in breeding programmes for resistance to MVD.     

Effect of glucocorticoid-treated dendritic cells on asthmatic Th2 response

AIM: To investigate the effect of dexamethasone-treated dendritic cells (DCs) on Th2 cytokine production from autologous T cells in asthmatic patients and explore the mechanisms by studying the effect of dexamethasone on differentiation, maturation and function of DCs from patients with asthma. METHODS: Human peripheral blood monocyte-derived DCs generated from asthmatic patients and healthy subjects were cultured in the absence or presence of dexamethasone. The phenotypic characterization of DCs was analyzed by flow cytometry. The mature DCs were harvested, washed, and then cocultured in vitro with autologous T cells purified by a nylon cotton column. The DC-T coculture supernatants were collected after 72 h incubation and analyzed for levels of IL-5 and IFN-γ by ELISA. RESULTS: The concentrations of IL-5 in the culture supernatants of DC-T coculture were significantly up-regulated in patients with asthma compared with that in healthy controls ［(145.13±89.76) ng/L vs (50.28±22.37) ng/L, P<0.01］. The level of IFN-γ in the DC-T coculture supernatants tended to be decreased in asthmatic patients than that in healthy controls, although this difference did not achieve statistical significance ［(197.58±76.32) ng/L vs (220.46±65.34) ng/L, P>0.05)］. There were significantly decreased levels of IL-5 by autologous T cells primed by dexamethasone-treated mature DCs from asthmatic patients ［(45.39±19.61) ng/L vs (145.13±89.76) ng/L, P<0.01］, alterations not observed from healthy controls (P>0.05). IFN-γ production was decreased by autologous T cells primed by dexamethasone-treated mature DCs from both asthmatic patients and healthy controls ［asthma group: (40.21±22.89) ng/L vs (197.58±76.32) ng/L, P<0.01; healthy controls: (56.78±20.37) ng/L vs (220.46±65.34) ng/L, P<0.01］. Dexamethasone-treated DCs exhibited decreased expression of CD83 (P<0.01) and increased expression of CD14 (P<0.01) in both asthmatic patients and healthy controls. CONCLUSION: DCs of asthmatic patients induce a Th2-skewed cytokine production from autologous T cells. Dexamethasone-treated DCs inhibit the Th2 reactions, and this effect is probably mediated through the pathway that dexamethasone inhibits DCs maturation and skews the macrophage/DC balance towards the macrophage side and thus directs the development more towards the macrophage lineage.     

纽荷尔脐橙幼树对不同供磷水平的光合响应

为探索不同供磷水平对纽荷尔脐橙[Newhall navel orange(Citrus sinensis Osbeck.)]幼树光合特性的影响,给幼龄脐橙果园磷肥的合理施用量提供科学依据,以枳砧纽荷尔脐橙幼树为材料,采用土培的方法研究了不同供磷水平条件下纽荷尔脐橙幼树叶片的光合速率日变化规律;不同供磷水平与光合速率、蒸腾速率、水分利用率的关系;不同供磷水平对光合色素含量的影响。结果表明,纽荷尔脐橙Pn日变化基本规律并不因供磷水平的高低而改变。供磷水平25 mg·kg-1的条件下,叶片中Chl.a、Chl.b和Car.含量也最高,全天的Pn都维持在最高水平,这一供磷水平最有利于纽荷尔脐橙发挥光合效率。不同供磷水平与纽荷尔脐橙叶片Pn、Tr和WUE之间表现出极显著的非线性一元二次回归关系。供磷水平低于或高于25 mg·kg-1,纽荷尔脐橙幼树叶片的Pn、Tr和WUE和Chl.a、Chl.b及Car.含量都极显著地降低了;供磷水平大于45 mg·kg-1对Chl.a、Chl.b合成和Pn的抑制作用要比低于25 mg·kg-1供磷水平的强得多。     

Effect of tachykinin on cough response in an ovalbumin-sensitized guinea pig model

AIM: To investigate the role of tachykinin in airway in cough response in guinea pigs sensitized and challenged with ovalbumin. METHODS: 20 normal and 20 sensitized guinea pigs were challenged with the aerosol of ovalbumin. twenty-four hours later, cough response to inhaled capsaicin was measured after the normal and sensitized guinea pigs (10 of each) introperitoneally injected either with 0.1 mg/kg, 0.3 mg/kg and 1.0 mg/kg of NK1 antagonist SR140333 or NK2 antagonist SR48968, respectively. Specific airway resistance was recorded with noninvasive technique. RESULTS: Cough response increased in sensitized guinea pigs compared with control ［(19.5±5.7） times/3 min vs （9.3±1.2） times/3 min, P<0.05］. SR48968FR decreased the cough response by 30% in control guinea pigs (P<0.05), but SR140333 did not. Both prevented an increase in airway resistance after the inhalation of capsaicin. However, SR48968FR and SR140333 inhibited increased cough response ［(9.9±4.7） times/3 min, （8.0±1.6） times/3 min, P<0.05］ and airway resistance induced by the inhalation of capsaicin. CONCLUSION: Neurokinin (NK) antagonist inhibits increased cough response in guinea pigs sensitized and challenged with ovalbumin. Tachykinin may be an important mediator in cough associated with eosinophilic airway inflammation.     

The scale of landscape effect on seed dispersal depends on both response variables and landscape predictor

Landscape Ecology - Landscape structure can affect seed dispersal, but the spatial scale at which such effect is maximized (scale of effect, SoE) is unknown. We assessed patterns and predictors of...     

Effects of deep-frozen treatment on the immune response of bone-patellar tendon-bone xenograft rejection

AIM: To investigate the effects of deep-frozen treatment on the immune response of bone-patellar tendon-bone (BPB) xenograft rejection. METHODS: A muscle pocket model was used to study the immune response of rat to deep-frozen treated BPB xenograft from guinea pig, autograft and fresh xenograft served as controls. The expression of T-cell surface activation antigen CD25 in the peripheral blood and the morphological changes of the implants were used to measure the immune response. RESULTS: The expression of CD25 in CD4+, CD8+ cells greatly increased 3 d after fresh BPB xenograft, the obvious difference to that of autograft (P<0.05) was observed. It reached a peak level 14 d after fresh BPB xenograft and didnt decrease 35 d after transplantation. The expression of CD25 in CD4+, CD8+ cells was greatly inhibited in deep-frozen treated BPB xenograft. Its expression was delayed and just had a small increase 14 d after transplantation. The P values were all less than 0.05 compared to those of fresh xenograft at every time-point after transplantation. Histologic examination showed that there were a few lymphocytes surrounding the bone and tendon tissue in deep-frozen treated BPB xenograft, but the lymphocytes hadnt invaded into the tissues. No tissue necrosis, but a clear tendon structure and regular fibrogen arrangement were observed. There were large amount of fragmentary lymphocytes infiltrating into or surrounding the bone and fibrogen tissues after fresh xenograft, the bone was broken into pieces, the tendon structure was unclear and the fibrogen arrangement was irregular, quite a few of inflammatory cells such as acidophilic granulocytes and macropolycytes were found in some slices. CONCLUSION: Deep-frozen treatment markedly reduces BPB xenograft antigenicity and inhibits the immune rejection.     

Effect of landscape connectivity on plant communities: a review of response patterns

Landscape Ecology - Fragmentation in agricultural landscapes is considered as a major threat to biodiversity. Thus, ecological corridors are deployed at multiple scales to increase connectivity....     

Climatic response and impacts of drought on oaks at urban and forest sites

This study focuses on the climate and growth response of the sessile oak (Quercus petraea (Matt.) Liebl.) and the northern red oak (Quercus rubra L.) using dendrochronological methods. Tree-ring series of street trees in the city of Dresden, Germany and in a nature reserve close to the urban area were analysed, and the climate and growth response and moving correlation functions (CF) were computed. Moreover, the impact of 13 years of drought was examined by superposed epoch analysis (SEA). Our results show that differences emerge from peculiarities of the different site conditions, indicating that city oaks contain a higher level of noise in their ring width data due to human activities that degrade the strength of growth-climate associations. Importantly, climatic conditions during the previous summer and autumn and during the current spring season display significant correlations with annual growth. The stability of the climate–growth relationship was tested via moving correlation functions. A strong increase in the correlation with the temperature and precipitation in April was found for the trees of northern red oak in forests. Drought years induced significant reductions in radial growth for the northern red oak only. Nevertheless, the long-term impact of drought years must be considered as marginal because of the fast recovery of the radial growth after one to two years. In the future, the growth of the northern red oak may be restricted by an increased frequency of droughts and warmer and drier conditions in April.