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1.
2010年我国大蒜价格与出口情况及2011年形势展望   总被引:1,自引:1,他引:0  
回顾了2010年我国大蒜的销售与出口情况,分析了2010年影响大蒜价格走高的因素及2011年大蒜的行情走势,阐述了应对大蒜产业发展挑战的措施与途径.  相似文献   

2.
Suspended sediment in the Rhine-Meuse estuary contained as little as one third of the trace metal content of the river-borne suspended matter. It is shown that the strong seawardly decreasing gradient in the trace metal content of the suspended particulate matter is not due to desorption processes, but can be explained simply by the mixing of river-borne and marine-derived suspended sediments.  相似文献   

3.
进入21世纪,农业科技革命的先导是种子革命,农产品市场竞争的核心是良种竞争。目前,世界发达国家的种子产业已形成集科研、生产、加工、销售、技术服务为一体,相当完善、颇具活力的可持续发展的体系。据联合国粮农组织(FAO)统计分析,近十年,良种在全球粮食单产提高中的作用率占25%以上。有关专家预。言“种子将成为今后国际农业竞争乃至国际经济竞争的新焦点。”目前,我国主要农作物良种覆盖率达到95%以上,种子在农业增产中的贡献份额占30%。玉米种业作为我国种子产业的前导,其竞争将日趋激烈。  相似文献   

4.
种子病理学的回顾与展望   总被引:2,自引:1,他引:2  
本文主要介绍了种子病理学的起源、发展状况压存在问题,对我国种子病理学的研究和教学提出了自己的看法。  相似文献   

5.
Acidity and sweetness in apple and pear   总被引:2,自引:0,他引:2  
Summary Sweetness and acidity in apple and pear inherit independently and can be organoleptically evaluated separately, but less accurately in pear than in apple. For breeding purposes an analysis of fruits for acidity and sweetness with pH indicator paper and a hand refractometer is to be prefered to the organoleptic method.In apple, the acidity-decreasing with time-of the unripe fruit was already strongly indicative of that of the eating-ripe fruit; sugar-increasing with time-not before the fruit was picking ripe. Sugar content in apple and pear, and the pH in pear, appeared to be normally distributed; the pH in apple showed a segregation into an acid and a low-acid group, which occurred in both the unripe and ripe stage. The segregation ratio between these groups was found to be highly variable. On the whole, the mean acidity and sugar content of apple and pear progenies is significantly determined by that of the parents. Most of the observations made did not support the theory that low acidity in apple is determined by one recessive gene. The relationship between the pH of leaf juice and fruit juice in apple may offer a possibility for pre-selection.  相似文献   

6.
牦牛与普通牛的种间杂种犏牛雄性不育机理一直是畜牧科学研究的热点之一,对牦牛、犏牛睾丸组织特异表达基因的比对分析,可为犏牛雄性不育分子调控机制提供基因参考。通过对牦牛及杂种犏牛TB-RBP基因进行克隆,并利用实时荧光定量PCR技术对候选基因进行组织表达差异分析。结果表明,克隆获得牦牛TB-RBP基因CDS全序列873 bp,犏牛TB-RBP基因部分CDS区序列587 bp;系统进化树显示不同物种TB-RBP基因编码区序列高度保守,遗传相似性较高;蛋白功能预测TB-RBP蛋白属于Translin结合蛋白家族,对精子发生等生物过程具有重要调控作用。TB-RBP基因在犏牛和牦牛的睾丸组织中均有表达,TB-RBP基因的表达水平在牦牛与犏牛组间差异显著(0.01P0.05),牦牛显著高于犏牛。TB-RBP基因是精子正常发育的关键基因,而在犏牛睾丸组织中表达量较低,表明犏牛雄性不育与精子发生异常有关,为今后开展TB-RBP基因与犏牛雄性不育的相关分析以及基因定位、表达调控和牦牛分子育种奠定了理论基础。  相似文献   

7.
J. Gopal 《Euphytica》2001,118(2):145-151
Relative behaviour of genetic parameters and character associations for in vitro and in vivo systems was studied by evaluating 22 potato genotypes for seven morpho-agronomic characters under six in vitro and four in vivo conditions. There was considerable similarity between in vitro and in vivo systems with regard to pattern of coefficient of variation (both phenotypic and genotypic), heritability (broad sense), genetic advance (as% of mean) and correlation coefficients (both phenotypic and genotypic) between characters. The magnitude of various genetic parameters was higher under in vitro than in vivo conditions, particularly for tuber yield and its components. Treatment-to-treatment variation in genetic parameters and character associations was higher under in vivo than in vitro conditions. In vitro selection for agronomic characters in potato may be possible. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

8.
山西运城小麦和玉米苗期地下害虫调查与防控技术研究   总被引:4,自引:3,他引:1  
为了解山西运城地下害虫对主要粮食作物小麦和玉米的危害并有效控制,调查了2011年山西南部运城市小麦和玉米的地下害虫发生情况,同时研究植物源农药苦参碱及常用的化学制剂吡虫啉和氟虫腈3种药剂拌种对小麦和玉米种子的出苗率、被害株率、防虫效果以及保苗效果的影响进行统计分析,并对拌种后幼苗的株高、根长及相关的抗氧化酶SOD、POD活性及膜脂过氧化产物MDA进行测定。结果表明,小麦和玉米的苗期地下害虫主要有金针虫、地老虎和蛴螬3种,为害程度因地块变化较为明显;苦参碱对小麦和玉米的种子萌发有一定促进作用,但效果不显著,而对地下害虫的防效和保苗效果相对低于吡虫啉和氟虫腈;幼苗的抗氧化酶SOD和POD活性相对提高,抗性增强,且植物源农药对环境友好,可以在农业中推广。  相似文献   

9.
杭州市典型茶园土壤与茶叶中重金属的积累与来源分析   总被引:7,自引:3,他引:4  
为了解杭州市茶园土壤与茶叶中重金属的污染状况及其重金属的可能污染来源,选择杭州市典型茶园20个,按区位与施肥的不同分为城郊-化肥、城郊-有机肥、山区-化肥和山区有机肥等4种类型,采集了0~15、45~60 cm分层土样及茶树新叶和老叶样品,分析土样和茶叶样品中Pb、Zn、Cu、Cd、Hg、Cr和Co等重金属含量。结果表明,研究土壤Pb、Zn、Cu、Cd、Hg、Cr和Co污染程度较轻,其含量均低于土壤环境质量二级标准。除老叶样中Pb有25%样品超标外,新叶及老叶的其他重金属元素都在限值以下。城郊区茶园土壤的Pb、Cd和Hg含量普遍高于山区茶园。施用化肥的茶园土壤Cd略高于施用有机肥的茶园,施有机肥的茶园土壤Hg略高于施用化肥的茶园。施用有机肥的茶园土壤Zn和Cu明显高于施化肥的茶园。施用有机肥可轻微提高茶园土壤中Cr的积累;土壤中Co的积累受人为影响较小。研究认为,研究区茶园土壤中重金属Pb、Cd和Hg的积累主要与大气沉降有关,而Zn和Cu的积累主要与有机肥料的施用有关。  相似文献   

10.
回顾2014年我国大蒜的产贮销状况,分析大蒜价格的影响因素和2015年大蒜产业面临的机遇与挑战,并提出相应的经营对策,旨在为我国大蒜产业的健康持续发展提供有益的参考。  相似文献   

11.
Summary Germination of pollen grains and growth of pollen tubes were studied to determine the cause of barreness in crosses among annual Cicer species. In vivo and in vitro time-course studies and fluorescent microscopy revealed no pollination incompatibility among the selfs, crosses and reciprocals of C. arietinum L., C. reticulatum Lad. and C. cuneatum Rich. In general, Cicer pollen grains germinated and grew on styles of Cicer species. Pollen tube growth was characterized by irregularly spaced and intermittent callose deposits. Failure of seed formation in interspecific pollinations may be attributed to the slowness of pollen tube growth or collapse of fertilized ovules. In addition to these causes, shortness of stamens and sparsity of pollen grains were responsible for flower drop in natural selfs. Although the number of pollen tubes entering the micropyle in interspecific pollinations was low, it may be possible to grow the fertilized ovules on an artificial medium to obtain F1 plants.  相似文献   

12.
Low-temperature adapted Andean potato clones and low-temperature sensitive European clones cultivated at 20/10°C were compared during stress occuring as the result of low-temperature treatments. The stress response of leaf tissue was assessed by measuring the decrease in chlorophyll fluorescence (Fv/Fm) in detached leaves during a period of six days. After temperature stress combined with light Fv/Fm decreased only slightly in the Andean clones, but was markedly lower than the initial values in the European clones, However, after a 2°C treatment in darkness no difference between clones of different origins was detected. In general, chlorophyll and carotenoid contents of the Andean clones were higher than those of the European clones. They were markedly lower in all clones in treatments where low temperature was combined with light, than at 20/10°C and at 2°C in the dark. The contents of carotenoids and total chlorophylls decreased more in the European than in the Andean clones when leaves were transferred to a higher light intensity and then the lowest temperature used was combined with light. Thus carotenoids and chlorophylls in the Europeans clones were more sensitive to photo-oxidation at low temperatures than in the Andean clones. The changes in chlorophyll fluorescence in illuminated, detached leaves induced by a decrease in temperature were found to correlate with the low temperature performance of the genotypes. The correlation between low temperature performance and photosynthetic activity was highly significant and could be used by plant breeders to identify plants that perform well at low temperatures.  相似文献   

13.
水稻Cd吸收、转运机理研究进展   总被引:3,自引:2,他引:1  
综述水稻不同营养器官Cd吸收途径以及水稻根系Cd吸收、根系Cd外排、细胞壁Cd固定和液泡区室化作用、根系向地上部运输Cd等过程中参与Cd运输的各种转运蛋白功能的研究,并阐述影响水稻Cd吸收、转运的内在和外在因素,在此基础上提出问题和今后研究方向。  相似文献   

14.
This study investigated the effects of ethylene in storage and 1-methylcyclopropene (1-MCP) pretreatment on post-storage leaf senescence as measured by changes in photosynthesis and chloroplast degradation of two Aglaonema cultivars. Potted plants of ‘Chalit's Fantasy’ and ‘White Tip’ with or without 1-MCP treatment (600 nL L−1 1-MCP for 6 h) were exposed to 3.0 μL L−1 ethylene, while being stored for 5 d at 16 °C in the dark, and then placed under an indoor environment for further observation. Plants that did not receive 1-MCP and ethylene served as controls. Ethylene did not affect the stomatal conductance in either cultivar. Ethylene reduced the net CO2 assimilation rate and Fv/Fm (potential photochemical efficiency of photosystem II) in ‘White Tip’, but not in ‘Chalit's Fantasy’. Chloroplast number in a palisade or spongy mesophyll cell did not differ among treatments in ‘Chalit's Fantasy’. However, ethylene-treated ‘White Tip’ had fewer chloroplasts in the mesophyll cells, had more and larger plastoglobules in the chloroplasts, and had looser granal stacking with enlarged thylakoid lumens. ‘Chalit's Fantasy’ plants that were treated with 1-MCP before exposure to ethylene had higher net CO2 assimilation rates and stomatal conductance than the control or plants that were exposed to ethylene without 1-MCP pretreatment. 1-MCP pretreatment mitigated the injurious effect of ethylene on ‘White Tip’ by increasing net CO2 assimilation rate and Fv/Fm, and maintaining the quantity and structural integrity of chloroplasts.  相似文献   

15.
水稻超高产栽培的途径与技术   总被引:12,自引:0,他引:12  
水稻是中国最重要的粮食作物,实现水稻超高产对保证中国粮食的安全具有十分重要的意义。本文阐述了水稻超高产研究的由来、超高产概念及超高产研究的必要性,讨论了水稻超高产的几个栽培学问题,介绍了水稻超高产栽培的途径与技术,提出了当前和今后一段时间内水稻超高产栽培理论与技术研究的重点。  相似文献   

16.
回顾了2009年我国大蒜出口的国家、数量与价格,分析了2010年大蒜出口的形势、面临的问题及应采取的应对措施。  相似文献   

17.
Academy is a special education organization and academic research institute in ancient China, founded in the Tang Dynasty, and prospered in the Ming and Qing Dynasty. Academy garden as a type of classical Chinese garden shows ethnic characteristics in the regions inhabited by ethnic groups.  相似文献   

18.
山东夏季及夏季各月降水的时空分布特征   总被引:2,自引:2,他引:0  
旱涝是山东的主要气象灾害之一,为了研究山东的旱涝特征特别是夏季的降水规律,笔者统计了山东省26个气象站1961—2010年共50年的夏季降水资料,以降水量距平百分率为主要指标衡量夏季降水的年际变化,并用谱分析的方法对其进行分析,得到了山东夏季及夏季各月降水的总体趋势、周期特征和空间分布特征。在此基础上,对夏季旱涝年进行了划分,并用标准差的空间分布进一步分析了夏季降水的年际变化。结果表明:山东夏季及夏季各月降水都具有2.1~3.3年左右的短周期和10年左右的长周期;从降水趋势来看,7月和夏季都呈减少的趋势,7月减少的趋势最明显,而6月和8月则呈略微增加的趋势;山东夏季和夏季各月降水的空间分布极为不均,具有明显的地域性特征;夏季旱年和涝年分别为7年和5年。通过本研究发现,山东夏季和夏季各月降水的时间和空间分布都极为不均,因此认识其特征是非常有必要和有意义的。  相似文献   

19.
中国退耕还林还草现状及问题分析   总被引:7,自引:0,他引:7  
通过研究中国退耕还林还草的现状及问题,指出由于退耕区域布局缺少严密的科学论证,监督检查没有科学的评价体系,致使政策效果大打折扣;退耕补偿政策的不合理、不公平性以及退耕地未来收益的不确定性,又使退耕还林还草成果巩固面临潜在威胁。据此提出了合理界定退耕还林还草的政策操作区域,建立科学的监测评价体系,实行分区调控政策,适当细化退耕补偿标准,建立长期的退耕补偿机制等政策建议。  相似文献   

20.
中国栽培和野生大豆豆腐与豆乳得率的遗传变异   总被引:1,自引:0,他引:1  
王春娥  赵团结  盖钧镒 《作物学报》2007,33(12):1928-1934
我国不同生态区大豆种质豆腐与豆乳得率的遗传变异是专用型品种选育的基础。以来自各生态区的564份地方品种、101份育成品种、193份野生大豆加上88份国外品种,合计946份大豆种质为材料,采用小样品定量分析技术,测定干豆腐与干豆乳得率,研究其遗传变异。结果表明,全国野生大豆和栽培大豆的干豆腐与干豆乳得率均存在很大变异,干豆腐得率变幅分别为25.32~69.59、25.52~85.89 g 100 g-1,干豆乳得率变幅分别为40.75~82.86、39.05~91.86 g 100 g-1,栽培大豆两者的得率在野生豆基础上均有较大幅度改进;各生态区均存在与全国相同的变异情况,区内变异大于区间变异,但南方一些生态区栽培种豆腐(乳)得率变异程度相对较大,高得率材料相对较多,因本底(野生种)得率与地理纬度无关,推测与各地区栽培大豆利用方向的不同有关而形成了栽培种微弱的地理相关性;栽培材料中2.75%干豆腐得率超过75 g 100 g-1,5.50%干豆乳得率超过85 g 100 g-1,从中优选出来自Ⅱ、Ⅲ、Ⅳ、Ⅵ生态区的双高种质14份,可供各地区豆腐(乳)育种利用。  相似文献   

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