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排序方式: 共有150条查询结果,搜索用时 15 毫秒
1.
银海枣褐斑病的病原鉴定与化学防治 总被引:3,自引:0,他引:3
对广东省新近发现的一种银海枣叶部病害进行了病原鉴定,该病病原为链格孢Alternaria alternata(Fr.)Keissl.以生长速率法和孢子萌发法对该病害进行化学防治试验的结果表明:在参试的11种杀菌剂中,叶斑净和世高的防治效果最好,对病斑扩展的抑制率分别达52.82%和33.62%. 相似文献
2.
对加拿利海枣叶斑病的病原进行分离鉴定和农药抑菌试验.结果表明:加拿利海枣叶斑病病原为半知菌亚门黑盘孢目的掌状拟盘多毛孢(Pestalotiosis palmarum);6种杀菌剂的抑菌效果为10%苯醚甲环唑水分散粒剂>450 g/L咪鲜铵水乳剂>80%代森锰锌可湿性粉剂>40%百菌清悬浮剂>70%甲基硫菌灵可湿性粉剂>80%乙蒜素乳油,且6种杀菌剂在生产上对加拿利海枣叶斑病菌都有较好的抑制作用. 相似文献
3.
4.
[目的]通过ARIMA模型和传递函数模型的预测精度比较找到广东省台风预测中心气压的最好方法。[方法]利用时序图和相关系数对台风的风力、最大风速和中心气压进行相关性分析,得到它们具有很强的相关性。[结果]使用台风风力和最大风速作为输入变量的传递函数模型对样本内数据具有更好的预测效果。[结论]将现代时间序列分析的理论与方法应用于气象预报具有重要的实际意义。 相似文献
5.
为了检验FVCOM海洋模式模拟台风浪的效果,分别以CCMP风场和WRF模式模拟风场构建驱动台风浪的海面风场模型,基于FVCOM海洋模式,以2010年的"凡比亚"台风为例进行台风浪数值模拟,并用站点浮标资料进行了模拟结果检验。结果表明,FVCOM海洋模式模拟的水位、有效波高结果与实际观测结果的整体误差较小,模拟效果较好;受到风场与地形的影响,最大增水与减水的区域分别位于台风中心的左侧沿岸和右侧沿岸;风场与表面流场的模拟结果也符合台风过程中的风生流分布特征,即风场与表面流场方向、大小存在一致性。此外,对比分析2种不同海面风场模型下的台风浪模拟结果发现,二者均能较好地模拟此次台风过程,但存在一定的差异,增加WRF模式模拟风场作为强迫驱动风场模拟的有效波高更接近观测值。 相似文献
6.
Occurrence of an antifungal principle in the root extract of a Bayoud — resistant date palm cultivar
G. M. Assef K. Assari E. J. Vincent 《European journal of plant pathology / European Foundation for Plant Pathology》1986,92(1):43-47
An hexane extract from roots of Black Boo Stammi, a cultivar of date palm, resistant toFusarium oxysporum f. sp.albedinis, contained substances which inhibited the spore germination and the growth of the germ tubes of the three isolates of the pathogen that were tested. Extract from roots of Jihel, a susceptible cultivar, lacked these substances.Samenvatting In een hexaanextract van wortels van de dadelpalm, cv. Black Boo Stammi die resistent is tegen de Bayoudziekte, bevonden zich stoffen die de sporekieming en de groei van kiembuizen onderdrukken. Dit gold voor alle drie isolaten vanFusarium oxysporum f. sp.albedinis, die werden getoetst. In extracten van de vatbare cultivar Jihel werden de kieming en de groei niet geremd. 相似文献
7.
Water spray as a potential thinning agent for date palm flowers (Phoenix dactylifera L.) c.v. ‘Lulu’
Flower or fruit thinning is a critical cultural practice in the date palm production chain that affects fruit development, quality and yield and regulates tree yearly bearing. Development of a save and economic thinning agent for date palm is critically required especially under harsh conditions. During 2004 and 2005 seasons, water spray for 3 min was applied at different times following mechanical pollination on ‘Lulu’ date palm cultivar growing under Al-Ain oasis conditions. The results showed that water spray following pollination generally decreased fruit set percentage to different extent depending of the time of application. In this respect, the most effective treatment was water spray after 4 h following pollination. This treatment significantly decreased fruit set percentage (48%) compared to the control (79%), as the mean of both seasons. However, the other treatments including water spray 1 h before pollination also decreased fruit set percentage but to a lesser extent. Fruit quality characteristics especially fruit and flesh weight, length and diameter were significantly increased by water spray treatments during the 2004 season, in contrast to the 2005 season. Thinning with water significantly decreased both bunch weight and total yield per tree at the Tamr stage especially when applied after 4 h following pollination. To the best of our knowledge, this is a pioneer study investigating the role of water as a potential thinning agent for date palm flowers. The use of water spray as a save and economic thinner needs, however, more research work to justify the time following pollination and duration of application which may vary upon cultivar, method of pollination and district. 相似文献
8.
一种新的棕榈科枣椰属的种的检索方法兼评《海枣引种栽培初探》 总被引:1,自引:0,他引:1
指出《海枣引种栽培初探》一文误将枣椰属的3个种当作1个种的3个品系并误用了一些形态学术语,给出了枣椰属的检索表. 相似文献
9.
Yasuhiro Kubota 《Journal of Forest Research》2006,11(3):191-201
This article reports the regeneration dynamics of a temperate Abies–Tsuga forest in Kirishima Yaku National Park, southwestern Japan, and examines the influence of species coexistence mediated by
gap disturbances on biomass production. All trees taller than 2 m in a 1-ha plot were monitored over four growing seasons.
Three growth-form groups occupied different vertical layers. Evergreen conifers and deciduous broad-leaved trees tended to
be spatially segregated from evergreen broad-leaved trees, which formed thickets in the understorey. The regeneration of understorey
evergreen broad-leaved trees was affected by canopy gaps. The recruitment of conifers and deciduous broad-leaved species was
not observed during the four growing seasons. This suggests that regeneration is sporadic and the present environmental conditions
are not favorable for these canopy species. The mortality and unsuccessful recruitment of conifers and deciduous trees appeared
to cause fluctuations in the productivity of the stand. However, an abundance of canopy gaps accelerates the regrowth of shorter
species, and the fluctuation of productivity resulting from the population dynamics of canopy species would be partly mitigated
by the regeneration of evergreen understorey species. The horizontal and vertical heterogeneity of the temperate mixed forest
was a result of the patch structures of the three growth-form groups. The different regeneration patterns among the three
groups, which were driven by interactions of species-specific regeneration niches and disturbance regimes, might be an important
factor in maintaining the aboveground productivity in a transitional mixed forest between warm-temperate and cool-temperate
zones. 相似文献
10.