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导读：番茄褪绿病毒病是近年在我国部分省份暴发的一种新病害，相继在河北、天津、山东等省暴发和流行，严重影响了番茄生产。2013年在山东省大面积暴发，部分温室发病株率20%～100%，造成番茄减产10%～40%，本文介绍了番茄褪绿病毒病不同时期的发病症状，分析了发病原因，提出了综合防治措施，以供参考。 相似文献
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根据我们在湖北省仙桃、孝感、武汉、潜江、石首、荆州等地的调查，今年江汉平原地区甜瓜病毒病大暴发，表现型以花叶为主，缩叶次之，黄化和厥叶等也有少许发生，造成约５０％的面积减产达 ３０％～５０％，有２６０ｈｍ２以上的面积绝收，是本区有记载以来甜瓜病毒病发生最重、区域最广、减产幅度最大的一年。故此我们对甜瓜病毒病暴发的主要原因进行了认真调查，并提出了防治的对策，以供瓜农在今后种植甜瓜防治病毒病时参考。１病毒病暴发的主要原因１．１相对长期高温、干旱、强光照是病毒病暴发的主要因素 从３月起，江汉平原气温相对… 相似文献
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古田县是福建省油[木奈]的原产地，现有种植面积3800hm^2，产量达5万吨，产值1亿多元。油[木奈]是古田县最大宗的名优特水果，自1991年起大规模开发种植。以往未发现红蜘蛛大面积为害，然而从2003年4月开始，湖滨、松吉、风埔、大桥、吉巷等油[木奈]主要种植乡镇普遍发生为害，6月份暴发成灾。据不完全统计，全县60％的[木奈]园受害，发展快、区域广、持续时间长。2003年也是古田县少有的干旱年份，这种特殊的气候年型与[木奈]园红蜘蛛暴发有着一定的关系。本文拟通过对红蜘蛛暴发的气象条件进行分析，找出暴发的气候成因，为今后类似年份提早防治提供参考。 相似文献
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对防治柑桔疮痂病的几点看法近年来，柑桔疮痂病的蔓延有逐年加重的趋势，尤其是１９９４年，该病在一些温州蜜柑产区暴发流行，导致大量落花落果，其范围之广，疫情之重，为近几年之最。在一些地区，连抗病性较强的柑也严重发病。１１９９４年疮痂病暴发流行的主要原因１... 相似文献
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浙江桔区黑刺粉虱暴发原因与防治对策探讨虞轶俊，方培林（浙江省植物保护总站杭州３１０００４）（浙江省衢县柑桔病虫测报站３２４０１４）柑桔墨刺粉虱是桔园的常见害虫，以往发生为害不十分严重。９０年代以来，在浙江各大桔区相继暴发成灾，已由次要害虫上升为主要害... 相似文献
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福建古田县现有油Nai 3800hm^2，产量达5万t，产值1亿多元。自1991年大规模开发以来，未发现红蜘蛛危害，但2003年4月开始，湖滨、松吉、凤埔、大桥、吉巷等油Nai主产乡镇普遍发生，全县60％的油Nai园受害，6月份暴发成灾。2003年是古田历年少有的干旱年份，笔者分析了红蜘蛛暴发与这种特殊气候的相关性。 相似文献
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Fruit cracking after rain limits the production of a number of crops, including some Ribes species. To gain a better understanding of the factors involved in cracking, fruit growth, deposition of the cuticular membrane (CM), water uptake and fruit cracking were studied in black currant (Ribes nigrum L. cv. Zema), gooseberry (Ribes uva-crispa L. cv. Rote Triumph), and jostaberry (Ribes nidigrolaria B. cv. Jostine). Fruit surface area and fresh mass increased continuously throughout development, whereas deposition of the CM was biphasic. CM mass per fruit increased rapidly up to 42, 41, and 49 days after full bloom (DAFB) in black currant, gooseberry, and jostaberry, respectively. Thereafter, CM mass per fruit remained constant in gooseberry and jostaberry or increased at a lower rate in black currant. The cessation of or reduced rate of CM deposition resulted in a decrease in CM mass per unit area in all berries. Elastic strain of the CM at maturity averaged 23.8% and 19.5% in gooseberry and jostaberry, respectively, and only 8.2% in black currant. Microcracks in the CM were observed first in gooseberry and jostaberry 64 DAFB, whereas there were no microcracks in black currant. Water uptake into mature detached berries was linear over 2 h of incubation. Rates of uptake were highest in gooseberry followed by black currant and jostaberry. Relative uptake was similar via the cut end of the pedicel (32.1%), the apex of the fruit (34.7%) and the fruit surface (33.2%). Rates of water uptake through the fruit surface were positively related to surface area. Average fruit water potential for black currant, gooseberry, and jostaberry was −2.14 ± 0.17, −1.24 ± 0.03, and −1.89 ± 0.20 MPa, while the permeability for osmotic water uptake was 7.7 ± 0.4 × 10−8, 5.2 ± 0.1 × 10−8, and 3.3 ± 0.3 × 10−8 m s−1. Incubating whole fruit in deionized water for 72 h resulted in more cracked jostaberries (94%) than black currants (74%) or gooseberries (50%). A comparison of our findings in Ribes berries with published data for the sweet cherry drupe revealed that the berries fitted the relationships established in sweet cherry among fruit growth, cuticle deposition, strain of the cuticle, microcracking, permeability for osmotic water uptake, frequency of stomata and cracking. The Ribes berries were less susceptible to cracking than sweet cherry. 相似文献
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Robert Rosen 《Landscape Ecology》1989,3(3-4):207-216
An exceptionally rich and colorful literature, drawn in almost equal parts from pure mathematics, from the sciences, and from the technologies, has grown up over the years, which bear in different ways on the topics under discussion. It is the intent of the present paper to survey this far-flung literature, point out some of the commonalities and interrelationships which underlie it, and briefly indicate how it has been and can be applied. To my knowledge, this kind of review has not been attempted before. 相似文献
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Wetlands, carbon, and climate change 总被引：3，自引：0，他引：3
William J. Mitsch Blanca Bernal Amanda M. Nahlik Ülo Mander Li Zhang Christopher J. Anderson Sven E. Jørgensen Hans Brix 《Landscape Ecology》2013,28(4):583-597
Wetland ecosystems provide an optimum natural environment for the sequestration and long-term storage of carbon dioxide (CO2) from the atmosphere, yet are natural sources of greenhouse gases emissions, especially methane. We illustrate that most wetlands, when carbon sequestration is compared to methane emissions, do not have 25 times more CO2 sequestration than methane emissions; therefore, to many landscape managers and non specialists, most wetlands would be considered by some to be sources of climate warming or net radiative forcing. We show by dynamic modeling of carbon flux results from seven detailed studies by us of temperate and tropical wetlands and from 14 other wetland studies by others that methane emissions become unimportant within 300 years compared to carbon sequestration in wetlands. Within that time frame or less, most wetlands become both net carbon and radiative sinks. Furthermore, we estimate that the world’s wetlands, despite being only about 5–8 % of the terrestrial landscape, may currently be net carbon sinks of about 830 Tg/year of carbon with an average of 118 g-C m?2 year?1 of net carbon retention. Most of that carbon retention occurs in tropical/subtropical wetlands. We demonstrate that almost all wetlands are net radiative sinks when balancing carbon sequestration and methane emissions and conclude that wetlands can be created and restored to provide C sequestration and other ecosystem services without great concern of creating net radiative sources on the climate due to methane emissions. 相似文献
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J. Van Bragt 《Scientia Horticulturae》1982,17(2):199
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Harold S. J. Zald Thomas A. Spies Manuela Huso Demetrios Gatziolis 《Landscape Ecology》2012,27(8):1197-1212
Tree invasions have been documented throughout Northern Hemisphere high elevation meadows, as well as globally in many grass and forb-dominated ecosystems. Tree invasions are often associated with large-scale changes in climate or disturbance regimes, but are fundamentally driven by regeneration processes influenced by interactions between climatic, topographic, and biotic factors at multiple spatial scales. The purpose of this research was to quantify spatiotemporal patterns of meadow invasion; and how climate, larger landforms, topography, and overstory trees have interactively influenced tree invasion. We combined airborne Light Detection and Ranging (LiDAR) characterizations of landforms, topography, and overstory vegetation with historical climate, field measurements of snow depth, tree abundance, and tree ages to reconstruct spatial and temporal patterns of tree invasion over five decades in a subalpine meadow complex in the Oregon Cascade Range, USA. Proportion of meadow occupied by trees increased from 8?% in 1950 to 35?% in 2007. Larger landforms, topography, and tree canopies interactively mediated regional climatic controls of tree invasion by modifying depth and persistence of snow pack, while tree canopies also influenced seed source availability. Landscape context played an important role mediating snow depth and tree invasion; on glacial landforms tree invasion was negatively associated with spring snowfall, but on debris flows tree invasion was not associated with snow fall. The importance of snow, uncertain climate change impacts on snow, and mediation of snow by interacting and context dependent factors in complex mountain terrain poses substantial hurdles for understanding how these ecotones may respond to future climate conditions. 相似文献
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Ralph E. J. Boerner 《Landscape Ecology》2012,27(8):1235-1236
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AIM: To detect the treatment of K562 leukemia cells with bortezomib altering the expression of genes fas, bcl-2, bcl2l12, bim, bax, caspase-9 and caspase-3.METHODS: MTT assay was used to detect the inhibition of proliferation. Apoptosis was detected by Annexin-V staining and mitochondrial transmembrane potential (Δψm). RT-PCR was used to analyze the mRNA expressions of fas, bcl-2, bcl2l12, bim, bax, caspase-3 and caspase-9.RESULTS: Bortezomib caused a time- and dose-dependent inhibition of cell proliferation and IC50 of 24 h and 48 h were 161.41 nmol/L and 96.33 nmol/L, respectively. At the concentration of 104 nmol/L, bortezomib induced apoptosis in a time-dependent manner, including increasing annexin-V positivity and decreasing the Δψm. RT-PCR showed that bortezomib up-regulated the mRNA expression of fas, bcl2l12, caspase-9 and caspase-3, but mRNA expressions of bcl-2, bim and bax did not changed obviously.CONCLUSION: Bortezomib inhibits the proliferation of K562 and induces apoptosis, in which fas, bcl2l12, caspase-9 or caspase-3 gene is one of the main genes taking part in. 相似文献
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K.C. Sink 《Scientia Horticulturae》1978,8(1):91-92
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氮磷钾硼肥配施对青花菜养分吸收分配及产量和品质的影响 总被引：4，自引：0，他引：4
研究了不施肥处理,氮磷钾配施和增施硼肥对青花菜养分吸收分配及产量和品质的影响。结果表明,现蕾期至花球膨大期,青花菜对氮、磷、钾的吸收量最大,整个生长期对钾的吸收最多,氮次之,磷最少。氮磷钾主要分配在叶片中,现蕾后逐渐向花球转移,从现蕾到采收时,叶片中氮、磷、钾分配率分别降低了19.6%、10%和9.0%,花球中氮磷钾分配率分别提高了23.1%、15.9%和11.1%。不施氮、磷、钾肥显著降低了花球产量、维生素C含量和成品率,增施硼肥处理的花球成品率较氮磷钾肥处理提高了4.8%,不施氮肥和钾硫肥(K2SO4)显著降低了花球中的硫代葡萄糖苷含量。相关性分析表明,青花菜产量与植株内氮、钾积累量显著正相关,成品率与植株内磷营养显著正相关。 相似文献
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August De Hertogh 《Scientia Horticulturae》1974,2(4):313-355
Systematic investigations on the forcing of tulips, hyacinths, daffodils, Easter lilies and Dutch iris have produced a fairly complete set of scientific principles. In this review, these principles have been classified into a 3-phase concept of forcing. These are: production, programming, and greenhouse. The production phase is defined as all processes which occur during bulb production and it terminates with the harvesting of the bulbs. The programming phase comprises all handling of the bulbs from harvesting until they are placed under greenhouse conditions. The greenhouse phase is the accelerated development of the bulbs until anthesis or marketing of the plants. These phases have been discussed relative to floral and root development and the basic environmental requirements of the bulb species. 相似文献