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51.
萝卜离体再生的影响因素   总被引:5,自引:0,他引:5  
对影响萝卜离体再生的因素进行了研究,结果表明,不同基困型材料均以带柄子叶的再生频率最高;不同基因型材料所需的最适激素浓度和配比不同,在一定范围内提高6-BA浓度可促进不定芽的分化;苯基脲类细胞分裂素TDZ与嘌呤型细胞分裂素6-BA和KT相比,对促进萝卜不定芽分化的效果更好;AgNO_3可显著提高不定芽再生频率;NAA诱导生根的效果优于IAA。  相似文献   
52.
夏大豆成熟期害鼠防治指标的研究潘学锋(安徽省霍邱县植保站237400)刘同群(霍邱县城西湖乡农技站)摘要本文通过大田调查夏大豆田的害鼠发生种类及其密度与产量损失的关系,结果表明,沿淮地区夏大豆田的害鼠种类为黑线姬鼠、黑线仓鼠、褐家鼠、小家鼠等,其中以...  相似文献   
53.
苯丙烯酸对黄瓜幼苗光合作用和细胞超微结构的影响   总被引:13,自引:0,他引:13  
 通过基质栽培研究不同浓度的苯丙烯酸对黄瓜幼苗光合作用和超微结构的影响。结果表明,苯丙烯酸浓度在80 µmol·L 时显著地降低了黄瓜幼苗的叶面积、叶绿素a含量、光合速率、蒸腾速率、根系活力和气孔张开数(P<0.05);叶绿体和线粒体等超微结构也受到破坏,而浓度在150 µmol·L 时显著减少了全株干质量和气孔总数,细胞器出现解体现象。  相似文献   
54.
苹果早熟新品种‘早翠绿’选育   总被引:3,自引:0,他引:3  
早翠绿是以辽伏为母本,岱绿为父本杂交育成的早熟苹果新品种。果实圆形或圆锥形,平均单果重151.3g,最大204g,7月中下旬成熟,果皮绿色,肉质细脆汁多,酸甜适口,香味浓,较耐贮藏,早果,丰产。  相似文献   
55.
葡萄品种浆果成熟期多样性及归类标准评价   总被引:5,自引:0,他引:5  
对郑州葡萄圃内260个鲜食和153个酿酒品种的浆果成熟期进行了鉴定评价。在郑州地区,最早熟的葡萄种质材料早莎巴珍珠6月29日生理成熟,果实发育期48d;最晚熟的种质材料大宝10月12日成熟,果实发育期144d,在其间的103d时间里不断有成熟的葡萄品种,表现了丰富的多样性。酿酒葡萄的果实成熟期相对集中,大多数酿酒葡萄品种在8月中旬成熟,7月份和9月份成熟的葡萄品种所占的比例极少。果实发育期≤60d、61~80d、81~100d、101~120d、≥121d的品种次数呈正态分布,果实发育期81~100d的品种占收集品种的53.03%;果实发育期少于60d的极早熟品种和果实发育期多于120d的极晚熟品种所占比例较少。早、中、晚熟品种按照浆果发育期进行归类较为简便。  相似文献   
56.
Large mammalian herbivores are notorious for their propensity towards population irruptions and crashes, yet many herbivore populations remain relatively stable. I explore how resource heterogeneity within landscapes dampens population instability, using a metaphysiological modelling approach considering patch state distributions. Resource heterogeneity is functionally stabilizing through spreading consumption away from preferred resources before these become critically depleted. Lower-quality resources act as a buffer against starvation during critical periods of the seasonal cycle. Enriching resource quality is destabilizing, even if patch diversity is maintained, because food quantity then becomes the limitation. The potential consequences of landscape fragmentation are explored using the Serengeti ecosystem, characterised by broadscale resource gradients, as a hypothetical example. Further insights provided by the model are illustrated with specific examples concerning the effects of patch scales and waterpoint distribution. A metaphysiological modelling approach enables the basic consequences of landscape heterogeneity to be distinguished from further effects that may arise from specific patch scales and configurations, without the distracting detail of spatially explicit models.  相似文献   
57.
湿地松粉蚧三种寄生蜂蛹及蛹壳的比较   总被引:2,自引:0,他引:2  
本文主要通过对湿地松粉蚧Oracella acuta(Lobdell)两种引进天敌迪氏跳小Zarhopalus debarri、火炬松短索跳小蜂Acerophagus coccois与本地天敌粉蚧长索跳小蜂Anagyrus dactylopii(Howard)的蛹及蛹壳的比较,指出可通过寄生蜂蛹及蛹壳的形状、颜色、羽化孔、表面结构特征等对上述三种寄生蜂进行区分。  相似文献   
58.
AIM: To investigate the relationship between osmolarity, cell volume and cell proliferation in nasopharyngeal carcinoma cells. METHODS: MTT method was applied to detect the proliferation ability of the poorly-differentiated nasopharyngeal carcinoma cell (CNE-2Z) under various osmolarity conditions. The flow cytometry was used to analyse cell cycle distribution. Cell volume was obtained by the image analysis of living cells and cell viability was determined by the trypan blue assay. RESULTS: Cultivation of cells under the hypertonic conditions of 370 and 440 mOsmol/L increased cell volume by 8.7% and 27.8% and facilitated cell proliferation by 22.2% and 33.9%, respectively. However, hypotonic incubation of cells with osmolarity of 160 and 230 mOsmol/L decreased cell volume by 12.8% and 4.1% and inhibited cell proliferation by 34.0% and 15.6%, respectively. Cell volume was positively correlated with cell proliferation rate. Long-term cultivation of cells under anisotonic conditions did not significantly alter cell cycle distribution, but hypotonic cultivation decreased cell viability. CONCLUSION: Proliferation of nasopharyngeal carcinoma cells was closely correlated with the osmolarity of culture medium and cell volume. Hypotonic cultivation may inhibit cell proliferation by decreasing cell volume to facilitate cell death mechanisms.  相似文献   
59.
Xiphinema diversicaudatum and X. index are vector nematode species of economic importance in viticulture regions as they can transmit Arabis Mosaic, Grapevine Fanleaf and Strawberry Latent Ringspot viruses to grapevine. Wang et al. (2003) designed species-specific diagnostic primers from ribosomal genes for both these vector species as well as a vector and a non-vector species X. italiae and X. vuittenezi, respectively. Our study aimed to confirm the specificity and determine the sensitivity and reliability of the primers for the two vector species, X. diversicaudatumand X. indexwhen challenged with closely related longidorid species and general nematode communities typical of vineyard soil. With one exception, no PCR product was observed when the primers were tested against six Longidorus, one Paralongidorus and one Xiphinema non-target species. Occasionally (three out of eight replicate PCR reactions) a weak PCR product was noted when primers for X. index were tested with L. elongatus. Furthermore, when challenged with a range of non-target nematode species comprising the nematode community typical of viticulture soil, no PCR product was amplified. An experimental dilution series of extracted DNA rigorously demonstrated that DNA from an equivalent single specimen of the target virus-vector species, X. diversicaudatum and/or X. index, could be detected amongst 1000 equivalent non-targetX. vuittenezi. Also, extracted DNA from an equivalent single target specimen was detected when added to DNA extracted from the overall soil nematode community. The primers were assessed further by using serial mixtures of actual nematodes rather than extracted DNA to simulate field soil. Using this method, a single target nematode could be detected amongst 200 non-target specimens. Given their specificity, sensitivity and reliability, it appears that these diagnostic primers will be of great benefit to phytosanitary/quarantine services related to the viticulture industry.  相似文献   
60.
秦川牛是我国著名地方良种黄牛 ,我县从 2 0世纪 5 0年代开始引进秦川种公牛改良当地黄牛 ,2 0世纪 70年代末推广牛的冷配技术 ,引进秦川种公牛冷冻精液颗粒、细管 ,坚持本交与人工授精相结合。全县累计引进秦川牛 670 0多头 ,改良配种 9.0 1万头 ,产改良牛 6.5 8万头。秦川牛的引进 ,丰富了我县黄牛遗传基因库 ,优化了牛群整体结构 ,改良效果明显 ,社会经济效益显著  相似文献   
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