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Harrington Timothy B. Minogue Patrick J. Lauer Dwight K. Ezell Andrew W. 《New Forests》1998,15(1):89-106
Eight herbicide combinations containing imazapyr alone or in mixture with glyphosate, triclopyr, or picloram+2,4-D were applied July–August 1991 at each of three upland sites in the southeastern U.S., with or without a subsequent broadcast burn in September. Seedlings of loblolly (Pinus taeda L.) or slash (P. elliottii Engelm. var. elliottii) pine were planted that winter. Second-year (August 1993) vegetation responses indicate that broadcast burning, in combination with herbicides, was associated with increased abundances of grasses, forbs, and shrubs and decreased abundances of vines and hardwood trees. In the presence of burning, imazapyr-in-mixture treatments were associated with a high abundance of grass (53% cover) and a mean size of pines less than that of seedlings growing in imazapyr-alone treatments. In the absence of burning, imazapyr-alone treatments were associated with a high abundance of blackberry (21% cover), an average height of hardwoods (131 cm) exceeding that of pines (71 cm), and a mean size of pines less than that of trees growing in imazapyr-in-mixture treatments. Hardwood height in the absence of burning was less when imazapyr was combined with glyphosate (75 cm) than with triclopyr (102 cm). Regardless of the presence or absence of burning, size of pines and abundance of shrubs and hardwoods did not differ between imazapyr rates of 0.56 and 0.84 kg acid equivalent/ha or among herbicides applied in mixture with imazapyr. 相似文献
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以红泡刺藤(R.niveus)、栽秧泡(R.ellipticusvar.obcordatus)和插田泡(R.coreanus)绿枝或硬枝扦插生根的根尖为材料,通过取材时季与扦插环境气温,8-羟基喹啉、秋水仙素和对二氯苯3种药剂在不同的温度下预处理不同时间,混合酶液和盐酸在不同温度下解离,醋酸洋红、卡宝品红、席夫试剂和铁矾-苏木精各染色剂染色压片等的对比研究,并以细胞中有丝分裂中期分裂相的数目、染色体的清晰性、分散程度和聚缩程度以及染色体的形态为衡量指标,探索出适于树莓属植物核型分析的根尖压片方法是:当根尖长至1~2 cm、扦插环境气温17~23℃时取材,卡诺氏固定液I低温固定24 h,用0.002 mol/L 8-羟基喹啉在0~4℃下预处理24 h,再用1 mol/L HCl(60±1)℃恒温解离4~7 min,最后用卡宝品红染色压片能获得效果好树莓染色体标本,该染色体标本完全适用于核型分析。 相似文献
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A total of 73 Erwinia amylovora strains obtained from 13 Maloideae host species and from Rubus spp., and isolated from different geographic areas, were assessed using RFLP and DNA sequencing analysis of the 3' hrp N gene and/or of a fragment of 1341 bp of the dsp A/E region. An Erwinia pyrifoliae strain, used as outgroup, was checked in the same way. For the three strains isolated from Rubus spp. and for one strain from Amelanchier sp., RFLP analysis of the hrp N gene using the Rsa I enzyme yielded a PCR product 60 bp smaller than that of all the other strains. Sequence analysis of the gene revealed this was due to the absence of a 60 bp fragment in the noncoding region downstream of the gene. The strain PD 2915, isolated from Amelanchier sp. grown in Canada, showed five same-sense substitutions and one missense substitution at position 868 of the hrp N gene, converting aspartic acid into asparagine. Also, restriction analysis of a fragment of 613 bp of the dsp A/E region with Cfo I revealed an RFLP pattern suitable for differentiating the E. amylovora strains isolated from Rubus spp. and Amelanchier sp. from all the others. In the dsp A/E coding region, the four strains showed 13–14 missense point mutations, in some cases yielding drastic amino acid substitutions. In addition, partial sequencing of the dsp A/E region of PD 2915 from Amelanchier sp. indicated a higher similarity to E. amylovora strains isolated from Rubus spp. than towards strains from other Maloideae hosts. The E. pyrifoliae strain showed 23 single nucleotide substitutions along the hrp N gene and 88% of nucleotide identity with E. amylovora strains in the portion of dsp A/E region. Artificial inoculations on immature pear fruits and young shoots of Maloideae and Ruboideae showed a restricted pathogenicity for the strains from Rubus and Amelanchier , with the latter inciting blight symptoms only on Amelanchier . 相似文献
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Nickolas?G.?KavallieratosEmail author George?J.?Stathas Christos?G.?Athanassiou George?Th.?Papadoulis 《Phytoparasitica》2002,30(3):231-242
The role of the self-sown shrubsDittrichia viscosa (L.) W. Greuter andRubus ulmifolius Schott as reservoirs of aphid parasitoids was investigated. In the field studies conducted,D. viscosa grew adjacent to crops of durum wheat and barley andR. ulmifolius grew adjacent to cotton. The relative abundance of the parasitoids of(a) Capitophorus inulae (Passerini) onD. viscosa, (b) Rhopalosiphum padi (Linnaeus) on durum wheat and barley,(c) Aphis ruborum (Börner) onR. ulmifolius, and(d) Aphis gossypii Glover on cotton in various parts of Greece, was assessed during the years 1996–2000. In 2000, the fluctuation of parasitization of the above four aphid species was recorded and the action of the aphidophagous predators of the family Coccinellidae was studied. It was observed thatAphidius matricariae Haliday predominated onC. inulae andR. padi in all sampling cases. In contrast,Lysiphlebus fabarum (Marshall) was the dominant species parasitizingA. ruborum onR. ulmifolius andA. gossypii on cotton in Thessaly (central Greece) and Macedonia (northern Greece), whereasLysiphlebus confusus Tremblay et Eady andBinodoxys acalephae (Marshall) were the dominant parasitoid species in Thrace (northern Greece).Coccinella septempunctata Linnaeus was the most abundant coccinellid species on durum wheat, whereasAdonia variegata (Goeze) predominated on cotton. However, coccinellid individuals were scarce on bothD. viscosa andR. ulmifolius. The present study indicated that these two shrubs can be regarded as useful reservoirs of aphid parasitoids. 相似文献
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甜叶悬钩子植物组织培养褐化现象控制研究 总被引:1,自引:0,他引:1
[目的]寻求甜叶悬钩子组织培养中的最佳抗褐化剂。[方法]以甜叶悬钩子的茎和叶为外植体,必MS为基本培养基,加入不同浓度的抗褐化剂(20%Na2S2O3、Vc和AC),研究不同抗褐化剂对甜叶悬钩子组织培养的影响。[结果]AC和Vc都能对不同外植体起到抗褐化作用,在加入20%Na2S2O3的培养基上,外植体的褐化程度与Na2S2O3的浓度成正比,培养基中20%Na2S2O3的添加量达20ml时,外植体褐化最为迅速;在加入Vc的培养基上,随着Vc添加量的增加,培养基变成液体或半固体培养基,接入的外植体容易死亡;在加入AC的培养基上,AC的添加量为5g/L时,外植体的褐化率可控制在5%以下。抗褐化控制处理后,可以在诱导愈伤组织的培养基上培养出大量的愈伤组织。1结论IAC是较为理想的抗褐化剂,用量为5g/L。 相似文献