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281.
镉对植物毒害与植物耐镉机理研究进展 总被引:18,自引:3,他引:18
综述了近年来镉对植物毒害与植物耐镉机理的相关研究成果。从植物生长、细胞结构、光合作用、酶活性等方面分析了镉的毒害机理,并从镉的吸收与转运,镉在细胞中的分布与区隔化,抗氧化酶活性的改变,以及螯合物的形成等方面探讨了镉胁迫下植物的耐性机制。 相似文献
282.
喜旱莲子草对重金属元素的耐性试验研究 总被引:1,自引:0,他引:1
[目的]研究喜旱莲子草[Alternanthera philoxeroides(Mart.)Griseb.]对部分常见重金属污染的耐性。[方法]测定了在不同浓度重金属(Cu、Zn和Pb)处理条件下植株高度、根长、节数和新萌蘖芽数等形态学响应指标。[结果]3种重金属的不同浓度特别是较高浓度处理时,喜旱莲子草的各个指标均呈明显的下降趋势,即重金属在较高浓度的处理时对该植物的生长具有抑制作用;通过比较,发现该植物对Pb的耐性较强。[结论]喜旱莲子草能够在一定浓度的重金属污染环境中生存,可以作为一种重金属富集植物。 相似文献
283.
介绍了植物对重金属的耐性机制及超富集植物的筛选依据,综述了我国在铅锌矿区进行重金属耐性植物与超富集植物筛选的研究进展,并指出了今后该领域的研究发展方向。 相似文献
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285.
Saflufenacil is a new herbicide being developed for pre-plant burndown for non-selective removal of broadleaf weeds and pre-emergence (PRE) broadleaf weed control in field crops, including maize, soybean, sorghum and wheat. As part of studying the potential use pattern of this herbicide, four field studies were conducted in 2006 and 2007 at Concord, northeast Nebraska, to determine winter wheat tolerance to PRE and post-emergence (POST) applications of saflufenacil. The fall POST applications were conducted at the 2–3 leaf stage (5 cm height) whereas the spring POST and tank-mixes studies were sprayed at the 4th node stage (40 cm height) of crop. Dose-response curves based on log-logistic model were used to determine the ED (effective dose) values of saflufenacil for visual ratings of crop injury and relative yield. There was no crop injury or yield reduction with PRE applied saflufenacil dose of up to 400 g a.i. ha−1. However, there was significant crop injury in the POST applications in the fall (up to 95%) and in the spring (up to 67%). There was also yield reduction of as much as 66% in the fall and 58% in the spring POST applications. Addition of adjuvants also increased crop injury levels. For example, at 14 days after treatment in the fall applications, about 5% visual crop injury (ED5) was evident with 82, 67 and 10 g a.i. ha−1 of saflufenacil compared with 51, 30 and 11 g a.i. ha−1 in the spring, with no adjuvant, or non-ionic surfactant (NIS), or crop oil concentrate (COC), respectively. Saflufenacil at half the proposed used dose of 25 g a.i. ha−1 was safe to mix with the currently used POST herbicides of wheat with no visible crop injury and yield reduction. PRE applications of saflufenacil would be safe for use in winter wheat; however, the POST application of saflufenacil alone or with the adjuvant NIS or COC produces unacceptable injury and yield loss. These results are similar to the proposed PRE use pattern of saflufenacil. In addition, the proposed label does not suggest the POST use of saflufenacil in winter wheat, or any other cereal crops, which is similar to what we have concluded from this study. 相似文献
286.
Greg C. Wilson Nader SoltaniFrancois J. Tardif Clarence J. SwantonPeter H. Sikkema 《Crop Protection》2010
Volunteer winter cereals are found sporadically in maize (Zea mays L.) fields across southern Ontario. Seven field trials were conducted over a two-year period (2006 and 2007) at four locations to determine the efficacy of five acetolactate synthase (ALS)-inhibiting herbicides for the control of volunteer cereals applied at two post-emergence application timings (2–4 and 4–7 maize leaf tips). The volunteer cereals were a hard red winter wheat (Triticum aestivum L.) (‘Hyland AC Morley’), soft red winter wheat (‘Pioneer 25R47’), soft white winter wheat (‘Pioneer 25W41’), and a autumn rye (Secale cereale L.) (‘FR’) cultivar. Volunteer cereal competition in maize resulted in a yield reduction of up to 44%. Foramsulfuron, nicosulfuron, nicosulfuron/rimsulfuron provided greater than 70% control of the volunteer cereals at 56 days after treatment (DAT), while primisulfuron and rimsulfuron provided greater than 60% control. Volunteer cereal control with early and late application was greater than 82 and 61%, respectively. Hard red winter wheat was the most sensitive to the ALS-inhibiting herbicides with control of 84–93%. Soft red and soft white winter wheat cultivars were intermediate in sensitivity with control of 76–87%, while autumn rye was the least sensitive with control of at 56–71% control at 56 DAT. Maize yields were improved when volunteer cereals were controlled with the use of herbicides compared to the weedy control, but were lower than the weed-free control. Early herbicide application resulted in improved control of volunteer cereals and higher maize yield. 相似文献
287.
288.
四缸干式缸体缸孔与缸套的公差进行极限公差配合后的最大间隙为0.045mm,最大过盈为0.015mm。在基本尺寸相对稳定的前提下,公差带相对较大,在此配合状况下进行装配时,装配车间反映在装完缸套后盘车的时候存在缸套被活塞带出来的现象。针对此问题进行缸体缸孔和缸套公差与配合的研究及应用。 相似文献
289.
采用不同浓度除草剂处理大豆叶片,对4个大豆品种的草铵膦和百草枯耐受性进行研究。结果表明,不同品种对两种除草剂的耐受性存在明显差异,以中豆32对百草枯耐受的最高浓度为0.24mg/L;中黄10号次之,为0.18mg/L;东农50和小粒豆最低为0.12mg/L。中豆32对草铵膦耐受的最高浓度为6mg/L;吉林小粒豆1号次之,为4mg/L;中黄10号和东农50的耐受浓度均为3mg/L。 相似文献
290.
《拇趾P紀事》讲述了主人公一实关于性的认识的探索过程。变身后的主人公从认为同性恋变态到逐渐接受以至于亲身经历。从对性和性特征看法的单一、固守转变为多样、宽容。体现了作者对异性恋优先权的质疑,对男性中心主义的反抗,呼吁社会应对性及性特征给予更宽容的态度。 相似文献