抗药性杂草与治理

抗药性杂草对农田杂草治理和农业生产构成严重威胁,成为备受全球关注的严重问题。随着长期、大量使用相对有限的化学除草剂,全球抗药性杂草发展迅猛,目前已有217种杂草对化学除草剂产生了抗药性,我国抗药性杂草发展也十分迅猛。本文在介绍杂草抗药性基本概念、抗药性杂草发展过程、抗药性杂草现状的基础上,重点描述了抗药性杂草治理策略,以期为我国抗药性杂草研究和治理提供参考。     

Dynamic root exudation of phenolic allelochemicals from Johnson grass (Sorghum halepense)

The phenolic allelochemicals from the root exudates of Johnson grass (Sorghum halepense) were collected at different developmental stages and analyzed using high performance liquid chromatography‐ultraviolet/photo‐diode array. The results revealed that three simple phenolic components, p‐hydroxybenzoic acid, p‐hydroxybenzaldehyde and ethyl p‐hydroxybenzoate, along with two flavonoids, diosmetin (3′,5,7‐trihydroxy‐4′‐methoxyflavone) and tricin (5,7,4′‐trihydroxy‐3′,5′‐dimethoxyflavone), were found in the root exudates of Johnson grass. However, the major phenolic compounds varied and the quality of each compound was dynamic at different developmental stages: the only phenolic compound that was detected in the seedling stage was p‐hydroxybenzoic acid; three simple phenolic allelochemicals, p‐hydroxybenzoic acid, p‐hydroxybenzaldehyde and ethyl p‐hydroxybenzoate, were found in the jointing stage; and five compounds, including the two flavonoids, tricin and diosmetin, appeared in the reproductive stage along with the other three simple phenolic allelochemicals. The highest diversity in phenolic constituents was in the reproductive stage, with five allelochemicals. Only p‐hydroxybenzoic acid was found in the whole life cycle of Johnson grass, with a range of 2.9 nmol to 6.8 nmol per plant per day. p‐Hydroxybenzaldehyde had the highest quality among all the compounds, with the highest releasing rate of 26.8 nmol per plant per day. The lowest‐content compounds were the two flavonoids, with the highest quality of 1.8 nmol per plant per day. The results suggest that the temporal dynamic of phenolic allelochemicals in the root exudates of Johnson grass corresponds with the dynamic of development.     

黑龙江省反枝苋对噻吩磺隆的抗性水平及其分子机制

正反枝苋Amaranthus retroflexus为一年生阔叶杂草,在我国分布广泛,严重危害大豆、玉米、棉花等作物(李晓晶等,2004)。噻吩磺隆是杜邦公司研发的一种磺酰脲类除草剂,对玉米等作物田的反枝苋、藜等阔叶杂草防效优良。黑龙江省部分地区长期单一使用噻吩磺隆防除反枝苋,防效已明显下降。本研究利用生物测定法及分子生物学手段分析黑龙江省部     

牛筋草ISSR-PCR反应体系的建立与优化

以牛筋草地上组织为材料,采用正交优化和单因子试验两种方法对影响牛筋草ISSR-PCR体系的Mg2+浓度、dNTP浓度、Taq DNA聚合酶浓度、引物浓度和DNA模板浓度5个因素进行优化试验,建立适合牛筋草ISSR-PCR的反应体系.结果表明,牛筋草ISSR-PCR反应体系的最佳条件为:Mg2+1.75 mmol/L,dNTP 0.4 mmol/L,Taq DNA聚合酶1 U/25 μL,引物0.3μmol/L,模板DNA 80 ng/25μL,10×PCR Buffer 2.5 μL/25 μL.利用优化体系进行牛筋草的ISSR-PCR反应,可获得稳定性高、重复性好、背景清晰的电泳结果.     

杂草对ACCase抑制剂的抗性

以乙酰辅酶A羧化酶（ACCase）为作用靶标的除草剂是高效、选择性的禾本科杂草除草剂,其在全球范围内的广泛、重复使用,导致了抗药性杂草的发生和发展。到目前为止,已经在30个国家有37种抗此类除草剂的杂草生物型。抗药性杂草严重威胁杂草治理和农业生产,由此引发的生态问题及粮食安全问题引起了广泛的关注。文章概述了ACCase抑制剂抗药性杂草的发生现状,从杂草ACCase突变、代谢解毒等几个方面综述了杂草抗ACCase抑制剂的抗性机制,以期为ACCase抑制剂抗性研究提供参考。最后讨论了阻止或延缓抗药性发生的杂草管理措施。     

转Bt基因作物对农田害鼠发生的影响分析*

转Bt基因作物的推广种植,正在改变着世界种植业格局。本文综述了实验室条件下转Bt基因作物对驯化鼠类影响的研究进展,结合近年来国内外农区鼠害的发生特征及其影响因素,分析了转Bt基因作物的推广种植对农田鼠类种群数量的潜在影响。     

Tribenuron-Methyl Resistant Flixweed （Descurainia sophia）

Flixweed seeds were collected from suspected winter wheat fields and remote hillside in Shaanxi Province, China, their sensitivities to tribenuron-methyl were evaluated in the greenhouse. Results revealed that biotype S was susceptible to tribenuron, and its GRs0 was 0.23 g a.i. ha^-1, whereas biotypes R1, R2, R3, and R4 were resistant to the tribenuron, and their GR50 were 161.99, 79.70, 439.80, and 312.30, respectively. Biotypes R1 and R2 showed moderate resistance with resistant indices （RI） of 615.23 and 302.7, respectively. Whereas biotypes R3 and R4 showed high resistance to the herbicide with RI values as high as 1 670.34 and 1 186.10, respectively.     

野燕麦对精噁唑禾草灵、炔草酯敏感性差异测定

为明确不同野燕麦种群对精噁唑禾草灵和炔草酯的敏感性水平,采用整株生物测定与种子生物测定分别检测了河南、湖北、江苏三省共11个野燕麦种群对精噁唑禾草灵和炔草酯的敏感性。结果表明,2种测定方法获得的野燕麦种群对2种除草剂的敏感性基本一致。整株生物测定结果显示,不同野燕麦种群对精噁唑禾草灵和炔草酸的敏感性存在显著差异,其中,金水闸野燕麦种群对精噁唑禾草灵和炔草酯敏感性最高,其GR50值（有效成分）分别为2.46、3.65 g/hm2,而辉县野燕麦种群对精噁唑禾草灵和炔草酯敏感性最低,GR50值（有效成分）分别为15.00、23.12 g/hm2,其余野燕麦种群对精噁唑禾草灵和炔草酯的敏感性介于金水闸种群与辉县种群之间。种子生物测定结果与整株生物测定结果趋势一致,但表现出的敏感性略高。     

抗草甘膦杂草及其检测方法发展现状

草甘膦在世界范围的多年大量使用已经引起了抗草甘膦杂草的产生。本文针对全球迄今为止发现的21种抗草甘膦杂草的发生、发展状况进行了论述。探讨了抗草甘膦杂草抗药性检测方法,分别从整株生物测定及生物化学等方面介绍了抗草甘膦杂草检测方法的研究现状,为抗草甘膦杂草检测方法的发展及其抗性监测方法的建立提供参考。     

中国鼠害防控需求的差异、矛盾、挑战与对策

绝大多数啮齿动物种类为植食性的小型哺乳动物，其生物学特性导致了鼠类危害的复杂性。当前，面对日益提高的生态安全需求，粮食安全、人民健康和生物安全以及生态安全对鼠害控制需求的差异造成了中国鼠害防控策略制定及实施的困扰。尤其在草原地区，如何在应急性灭杀和长效缓控之间找到一个平衡点是目前鼠害防控面临的一个巨大挑战。针对这些矛盾和挑战，该文分析了我国鼠害监测防控的现状、主要瓶颈与短板，并从技术层面提出“精准监测指导精准防控”可能会是解决这些矛盾的有效途径，是在有效控制鼠害暴发对粮食生产和人民健康安全威胁的前提下，推进生态保护和修复的有效途径。