几种杀菌剂对猕猴桃主要真菌性叶斑病菌的室内毒力测定

猕猴桃假尾孢Psedocercospora actinidiae Deighton和叶点霉菌Phyllosticta sp．是引起猕猴桃生长期的两种主要真菌病害。为了能筛选到对猕猴桃假尾孢和叶点霉菌具有高效抑制作用的杀菌剂,本文采用茵丝生长速率法测定了几种杀菌剂的毒力,结果表明,除腈菌唑外其余几种杀菌剂均可作为猕猴桃主要叶斑病的田间药效试验的首选药剂。     

Establishment of trees on mixtures of pulverized fuel ash and Gypsum. Part II: Nutrition and trace elements

Nutrients and trace elements were determined in the foliage of nine tree species grown in mixtures of pulverized fuel ash (PFA) and gypsum. No serious macronutrient deficiencies were observed. Treatments with PFA consistently increased foliar levels of boron, potassium and molybdenum, and the poor performance of some tree species in pure PFA was attributed to boron toxicity. Gypsum hindered the uptake of boron when mixed with PFA, however, and co-disposal of the two wastes could be used to minimize problems associated with boron toxicity.     

不同有机肥用量对黄瓜生长及养分吸收的影响

在温室基质栽培条件下,研究了配施等量化肥时不同用量有机肥对黄瓜生长及养分吸收的影响。试验采用有机肥系烘干鸡粪,所有供试肥料均以底肥形式一次施入。研究结果表明,高量有机肥处理(有机肥50,100 kg/m3)严重抑制了黄瓜定植初期的生长,黄瓜前期产量也明显低于不施或低量有机肥处理。随着施肥量的增加,黄瓜氮、磷、钾养分吸收量均显著增加。黄瓜定植后74 d,所有处理基质的速效氮养分均已处于极低的水平,黄瓜普遍出现缺肥症状。试验初步证明了长季节栽培条件下一次施用高量有机肥难以及时提供足量的速效氮源,无法满足蔬菜养分需求。     

黏虫CYP9A134基因的克隆及其解毒功能

昆虫体内的细胞色素P450酶系统在昆虫解毒过程中发挥着重要作用。本次试验通过转录组测序获得一条新的黏虫P450基因,经国际委员会命名为CYP9A134（登录号为MT990973）。该序列全长为1801 bp,开放序列长度为1596 bp,编码531个氨基酸,分子质量为61.42 kDa,等电点为4.90。在黏虫幼虫阶段用2.5%高效氯氟氰菊酯和20%氯虫苯甲酰胺诱导时该基因表达量会有不同程度上升,最高的可分别达对照组的2.6倍和6.5倍。RNA干扰后,该基因表达量最低下降了70%,以上2种杀虫剂LD30杀虫效果分别提高了13%和25%;在黏虫成虫阶段用20%氯虫苯甲酰胺LD30诱导时,该基因表达量最高可达7.8倍。RNA干扰后,该基因表达量最低下降了61%,LD30剂量的氯虫苯甲酰胺杀虫效果提高26%。结果表明,该基因可能在杀虫剂诱导的解毒代谢过程中发挥重要作用。     

氮磷钾用量对小麦冠层不同层次光截获和干物质分配的影响

为明确不同氮、磷、钾用量对小麦冠层不同层次光截获和干物质分配的影响,以济麦22为供试材料,设置F0（不施肥）、F1（N 180 kg·hm^-2,P₂O₅ 75 kg·hm^-2,K₂O 60 kg·hm^-2）、F2（N 225 kg·hm^-2,P₂O₅ 120 kg·hm^-2,K₂O 105 kg·hm^-2）和F3（N 270 kg·hm^-2,P₂O₅ 165 kg·hm^-2,K₂O 105 kg·hm^-2）4个施肥量处理,比较分析开花后不同氮、磷、钾用量对小麦叶面积指数、冠层不同层次光截获特性和成熟期干物质分配的影响。结果表明,F1处理下叶面积指数显著高于F0处理,而与F2和F3处理间无显著差异;开花后15 d,F1处理下小麦冠层不同层次及总PAR截获率和截获量均显著高于F0处理,而与F2和F3处理间无显著差异。F1处理下成熟期干物质在小麦冠层不同层次营养器官中的分配量、籽粒中的分配量及总干物质积累量显著高于F0处理,而与F2和F3处理间无显著差异。成熟期干物质在小麦冠层不同层次营养器官和籽粒中的分配量以及总干物质积累量与冠层上层（顶部至株高2/3）、中层（株高2/3至株高1/3）和总PAR截获率均呈显著正相关。F1处理（N 180 kg·hm^-2,P₂O₅ 75 kg·hm^-2,K₂O 60 kg·hm^-2）为本试验条件下的最优处理。     

Screening of Human CYP1A2 and CYP3A4 Inhibitors from Seaweed In Silico and In Vitro

Phenolic compounds and carotenoids are potential inhibitors of cytochrome P450s. Sixteen known compounds, phenolic compounds and carotenoids from seaweed were examined for potential inhibitory capacity against CYP1A2 and CYP3A4 in silico and in vitro. Morin, quercetin, and fucoxanthin inhibited the enzyme activity of CYP1A2 and CYP3A4 in a dose-dependent manner. The IC₅₀ values of morin, quercetin, and fucoxanthin were 41.8, 22.5, and 30.3 μM for CYP1A2 and 86.6, 16.1, and 24.4 μM for CYP3A4, respectively. Siphonaxanthin and hesperidin did not show any significant effect on CYP1A2, but they slightly inhibited CYP3A4 activity at high concentrations. In silico modeling of CYP’s binding site revealed that the potential inhibitors bound in the cavity located above the distal surface of the heme prosthetic group through the 2a or 2f channel of CYPs. This study presents an approach for quickly predicting CYP inhibitory activity and shows the potential interactions of compounds and CYPs through in silico modeling.     

增效磷肥对花生生长、产量和磷利用率的影响

采用大田试验,在正阳县酸性砂姜黑土和清丰县石灰性砂质潮土区,研究了磷肥与不同增效剂（腐殖酸、 复合氨基酸和草酸）配施对花生生长、产量及磷肥利用率的影响。结果表明,85%常规施磷与腐殖酸、氨基酸和草 酸配施对花生产量的作用效果受土壤类型影响,砂姜黑土区,分别比85%常规施磷增产8.82%、4.66%和-1.68%,砂 质潮土区分别比85%常规施磷增产8.40%、3.18%和12.08%,砂姜黑土区和砂质潮土区分别以85%常规施磷+腐植 酸和85%常规施磷+草酸处理对花生生长和增产的促进效果最好。施磷增效剂也提高了花生磷积累量和磷肥利用 率,其原因在于磷增效剂促进了土壤难溶性磷组分转化为活性较高磷组分,与85%常规施磷相比,砂姜黑土区85% 常规施磷+腐植酸和砂质潮土区85%常规施磷+草酸处理的花生磷积累总量分别显著增加26.31%和22.89%,磷肥 表观利用率分别提高7.74%和4.99%,磷肥农学效率分别提高5.54 g/kg和5.39 g/kg。因此,酸性砂姜黑土区磷肥减 量15%配施腐殖酸,石灰性砂质潮土区磷肥减量15%配施草酸,可提高磷肥利用率,确保花生不减产,实现磷肥减 量增效目标。     

稻稗HJHL-715种群对五氟磺草胺的抗药性水平及抗性机理分析

为明确东北稻区稻稗Echinochloa oryzoides HJHL-715种群对五氟磺草胺的抗性水平及抗性机制,采用整株生物测定法测定稻稗种群对五氟磺草胺的敏感性,明确抗性种群的交互抗性和多抗性情况,研究3种细胞色素P450抑制剂对其敏感性的影响;并应用分子生物学方法进行稻稗的乙酰乳酸合酶(acetolactate synthase,ALS)离体活性测定、ALS基因序列分析及其表达量测定。结果表明:在东北稻区,五氟磺草胺对稻稗HJHL-715种群鲜重的抑制中剂量GR50为62.53 g/hm^2;稻稗HJHL-715的ALS基因序列中未发现氨基酸突变,其ALS离体活性与敏感种群的ALS离体活性无显著性差异,ALS基因表达量显著低于敏感种群。1-氨基苯并三唑(1-aminobenzotriazole,ABT)、胡椒基丁醚(piperomyl butoxide,PBO)、马拉硫磷3种P450抑制剂显著提高了稻稗HJHL-715种群对五氟磺草胺的敏感性,使其对五氟磺草胺的GR50由原来的62.53 g/hm^2分别下降到5.78、5.02、3.53 g/hm^2。表明东北稻区已经出现了对五氟磺草胺具有高水平抗性的稻稗种群,稻稗HJHL-715种群对五氟磺草胺的抗性很可能是由细胞色素P450介导的代谢增强所致。