1,3,5-三芳基-2-吡唑啉类化合物的合成及其光活化除草活性

为了探讨具有光导性能的芳基吡唑啉类化合物的光活化除草作用,由α,β-不饱和酮与苯肼环化,合成了5个1,3,5-三芳基吡唑啉类化合物,其化学结构经IR、1H NMR、MS和元素分析确证,并讨论了其波谱性质。首次研究了这类化合物对稗草的光活化除草作用。结果表明,1-苯基-3,5-二噻吩吡唑啉(化合物 Ⅱ e )光照下对稗草根长的IC50值为4.46 μg/mL,光活化比为2.69,具有较好的光活化除草活性。     

Spontaneous ultraweak photon emission from rice (Oryza sativa L.) and paddy weeds treated with a sulfonylurea herbicide

All living organisms spontaneously generate ultraweak photon emissions, which originate from biochemical reactions in cells. Current research uses the ultraweak photon emissions from organisms as a novel tool to investigate the physiological states of plants. In this study, we found ultraweak photon emissions from leaf segments of rice and several paddy weed species treated with a sulfonylurea herbicide. There is a definite difference in photon emissions among plant species, and rice (Oryza sativa), barnyardgrass (Echinochloa crus-galli) and Cyperus serotinus showed extremely strong enhancement of photon emissions. Photon emissions from these three species treated with sulfonylurea herbicide were suppressed when the leaf segments were treated with the cytochrome P450 monooxygenase (P450) inhibitors, piperonyl butoxide and malathion. These results suggest that P450 inhibitors affect the ultraweak photon emissions from plants.     

Herbicide-resistant barnyardgrass (Echinochloa crus-galli) in global rice production

Barnyardgrass (Echinochloa crus-galli (L.) Beauv.), an annual species of the family Poaceae, is a major weed problem in rice-producing countries throughout the globe. Synthetic herbicides can effectively control this grass in rice paddies, but the development of resistant biotypes after the continuous use of the same active ingredients has led to low herbicide efficacy and yield losses. In this review, a summary of resistant-barnyardgrass cases in global rice production is reported based on data from the International Herbicide-Resistant Weed Database. The first case of resistant barnyardgrass in rice paddies was to the photosystem-II inhibitor propanil in the late 1980s. Eighty-five (85) out of 116 cases in the period from 1986 to 2022 refer to resistant barnyardgrass (E. crus-galli var. crus-galli, E. crus-galli var. formosensis and E. crus-galli var. zelayensis) in 16 countries. Barnyardgrass has been found resistant to acetolactate synthase (ALS) inhibitors (34 cases), acetyl-CoA carboxylase (ACCase) inhibitors (23 cases), photosystem-II inhibitors (11 cases), auxin mimics/cellulose biosynthesis inhibitors (9 cases), very long chain fatty acid inhibitors (6 cases), and microtubule assembly inhibitors (1 case). The majority of all resistance cases reported to the active ingredients penoxsulam, bispyribac-sodium, and imazamox (ALS inhibitors), cyhalofop-butyl and fenoxaprop-ethyl (ACCase inhibitors), propanil (photosystem-II inhibitors), and quinclorac (auxin mimics/cellulose biosynthesis inhibitors). Although target-site resistance with specific mutations has been identified, non-target site resistance mainly through herbicide detoxification is also of great concern increasing the chance of multiple herbicide resistance evolution. Rotation of herbicides should be adopted concerning the modes of action used as well as the application methods to mitigate resistance evolution of this weed in rice paddies.     

家稗丙酮酸磷酸双激酶(PPDK)基因的克隆及序列分析

为揭示C4植物家稗[Echinochloa crusgalli var frumentacea(Roxb.)W.F.Wight] PPDK结构和功能特点,探索改善作物高光效途径,采用RT-PCR技术,克隆了家稗[Echinochloa crusgalli var frumentacea (Roxb.) W. F. Wight]丙酮酸磷酸双激酶（PPDK）基因的cDNA全长。核苷酸序列分析表明, 该片段全长3 085 bp, 包含一个2 844 bp的ORF,编码948个氨基酸(GenBank登录号：AY 792619)。编码区核苷酸序列与高粱（Sorghum bicolor）、甘蔗（Saccharum officinarum）、玉米（Zea mays）等C₄型pdk基因同源率分别为85.1%、84.0%和82.0%;与水稻[Oryza sativa (japonica cultivar-group)] pdk基因同源性也高达82.6%。氨基酸序列进化树分析表明其与玉米、水稻等禾本科植物最为接近;半定量RT-PCR研究表明,pdk基因仅在绿色叶片中表达。     

Rice–weed competition in response to nitrogen form under high and low transpirational demand

Implementation of water-saving irrigation practices in lowland rice results in increased availability of nitrate (NO₃⁻) in the soil and favours germination of upland weeds. Since plant species show a specific preference for either ammonium (NH₄⁺) or NO₃⁻ as nitrogen (N) source, changes in both soil NO₃⁻ concentration and weed flora may affect the competition between rice and weeds. Further, the transpirational demand of the atmosphere might affect growth and competitiveness of lowland (wetland) and upland (dryland) weeds differently due to their adaptation to different ecological environments. Therefore, the study aimed to evaluate the effects of N source on growth, N uptake and competition between rice and common upland and lowland weeds under high and low vapour pressure deficit (VPD). Two rice (Oryza sativa) varieties (NU838 and KD18) differing in growth characteristics and two weed species (Echinochloa crus-galli and Solanum nigrum) differing in their natural habitat were selected and grown hydroponically as monoculture or mixed culture at low or high VPD. N was supplied as 75%/25% or 25%/75% NH₄⁺/NO₃⁻. N uptake rates were measured in the first week, whereas dry matter (DM), N concentration in the plant, total N uptake and the activities of nitrate reductase and glutamine synthetase in the fresh leaves were determined two weeks after the onset of treatments. Independent of N source, both rice varieties and E. crus-galli took up a larger share of NH₄⁺, whereas S. nigrum took up a larger share of NO₃⁻. N uptake of rice and E. crus-galli was hardly affected by N source, whereas high NO₃⁻ led to significantly higher N uptake rates and total N uptake of S. nigrum. NU838 showed a higher competitiveness against weeds than KD18. In competition, high NO₃⁻ decreased the competitiveness of E. crus-galli against NU838 but increased the competitiveness of S. nigrum against NU838. High VPD did not affect DM but increased N uptake of S. nigrum, leading to increased competitiveness of the weed at high transpirational demand. Competitiveness for N uptake appears to be an important trait as the relative N concentration in mixed plant communities was correlated with the activity of N-assimilating enzymes and leaf growth, with a stronger response in rice than in weeds. Our results support the hypothesis that increased availability of NO₃⁻ in aerobic rice soils may be advantageous for the competitiveness of upland weeds, especially at high VPD, whereas it may be disadvantageous for common lowland weeds.     

水稻与无芒稗的竞争和化感作用

用差时播种共培法的改进方法对105份水稻、6份巴西陆稻进行了化感作用抗稗草评价。 结果表明长匡7号、P4、Kogyoku、 IR27316、 Milyang 54和巴西陆稻AJ035等材料对无芒稗有较好的化感作用。盆栽研究表明,谷梅2 号、中156对无芒稗的抑制作用显著大于对照,而化感作用材料TN1对无芒稗的抑制作用与无化感作用材料秀水63无显著差异。中156的抑制作用强与其株高有关,而谷梅2号对无芒稗的抑制作用强主要在于其本身的化感作用。随着水稻密度增加,无芒稗受抑程度加剧,化感作用水稻对稗草根部的抑制似乎要比无化感作用水稻强。TN1对无芒稗的化感作用不明显,可能是由于对不同生态的稗的作用不同之故。     

辽宁省无芒稗对二氯喹啉酸的抗药性研究

对辽宁省稻区无芒稗对二氯喹啉酸抗药性进行研究,结果表明:辽宁省稻区的无芒稗对二氯喹啉酸都产生了一定程度的抗性,但抗性水平不高,抗性比值小于2的敏感性生物型14个,占37.83%,抗药性生物型23个,占62.17%,其中相对抗性比大于3的8个,占21.62%,高抗生物型的1个,占2.7%。     

化学试剂和GA3处理对稗草种子萌发的影响

研究了不同化学试剂NaOH、HCl、H2O2、KNO3及激素GA3处理对稗草种子萌发的影响.结果表明,不同化学试剂及激素GA3处理对稗草种子萌发率的影响存在较大差异.NaOH对其萌发促进作用最大,用1.5%NaOH溶液浸泡稗草种子24 h后,萌发率高达94.67%,显著高于对照(6.67%);HCl、H2O2、KNO3处理对稗草种子萌发虽有一定的促进作用,但萌发率均低于30%.GA3处理对稗草萌发有明显的促进作用,当浓度为800 mg/L时,萌发率为80%.     

湖南稷子种子标准发芽方法研究

湖南稷子(Echinochloa frumentacea)具有优良的抗逆性和较高的饲用价值,既可作为改良盐碱地的先锋植物又可用作青饲料以及调制干草或青贮。然而其种子具有一定的休眠性,休眠种子的发芽率较低,限制了湖南稷子的生产效率。本研究以2020,2021年收获的湖南稷子种子为研究对象,探究不同物理方法、化学方法、激素诱导方法对于解除湖南稷子种子休眠的效果。试验结果表明,0.05%GA₃ 20℃～35℃,0.05%GA₃ 20℃～30℃,预冷20℃～30℃,0.05%KNO₃25℃,预冷+0.05%KNO₃15℃～25℃处理可使种子发芽率平均达到86%以上,且幼苗生长状况良好。综合考虑发芽试验结果和实际操作上的难易程度后得出结论：采用培养皿纸上发芽法(Top of paper test on germination, TP),0.05%GA₃ 20℃～35℃,0.05%GA₃ 20℃～30℃处理为湖南稷子种子的最佳标准发芽方法。