Resistance Level and Metabolism of Barnyard-Grass (Echinochloa crusgalli(L.) Beauv.) Populations to Quizalofop-p-ethyl in Heilongjiang Province,China

Eleven barnyardgrass populations were assayed. The highest resistant population was Geqiushan R with RI 125.45 resulted from the seed assay and 87.29 resulted from the whole plant bioassay followed by 853 R with RI 2.79 resulted from the seed assay and 6.04 resulted from the whole plant bioassay. The resistance level of other nine populations was low with RI 1.13-2.61 resulted from the seed assay and 1.48-3.63 resulted from the whole plant bioassay. The activity of an important metabolic enzyme glutathione S-transferases （GSTs） and three protective enzymes （SOD, POD, and CAT） were determined in vivo for Geqiushan R, 853 R, and Wudalianchi R. Compared with the S controls, the activities of POD in Geqiushan R, GSTs in 853 R, and Wudalianchi R were increased.

Assessment of Gene Flow Through Detection of SexualCompatibility Between Transgenic Rice with barand Echinochloa crusgalli var.mitis

The possibility of gene flow between two varieties of transgenic rice with bar gene (Y0003 and 99-t) (male) and barnyard grass(Echinochloa crusgalli var. mitis ) (female) was studied by means of reproductive biology. The germination and growth of rice pollen grains on barnyard grass stigmas at 30 min, and 1-4 h after crossing by hand were observed with an optical microscope. The results were compared with the germination and growth of barnyard grass pollen grains at the corresponding time after self-pollination. The results showed that germination and growth of the pollen grains of the two varieties were similar on barnyard grass stigmas, but differed significantly from self-pollination of barnyard grass. Pollen grains germinated and pollen tubes penetrated stigmas normally, and the number of pollen grains being condensing or releasing their inclusions or having released them increased with the time after self-pollination. Pollen grains of transgenic rice on the stigmas of barnyard grass couldn't germinate or grow normally after crossing, neither could they penetrate the stigmas of barnyard grass. Therefore, it could be concluded that the sexual incompatibility between transgenic rice with bar gene and barnyard grass is due to the rice pollen being unable to penetrate the stigma of barnyard grass. Further proof of incompatibility lies in the fact that the emasculated barnyard grass pollinated with the rice pollen grains could not seed.

Study on the Resistance Levels of Different Echinochloa crusgalli Populations to Penoxsulam and Bispyribac-sodium

[Objectives]This study was conducted to screen the resistance of Echinochloa crusgalli in some paddy fields in Changde City,Yiyang City and Yueyang City in Hunan Province to penoxsulam and bispyribac-sodium.[Methods]The resistance to penoxsulam and bispyribac-sodium was screened in 11 E.crusgalli populations collected from rice production areas in Changde,Yiyang and Yueyang Cities,Hunan Province,and the resistance level of population HU-2 to penoxsulam was determined.[Results]HU-1 to HU-6 and HU-8 A,a total of seven populations showed high levels of resistance to penoxsulam and bispyribac-sodium.The resistance level of population HU-2 to penoxsulam was extremely high;population HU-7 showed low-level resistance to both drugs;HU-11 population showed low-level resistance to penoxsulam and was susceptible to bispyribac-sodium;and populations HU-8 and HU-9 were susceptible to penoxsulam and bispyribac-sodium.[Conclusions]This study provides a technical basis for the rational use of penoxsulam and bispyribac-sodium and the selection of control chemicals for E.crusgalli in paddy fields.

稗草对酰胺类除草剂抗药性水平的测定及对乙草胺的抗药性生理生化机制

通过盆栽法测定了成都平原水稻稗草种群对4种酰胺类除草剂的抗药性水平,以及3个代表性稗草种群对乙草胺胁迫的生理响应。结果表明,2018年和2019年成都平原稻区供试稗草种群对乙草胺均达中抗水平,抗性指数(RI)分别为12.37~16.46和16.15~21.86;对异丙甲草胺处于低抗或中抗水平,RI分别为9.41~10.44和9.69~10.98;对丁草胺处于低抗水平,RI分别为3.74~4.59和4.55~5.16;对苯噻酰草胺处于敏感或低抗水平,RI分别为2.45~3.79和2.73~3.98。在乙草胺胁迫下,抗性稗草种群与敏感种群实际光量子产额、胞间二氧化碳浓度、蒸腾速率、气孔导度等生理指标均呈下降趋势;生化指标谷胱甘肽S-转移酶(GSTs)、超氧化物歧化酶(SOD)活性逐渐下降,丙二醛(MDA)含量呈上升趋势,但抗性稗草的损伤明显低于敏感型稗草。因此,成都平原稻区供试稗草种群对常见酰胺类除草剂仍处于敏感至中等水平抗性,GSTs活性提高是稗草对乙草胺产生代谢抗性的主要原因。

Effects of Ppc Gene Construction of Monocotyledon on Seedling Growth of Transgenic Nicotiana tabacum

To compare the transformation effects of two different forms （cDNA in monocotyledonous plant Echinochloa crusgalli, DNA in monocotyledonous plant Zea mays） of phosphoenolpyruvate carboxylase （PEPC） gene （Ppc） on the growth of transgenic dicotyledonous plant, Agrobacterium-mediated transformation of Ppc genes into Nicotiana tabacum were carried out. Transgenic leaf plates and differentiated seedling leaves were verified by GUS histochemistry, PCR, and RT-PCR. Results showed that transgenic N. tabacum with Ppc-cDNA of E. crusgalli had relatively strong differentiation ability. However, N. tabacum after transformation of complete DNA sequence of Ppc genes in Z mays had relatively poor ability of growth. The differentiated green seedlings had the phenomenon of yellowing; and photosynthesis ability of leaves was poor. This might be caused by the misidentification and wrong splicing in transcription. This indicated that the expression rate of monocotyledonous complete DNA might be reduced in the monocotyledonous cells with relatively far genetic distances. Detection results of showed that Pn in most transgenic N. tabacum with Ppc-cDNA of E. crusgalli was was higher than that in control, which preliminarily proved that PEPC of monocotyledonous plant E. crusgalli had certain regulatory effects on photosynthesis of N. tabacum.

稗子用于微生物源生物除草剂筛选的研究

以马唐[Digitaria sanguinalis(L.)Scop.]作为参照靶标,使用水琼脂表面涂布微孔板法及小型盆栽法对稗子[Echinochloa crusgalli(L.)Beauv]的筛选敏感性进行试验。使用微孔板法对化学除草剂标准样品、真菌及放线菌除草剂标准菌株的发酵液进行了除草活性比较;使用小型盆栽法对真菌及放线菌除草剂标准菌株的发酵液进行了除草活性比较。结果表明,微孔板法中稗子的敏感性差,尤其不适用于针对稗子的微生物源生物除草筛选;小型盆栽法中稗子与马唐的敏感度相近,适用于针对稗子的微生物源除草筛选,具有稳定高、抗杂菌污染强、操作简单等突出优点;针对稗子用于除草剂筛选中敏感性低的缺点可以通过选择适当苗龄的方法加以优化。

不同除草剂防除单季直播稻田抗药性杂草的效果

选用13%氰氟·吡啶酯乳油等新型茎叶除草剂及其组合用药,在单季直播稻田稻苗3叶期进行茎、叶喷施防除抗药性杂草示范试验。结果表明,13%氰氟·吡啶酯乳油80 mL/667 m^(2)+10%氰氟草酯乳油100~150 mL/667 m^(2)组合施用,对直播稻田抗药性稗草、千金子及其他杂草具有较理想的防除效果;10%恶唑酰草胺乳油160 mL/667 m^(2)足液喷施,对直播稻田抗药性稗草、千金子防除效果理想;10%恶唑·氰氟乳油170~200 mL/667 m^(2),对抗药性稗草、千金子、鸭舌草等阔叶杂草、异型莎草等莎草科杂草的防除效果稍差。药后13 d,参试药剂各处理对稗草的株防效为96.8%~98.8%、对总草的株防效为85.0%~98.0%;药后30 d,参试药剂各处理对稗草的株防效高达97.2%~99.0%、鲜重防效高达95.4%~99.5%,对总草的株防效高达94.1%~98.1%、鲜重防效高达94.6%~99.2%,但田间残留稗草仍能造成危害。提出了直播稻田抗药性稗草防除控草对策。

Survey and examination of the potential alternative hosts of Villosiclava virens, the pathogen of rice false smut, in China

Rice false smut is caused by ascomycete Villosiclava virens, whose potential alternative hosts have been assumed previ- ously. Here its potential alternative hosts were surveyed and identified from 2008 to 2013 in the main rice-growing regions in China. Two common weeds in paddy fields, Digitaria sanguinalis Scop. and Echinochloa crusgalli （L.） Beauv., were found to present the similar symptoms to smut diseases in a few individuals in 2012 and 2013 in Zhejiang and Sichuan provinces of China, respectively. After the examinations of the spore morphology, their infection and extension mode in hosts, pathogen cell wall components, and molecular identification, the two pathogens were identified to be the Basidiomycetes, Ustilago syntherismae and Ustilago trichophora, respectively. So far there has been no alternative host of V. virens to be identified in China. These suggest that the alternative hosts of V. virens, if they do exist, are not possible to play an important role in the pathogen life cycle and the disease epidemics.

湖南省平江县水稻田杂草发生危害趋势调查

为探明平江县水稻田杂草的种类、危害程度及分布特点,采用倒置"W"九点取样法,系统调查和分析了水稻田杂草发生危害趋势。结果表明,平江县稻田杂草种类有13种,以禾本科稗草(Echinochloa crusgalli)和千金子(Leptochloa chinensis)为主,杂草种类丰富度低;同时发现空心莲子草[Alternanthera philoxeroides(Mart.)Griseb]、反枝苋(Amaranthus retroflexus L.)和大薸(Pistia stratiotes L.)等水生入侵杂草在平江县也有一定的分布。

Synergistic Effect of Adjuvant Green Orange Peel Oil on Different Herbicides

[Objective] The paper was to explore the synergistic effect of a novel adjuvant green orange peel oil on different herbicides in direct sowing paddy field. [Method] The synergistic test of green orange peel oil on 10% cyanoflurate SC and 10% metamifop EC was conducted in 2019.[Result] The control effect of green orange peel oil 150 mL/hm^(2)+ 10% cyanoflurate SC 1 275 mL/hm^(2) on Echinochloa crusgalli and Leptochloa chinensis were significantly superior to that of 10% cyanoflurate SC 1 500 mL/hm^(2). The control effects of green orange peel oil 150 m L/hm^(2)+10%cyanoflurate SC 1 200 m L/hm^(2) on E. crusgalli and L. chinensis was equivalent to that of 10% cyanoflurate SC 1 500 mL/hm^(2). The control effect of green orange peel oil 150 mL/hm^(2)+ 10% metamifop EC 1 275 mL/hm^(2) on E. crusgalli and L. chinensis was equivalent to that of 10% metamifop EC 1 500 m L/hm^(2). [Conclusion] The green orange peel oil had certain synergistic effect on cyanoflurate and metamifop.

Rice and Barnyardgrass:Water Stress and Initial Establishment

The present work aimed to evaluate the effect of different water stress levels on the development of both rice and barnyardgrass. The study was established into greenhouse, in completely randomized design, in factorial scheme 2 × 5, with four replications. Factor “A” comprised the plant species (rice cv. BRS Querência, or the weed Echinochloa crusgalli), and factor “B” comprised the water stress levels: (T1) continuous flood (CF);(T2) 0 kPa (saturated soil);(T3) 10 kPa;(T4) 40 kPa;and (T5) 100 kPa. Plant emergence was assessed every day;plant length was measured 30 days after planting. At the end of the experiment, the number of leaves per plant, root length and shoot and root dry mass were determined. Our data supply evidence that under moderate water stress, up to approximately 40 kPa, rice tends to perform better than barnyardgrass in the initial stage of crop growth, when under equivalent plant density. However, barnyardgrass is usually present in much higher plant density than crop plants in fields traditionally cropped with rice. Thus, efficient control of barnyardgrass should be accomplished to avoid damage to rice crop by competition for environmental resources.