Effect of δ-aminolevulinic acid on the herbicidal efficacy of foliar-applied MTB-951, a mycoherbicide to control Echinochloa crus-galli L.

The conidia of a plant pathogen ( Drechslera monoceras [Drechsler] Subram. et Jain [=  Exserohilum monoceras [Drechsler] Leonard et Suggs]), MTB-951, which was isolated from native Echinochloa species in Japan, were used as the herbicidal active ingredient. The effects of δ-aminolevulinic acid (ALA) on the efficacy of foliar-applied MTB-951 on Echinochloa crus-galli L. were examined. First, foliar-applied MTB-951 exhibited almost no efficacy when no dew period was provided. However, the efficacy increased depending on the length of the dew period. MTB-951 and ALA exhibited an additive effect on E. crus-galli under 3 day dew conditions, although they exhibited a significant synergistic effect under no-dew conditions. When the leaves of E. crus-galli were immersed in deionized water containing the conidia of MTB-951, cellular electrolyte leakage from the leaves was observed. The ALA increased the electrolyte leakage by MTB-951 synergistically. Also, ALA increased the number of lesions on the leaves of E. crus-galli caused by MTB-951 under light conditions but failed to increase the number under dark conditions. These results suggest that ALA promotes infection with MTB-951 for E. crus-galli through its photodynamic action.     

Differential gene expression of the α-chain of mitochondrial H+-transporting ATP synthase between dormant and non-dormant seeds of paddy Echinochloa weeds

Gene expression was compared under favorable germination conditions between dormant and non-dormant seeds of rice paddy Echinochloa weeds and a domesticated Echinochloa species lacking dormancy. Two dormancy-specific cDNAs, Ecd1 and Ecd2 , were identified by differential display. Northern blot analysis revealed that these genes were more strongly expressed in dormant seeds than in non-dormant seeds. A database search for the Ecd1 sequence revealed no significant homology with any known proteins, but the Ecd2 sequence was highly homologous with the α-chain of mitochondrial H⁺-transporting adenosine triphosphate (ATP) synthase in rice ( Oryza sativa L.). These findings indicate that the gene encoding the enzyme associated with conventional aerobic respiration is more abundantly transcribed in dormant seeds. The results reported in the present study suggest that dormant seeds of paddy Echinochloa weeds, which appear during the period when paddy soil becomes aerobic by drainage, may maintain viability primarily by efficient conventional aerobic respiration, including ATP synthesis catalyzed by the mitochondrial H⁺-transporting ATP synthase.     

Molecular identification of Echinochloa oryzicola Vasing. and E. crus-galli (L.) Beauv. using a polymerase chain reaction–restriction fragment length polymorphism technique

Polymerase chain reaction (PCR) and polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) techniques were applied for establishing the reliable practice in identification of Echinochloa oryzicola Vasing. and E. crus-galli (L.) Beauv. (barnyardgrass). Total DNA was extracted from 18 accessions and 86 individuals of E. oryzicola , 33 accessions and 140 individuals of E. crus-galli var. crus-galli , 23 individuals of E. crus-galli var. praticola , and six individuals of E. crus-galli var. formosensis that were collected from Japan. A partial region of intergenetic spacer between trn T and trn L, and an intron of trn L were amplified separately using a trn-a and trn-b1 primer set, and a trn-c and trn-d primer set, respectively. All individuals of E. oryzicola showed the same fragment amplified by the trn-a and trn-b1 primer set. The fragment was 481 bp in length, and was undigested by Eco R I, whereas all individuals of E. crus-galli , including three botanical varieties, showed the same fragment with a 449-bp length. The fragment was digested by Eco R I into two fragments (178 and 271 bp). The fragment amplified by the trn-c and trn-d primer set in all individuals of E. oryzicola was digested by Alu I into two fragments (174 and 452 bp), but undigested by Dra I. In contrast, the fragment amplified by the trn-c and trn-d primer set in all individuals of E. crus-galli was digested by Dra I into two fragments (134 and 487 bp), but undigested by Alu I. There was no intraspecific variation in these regions; thus, these two species are easily identifiable by using our method.     

N-硝基二苯基脲衍生物的除草活性研究

测定了6个N-硝基二苯基脲衍生物( Ⅰ )在500 mg/L浓度下对稗草Echinochloa crusgalli和绿苋Amaranthus viridis的除草活性,从中筛选出两个化合物 Ⅰ b 、 Ⅰ e 做系列浓度试验。结果表明,它们对稗草、绿苋均表现出一定的抑制活性,且随着浓度增加,抑制活性增强。     

不同处理方法对稗草种子萌发的影响

以湘中地区稗草种子为材料,研究了不同处理方法对其萌发的影响.结果表明,GA3、浓硫酸、KNO3、NaOH及温度处理等都有利于稗草种子的萌发,但促进效果存在较大差异.GA3 1 000～1 500 mg/L浸种24 h和浓硫酸浸种15～20 min均能促使稗草种子萌发率保持在70.0％以上;NaOH 1.5％处理使稗草种子萌发高达93.7％,但高于该浓度处理时萌发率显著降低;KN03处理对稗草种子虽具有一定作用,但效果不甚理想,萌发率低于35.5％;20～25℃温度处理能有效促进稗草种子萌发,发芽率在68.2％～75.8％.     

Plant links between eastern Asia and eastern Australia*

Plant links between eastern Asia and eastern Australia, regions showing considerable climatic differences, are discussed under five headings, namely, garden plants or ornamentals; naturalized plants; plants used in traditional Chinese medicine or Oriental Materia Medica; plants not yet well enough studied whose distribution suggests they may have originated in regions of the western Pacific; and comparisons between barnyardgrasses (Echinochloa spp.) in the two regions. A table is presented showing simple climatic data; mean monthly maximum and minimum temperatures and mean monthly and annual precipitation, along with latitude and altitude for 25 places extending from Monbetsu (about 44 N) in Hokkaido, Japan, through the subtropics and tropics to Hobart (approximately 43 S) in Tasmania, Australia.     

8种稗草(Echinochloa）对扫茀特耐药性的比较

2001年10月采集南京地区8种稗草（Echinochloa）种子,分别用0、0.01、0.10、1.00、10.00 mg/L扫茀特浸稗草种子,萌发后测定其形态、结构及α 淀粉酶活性。结果表明,无芒稗的株高、叶片及叶鞘细胞的长度、α 淀粉酶活性受扫茀特抑制的程度最低,旱稗、稗、西来稗次之,光头稗最高。说明不同稗草的种及变种间存在耐药性的差异,其中无芒稗的耐药性最强,光头稗最弱。关键词:     

狭卵链格孢菌毒素细交链孢菌酮酸对稗草细胞膜脂质过氧化作用的影响

为明确狭卵链格孢菌Alternaria augustiovoide菌株AAEC05-3产生的毒素细交链孢菌酮酸(tenuazonic acid,TeA)的作用机制,利用离体试验,研究了TeA对稗草叶片细胞膜脂质过氧化的影响。结果显示,低浓度TeA处理对稗草叶片的细胞膜透性和脂质过氧化影响不大;用高浓度TeA处理稗草叶片24 h后,稗草叶片细胞膜透性和脂质过氧化作用显著增强。TeA浓度为100 μmol/L时,稗草叶片相对电导率和丙二醛(MDA)含量分别增加28.21%和63.58%;脂氧合酶(Lox)活性增高61.59%,且不饱和脂肪酸含量显著降低,亚油酸(18∶2)和亚麻酸(18∶3)分别降低19.56%和17.20%,脂肪酸氢过氧化物在叶片中大量积累。表明TeA可以诱导稗草叶片细胞膜的脂质过氧化作用。     

三种杂草对草甘膦的敏感性及处理后植株体内莽草酸积累量差异

为明确不同杂草对草甘膦的敏感性,以稗 Echinochloa crusgalli 、马唐 Digitaria sanguinalis 、藜 Chenopodium album 为供试材料,采用生物测定法和吸光光度法分别测定了草甘膦对3种杂草的抑制中浓度(GR50),以及不同剂量处理后杂草体内莽草酸积累量的变化。经410 g/hm2(有效成分)的草甘膦处理后,稗体内莽草酸积累量呈上升-下降-上升趋势,而马唐和藜则表现为缓慢上升,根据此剂量处理下莽草酸积累趋势得出,3种杂草对草甘膦的敏感性由高到低依次为稗、藜和马唐,与生测法的结果一致。经820~3 280 g/hm2(有效成分)的草甘膦处理后,3种杂草体内莽草酸积累量从第2 d开始急剧升高,增长速率随着草甘膦处理剂量的增加而加大;处理后稗、马唐和藜体内莽草酸积累量最高值差异显著,分别为1 137.9、4 989.7和2 084.2 μ g/g,为各自对照水平的16.7、23.7和82.9倍。该研究结果可为系统检测杂草对草甘膦的敏感性提供依据。     

抗旱耐盐碱、粮草兼收作物新品种−谷稗

\t\t\t\t\t目的\t\t\t\t\t探究不同⁶⁰Co-γ 射线辐射对朝牧1号谷稗种子幼苗生长以及生理效应的影响。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t以朝牧1号谷稗种子为试材,采用0、50、100、150、200和250 Gy的⁶⁰Co-γ 射线辐射谷稗种子,对不同辐射剂量的谷稗种子进行幼苗培养,测定辐射对其幼苗的生长和叶片生理生化的影响,并对各指标进行相关性和主成分分析。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t辐射抑制了谷稗幼苗的生长,250 Gy对其幼苗的生长抑制作用较强;随着辐射剂量的增加,可溶性糖、脯氨酸、可溶性蛋白和总叶绿素含量均呈先增后减的变化趋势,相对电导率和丙二醛含量呈先减后增的变化趋势,过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性均呈先增后减的变化趋势。\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t综合主成分的方差贡献率和主成分的原性状相关矩阵值计算出特征向量分析发现,50~200 Gy辐射剂量可用于谷稗的辐射育种。 \t\t\t\t