稗

In order to ascertain the allelopathy activity of Trifolium repens on weeds, the allelopathic effect of aqueous extract from the aerial part and root of T. repens under different concentrations on the germination rate, physiological and biochemical mechanism of germinating seeds of Abutilon theophrasti Medic.

为进一步明确白三叶草对杂草的化感作用，研究了不同浓度的白三叶草地上部分水浸液和根部水浸液对苘麻和稗草种子发芽率和种子萌发过程中生理生化机理的影响。

In order to ascertain the allelopathy of T.repens on weeds, the allelopathic effect of aqueous extract from the aerial part and root of T. repens. with different concentrations on the germination rate, physiological and biochemical mechanism of germinating seeds of Abutilon theophrasti Medic.

为进一步明确白三叶草对杂草的化感作用，研究了不同浓度的白三叶草地上部分水浸液、根系分泌物、挥发物对苘麻和稗草种子发芽率和杂草幼苗生长过程中生理生化机理的影响。

The research result as follows. 1. The allelopathic effects of aqueous extract, volatile oil and root exudates of White clover (Trifolium repens L.) were studied on four crops: Abutilon theophrasti Medic., Echinochloa crusgalli L.

研究结果如下： 1、以稗草、反枝苋、苘麻和白三叶草自身为受体，对白三叶草地上部分水浸液、挥发物和根系分泌物的化感作用进行生物测定。

The chloroform phase was isolated into 7 phases by column chromatograpathy, and the bioassy showed that the 1 phase has strong inhibitory effect, was 91.01% on Abutilon theophrasti M., root length, 51.35%、63.93%on Echinochloa crusgalli L, seedling length and root length, and the Amaranthus retroflexux L.,germination rate is 0, the secondly was 2 phase and 5 phas, and next we continued iaolated these two phases.

用硅胶柱对氯仿组分进行分离得到7个组分，生物测定表明组分1化感作用最强，对苘麻根长抑制率为91.01%，对稗草芽长和根长的抑制率分别为51.35%、63.93%，反枝苋的发芽率为0；其次是组分2和组分5，由于组分2的含量相对较少，对组分1和组分5继续分离。

Aqueous extract of cotton has allelopathic effect on Raphanus sativus, Brassica campestris, Lactuca indica, Brassica campestris, Echinochloa crusgall, Setaria viridis and Abutilon theophrasti and its inhibition effect gradually strengthens with increasing concentration. Aqueous extracts from stems, leaves and roots of cotton inhibit or accelerate seed germination and seedling growth, and activity of enzyme of seedling root of cotton. While aqueous extracts from stems and leaves of cotton are 0.02 gmL^(-1), root length, shoot length, lateral root number and dry weight of cotton respectively increase by 10.3%, 3.1%, 22.9% and 2.4% over the control. The above mentioned indexes are lower than the control by 34.4%, 39.2%, 40.6% and 19.0% respectively as the aqueous extracts are 0.1 gmL^(-1). At the same time, root activity and SOD activity decrease by 38.2% and 36.7%, while POD activity and MDA content increase by 52.3% and 36.5%. Growth indexes of plant receptors increase at low concentrations but decrease at high concentrations of aqueous extracts. The allelopathic effect of aqueous extract of stems and leaves is stronger than that of root.

结果表明：棉花植株水浸提液对萝卜、白菜、莴苣、油菜、稗草、狗尾草、苘麻均具有化感效应，随着作用浓度增加，抑制效应逐渐加强；棉花茎叶和根系水浸提液对棉花种子萌发、幼苗生长、幼苗根系活力、根系酶活性有抑制或促进作用，当茎叶浸提液浓度为0.02 gmL^(-1)时，棉花根长、苗高、侧根数、干重分别比对照增加10.3%、3.1%、22.9%和2.4%，当浓度为0.1 gmL^(-1)时，上述指标与对照相比分别降低34.4%、39.2%、40.6%和19.0%，而根系活力、SOD活性比对照降低38.2%、36.7%，POD活性、MDA含量较对照增加52.3%和36.5%，不同浓度棉花植株水浸提液对棉花生长呈现"低促高抑"的规律，且茎叶浸提液作用效应大于根系浸提液。

It,s allelchemicals were isolated through extraction, thin-layer chromatography, and column chromatograpathy. After the white clover was infused in ethanol and evaporation, the leavings was dissolved by water. The aqueous extract was extracted by petroleum,chloroform, ethyl acetate and n-Butanol successively, and the bioassay showed that the chloroform phase has obvious inhibitory effect, the inhibitory rate was 44.32%,88.08% on Abutilon theophrasti M., seedling length and root length, 82.08%,92.16% on Echinochloa crusgalli L., seedling length and root length, and the Amaranthus retroflexux L., germination rate is 0, the secondly was ethyl acetate phase.

运用萃取、薄层层析、柱层析等方法对白三叶草地上部分的化感物质进行初步分离，结果表明，白三叶草经乙醇浸提旋转蒸发后用蒸馏水溶解，依次用石油醚、氯仿、乙酸乙酯、正丁醇萃取，生物测定表明氯仿组分对杂草的抑制作用最强，对苘麻芽长和根长抑制率分别为44.32%、88.08%，对稗草芽长和根长的抑制率分别为82.08%、92.16%，反枝苋的发芽率为0；其次是乙酸乙酯相。

The study shows that weed density in paddy fields significantly decreases with more than 94% grass-controlling effect under SF compared with CK. Before rice booting stage, weeds compose mainly of Alopecurus pratensis, Echinochhloa crausgalli, Cynodon dactylon, Alternanthera philoxeroides, Mouochoria vaginalis, Murdannia triquetra and Eclipta prostrata in SF. During heading to ripe stage, weeds are mainly A. philoxeroides, E. crausgalli, C.

结果表明：规模稻鸭生态种养杂草密度显著降低，与水稻单一种植比较防效为94%；水稻分蘖到孕穗期稻田杂草主要由看麦娘、稗草、狗牙根、水花生、鸭舌草、水竹叶和鳢肠组成，抽穗期到成熟期主要由水花生、稗草、狗牙根和水竹叶组成。

Barnyard grass, Echinochloa crus-galli, is one of the notorious weeds worldwide. To explore the potential of Alternaria augustiovoidea strain AAEC05-3 as mycoherbicide to control barnyard grass, the effect of inoculum potential and spray volume on the pathogenicity of strain AAEC05-3 to barnyard grass and host specificity of strain were studied using pot experiment.

为了确定稗草生防菌狭卵链格孢Alternaria augustiovoidea菌株AAEC05-3防除稗草的潜力，研究了其孢子接种浓度和喷液量对该菌株致病力的影响及菌株的寄主专化性。

The dominant species in Azonopus cornpressus community were Chrysopogon acicvlatvs , Cynodon dactylon , Erernochloa ophiuroides , Paspalurn paspaloides ,Paspalurn conjugaturn and Elephantopus tornentosus.

地毯草群落结构中主要的优势植物种有竹节草、狗牙根、假俭草、双穗雀稗、两耳草以及百花地胆头等，其中以地毯草＋竹节草＋双穗雀稗和地毯草＋竹节草＋狗牙根两种群落组成类型较多。

Soil samples were collected from different ecological conditions. More than 70 Streptomyces hygroscopicus strains were isolated from the soil samples. Fermentation centrifugal supernatant of the strains were used as biocontrol agents to bioassay the seedling of rice and barnyard grass and rice pathogens of sheath blightand bakanae. Three strains showed good effects of inhibitingbarnyard grass seedling, the another three strains well inhibited the growth of rice pathogenic fungi.

从国内外不同生态条件下采集的土壤标本中分离到70多个吸水链霉菌，用其发酵离心上清液对水稻、稗草秧苗和稻纹枯病菌、恶苗病菌进行生物测定，结果有3个菌株对稗草根的生长具有较好的抑效果；有3个菌株对水稻病原菌有很好的抑制生长作用。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。