The effect of C-2-carboxyphenyl derivatives of certain heterocyclic compounds on root geotropism in cress seedlings

The effects on root geotropism of 2-carboxyphenyl derivatives of various five- and six-membered heterocyclic compounds have been assessed. In an assay involving cress seedlings, appropriately substituted derivatives of isoxazole, 1,3,4- and 1,2,4- oxadiazoles, 1,3,4-thiadiazole, 1,2,4-triazole, thiazoie, pyridine, pyrimidine and pyridazine were highly effective in eliminating the geotropic response.     

The effect of waterlogging on Phytophthora root rot of red raspberry

Red raspberry plants were subjected to waterlogging after inoculation with different species of Phytophthora isolated from field outbreaks of root rot. The commonest species, a form of P. megasperma , was highly pathogenic to raspberry whether the plants had been waterlogged or not, but waterlogging increased the severity of disease caused by other species. P. cambivora and P. drechsleri were moderately pathogenic and non-pathogenic respectively in non-waterlogged conditions but killed plants that had been waterlogged for 4 days. P. megasperma var. megasperma required longer periods of waterlogging to cause severe symptoms and did not kill plants. Root rotting of waterlogged and non-waterlogged plants was controlled with a metalaxyl and copper mixture. The results indicated that several species of Phytophthora may contribute to poor growth and death of raspberries grown in poorly drained sites.     

Effect of substituted pyrazoles and related compounds on geotropism in cress seedlings

The effects on root geotropism of three series of compounds related to 2-phenyl-8H-pyrazolo[5,1-a]isoindol-8-one (IV), its 3,3a-dihydro derivative (V) and 5-(2-carboxyphenyl)-3-phenylpyrazole (VI) have been assessed using cress seedlings. Compounds (IV) and (VI), and their derivatives, are highly active, destroying geotropism at concentrations of 10^?7-10^?9M. Substitution with various functional groups and increased molecular size resulted in only minor variation in the level of activity.     

灌溉对粮饲兼用玉米根系分布及产量影响

通过大田试验,在灌溉量2700m3/hm2、3600m3/hm2、4500m3/hm2条件下,对粮饲兼用玉米根系分布特征及产量影响进行了研究。结果表明:1)3600m3/hm2的灌溉量在0～40cm土层的土壤含水率较充分灌溉显著提高4.78%～19.3%;2)各灌溉条件下,根系随生育进程不断向下发展,随灌溉量的减少,根系有向深层发展的趋势;3)3600m3/hm2的灌溉条件下,粮饲兼用玉米籽粒产量较充分灌溉显著提高11.3%;4)秸秆产量在充分灌溉条件下较高,尤其在抽雄至乳熟期达到最高。     

Bioassay to assess root rot in pea and effect of root rot on yield

Infection of pea roots by soil-borne pathogens causes foot and root rot. In 1985 research was started to develop a method to predict the root rot likely to occur in prospective pea fields. In a bioassay the pea cultivar Finale was sown in a composite soil sample from each field in pots under standardized conditions in the greenhouse. The plants were removed at the green bud stage and the severity of root rot recorded. Between 1985 and 1988 approximately 200 field pea crops were monitored for root rot development. Forty-eight fields were bioassayed in 1986, 51 in 1987 and 30 in 1988. Each year, root rot readings in the bioassay and disease severity readings at field sampled plants at flowering and green pod were linearly correlated (P<0.001). As the degree of root rot in the field crop increased, there was a proportional lower yield. In heavily infested fields, up to a 50% yield reduction occurred.The bioassay in pots proved to be a reliable method for predicting root rot severity in sampled pea fields.     

人参根系腐解物对十字花科植物的化感作用

采用人工腐解方法研究了人参根系腐解物对3种十字花科作物小白菜、油菜和萝卜的化感作用.结果表明,人参根系腐解物对小白菜和油菜种子的萌发有抑制作用,且降低了α-淀粉酶的活性;对小白菜和油菜幼苗的生长表现为低浓度促进、高浓度抑制的作用;对萝卜种子的萌发和o-淀粉酶活性表现为中、低浓度促进生长,高浓度抑制,对其下胚轴和鲜重均有促进作用.     

水分胁迫持续时间对冬小麦根冠生物量累积的影响

为了解冬小麦根、冠对土壤含水量变化的响应,对不同水分条件下温室盆栽冬小麦作了分析研究。该试验包括七个水分状态,充分供水A处理(75%~100?,FC为田间持水量),中度胁迫B处理(55%~65?)和重度胁迫C处理(35%~45?)以及分蘖期开始中度、重度胁迫到孕穗期复水的BA1、CA1处理和抽穗期复水的BA2、CA2处理。试验结果表明:分蘖期开始的水分胁迫无论何时恢复供水都不影响冬小麦根、冠生长过程的总趋势;但随胁迫程度、胁迫持续时间的增加,胁迫期内根、冠的相对生长率,根、冠总重均降低,但根重占有量增大,且水分供应量的减少和胁迫时间的延长使冬小麦生育周期提前结束;随胁迫的增加,胁迫时间的延续,最大根重减小,但较大根重维持的时间延长;当复水后,各处理对复水存在不同程度的滞后效应和激发补偿生长,导致短期胁迫的根重占有量小于长期胁迫处理,中度胁迫小于重度胁迫,冠重也随之改变。造成此现象的原因:水分胁迫影响植株的功能,但自适应能力的作用促使分配于根系的同化物质增加,改善和提高根系的吸水能力,缓减植株由于缺水造成损失;对于供水超过75?的植株,生育后期的冠重占有量较小,根重较大则归因于生长过程已形成的庞大根系。     

The effect of three irrigation practices on phytophthora crown and root rot of apple trees under field conditions

The effect of microjet, drip, and two durations of sprinkler irrigation systems on phytophthora crown and root rot of apple trees was examined under field conditions. This eight year study indicates that crown and root rot caused byPhytophthora cactorum was most severe where young MM. 106 rootstock trees were watered by microjet irrigation for 2.3 h each day. There was no difference in infection byP. cactorum when trees were irrigated either by drip or sprinkler irrigation systems. The MM.106 apple rootstock trees watered by drip irrigation for 2.6 h each day were least affected by phytophthora crown and root rot.     

8种杀菌剂对白术根腐病防治研究

本研究利用室内毒力测定法测定了白术角担菌对8种杀菌剂的敏感性,同时开展田间试验测定了8种杀菌剂对白术根腐病的防治效果。结果表明:50%多菌灵可湿性粉剂、40%五硝·多菌灵可湿性粉剂、30%苯甲·丙环唑乳油和430g/L戊唑醇悬浮剂对角担菌的菌丝抑制率相对较高,EC50均低于10mg/L。田间试验结果表明:末次施药20d后40%五硝·多菌灵可湿性粉剂1 000倍液、50%多菌灵可湿性粉剂1 000倍液、30%苯甲·丙环唑乳油2 000倍液和430g/L戊唑醇悬浮剂3 000倍液的防效均超过58%,而且防效之间无显著性差异,各药剂处理对白术的生长无显著性影响。     

黄瓜根分泌物中的7,8-苯并黄酮及其对枯萎病发生的影响

分别提取黄瓜枯萎病感病品种津研4号和抗病品种中农10号的根分泌物,感病品种根分泌物甲醇提取液能够刺激枯萎病菌的菌丝生长,而抗病品种根分泌物甲醇提取液则抑制病原菌生长。利用LC-MS/MS技术分别对感病品种和抗病品种根分泌物中的差异物质进行分析鉴定。与感病品种津研4号相比,抗病品种中农10号根分泌物中含有7,8-苯并黄酮(7,8-BF),含量为0.02μg/株。50μg/mL的7,8-BF能够显著抑制黄瓜枯萎病菌菌丝生长和孢子萌发,而100μg/mL的7,8-BF能显著抑制抗感品种侧根形成,但是抗病品种的耐受力高于感病品种。用7,8-BF处理黄瓜种子,枯萎病侵染程度显著降低。当7,8-苯并黄酮浓度为50μg/mL时,感病品种病情指数从71.7降为30.8,达到中抗水平。     

Interaction ofPseudomonas fluorescens withRhizobium for their effect on the management of peanut root rot

A biocontrol agent (Pseudomonas fluorescens) and a phytostimulator (Rhizobium) have been shown to have beneficial effects on plant growth and health. The study of plants inoculated withPseudomonas andRhizobium requires special attention because of the possibility that these agents may influence each other. Our study was conducted to test the effect of these inoculants on co-inoculation in peanut to control root rot, a severe soilborne disease caused byMacrophomina phaseolina. One fluorescent pseudomonad strain, Pf 1, which effectively inhibited the mycelial growth ofM. phaseolina underin vitro conditions, was studied for its compatibility with the biofertilizer bacterial strainRhizobium TNAU 14. Dual culture and colorimetric studies indicated the existence of a positive interaction between the microbial inoculants. However, glasshouse and field studies showed seed treatment and soil application ofPseudomonas fluorescens Pf 1 to be the most effective treatment in reducing root rot incidence and improving the crop vigor index, in comparison with treatments in which both inoculants were applied. http://www.phytoparasitica.org posting Feb. 11, 2002.     

长期膜下滴灌对根区土壤盐分及棉花生长影响研究

通过比较典型灌区内7个(试验设计两个研究区共14块棉田)不同膜下滴灌年限棉田盐分分布,尝试揭示长期膜下滴灌农田根区土壤中盐分演变趋势。两研究区均表现为,应用膜下滴灌技术棉田根区盐分随着该技术应用年限的延长而逐渐降低;且表现为滴灌<6a为迅速脱盐阶段,6~8a为平稳脱盐阶段,>8a为盐分稳定阶段。头年10月至翌年4月,膜下滴灌棉花根层盐分降低显著。滴灌棉田根层盐分的逐年降低,使得棉花根区生境得到改善,应用膜下滴灌技术5~7a内,其对棉花根层生境改良效果较明显,3~7a棉花成活率年均增幅大于26.75%、产量年均增幅超过19.57%。滴灌7~9a以上,棉花根层生境良好,成活率大于82%,产量超过5200.00kg/hm2。     

Investigations on the effect of haulm destruction and additional root cutting on black scurf on potato tubers

In greenhouse experiments factors which are involved in the stimulation of sclerotia formation byRhizoctonia solani Kühn on potato tubers after haulm destruction were investigated. Cutting off the shoot stimulated the production of sclerotia as much as chemical haulm destruction. This was also observed when potato tubers were grown away from the roots in a separate compartment filled with steamed perlite. Fewer sclerotia were produced when roots were cut in addition to haulm destruction compared to haulm destruction alone. Cutting off the roots alone often stimulated sclerotia production. The data indicate that sclerotia production was directly affected by the tuber and probably due to physiological changes in the tuber caused by elimination of the shoot.Samenvatting In kasproeven werd onderzocht welke factoren betrokken zijn bij de stimulering van de produktie van sclerotiën op aardappel doorRhizoctonia solani Kühn als gevolg van loofvernietiging. Afknippen van het loof stimuleerde de vorming van sclerotiën evenzeer als chemische vernietiging. Na afknippen van het loof trad de stimulering ook op bij knollen, die zich ruimtelijk gescheiden van de wortels in gestoomd vochtig perliet konden ontwikkelen. Doodspuiten plus doorsnijden van de wortels resulteerde in minder lakschurft dan doodspuiten alleen. Wanneer alleen de wortels werden doorgesneden resulteerde dat vaak in meer lakschurft. De vorming van sclerotiën wordt dus direct door de knol beïnvloed. Dit effect lijkt voort te komen uit fysiologische veranderingen in de knol.     

12种生物源杀菌剂对白术根腐病的防效

利用室内毒力测定法测定了白术角担菌对12种生物源杀菌剂的敏感性,同时开展田间试验测定了7种生物源杀菌剂对白术根腐病的防治效果.结果 表明:0.5％小檗碱水剂、0.3％丁子香酚可溶性液剂、1％蛇床子素水乳剂、3％中生菌素可湿性粉剂、0.5％大黄素甲醚水剂、80％大蒜素乳油和0.5％苦参碱水剂对角担菌的菌丝生长抑制率相对较...     

3种种衣剂对芸豆根腐病的防治效果

为了筛选对芸豆根腐病安全有效的药剂,开展了3种种衣剂对芸豆的室内安全性和根腐病田间防治效果研究。结果表明,25%噻虫·咯·霜灵悬浮种衣剂、25g/L咯菌腈悬浮种衣剂和38%多·福·克悬浮种衣剂在试验设定的包衣药种比下处理种子,对芸豆种子发芽和秧苗生长安全;田间试验结果表明,在芸豆出苗后10d,25g/L咯菌腈悬浮种衣剂和25%噻虫·咯·霜灵各处理的防效均在80%以上,其中药种比为2g/kg的25g/L咯菌腈悬浮种衣剂处理的防病效果最好,达到92.92%。芸豆出苗后30d,药种比为2g/kg的25%噻虫·咯·霜灵悬浮种衣剂的防病效果最好,为59.83%,且考种期测产结果表明,增产幅度达29.43%。但25g/L咯菌腈悬浮种衣剂处理防治效果持效期较短,芸豆出苗30d后防效均降到50%以下且产量增幅较低。综上所述,25%噻虫·咯·霜灵悬浮种衣剂对芸豆根腐病防治效果最好且安全。     

4种药剂对豇豆根结线虫病的防治效果

为了更好地防治豇豆根结线虫病,对4种杀线虫剂进行了田间防效评价试验。结果表明,供试的4种药剂均对豇豆根结线虫有一定的防效,能控制土壤中２龄幼虫的数量和抑制根结的形成,其中10％噻唑膦颗粒剂对豇豆根结线虫的防效最好,具有低残留、持效期长等优点,可作为防治豇豆根结线虫的首选药剂; 其次为５％阿维菌素颗粒剂。同时供试的4种药剂在试验剂量范围内均对豇豆安全,建议在生产上推广应用10％噻唑膦颗粒剂和５％阿维菌素颗粒剂来防治豇豆根结线虫病。     

Thick root of cucumber: other susceptible plants and the effect of pH

Thick root is a relatively new disorder of cucumber grown in artificial substrates. Plants of cucumber, tomato, sweet pepper, lupin, anthurium, Cucurbita ficifolia , C. maxima and two lines from crosses between C. maxima and C. moschata were grown in thick root disease (TRD)-infested nutrient solutions containing the TRD agent. Plants from each species or line, except anthurium, developed TRD symptoms. Growth of diseased plants, except those of the line C. maxima  × C. moschata RS841, was significantly reduced compared with the nondiseased controls. Two weeks after infestation, by adding TRD-affected nutrient solution to fresh nutrient solution, the presence of the infective TRD agent was shown in each of the nutrient solutions in which the plants had been grown, including anthurium. No infective TRD agent could be shown in nutrient solution that had not been in contact with roots of living plants. The minimum pH for thick root formation was shown to be between 5·0 and 5·5. Nutrient solutions with pH values ranging from 4·0 to 6·5 and infested with the TRD agent lost their infectivity within 8 days. The infective period decreased with decreasing pH (pH 4·0–6·5) and a pH effect on the infectivity of a nutrient solution was shown within 1 h of infestation. The data show that the risk of TRD can be reduced by decreasing the pH of the nutrient solution.     

不同土壤处理剂对设施蔬菜黄瓜根结线虫防治技术研究

为了筛选蔬菜根结线虫的防治技术,在赤峰市进行了7种不同土壤处理药剂对黄瓜根结线虫的防治效果田间试验,结果表明,应用7种不同土壤处理药剂进行土壤处理,揭膜放气5d后定植黄瓜,对黄瓜生长无不良影响,而且对根结线虫均有较好的抑制作用,其中98.1％1,3-二氯丙烯-氯化苦复配胶囊16 kg/667 m2、95％1,3-二氯丙烯液剂65 kg/667m2及10％液体石灰氮65 kg/667m2对黄瓜根结线虫的防治效果达90％左右,优于目前生产中常用药剂42％威百亩水剂6 kg/667m2和10％噻唑磷颗粒剂2 kg/667m2的防治效果,并且可以显著地提高黄瓜产量,适于在设施蔬菜生产上推广使用.     

The behaviour of certain chemotherapeutants in laboratory and greenhouse tests

The use of a series of tests in the assessment of systemic and chemotherapeutic activity of new compounds is discussed and illustrated with structure-activity studies on analogues of triforine, chloraniformethan and carboxin.