11%精甲·咯·嘧菌悬浮种衣剂防治水稻立枯病和恶苗病效果研究

采用种子包衣和拌种处理研究了11%精甲·咯·嘧菌悬浮种衣剂(FSC)对水稻种子出苗的影响及对立枯病和恶苗病的防治效果?结果表明:11%精甲·咯·嘧菌FSC按照药种质量比(m/m)1∶285?1∶235?1∶200包衣-浸种-催芽-播种处理, 种子发芽率和出苗率分别为79.33%~85.67%和70.20%~77.45%, 与空白对照无显著差异; 对水稻立枯病和恶苗病的防效分别为79.36%~85.29%和80.73%~89.91%?种子浸种-拌种-催芽-播种处理, 种子发芽率和出苗率分别为76.67%~81.00%和45.22%~49.14%, 其出苗率显著低于空白对照; 对水稻立枯病和恶苗病的防效分别为88.25%~90.78%和88.99%~92.66%?种子浸种-催芽-拌种-播种处理, 种子发芽率和出苗率分别为79.33%~81.67%和68.38%~71.12%, 其出苗率略低于空白对照, 对水稻立枯病和恶苗病的防效分别为73.55%~77.72%和64.33%~80.73%?因此, 11%精甲·咯·嘧菌FSC防治水稻立枯病和恶苗病的药种比(m/m)推荐采用1∶285?1∶235?1∶200, 方法为种子包衣-浸种-催芽-播种?     

假高粱种籽休眠期新探

当年成熟的假高粱种籽(颖果),无论在野外自然条件下,或在室内催芽,采种后20d开始催芽,5～7d后就能陆续萌芽,且催芽期渐迟发芽率递增,2个月后发芽率可达45%以上,3个月后发芽率能达80%以上.这说明它的休眠期只需3个月,不存在过去报道的有5～7个月的休眠期.     

防治玉米地下害虫的催芽种子包衣技术

玉米催芽种子包衣,是解决黑龙江省西部干旱地区玉米催芽坐水埯种防治地下害虫的一项关键性技术。１９９６年开始组织大面积研究应用,当年研究应用面积７万ｈｍ２;１９９７年绥化地区推广玉米催芽种子包衣面积１４．７万ｈｍ２;１９９８年研究应用推广面积２０．７万ｈ...     

四月黄瓜管理小窍门

【催芽播种】前2—3天应进行种子催芽。用新高脂膜拌种（可与种衣剂混用），能驱避地下病虫，隔离病毒感染，不影响萌发吸胀功能，加强呼吸强度，提高种子发芽率。催芽过程中要常翻动种子，使其均匀承受温度，24小时左右可开始出芽。发现种子稍露芽尖时，温度可适当降低，维持25℃左右，经2～3天种子就能出齐。芽出齐后进行播种。播种时芽端朝下，最好是使芽朝同一个方向。     

3种不同种子处理方法对水稻发芽及幼苗素质的影响

室内采用滤纸法,研究种子包衣后浸种、浸种后种子包衣和催芽后种子包衣3种不同的处理方式对稻花香、天优华占和保丰3个水稻品种发芽率及幼苗素质的影响.结果显示：在所测试的浓度范围内,分别采用3种不同的处理方式,每个水稻品种的发芽率均随着噻虫嗪·苯醚甲环唑23％悬浮种衣剂用量的增加而增加.且随着悬浮种衣剂用量的增加水稻病苗率降低;同一用量条件下,3个水稻品种发芽率由高到低依次为：催芽后种子包衣＞种子包衣后浸种＞浸种后种子包衣.病斑率由小到大依次为：催芽后种子包衣＞种子包衣后浸种＞浸种后种子包衣.这表明噻虫嗪·苯醚甲环唑23％悬浮种衣剂可以明显抑制水稻种子携带的病原菌;随着种衣剂用量的增加水稻幼苗的根数、主根长和株高增加.对天优华占、稻花香和保丰3个水稻品种幼苗素质影响由大到小依次为：催芽后种子包衣＞种子包衣后浸种＞浸种后种子包衣.这表明：水稻种子处理方法对水稻幼苗素质有一定的影响.     

吉兰泰荒漠绿洲过渡带白刺灌丛沙堆形态示量特征

白刺（Nitraria tangutorum）灌丛沙堆是吉兰泰荒漠绿洲过渡带常见的自然景观。在不同背景植被盖度下，白刺灌丛生长与沙堆形态特征如何变化，仍然未知。通过对白刺灌丛和沙堆形态参数的测量，定量分析不同背景植被盖度下白刺灌丛和沙堆形态参数的差异性，以及白刺灌丛生长特征与白刺灌丛形态之间的关系。探讨背景植被盖度对白刺灌丛沙堆演化的影响。结果表明：（1）4种背景植被盖度下白刺灌丛沙堆演化稳定，白刺灌丛沙堆各形态参数随着背景植被盖度增加逐渐向大规模、小密度方向发展。（2）从整体来看，不同背景植被盖度下白刺灌丛沙堆各形态参数之间存在良好的相关关系。（3）吉兰泰荒漠绿洲过渡带白刺灌丛沙堆长轴与短轴之间存在二次函数或幂函数关系；除样地1外，白刺沙堆高度和水平尺度之间存在幂函数关系。（4）吉兰泰荒漠绿洲过渡带白刺灌丛盖度主要集中于40%～80%，占灌丛沙堆总量的64.62%，说明研究区白刺灌丛生长状况良好。据此认为研究区白刺灌丛沙堆发育良好，暂时不会成为风沙危害绿洲的策源地。     

不同寄主对白茨粗角萤叶甲生长发育和繁殖的影响

为探究不同寄主植物对温性荒漠草原主要害虫白茨粗角萤叶甲Diorhabda rybakowi的产卵选择、生长发育及繁殖的影响,本研究以唐古特白刺、泡泡刺和大果白刺为试验材料,在实验室养虫箱恒温（27℃）条件下,以3种白刺饲养白茨粗角萤叶甲,观察记录白茨粗角萤叶甲各虫态的发育历期、存活率、羽化率、成虫寿命等生物学特性,以及白茨粗角萤叶甲成虫的产卵偏好选择;同时测定了3种白刺叶片中的可溶性糖、淀粉和游离氨基酸含量。结果如下：白茨粗角萤叶甲成虫在3种白刺上的产卵量及着卵率由高到低均为唐古特白刺,泡泡刺,大果白刺。取食3种白刺植物后,白茨粗角萤叶甲均能正常完成各阶段的生长发育;饲喂唐古特白刺的白茨粗角萤叶甲幼虫发育历期最短（13.50d）,饲喂大果白刺的幼虫发育历期最长（16.70 d）,同时,饲喂唐古特白刺的幼虫存活率最高,为97.78%,大果白刺上幼虫的存活率仅为10.54%。相应地,饲喂唐古特白刺后羽化成虫的寿命和繁殖力最高,大果白刺上成虫寿命和繁殖力最低。相关性分析表明,可溶性糖、淀粉和游离氨基酸含量与白茨粗角萤叶甲蛹期、成虫寿命、孵化率和羽化率无显著相关性,而幼虫总历期与各营养含量呈极...     

早杂2号丝瓜栽培技术

<正>1.品种选择丝瓜选用早杂2号。2.催芽播种种子先用55℃热水烫种消毒10~15 min,待水温降至20~30℃丝瓜继续浸种10~12 h,苦瓜浸种24~36 h,催芽湿度为25~30℃,当种子露白后,在大中棚内两侧靠棚膜的畦边直播,每穴播2粒,穴距l m。3.田间管理(1)水肥管理:丝瓜(或苦瓜)幼苗3~6片叶期,追施10%~20%有机肥,l~2次提苗;采收期每     

3种寄主植物对白刺夜蛾生长发育、繁殖和寿命的影响

白刺夜蛾Leiometopon simyrides是荒漠植物白刺的重要害虫, 为明确寄主植物对白刺夜蛾生长发育的影响, 以便对其进行科学监测和防控，本研究在27℃下, 利用3种寄主植物(大果白刺、泡泡刺、唐古特白刺)饲养白刺夜蛾, 观察记录白刺夜蛾幼虫的取食量、各阶段的发育历期、存活率、羽化率、雌雄性比和成虫寿命等生物学特性, 同时测定各寄主植物叶片的营养和次生代谢物质含量。结果表明, 白刺夜蛾幼虫取食大果白刺叶片的总量最少, 取食唐古特白刺的量最多。取食唐古特白刺的白刺夜蛾幼虫发育历期最短, 其次为取食泡泡刺, 取食大果白刺时历期最长。取食泡泡刺和唐古特白刺后, 白刺夜蛾幼虫的存活率和羽化率较高, 取食大果白刺存活率最低, 且无成虫羽化。在唐古特白刺上, 白刺夜蛾雌虫占比较高, 成虫寿命较长。大果白刺的叶片总酚含量和简单酚含量最高, 各营养物质含量最低, 不利于白刺夜蛾的生长发育;唐古特白刺和泡泡刺酚类物质含量较低, 营养物质含量较高, 较适宜白刺夜蛾的生长发育和繁殖。唐古特白刺为白刺夜蛾的最适宜寄主植物, 其次为泡泡刺。     

假高梁种籽休眠期新探

当年成熟的假高粱种籽（颖果），无论在野外自然条件下，或在室内催芽，采种后20d开始催芽，5～7d后就能陆续萌芽，且催芽期渐迟发芽率递增，2个月后发芽率可达45％以上，3个月后发芽率能达80％以上。这说明它的休眠期只需3个月，不存在过去报道的有5～7个月的休眠期。     

盐和PEG模拟干旱胁迫对沙米种子萌发及幼苗生长的影响

研究不周浓度盐溶液(NaCl、MgSO4、盐渍土壤)和PEG模拟干旱胁迫对沙米种子吸胀、萌发和幼苗生长的影响,并观察胁迫解除后种子的反应.结果表明:随着NaCl、MgSO4和PEG浓度的升高,沙米种子吸胀率先升后降,种子萌发率呈现不同程度降低,盐渍土壤溶液对萌发率没有显著影响;对沙米种子萌发和幼苗生长的胁迫效应是NaC...     

Factors affecting germination of oospores of Peronospora viciae f.sp. pisi in vitro

The effects of host plant exudates, light and temperature on germination of oospores of Peronospora viciae f.sp. pisi in vitro were investigated. Seed and root exudates did not increase percentage germination, whereas light inhibited germination. The first germ tubes appeared after 4, 7, and 14 days of incubation at 15, 10 and 5 °C, respectively. The eventual level of germination was highest and had similar values at 5 and 10 °C. At 20 °C germination was poor and at 25 °C no germination was observed. Oospores placed on membrane filters were incubated on soil. When oospores were retrieved from the membrane filters after six days and placed in water at 10 °C, they germinated within 2 days. On soil significantly less oospores germinated than in water. Germinability of oospores stored in the dark at 5 or 20 °C at 30 or 76% RH was studied over a two-year period. Germinability generally increased over time, but fluctuations were observed indicating the occurrence of secondary dormancy. Time courses of germinability were generally similar for oospores stored at several temperatures and humidities. No effect of light on time course of germinability was found when oospores were exposed to alternating light-dark periods or stored in continuous dark for 140 days. Percentage germination observed in a germination assay was correlated with percentage infection determined in a bioassay.     

马唐生物学特性初步研究

通过室内试验研究温度、土壤含水量、水层和土层深度对马唐萌发和生长的影响。结果表明,马唐最适萌发温度为25-35℃,最低萌发温度为10-15℃,最高萌发温度为40～45℃;马唐萌发最适土壤含水量为40％,土壤含水量低于10％、大于50％时,萌发率显著降低;水层对马唐影响较大,水层处理可显著降低马唐的出苗率;随着土层深度的增加,马唐出苗率逐渐降低,土层深度〉7cm则马唐不能出苗。     

Effect of conditions during storage of infested soil on infection of bait plants by Polymyxa betae and beet necrotic yellow vein virus

Infectivity of resting spores ofPolymyxa betae in soil stored air-dry or moist was determined by assessing infection of bait plants that were exposed to the soil. Storage of soil under air-dry conditions at room temperature resulted in a delayed onset of germination of resting spores compared to germination in soil stored under moist and cool conditions, as inferred from the infection of the bait plants. Bait plants had to be exposed for more than 12 h to flooded infested soil before germination and infection had occurred. However, when soil was prewetted for 24 h before exposing bait plants, germination, infection and transmission of beet necrotic yellow vein virus (BNYVV) were accomplished within 12 h, but only with the moistly stored soil. When resting spores isolated from roots were stored for 4 and 8 weeks under dry conditions at 22°C, germination of viruliferous spores, as measured by detection of BNYVV in bait plants exposed for 48 h to the spores, was less than that of spores stored in moist soil at 22°C. Approximately 100% of bait plants were infected after exposure to resting spores that were frozen in demineralized water or stored cool (5°C) in water or moist soil for 42 weeks. Air-dry cool storage for 42 weeks resulted in a low percentage of infection. Storage conditions of soil influence the results of bioassays for detection of rhizomania when short baiting periods are applied, whereas differences in infectivity were not detected using a bioassay with long duration.     

绿洲边缘白刺林退化植被恢复与重建技术研究

本文针对绿洲边缘天然白刺灌丛植被退化发生机制 ,采取平茬和人工降雨两种措施 ,从白刺灌丛的生长量、生物量、物种多样性以及沙丘内部水分变化量等方面入手 ,对白刺灌丛的复壮进行了初步的研究。平茬可在一定程度上促进白刺个体的生长并较小范围内改善浅层土壤水分条件。对结皮不同程度处理并结合人工降雨措施 ,均能促进白刺灌丛的生长 ,对浅层土壤水分条件具有较大幅度的影响 ,但对深层土壤水分条件不产生影响。 0 - 1 40cm范围内土壤水分条件的优劣是白刺灌丛生存生长的关键因素之一 ,改善该范围内沙丘内部水分条件对白刺灌丛的复壮具有重要的意义。     

Forecasting sclerotinia disease on lettuce: toward developing a prediction model for carpogenic germination of sclerotia

ABSTRACT The feasibility of developing a forecasting system for carpogenic germination of Sclerotinia sclerotiorum sclerotia was investigated in the laboratory by determining key relationships among temperature, soil water potential, and carpogenic germination for sclerotia of two S. sclerotiorum isolates. Germination of multiple burials of sclerotia to produce apothecia also was assessed in the field with concurrent recording of environmental data to examine patterns of germination under different fluctuating conditions. Carpogenic germination of sclerotia occurred between 5 and 25 degrees C but only for soil water potentials of >/=-100 kPa for both S. sclerotiorum isolates. Little or no germination occurred at 26 or 29 degrees C. At optimum temperatures of 15 to 20 degrees C, sclerotia buried in soil and placed in illuminated growth cabinets produced stipes after 20 to 27 days and apothecia after 27 to 34 days. Temperature, therefore, had a significant effect on both the rate of germination of sclerotia and the final number germinated. Rate of germination was correlated positively with temperature and final number of sclerotia germinated was related to temperature according to a probit model. Thermal time analysis of field data with constraints for temperature and water potential showed that the mean degree days to 10% germination of sclerotia in 2000 and 2001 was 285 and 279, respecttively, and generally was a good predictor of the observed appearance of apothecia. Neither thermal time nor relationships established in the laboratory could account for a decline in final percentage of germination for sclerotia buried from mid-May compared with earlier burials. Exposure to high temperatures may explain this effect. This, and other factors, require investigation before relationships derived in the laboratory or thermal time can be incorporated into a forecasting system for carpogenic germination.     

UNTERSUCHUNGEN ZUR BIOLOGIE UND ÖKOLOGIE DER HÜHNER-HIRSE ECHWOCHLOA CRUS-GALLI L. BEAUV.

Summary. 1. Echinochloa crus-galli is a typical grass weed of root crops in warmer regions, germinating late and thus covering the soil at a late stage. It originates in central and east Asia and is now a weed of world-wide importance.
2. High temperatures are necessary for germination which begins in spring, but not before the soil temperature reaches 15° C. Minimum, optimum and maximum germination temperatures of 13° C, 20–30° C and 40° C were found in S.W. Germany.
3. Seeds of E. crus-galli are dormant during the first 3–4 months after harvest. Those developing relatively early in the growing season require rather longer for after-ripening than seeds which mature later.
4. For optimum germination, water saturation of the soil of 70–90% is required.
5. Soil acidity has some influence, and there is an apparent germination optimum around neutrality. Light also induces germination.
6. Seeds can emerge from a relatively wide range of depths. Greatest emergence and the strongest plants resulted from seeds at 2–6 cm, but even from 10 cm a high percentage of seedlings is likely to emerge.
7. Further development proceeds rapidly. The first panicles arc already formed 6–7 weeks after emergence in favourable conditions, but full maturity is possible only if there are high temperatures in late summer.
8. E. crus-galli is a hygrophilous species, with best development on medium heavy soil, sandy loam or loamy sand with sufficient water supply.
9. E. crus-galli is indifferent to the lime content of the soil.
10. Best development occurs with high fertility, and a rich supply of nitrogen is especially important.
Recherches sur la biologie et écologie du panic Echinochloa crus-galli (L.) Beauv.     

Germination and seedling emergence of glyphosate‐resistant and susceptible biotypes of goosegrass (Eleusine indica[L.] Gaertn.)

Effects of environmental factors on the germination and seedling emergence of glyphosate‐resistant (R) and ‐susceptible (S) biotypes of Eleusine indica (L.) Gaertn. were examined under laboratory and greenhouse conditions. The R biotype exhibited a higher germination percentage compared with the S biotype at constant temperatures of 20 and 35°C under dark conditions, and alternating temperatures of 30/25°C, and 35/25°C during a 12 h photo period. For both biotypes, germination was optimal at alternating temperatures of 30/20°C and 35/20°C. However, there was no significant difference (P > 0.05) in the germination between the R and S biotypes at these temperature regimes. The germination of both biotypes was inhibited by osmotic stress imposed by a water potential of ?0.80 MPa. When the moisture stress was released and the seeds were subsequently transferred to distilled water, the germination was enhanced to approximately 90% and 16% for the R and S biotype seeds, respectively. Higher emergence rates were obtained in shallow seed depths (0 or 2 cm) compared to deep depths. Emergence percentage of the R biotype was higher than that of the S biotype at 0 cm and 2 cm depths. The maximum emergence percentage of the R biotype was higher than that of S biotype when seeds were sown on the surface of either loamy or clay loam soil taken from three different sites.     

Microbe-Mediated Germination of Ascospores of Monosporascus cannonballus

ABSTRACT Ascospores of Monosporascus cannonballus germinated readily in the rhizosphere of cantaloupe plants growing in field soil. However, little or no germination occurred in the rhizosphere of melon plants growing in field soil that was autoclaved prior to infestation with ascospores. The latter data suggested that root exudates alone do not stimulate ascospore germination and that the soil microflora may be involved in the induction of ascospore germination. Amending field soil with streptomycin (which inhibits gram-negative microorganisms) did not suppress ascospore germination in the rhizosphere of cantaloupe plants. However, amending the soil with penicillin (which inhibits gram-positive microorganisms) did suppress ascospore germination. Pentachloronitrobenzene (PCNB), which inhibits the gram-positive actinomycetes but does not inhibit gram-positive or gram-negative bacteria, also suppressed ascospore germination. These results suggest that actinomycetes, either directly or indirectly, are involved in the induction of ascospore germination in field soil in the presence of exudates from cantaloupe roots. Optimum germination occurred at temperatures ranging from 25 to 35 degrees C, and data indicate that a high percentage (>/=72%) of the ascospore population within 500 mum of a root are capable of germination and subsequent penetration of cantaloupe roots.     

Allelopathic potential of wild onion (Asphodelus tenuifolius) on the germination and seedling growth of chickpea (Cicer arietinum)

Water extracts obtained from the roots, shoots, and fruits of mature wild onion ( Asphodelus tenuifolius ) plants and soil taken from an A. tenuifolius field were used to determine their allelopathic effects on the germination and seedling growth of chickpea ( Cicer arietinum ) in the laboratory. The roots, shoots, and fruits of A. tenuifolius were soaked individually in water in a ratio of 1:20 (w/v) for 24 h to prepare the extracts. Distilled water was used as the control. The germinated seeds were taken out from the Petri dishes and counted every day for 12 days. The seeds of chickpea were also sown in sand and in each of the controlled, normal soil and the soil taken from the A. tenuifolius -infested field in Petri dishes to record the length and weight of the roots and shoots 18 days after sowing. The mean germination time reached the maximum amount for the stem and fruit extracts. The fruit extract caused the most reduction in the germination index and the germination percentage of chickpea. The different wild onion organ extracts significantly reduced the root and shoot length and biomass of the chickpea seedlings compared with the distilled water. The fruit extract of wild onion proved to be the most detrimental to the root length, shoot length, and dry weight of the chickpea seedlings. The soil beneath the A. tenuifolius plants significantly reduced the emergence, root length, shoot length, shoot dry weight, and seedling dry weight but increased the root dry weight of the chickpea seedlings. It is suggested that A. tenuifolius releases phytotoxic compound(s).