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1.
The effect of agronomic doses of three suspension concentrate formulations and two anionic surfactant adjuvants on the solubilisation and sorption characteristics of triticonazole fungicide in a loamy clay soil was investigated. Soil sorption of [14C]triticonazole alone, in the formulations, and in the presence of increasing doses of formulation additives was measured using the classical batch equilibration technique. Triticonazole solubilisation in water‐formulation systems was also evaluated using a batch procedure, and sorption of the formulation aqueous phases on soil was examined. Solubilisation of triticonazole in the formulation systems occurred in excess of the solubility in water (Sw). This was attributed to triticonazole association with surfactant monomers. Sorption isotherms of triticonazole with diluted surfactants and other formulation additives were similar to that of triticonazole alone. We concluded that in soil‐formulation systems, triticonazole solubilisation in excess of the Sw may increase the amount available in soil solution for plant absorption. However, triticonazole molecules preferentially associated with the soil surfaces, and the presence of diluted amounts of the formulation adjuvants would not significantly affect the soil sorption process. © 2000 Society of Chemical Industry  相似文献   

2.
The uptake of 14C-labelled triticonazole by wheat caryopses during imbibition was investigated. The uptake from an aqueous solution appeared to be driven by mass flow rather than by accumulation in seed lipids. During treatment with a liquid seed-dressing preparation of triticonazole, c. 1 μg triticonazole per caryopsis (2·4% of applied triticonazole) entered the seed. During germination in soil, another c. 1 μg triticonazole per caryopsis entered the seed in 24 h. In killed seeds, no penetration was observed between 24 h and 72 h after the beginning of imbibition. After seed treatment and imbibition in soil, triticonazole appeared to be located in the seed coats and embryo, but not in endosperm; experiments suggested that the testa acted as a barrier. Under our conditions, the pathway from seed coats to shoots was not an important route for triticonazole uptake by the shoots. © 1997 SCI.  相似文献   

3.
Maize kernels were treated with the fungicide triticonazole (RP-727), belonging to the triazole family. The nuclear DNA content was analyzed in various maize plant organs by using flow cytometry. Two fluorochromes with different DNA binding mechanisms were used for probing nuclear DNA and chromatin structure. Results indicated nuclear alterations with the use of triticonazole and the alterations observed were different in the various tissues analyzed. Active meristematic plant organs, such as root tip, did not show any significant change in nuclear DNA, but chromatin structure was altered with increasing concentrations of fungicide. Stem and mesocotyl showed both DNA and chromatin condensation changes with triticonazole concentration, but the trends observed in these two plant organs were opposite. The magnitude of the alterations was minute in the different plant organs studied. These alterations do not appear to be deleterious for normal plant development.  相似文献   

4.
Following seed treatment of wheat (Triticum aestivum L.) with 14C-labelled triticonazole at a dose of 1·8 g kg-1 seed, the uptake of radioactivity by shoots and roots was investigated from the two- to three-leaf stage up to the beginning of the booting phase, 80 days after sowing. Triticonazole equivalents taken up by wheat plants reached 5·7% and 14·6% of the applied dose in the shoots and the roots, respectively. Between the two- to three-leaf stage and the beginning of the booting phase, the concentration of triticonazole equivalents in the shoots decreased from 2·5 to 0·15 μg g-1 fresh weight. This was attributed to uptake of triticonazole by roots not keeping pace with shoot growth and increased retention in the roots of triticonazole taken up. The main factor limiting the uptake of triticonazole by the roots may be the rapid growth of the uptake-active apical root parts out of the dressing zone which had formed in the soil. Distribution of triticonazole equivalents taken up by the main shoot showed a decreasing concentration gradient from the oldest to the youngest leaf. An increase in the seed treatment dose was investigated as a way to increase the concentration of triticonazole in the shoots, but its influence remained limited. © 1998 SCI  相似文献   

5.
The probability of seed consumption by surface-dwelling predators depends on the duration of seed exposure on the soil surface. We investigated seed burial using painted ceramic beads as surrogate seeds. Fifty beads of three size classes each were applied to small arenas within crop fields and their fates were followed from August to October. New sets of beads were applied as soon as most beads had disappeared from the soil surface. Bead availability on the soil surface declined immediately after placement, and then declined steadily over time, with increased loss during rain and management practices. Smaller beads were incorporated into the soil/litter matrix more easily than larger beads. Bead burial differed considerably among crop environments, with more burial in forage crops (red clover, lucerne) than in row crops (soyabean, maize). The fact that seed availability differed among crop environments suggests that it can be manipulated to maximise predation risk.  相似文献   

6.
The sorption of two anionic surfactants and a series of seven nonionic alkylphenolethoxylate surfactants of increasing hydrophilic/lipophilic balance (HLB) in a loamy clay soil was evaluated. The effect of low doses of these surfactants on the sorption characteristics of the fungicide triticonazole was investigated. The critical micellar concentration (CMC) of the surfactants in pure water and soil–water systems, and surfactant sorption were estimated by surface tension measurements using a batch equilibration technique. Triticonazole sorption, alone and in the presence of low doses of surfactants, was also measured by batch equilibration. CMC of the alkylphenol surfactants increased with their HLB. The sorption of surfactants increased with their lipophilicity. CMC in the soil–water systems were considerably higher than in pure water. Sorption of the most lipophilic alkylphenol surfactants at the higher doses significantly increased triticonazole sorption. Proposed mechanisms are modifications of soil surface properties, and increase of soil organic carbon content. Sorption of the other nonionic and anionic surfactants only resulted in monomeric surfactant concentrations in pore water, and did not affect triticonazole sorption. © 1998 Society of Chemical Industry  相似文献   

7.
采用ISTA滤纸法检测得出:20%邻烯丙基苯酚悬浮种衣剂按1∶ 30~1∶ 90药种比(质量比)包衣处理"中农8号"和"长春密刺"黄瓜品种的种子,对黄瓜种子安全,种子发芽率分别达到95.75%~97.75%和80.00%~84.25%;PDA平板上检测药剂包衣处理对黄瓜种子带菌消毒效果显示,消毒处理效果达到66.67%~100%。菌丝生长速率法和染色处理结合显微技术实验证实,邻烯丙基苯酚对危害黄瓜秧苗的土传病原菌腐霉病菌Pythium aphanidermatum和立枯丝核菌Rhizoctonia solani具有较强的抑制作用,EC50值分别为27.59和34.16 μg/mL;药剂处理使供试病菌的菌丝发生中空、解体断裂等异常现象。20%邻烯丙基苯酚悬浮种衣剂1∶ 30~1∶ 90包衣处理黄瓜种子后接种供试病菌,对腐霉病菌和立枯丝核菌的防病效果分别达到73.31%~100%和85.16％~100%;随着药剂包衣处理浓度的增大,邻烯丙基苯酚防治两种病原菌侵染危害黄瓜秧苗的效果提高,等效或者优于常规药剂福美双种子处理。  相似文献   

8.
为了探究石羊河流域地下水资源的利用方式,在甘肃省石羊河流域开展了为期2年的制种玉米咸水非充分灌溉田间试验,试验设置3种灌水水平即w1(1ETc)、w2(2/3ETc)、w3(1/2ETc),3种盐分水平即s1(矿化度0.71 g·L~(-1),淡水)、s2(矿化度3 g·L~(-1))、s3(矿化度6 g·L~(-1)),共9个试验处理,研究咸水非充分灌溉对土壤水盐动态及制种玉米生长的影响。研究结果表明:咸水非充分灌溉条件下,由于灌溉水量和灌水矿化度不同,土壤水盐动态表现出不同的特征,非充分灌溉处理土壤含水量低于充分灌溉处理,咸水灌溉处理土壤含水量高于淡水灌溉处理;充分灌溉处理盐分累积较深,非充分灌溉处理盐分主要累积在表层土壤和根系吸水层土壤。灌溉水量采用2/3 ETc的非充分灌溉方式进行灌溉,土壤盐分随着水分运移,盐分主要累积在表层土壤和根系吸水层土壤,短时期采用灌水矿化度为3 g·L~(-1)的微咸水灌溉,盐分不会在土壤产生大量累积。因此,在研究区灌溉水量控制在2/3 ETc左右,灌水矿化度不超过3 g·L~(-1),对制种玉米生长的影响较小,减产幅度在11%以下,能够达到合理利用地下咸水资源和节水灌溉的目的。  相似文献   

9.
Understanding the characteristics of soil seed banks in sand dunes is crucial to stabilize the dune systems and maintain the plant populations in deserts. In this study, we conducted a survey investigation in the field and a seed germination experiment in the laboratory to explore the characteristics of soil seed banks at various geomorphic positions of longitudinal sand dunes in the Gurbantunggut Desert, China. Totally, 17 plant species belonging to 17 genera and 9 families were identified in soil seed banks, and 35 plant species belonging to 34 genera and 17 families were identified in aboveground vegetation. Plant species richness in soil seed banks decreased with increasing soil depth. The highest species richness was presented in the upper slope of the windward slope and the lowest species richness was presented in the base of the windward slope. There was no significant difference in seed density of soil seed banks among the examined seven geomorphic positions. The highest seed density occurred in the lower slope of the leeward slope while the lowest occurred in the crest. Moreover, seed density decreased with increasing soil depth, being the highest in the upper soil layer(0–2 cm). For both soil seed banks and aboveground vegetation, there was no significant difference in Simpson's diversity index among the seven geomorphic positions; however, Shannon-Wiener diversity index and Pielou's evenness index showed significant differences among the seven geomorphic positions. Those results showed that although there was no significant difference in seed density of soil seed banks among the seven geomorphic positions, the geomorphic positions significantly affected the species richness, diversity and distribution of soil seed banks. Therefore, understanding the characteristics of soil seed banks at different geomorphic positions of sand dunes is essential to vegetation restoration or reestablishment. Furthermore, the Jaccard's similarity coefficients of plant species between soil seed banks and aboveground vegetation at the seven geomorphic positions were low, suggesting that vegetation restoration or reestablishment processes should be promoted through adding seeds to surface layers.  相似文献   

10.
Wheat (Triticum aestivum cv. Lakhish) seeds were coated with Promet 666, a seed dressing formulation of furathiocarb, a systemic soil insecticide, at 5 and 15 ml/kg seeds. This treatment was evaluated forPratylenchus mediterraneus control and wheat grain yield and compared with soil application of a granular formulation of Promet and with a nontreated control. AU Promet treatments reduced the nematode population level and increased the yield. The best nematode kill (75%) was achieved by the soil application, followed by the high-dosage seed dressing (50%). The highest yield was obtained in the high-dosage seed dressing treatment, followed by the soil application. The results suggest that seed dressing protects the germinating seedling from nematode attack at the critical stage of its root system development.  相似文献   

11.
采用菌丝生长速率法，测定了灭菌唑对水稻恶苗病菌的毒力，测得灭菌唑对10株水稻恶苗病菌的EC50值范围为0.0664~0.7661 μg/mL。采用有效成分质量浓度分别为60、120和240 μg/mL的25 g/L灭菌唑种子处理悬浮剂处理水稻种子后，对水稻发芽率、株高、鲜重均无影响。表明灭菌唑对水稻恶苗病菌具有较好的抑制活性，且对水稻安全，可用于水稻恶苗病的化学防控。氰烯菌酯对10株水稻恶苗病菌的EC50值范围为0.0076~0.2629 μg/mL。将氰烯菌酯和灭菌唑分别按质量比4 : 1、3 : 1、2 : 1、1 : 1、1 : 2、1 : 3和1 : 4复配，测定了复配药剂对水稻恶苗病菌的联合毒力，所得增效系数在0.5~1.5之间，均为相加作用。研究表明，将氰烯菌酯与灭菌唑复配后施用，不仅能显著降低单剂的使用剂量，且能降低氰烯菌酯对病原菌群体的选择压力，延缓抗药性的发生和发展速度，保障病害防效和水稻生产安全。  相似文献   

12.
The sites of uptake of chlorsulfuron in maize (Zea mays L.) were investigated at three different growth stages. Exposure of seedling roots, or shoots separately, to herbicide-treated sand over 4 days resulted in inhibition of both roots and shoots. Exposure of seedling roots to chlorsulfuron-treated soil over 21 days severely inhibited both roots and foliage, while separate shoot exposure also reduced both foliage and root growth. After plant emergence, exposure of the crown root node, growing point and lower stem to treated soil reduced foliage and root growth, but exposure of the shoot above the growing point caused only slight inhibition of foliage and had no effect on roots. The herbicide safener 1,8-naphthalic anhydride (NA) applied as a dust (10 g kg?1 seed weight), or as a 50 mg 1?1 suspension in water to maize seeds, reduced the root inhibition by chlorsulfuron in 4-day-old seedlings. NA completely prevented both foliage and root injury when chlorsulfuron was placed in soil in the shoot zone before emergence, or in the shoot zone below the soil surface after plant emergence. NA slightly decreased injury to foliage, but not to roots when chlorsulfuron was placed in soil in the root zone before emergence. NA seed treatment protected both roots and foliage against injury from foliarly applied chlorsulfuron. Plants were also protected when a suspension of NA in water was sprayed on the foliage seven days before chlorsulfuron. When a mixture of NA and chlorsulfuron was applied to foliage, root injury was reduced more than foliage injury.  相似文献   

13.
The triazole fungicides, triadimenol and triticonazole, applied as seed treatments at various rates on spring wheat, affected plant growth, shoot development, and root axis production. The main growth regulatory effects were reductions in lengths of the coleoptile, the first leaf and the subcrown internode. A marked effect on tiller appearance occurred with high rates of triadimenol. Modification of root-system development included a reduction in the number of seminal roots, increased outgrowth of roots associated with the coleoptilar node, and a reduction of roots at the first foliar node (correlated with reduced production of Tiller 1). Seed treatment effects on both shoot and root development illustrated the close relationship between these plant structures. Both fungicides induced both beneficial and deleterious effects on wheat growth and development, but the magnitude of deleterious effects was less with triticonazole than with triadimenol.  相似文献   

14.
Plant products are receiving greater attention as prophylactics against several species of plant-parasitic nematodes. Numerous experiments have shown the potential nematicidal value of plant parts and their by-products when incorporated into soil or when the plants themselves are interplanted as seedlings among crop plants. Various products (oils, cakes, extracts, etc.) prepared from the leaves and seeds of the neem plant (Azadirachta indica A. Juss) (Family Meliaceae) have been reported as effective protectants against nematode pests when used as root-dips and seed treatments. Nemato-toxic compounds of the neem plant, especially the azadirachtins, are released through volatilization, exudation, leaching and decomposition. The modes of action of these compounds are complex, and a number of mechanisms in relation to nematode management are yet to be fully explored. This review critically assesses the potential of these products in the management of nematodes in tropical agriculture.  相似文献   

15.
三唑酮种衣剂在小麦种表的超微分布及抗脱落淋失研究   总被引：5，自引：0，他引：5  
 应用扫描电镜观察到三唑酮种衣剂(Tri SCF)以具网眼结构的膜状物包被于小麦种子表面,膜状物厚度约4~7.5μm,种表包被率达95%;对照处理三唑酮可湿性粉剂(TriWP)拌种在小麦种表呈点状或片状零散分布,种表被药剂覆盖率低于80%。振荡试验中TriSCF包衣药剂脱落率为2%,显著低于TriWP干拌种(43%)或湿拌种(25%)。放射性同位素示踪检测表明,TriSCF包衣处理的小麦种子在17%含水量砂床上发芽1~7d内,保持种子内的14C-二唑酮放射性强度显著高于TriWP拌种处理,而然失到砂床上的14C-三唑酮放射性强度低开Tri WP拌种处理。  相似文献   

16.

The possibility of reducing Striga hermonthica (Del.) Benth. parasitism in severely infested fields, by means of deep planting - thereby reducing the root length in the upper layers of the soil where Striga seeds are predominantly found - was tested in field trials with maize and sorghum in western Kenya. Sorghum seeds were planted in Striga-infested fields approximately 2.5 cm deep in the soil or at the bottom of conically-shaped plant holes (15-20 cm deep). Depth of plant holes for maize varied from 0 to 30 cm, in un-tilled soil. Deep planting in un-tilled soil gave higher (up to double) grain yields, compared with standard planting in tilled soil. Parasite emergence was related negatively to planting depth of maize (p< 0.05). Deep planting in tilled soil gave 74% more sorghumgrain yield relative to standard planting. In this treatment Striga seed production was not reduced but in un-tilled fields with deeply planted sorghum Striga seed production was completely suppressed. Therefore, a combination of zero-tillage and deep planting seems to be the most effective treatment. The probable mechanism causing these results is avoidance of Striga seed by the host root system, resulting in a delay in the onset of Striga attachment and the formation of smaller numbers of attachments.  相似文献   

17.
对营养竞争拮抗测定方法进行了改进,对接法将芽孢杆菌JPC-2与小麦纹枯病菌接种于大豆麦麸(SWB)培养基上,JPC-2可在SWB培养基上迅速扩展并完全抑制小麦纹枯病菌的菌丝生长。田间试验表明,芽孢杆菌JPC-2液体菌剂(107cfu/mL,1∶100)处理种子对小麦纹枯病的冬前期防效高于扬花期防效,防治效果为61.9%,高于3%苯醚甲环唑包衣处理(用量为种子质量的0.3%);对小麦根腐病的防治效果可达46.8%,与空白对照差异显著(p<0.05);并使小麦增产73.5%,高于3%苯醚甲环唑种衣剂。芽孢杆菌JPC-2固体菌剂(106cfu/mL,225kg/hm2)沟施于土壤,再播种液体菌剂包衣(107cfu/mL,药种比1∶30)的小麦种子,对小麦纹枯病菌的冬前期防效为68.9%,扬花期防效为59.7%,小麦增产38.9%,与0.2%戊唑醇种衣剂(1∶50)增产效果相当。  相似文献   

18.
种衣剂对山农饲玉7号玉米幼苗生长和相关酶活性的影响   总被引：4，自引：1，他引：3  
以室内沙培法,测定了3种种衣剂对山农饲玉7号玉米幼苗生长的影响。结果显示:吡虫啉·戊唑醇(5%+0.4%)种衣剂(药种比为1∶ 100)处理山农饲玉7号后,幼苗期株高、初生根长和鲜重比对照分别提高了1.68 cm、2.44 cm和0.17 g,比毒死蜱·戊唑醇·福美双(5%+0.3%+15%)种衣剂作用明显,克百威·福美双·三唑酮(7%+7%+1%)种衣剂对其则有抑制作用。离体酶活性测定结果表明,吡虫啉·戊唑醇种衣剂处理使幼苗地上部分和地下部分抗病性相关酶超氧化物歧化酶(SOD)活性分别提高了47.1%和100.2%,苯丙氨酸解氨酶(PAL)活性分别提高了59.5%和58.6%,丙二醛(MDA)含量分别降低了54.0%和26.2%,过氧化氢酶(CAT)、过氧化物酶(POD)活性也有不同程度的提高。结果表明:5.4%吡·戊种衣剂在试验剂量下能够显著提高山农饲玉7号幼苗期多种抗逆防病相关酶活性,对幼苗生长促进作用显著。  相似文献   

19.
冻土荒漠区分离低温适生PGPR菌的鉴定及其抗菌促生特性   总被引：1，自引：0，他引：1  
对分离自青海昆仑山口冻土荒漠区植被根围的7株可在4及10℃低温条件下正常生长的低温适生菌进行鉴定分析,并检测其拮抗病原菌活性及催芽促生特性。综合理化测定、BOX-PCR 及 ERIC-PCR 指纹图谱分析、16S rDNA及基因gyrB序列鉴定结果,其中6株菌株为简单芽孢杆菌Bacillus simplex,1株菌株为B. malacitensis。平板对峙试验表明,7株菌株对油菜菌核病原菌Sclerotinia sclerotiorum及水稻白叶枯病原菌 Xanthomonas oryzae pv. oryzae 具有显著拮抗效果。以菌株 KLD2（B. simplex）及 KLD5（B. malacitensis）发酵菌液处理玉米种子及拟南芥幼苗,结果表明菌株发酵液可明显促进种子萌发及幼苗生长,其鲜重、根长、须根数等表征均有显著增加。几株低温适生PGPR（plant growth promoting rhizobacteria）芽孢杆菌具备抗菌、催芽及促生特性,具有农业应用潜力。  相似文献   

20.

Striga hermonthica is a serious parasite of cereals in most of the semi-arid savanna zone of West Africa, causing substantial yield loss. It has been observed that some soybean cultivars are capable of stimulating germination of S. hermonthica seed, which would reduce the seed bank in the soil. This study was undertaken to quantify the effect of a soybean crop (compared with a sorghum control) on S. hermonthica emergence in subsequent maize in three farmers' fields in northern Nigeria. Soybean cultivar TGx 1740-7F, previously identified as efficacious for S. hermonthica seed germination, was grown at four densities without P fertilizer to test the effect of increasing plant density of soybean on subsequent S. hermonthica parasitism. The effect of P as single super phosphate was tested on the two highest soybean densities. S. hermonthica parasitism on maize was significantly lower after unfertilized soybean than after the sorghum control treatment at two of three trial sites. Soybean rotation increased maize yield by approximately 90% for the three sites combined. Increasing soybean plant density did not result in lower emerged S. hermonthica. Application of P to soybean at the higher soybean densities resulted in higher root length density, lower emerged S. hermonthica on maize (P<0.15), and significantly higher maize yield. The results suggest that an efficacious cultivar of soybean reduces S. hermonthica parasitism on a succeeding maize crop and that the effect is increased by application of P to the soybean.  相似文献   

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