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51.
Response of spring wheat (Triticum aestivum) to interactions between Pseudomonas species and Glomus clarum NT4 总被引:1,自引:0,他引:1
The effects of interactions between pseudomonads (Pseudomonas cepacia strains R55 and R85, P. aeruginosa strain R80, P. fluorescens strain R92, and P. putida strain R104) and the arbuscular mycorrhizal fungus Glomus clarum (Nicol. and Schenck) isolate NT4, on spring wheat (Triticum aestivum L. cv. Laura), grown under gnotobiotic and nonsterile conditions, were investigated. Although plant growth responses varied,
positive responses to pseudomonad inoculants generally were obtained under gnotobiotic conditions. Shoot dry weight enhancement
ranged from 16 to 48%, whereas root enhancement ranged from 82 to 137%. Shoot growth in nonsterile soil, however, was unaffected
by pseudomonad inoculants, or reduced by as much as 24%. Shoot growth was unaffected or depressed by G. clarum NT4 whereas early root growth was enhanced by 38%. Significant interactions between the pseudomonad inoculants and G. clarum NT4 were detected. Typically, dual inoculation influenced the magnitude of response associated with any organism applied
alone. The effect of these pseudomonads on G. clarum NT4 spore germination was investigated. Germination was inhibited when spores were incubated either on membranes placed directly
on bacterial lawns of strains R85 and R104 (i.e., direct assay), or on agarose blocks separated from the bacteria by membranes
(i.e., diffusion assay). When the agarose blocks were physically separated from the pseudomonad (i.e., volatile assay), there
was no evidence of inhibition, suggesting that a nonvolatile, diffusible substance(s) produced by both strains R85 and R104
may inhibit G. clarum NT4 spore germination.
Received: 11 December 1995 相似文献
52.
对柱花草炭疽病菌的鉴定及生物学特性测定结果表明:柱花草炭疽病菌为盘长孢状刺盘孢菌[Colletotrichumgloeosporioides(Penz)Sacc].病菌生长温度15~36℃;适宜生长温度25~30℃;分生孢子萌发的温度6~40℃,最适萌发温度为28℃;分生孢子在饱和湿度下萌发率为83.1%,在饱和湿度加水滴中达87.9%;分生孢子的致死温度为49℃10min;病菌生长的pH值是2.5~14.0,最适pH值为6.4~7.2;病菌对碳源的利用较氮源好。 相似文献
53.
The effect of termites on the breakdown of Pennisetum pedicellatum straw under Sahelian conditions was studied in northern Burkina Faso during the dry and wet seasons of 1995. Litterbags were
laid on plots treated with drieldrin at a rate of 500 g a.i. (active ingredient) ha–1 to exclude termite activity and on untreated plots. Termites were the only macroscopically visible consumers which were observed
in the litterbags during the dry and wet season. In litterbags with no termites present the rate of breakdown of straw was
lower during both the dry or wet seasons than in litterbags with termites. In the litterbags with termites, much of the mulch
was taken off and replaced by termite-made sheeting. From April to September over 60% of the added material disappeared from
termite litterbags, while only 18% of the added straw disappeared from litterbags without termites. From October to December,
28% of the straw disappeared from termite-infested litterbags versus 8% from litterbags without termites. The contribution
of termites to the breakdown of straw was estimated to be over 70% for each of the two experiments. Under Sahelian conditions,
the breakdown of organic residues is strongly influenced by termites.
Received: 6 May 1998 相似文献
54.
Summary We studied the effect of three successive cuttings on N uptake and fixation and N distribution in Leucaena leucocephala. Two isolines, uninoculated or inoculated with three different Rhizobium strains, were grown for 36 weeks and cut every 12 weeks. The soil was labelled with 50 ppm KNO3 enriched with 10 atom % 15N excess soon after the first cutting. Except for the atom % 15N excess in branches of K28 at the second cutting, both the L. leucocephala isolines showed similar patterns of total N, fixed N2, and N from fertilizer distribution in different parts of the plant at each cutting. The Rhizobium strain did not influence the partitioning of 15N among the different plant parts. Significant differences in 15N enrichment occurred in different parts. Live nodules of both isolines showed the lowest atom % 15N excess values (0.087), followed by leaves (0.492), branches (0.552), stems (0.591), and roots (0.857). The roots contained about 60% of the total plant N and about 70% of the total N derived from fertilizer over the successive cuttings. The total N2 fixed in the roots was about 60% of that fixed in the whole plant, while the shoots contained only 20% of the fixed N2. We conclude that N reserves in roots and nodules constitute another N source that must be taken into account when estimating fixed N2 or the N balance after pruning or cutting plants. 15N enrichment declined up to about fivefold in the reference and the N2-fixing plants over 24 weeks following the 15N application. The proportion and the amounts of N derived from fertilizer decreased, while the amount derived from N2 fixation increased with time although its proportion remained constant. 相似文献
55.
4种木霉对核盘菌的抑制作用 总被引:5,自引:0,他引:5
通过对峙培养以及对木霉菌(Trichoderma spp.)次生代谢物对病原菌的抑菌率进行了测定,结果表明,供试哈茨木霉(T.harzianum)、绿色木霉(T.viride)、康氏木霉(T.koningii),以及一株未知种名的木霉菌株TY(Trichoderma sp.)均对核盘菌(Sclerotinia sclerotiorum (Lib) de Bary)有明显的抑制作用.在对峙培养中,木霉菌菌落与核盘菌的菌落相向生长一定时间后,挑取核盘菌菌落内部的菌丝进行镜检,发现有木霉菌孢子存在,且核盘菌发生菌丝变形,如原生质浓缩,菌丝断裂,或菌丝消解等现象.并发现不同种木霉所产生的次生代谢物的活性不同,对核盘菌的抑制作用也存在显著差异. 相似文献
56.
57.
为降低澳洲坚果采收成本,提高采收效率,以澳洲坚果主栽品种‘HAES800’和‘HAES294’为材料,在果实成熟期喷施浓度为1.5 g/L、2.0 g/L和2.5 g/L的乙烯利溶液,对喷施乙烯利溶液后的落果情况、落叶情况和果实品质进行了研究,并对该方法的促落果效果和使用成本进行了评估。结果表明,品种‘HAES800’喷施上述浓度乙烯利溶液4周后的落果率分别达到94.10%、94.08%和93.67%,而同一时期CK的落果率仅有24.64%;品种‘HAES294’喷施上述浓度乙烯利溶液6周后的落果率则分别达到90.89%、93.17%和91.80%,而同一时期CK的落果率仅有53.27%;相比而言品种‘HAES800’对乙烯利溶液更敏感;建议在生产中品种‘HAES800’和‘HAES294’分别采用1.5 g/L和2.0 g/L的乙烯利溶液进行促落果采收;尽管喷施乙烯利会引起部分落叶,但不会对树体生长和果实品质产生影响。应用本方法可使澳洲坚果采收成本降低25.07%,具有巨大的推广应用前景。 相似文献
58.
以南方地区的蓝莓品种为主要对象,利用SSR标记分析现有品种种质的遗传多样性。设计合成了56对蓝莓SSR分子标记引物,进行扩增和多态性引物筛选,将多态性好的引物用于66份蓝莓不同类型种质的遗传多样性分析。结果表明,56对引物均能扩增出预期大小条带,其中条带清晰多态性较好的引物为25对,占比引物数的44.64%,多数引物扩增的位点数在5~7个之间。25对引物在66份蓝莓供试种质中检测多态性,共检测到165个等位变异,平均每个位点有6.6个等位变异,PIC值变幅为0.656~0.947,平均值为0.777。多态性最好的引物Vc26可以检测到15个等位基因数目。北方高丛、南方高丛和兔眼类型66份蓝莓种质的遗传相似系数位于0.60~0.96之间,品种间遗传差异较丰富。利用UPGMA聚类将3种类型种质进行分析,发现除了兔眼类型品种‘红粉佳人’外,其余明显分为3个类群,且同一类型的种质基本聚在一起。结合不同类型种质的系谱分析,发现分类与品种种质的遗传成分相似有一定的相关。研究利用SSR分子标记揭示了蓝莓不同类型种质的遗传多样性,对今后杂交育种亲本选择利用有一定借鉴意义。 相似文献
59.
草莓炭疽病是草莓定植时期最易造成死苗的真菌病害。本文研究了生物刺激素(木霉菌、海藻酸、聚谷氨酸)协同灌根对草莓炭疽病的防治以及促生作用。结果表明,与对照相比,木霉菌、海藻酸、聚谷氨酸单剂灌根和木霉菌+海藻酸、木霉菌+聚谷氨酸的协同灌根处理均能显著降低炭疽病造成的死苗率,其中木霉菌+海藻酸的防效最高,可达78.26%。相比对照,所有处理均能显著提高净光合速率、1,5-二磷酸核酮糖羧化酶活性和加氧酶活性等光合指标,以及土壤脲酶活性。协同灌根处理显著提高草莓株高、根茎粗、叶柄长、叶面积等生长指标达15.62%~47.00%。其中木霉菌+海藻酸处理的净光合速率、土壤脲酶活性最高。综合而言,木霉菌与海藻酸协同灌根在促进生长、促进光合、提高土壤供氮水平以及防控草莓炭疽病方面均表现出显著的增效作用,可作为生物防治的一种有效手段。 相似文献
60.