首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Studies were conducted in the field in 2 years comparing the phenology and growth of Orobanche crenata (Forsk) (crenate broomrape) in lentils (Lens esculenta L.) cv. Castellana, peas (Pisum sativum L.) cv. Orix, vetch (Vicia sativa L.) cv. comun and broadbean (Vicia faba L. cv. Alameda. First attachment of O. crenata to these crops took place 9–14 weeks after mid-November planting and earlier after later plantings, Differences in the first O. crenata attachment dates and in the duration of the underground growth period of O. crenata were much greater between years for any given crop than between crops in a given year: both attributes were apparently affected more by seasonal climatic conditions than by crop species, Furthermore, there was no consistent relationship found between crop growth stages and time after first attachment of the parante. This occurred in lentils and vetch while they were vegetative, in peas at late vegetative-early flowering stages, and at widely varying growth stages in broadbean, depending on planting dates and years. The maximum number of O. crenata plants successfully attached to each individual crop plant decreased in the order: peas > broadbean > lentil > vetch, with 21, 14, 10 and 8 per plant, respectively, averaged over the two seasons. Similarly, plant parasites: host dry weight ratio were 1.0, 0.7, 0.3 and 0.2 For each of these crops, respectively.  相似文献   

2.
Orobanche species (broomrapes) are parasitic weeds which dramatically decrease the yields of many economically important dicotyledonous crops, including pea (Pisum sativum), in Mediterranean areas. Previously, we identified some Rhizobium leguminosarum strains, including P.SOM, which could both promote pea development and significantly reduce infection by Orobanche crenata, notably through induction of necrosis of attached parasites. In the present study, induced resistance against broomrape in the nodulated pea was shown to be associated with significant changes in rates of oxidative lipoxygenase (Lox) and phenylpropanoid/isoflavonoid pathways and in accumulation of derived toxins, including phenolics and pisatin (pea phytoalexin). Changes were followed for 5 weeks after inoculation and attack by Orobanche. In contrast to non‐inoculated plants or Orobanche only infected plants, polyphenoloxidase (PPO) activity and hydrogen peroxide content increased in response to bacteria inoculation indicating the involvement of oxidative processes. In parallel, the nodulated roots displayed high Lox activity related to the overexpression of the lox1 gene. Similarly, the expression of phenylalanine ammonia lyase (PAL) and 6a‐hydroxymaackiain 3‐O‐methyltransferase (Hmm6a) genes were induced early during nodule development, suggesting the central role of the phenylpropanoid/isoflavonoid pathways in the elicited defence. As a consequence, the derived products, phenolics and pisatin, accumulated in response to rhizobacteria and conferred mechanical and chemical barriers to the invading parasite. These results highlight the likely role of signalling pathways in induced resistance and suggest these mechanisms should be enhanced through integrated Orobanche management practices.  相似文献   

3.
Orobanche foetida is widely distributed in western Mediterranean countries infecting wild legumes. Recently it has been reported in Morocco infecting common vetch, presenting a further constraint for legume production in this area. Comparative studies between Orobanche populations attacking wild species and Orobanche populations growing on crops from the same region may help to clarify whether a host specialisation process occurred. In the present study, the genetic variability of five O. foetida populations, four infecting wild plants and one infecting cultivated vetch in Morocco was characterised using amplified fragment‐length polymorphism (AFLP) markers to elucidate the existing genetic relationship between populations and to suggest a potential origin for the recently detected vetch‐infecting population. Analysis of molecular variance suggested the existence of genotypic differentiation among populations. The most genetic divergent population by cluster analysis was the population collected on Ornithopus sativus. The vetch‐infecting O. foetida population was closer to the three populations infecting Scorpiurus muricatus. The possibility of the presence of a reservoir of diversity is balanced against direct genetic adaptation and completely new introduction. The potential for this Orobanche species to shift host and become a threat to agriculture exists and has to be taken into account for future legume breeding for these areas.  相似文献   

4.
The susceptibility to Phytophthora cinnamomi of four crops (wheat, oat, vetch, and yellow lupin) commonly planted in rangeland ecosystems in southern Spain was evaluated. By means of in vitro infection experiments, the presence of the pathogen into the roots of yellow lupin (symptomatic) and vetch (asymptomatic) was observed, but never into wheat and oat roots (asymptomatic). It was also demonstrated that yellow lupin stimulated the production of zoospores of P. cinnamomi. Vetch, wheat and oat did not stimulate zoospore production. Under controlled conditions, only yellow lupin induced an increase in the number of viable chlamydospores in the soil. We concluded that the culture of wheat, oat, and vetch in rangelands did not influence the epidemiology of the Quercus root disease, even when asymptomatically-infected vetch is grown, and these crops can constitute an alternative to the culture of yellow lupin in rangeland ecosystems affected by Quercus root rot.  相似文献   

5.
Broomrape (Phelipanche and Orobanche spp.) are obligate holoparasites that attack roots of almost all economically-important crops in semiarid regions of the world. Broomrape seeds are extremely small (dust-like seeds), averaging 200 to 300?μm in size and because of the miniscule seed size it is difficult to detect and confirm via conventional methods. In this study our aim was to develop a PCR-based assay specific for broomrape soil-borne seeds and sensitive enough to detect a single or few broomrape seeds in a soil sample. For this purpose, we used complementary polymerase chain reaction (PCR) primers based upon unique sequences in the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA of Phelipanche aegyptiaca. Genomic DNA was extracted from soil samples artificially infested with broomrape seeds or tissue of Phelipanche aegyptiaca Pers., Orobanche cumana Wallr. and Phelipanche crenata Forsk. and subjected to PCR analysis. Using ITS-350 primers, a specific PCR product (350?bp) was amplified and detected in all samples containing broomrape species, but was not detected in soil sample free of broomrape seeds or tissues. Additionally, the PCR-based assay was sensitive enough to detect even a single broomrape seed in the soil. As expected the universal internal control primers amplified a PCR product (555?bp) of genomic DNA extracted from soil samples with or without broomrape tissues or seeds. This diagnostic method is simple, reliable and rapid and could help for assessment of broomrape seed contamination in a crop field.  相似文献   

6.
The effects on plant growth of applying trifluralin or nitralin combination with simazine, atrazine, prometryne and linuron to the upper 5-cm root region of vetch (Vicia sativa L.), pea (Pisum sativum L.) and soybean (Glycine max) were investigated. Foliar injury due to herbicides of the second group was markedly reduced in each species by simultaneous treatment with trifluralin or nitralin both of which inhibited lateral root growth without affecting aerial plant growth or tap root extension growth. This inhibition of lateral root growth in roots treated with trifluralin or nitralin was associated with reduced uptake and subsequent transport to the foliage of 14C-labelled simazine in vetch and pea and 14C-labelled atrazine in soybean. This probably accounted for the reduction in simazine and atrazine phytotoxicity. In the presence of trifluralin or nitralin comparatively higher amounts of radioactivity were retained in the roots of pea and soybean and this reduced the amount of 14C available for transport to the foliage. This was not evident in vetch.  相似文献   

7.
Weeds of the genus Orobanche are obligatory chlorophyll-lacking root parasites that infect and severely damage many dicotyledonous agricultural crops in warm-temperate and subtropical regions of the world. The genus comprises over 100 species, at least six of which are notable weeds. Orobanche palaestina Reut. is an endemic Mediterranean species, previously reported to parasitize thistles [Notobasis syriaca (L.) Cass. and Cirsium phyllocephalum Boiss. & Bl.] and annual legumes in native Mediterranean habitats, mainly in disturbed places such as roadsides and waste sites. In recent years, we have observed a rapid expansion of O. palaestina populations adjacent to commercial agricultural fields in the Jezreel Valley of Israel. The ability of O. palaestina to infect crops was tested in pots under nethouse conditions. The experiments revealed that O. palaestina is able to parasitize agricultural crops. Safflower (Carthamus tinctorius L.), lettuce (Lactuca sativa L.), gazania (Gazania uniflora Gaertn.), vetch (Vicia sativa L.) and artichoke (Cynara scolymus L.) were found to be potential hosts for this parasite, and all of them, except vetch and artichoke, were preferred to thistle, the native host. Sunflower (Helianthus annuus L.) induced O. palaestina seed germination and root attachment, but the attached parasites could not reach maturity and died soon after the attachment stage. Tomato (Lycopersicon esculentum Mill.), carrot (Daucus carota L.), garland chrysanthemum (Chrysanthemum coronarium L.) and cabbage (Brassica oleraceae L.) were not parasitized by O. palaestina.  相似文献   

8.
Phaeomoniella chlamydospora (Pch) and Togninia minima (Tmi) produced scytalone, isosclerone and pullulans in liquid cultures, as well as in calli. Secondary metabolites and host defense compounds were shown to occur in calli of Vitis vinifera cv. Italia and cv. Matilde infected by the esca-associated fungi Pch, Tmi and Fomitiporia mediterranea (Fme). Calli of both cvs. were grown as dual cultures with Pch, Tmi and Fme. The fungi grew well in the presence of calli of both cvs., but callus growth was reduced. Accumulation and changes of total phenolics and recurring phenolics, and of two phytotoxic pentaketides and pullulans were analyzed by HPLC. On comparing results for cv. Italia and cv. Matilde, it can be seen that concentrations of phenolics are strongly related to the cv. The paper discusses the possible relationship between melanin biosynthesis in Pch and Tmi, which utilize pentaketide metabolites as intermediates and their pathogenicity related to phytotoxity of scytalone and isosclerone.  相似文献   

9.
The correlation between intensity of lipid peroxidation and changes in antioxidant capacity of sugar beet plants (cv. ‘Drena’) infected with Rhizoctonia solani Kühn isolate (AG 2-2 IIIB group) was studied. Successful inoculation was confirmed by the presence of infection cushions in a cross section of leaf petioles. On the 7th day of the experiment, phenylalanine ammonia-lyase (PAL; EC. 4.3.1.5) activity was in negative correlation with intensified lipid peroxidation process in leaves of sugar beet plants (r= –0 .99). Also, in leaves and roots of inoculated sugar beet plants, total flavonoids content (35% and 20%, respectively) and 1,1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity (80% and 55%, respectively) were significantly reduced. Necrotic processes resulting from R. solani infection of sugar beet plants was followed by induction of plant phenolics metabolism; however, antioxidant capacity of these plants was reduced.  相似文献   

10.
The effect of chocolate spot disease (incited byBotrytis fabae) on the host plant quality of two cultivars of faba beans (Vicia faba) for the black bean aphid (Aphis fabae), was investigated under greenhouse conditions. Faba bean cultivar Bolero is resistant to the aphid, whereas cv. Diana is susceptible. On healthy leaves of cv. Bolero, aphids completed their development one day later than the aphids reared on infected leaves of this cultivar and those which matured on healthy or infected leaves of cv. Diana. Mean weight of apterous virginoparae, mean relative growth rate, and intrinsic rate of natural increase were enhanced if the aphids were reared on infected leaves of either cultivar. Mean total progeny per female increased only on infected leaves of cv. Bolero, but not on cv. Diana.  相似文献   

11.
A strain of Fusarium verticillioides was isolated from the tubercles of the parasitic weed Orobanche cumana in Israel. The pathogenicity was tested in polyethylene bags on O. cumana, O. crenata, O. aegyptiaca and O. ramosa and in pots on O. cumana and O. crenata. F. verticillioides was highly pathogenic to O. aegyptiaca, O. ramosa and O. cumana in the polyethylene bags. In pots, the fungus caused wilting and necrotic areas on flowering shoots of O. cumana, but did not cause disease symptoms on O. crenata. F. verticillioides grown on liquid Czapek growth medium produced a phytotoxic metabolite, which in leaf-puncture bioassay caused large necrotic areas on Orobanche shoots and on leaves of various crops. An extract of the fungal growth medium caused complete mortality of O. cumana and O. aegyptiaca seedlings in vitro. The toxic metabolite was isolated and identified by spectroscopic methods as fusaric acid. The identity of the compound was confirmed by conversion into the corresponding methyl ester, and by TLC comparison against authentic fusaric acid. No other phytotoxic metabolites could be detected in the growth medium extracts.  相似文献   

12.
A method was developed by which the presence of broomrape (Orobanche spp.) seeds in vetch seeds was determined quantitatively. The broomrape seeds are washed out of the vetch seeds by a combination of two sieves. The vetch seeds remain on the top sieve and the broomrape seeds are collected on the lower sieve with square openings of 100 μm, which do not permit passage of the broomrape seeds. An appropriate statistical method for estimating the true mean number of broomrape seeds per sample in a large vetch seeds lot is presented and discussed. Détermination quantitative des graines d' orobanche dans des graines de vesce. Une méthode permettant de dénombrer la présence de graines d'orobanche dans un lot de graines de vesce a été mise au point. Les graines d'orobanche sont séparées de celles de vesce par une succession de deux tamis. Les graines de vesce sont maintenues sur le tamis supérieur et les graines d'orobanche sont collectées sur le tamis le plus bas avec une maille de 100 μm qui ne permet pas le passage des graines d'orobanche. Une méthode statistique appropriée pour estimer la quantité réelle d'orobanches dans un grand lot de semences de vesce est présentée puis discutée. Quantitative Bestimmung von Orobanche-Samen in Wicken-Saatgut Es wurde eine Methode entwickelt, mit der Orobanche-Samen in Wicken-Saatgut quantitativ erfasst werden können. Zum Trennen der Samen wurden 2 Siebe verwendet, wobei die Wicken-Samen im oberen, die Orobanche-Samen im unteren mit einer Maschenweite von 100 μm gesammelt wurden. Eine statistische Methode für die Schätzung der Orobanche-Samenmenge in grossen Wicken-Saatgutpartien wurde vorgestellt und diskutiert.  相似文献   

13.
BERNHARD  JENSEN  ANDREASEN 《Weed Research》1998,38(3):191-197
Root parasites of the genus Orobanche cause serious losses in many subtropical crops. Direct control options are very limited and crop yield loss can reach 100%. Prediction of potential damage in a crop before sowing or planting would support farmers in their choice of crop. This paper discusses the relationship between the number of Orobanche spp. seeds in the field and yield loss in peas (Pisum sativum L.) and carrots (Daucus carota L.) in Israel. Yield loss due to Orobanche crenata Forsk. in peas was 100% at high infestations, whereas in carrots when O. crenata and O. aegyptiaca were present it stabilized at about 50% for moderate infestations of 200 seeds per kg of soil. Statistical analyses related the yield loss from parasitism in peas and carrots to the numbers of Orobanche seeds remaining in the soil. A rectangular hyperbolic model, previously applied to competition data, fitted the data well. Confidence intervals for per cent yield loss were calculated using the bootstrap method. The practical applications of these models in predicting yield loss are discussed.  相似文献   

14.
Broomrapes (Orobanche spp.) are parasitic weeds that cause significant losses of crop yield. Experiments were conducted to investigate the seed response to the artificial germination stimulant GR24 in three species of Orobanche subjected to preconditioning under various temperatures, water potentials and with plant growth regulators. The highest germination percentages were observed in Orobanche ramosa, Orobanche aegyptiaca and Orobanche minor seeds conditioned at 18°C for 7 days followed by germination stimulation at 18°C. With the increase of the conditioning period (7, 14, 21 and 28 days), the germination percentage of O. ramosa and O. aegyptiaca progressively decreased. When conditioned at −2 MPa, the germination percentage was lower than at 0 and −1 MPa, especially at 13 and 28°C. Orobanche minor seeds could retain relatively high germination if conditioned at 18, 23 or 28°C, even after significantly extended conditioning periods (up to 84 days). GA3 (30–100 mg L−1), norflurazon and fluridone (10–100 mg L−1), and brassinolide (0.5–1.0 mg L−1) increased seed germination, while 0.01 mg L−1 uniconazole significantly reduced germination rates of all three Orobanche spp. The promotional effects of GA3 and norflurazon and the inhibitory effect of uniconazole were evident, even when they were treated for 3 days. Germination of Orobanche seeds was much lower when the unconditioned seeds were directly exposed to GR24 at 10−6 m . This early GR24-induced inhibition was however alleviated or even eliminated by the inclusion of GA3 or norflurazon (10–50 mg L−1) in the conditioning medium. On the contrary, the inclusion of uniconazole increased the inhibitory effect of GR24, particularly in the case of O. ramosa.  相似文献   

15.
The effect of localized placement of trifluralin on uptake patterns of soil-applied 45Ca in vetch (Vicia sativa L.), pea (Pisum sativum L.) and soybean (Glycine max) and 32P in vetch and pea was investigated in two soil zones in the roots and in the shoot zone before and after plant emergence. When trifluralin was in the upper root zone severe inhibition of lateral roots occurred as well as a marked decrease in uptake of 45Ca and 32P from this zone. Root growth in the lower zone was unaffected, but uptake of 45Ca and 32P was slightly reduced. Compensatory adventitious root growth as well as a marked increase in uptake of 45Ca and 32P occurred in the shoot zone. Neither root growth nor uptake of 45Ca or 32P in the upper root zone were affected by the presence of trifluralin in the lower root region. When trifluralin was placed in the shoot zone after plant emergence, adven-titious roots on the shoots were inhibited and uptake of 45Ca and 32P was reduced.  相似文献   

16.
Secondary metabolites and host defense compounds were shown to occur in xylem sap, and leaves of Vitis vinifera cv. Italia and cv. Matilde naturally infected by the esca-associated fungi Phaeomoniella chlamydospora (Pch), Togninia minima (Tmi) and Fomitiporia mediterranea (Fme). Samples of xylem sap and leaves were collected from healthy vines and from vines showing severe symptoms of brown wood-streaking caused by Pch and Tmi, or from vines with symptoms of both brown wood-streaking and white rot caused by Fme. Xylem sap collection was carried out during the early spring of 2003 and 2004, corresponding to the phenological phases: (A) cotton bud; (B) green tip; (C) leaves out; (D) stretched out leaves; and (E) visible clusters. In the present work we have studied the accumulation of biomolecules (pentaketides and α-glucans), host defense compounds (benzaldehydes, benzoic acid and cinnamic acid derivatives, flavonols, flavanols, flavan-3-ol derivatives and stilbenes) at different stages of grapevine development. Accumulation and changes in total phenolics and recurring phenolics, and of three phytotoxic secondary metabolites (scytalone, isosclerone and pullulan) were analyzed by HPLC. On comparing results for cv. Italia and cv. Matilde, it can be seen that phenolic concentrations are strongly related to the cv.  相似文献   

17.
Orobanche amethystea Thuill.,O. loricata Reichenb. andO. pubescens D’Urv. were found to parasitize the roots of cultivated plants in Israel.Orobanche pubescens is known from the local flora, and was now found to cause damage in parsley fields and toTropaeolum majus L. (nasturtium) in ornamental gardens.Orobanche amethystea andO. loricata are known as occasional weeds in Europe and were recently found for the first time in Israel.Orobanche amethystea densely populated vetch fields in Israel, andO. loricata was found in ornamental gardens. A key for the identification ofOrobanche species in cultivated areas in Israel is given, based on morphological features. http://www.phytoparasitica.org posting Jan. 13, 2002.  相似文献   

18.
Field studies were carried out to evaluate the efficacy of imazaquin and glyphosate in controlling broomrape (Orobanche crenata Forsk. and O. aegyptiaca Pers.) in faba bean (Vicia faba L.) in Northern Syria. Several rates and times of application of the herbicides were tested. Nearly complete control of broomrape was achieved with both the herbicides when they were sprayed twice (when the broomrape attachments to the faba bean roots were at tubercle stage of develoment and 15 days later) at a rate of application of 80 g a.i. ha?1 for glyphosate and 10 g a.i. ha?1 for imazaquin. However, the yield of faba bean did not increase with these treatments, suggesting that the herbicides at these rates were still causing some physiological disorder in the plant that counteracted the beneficial effect of broomrape control on the performance of faba bean plants.  相似文献   

19.
A series of studies were carried out on Colletotrichum lentis which had been been identified in 2015 based largely on the distinctive shape of conidia and ITS sequences, and which has been causing severe anthracnose disease symptoms on common vetch plants (Vicia sativa) in Gansu Province in the northwest region of China. A key focus of the present studies was to determine how vetch crops become infected. The addition of residues from harvested common vetch crops to land being prepared as a seedbed was shown to result in the highest levels of disease severity indicating that this management practice was the most likely way for crops to become severely infected. Seed transmission was unlikely to be the cause of severe outbreaks as less than 5% of seeds harvested from severely infected plants carried C. lentis. To verify that the species causing the severe outbreaks of anthracnose disease of vetch crops was C. lentis, sequence analysis of the ITS, TUB2, ACT, HIS3 and GAPDH genes was conducted. C. lentis isolates from common vetch and lentil (Lens culinaris) formed a distinctive group among Colletotrichum species, including those species that infect other forage and field crops. The unique shape of conidia of C. lentis, straight with only one end curved, was confirmed as being reliable for rapid identification of disease outbreaks caused by this damaging fungal pathogen.  相似文献   

20.
The type and concentration of phenolics found in the cytosol (free), cell wall (bound), and nutrient solution of hydroponic pepper (Capsicum annuum L.) inoculated with Pythium aphanidermatum (Edson) Fitzp. were compared with non-inoculated controls. The quantities and types of free phenolics found in the roots and nutrient solution were greater in inoculated than in control plants. With regard to bound phenolics, while there was no difference between the types of phenolics in inoculated and control roots, quantities were greater in inoculated roots. High Pressure Liquid Chromatography analyses revealed two compounds in root extracts, and one in nutrient solution extracts that were contributors to root discolouration caused by Pythium aphanidermatum colonization. The compounds were subsequently isolated and identified as 4-hydroxybenzoic acid and 3-methoxy-4-hydroxybenzoic acid (vanillic acid) by their High Pressure Liquid Chromatography retention times, UV signature and Nuclear Magnetic Resonance spectroscopic comparisons with pure standards. Addition of various concentrations of 4-hydroxybenzoic acid or vanillic acid to the nutrient solution predisposed healthy plants to infection by zoospores of Pythium aphanidermatum when compared to plants treated with only Pythium aphanidermatum. 4-hydroxybenzoic acid and vanillic acid had little or no effect on colony growth of Pythium aphanidermatum in vitro, but respectively increased and decreased numbers of sporangia produced. These results are the first demonstration of host predisposition to infection by Pythium aphanidermatum caused by phenolic compounds that accumulate in inoculated roots and leach into the nutrient system of hydroponic systems.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号