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1.
Root and crown rot is the major soil-borne fungal disease in sugar beet. In Europe, the disease is mainly caused by the anastomosis group (AG) 2-2IIIB of the basidiomycete Rhizoctonia solani (Kühn). No chemical fungicide to control the disease has been registered in Europe. Therefore, agronomic measures must be optimized to keep the disease severity below an economic damage threshold and to minimize white sugar yield losses. R. solani AG 2-2IIIB infects many other crops besides sugar beet, including maize, where it causes root rot. Sugar beet and maize are frequently grown in the same crop rotation. The proportion of cultivated maize in several European sugar beet growing areas is expected to rise due to a projected increase in demand for renewable resources over the next few years. Although the susceptibility to and tolerance of the disease varies among cultivars in both crops, little is known about the effects of cultivar susceptibility in the pre-crop on a subsequent susceptible crop. The cultivation of R. solani-resistant maize genotypes in rotation with resistant sugar beet might therefore be a useful tool in an integrated control strategy against R. solani, eliminating the need to restrict the desired crop rotation for phytosanitary reasons. A crop rotation experiment with artificially inoculated R. solani was conducted in the field to investigate the pre-crop effects of maize cultivars which differed in their susceptibility to R. solani on a susceptible sugar beet cultivar. We hypothesized that the maize genotype would influence the inoculum potential and performance of a susceptible sugar beet genotype grown after a maize pre-crop, and that this would correlate with the susceptibility of the maize genotype. The results demonstrate that the susceptibility of maize genotypes is consistent over a period of years and that cultivated maize genotypes influenced the inoculum potential measured as disease severity in sugar beet. However, disease severity in sugar beet did not correlate with the disease susceptibility of the genotype of the maize pre-crop. Possible reasons for this missing relationship might be differences in the quality of maize residues for the saprophytic survival of the pathogen or a genotype-specific alteration of the antagonistic microbial community. However, our findings showed that in the presence of maize- and sugar beet-pathogenic R. solani, the most favourable maize cultivar for a crop rotation cannot be determined solely on the basis of its resistance level against Rhizoctonia root rot. 相似文献
2.
The systemic insecticides aldicarb 15G (15% granules) at 2·6 kg active ingredient (a.i.)/ha and phorate 1OG (10% granules) at 1·7 kg a.i./ha, applied as side dressings about 1 month after planting in 1979 and 1980, significantly increased the severity of root rot, caused by Rhizoctonia solani Kühn, in sugar beet (Beta vulgaris L.). Carbofuran 10G (10% granules) at 2·2 kg a.i./ha also increased root rot, but not significantly. Numbers of harvestable roots were reduced by all treatments but significantly by phorate only. Both aldicarb and phorate were slightly fungistatic to R. solani when the pathogen was grown on potato-dextrose agar incorporating 0·5, 5·0, and 25 μg a.i./ml. Trichoderma sp., a potential antagonist of Rhizoctonia, was slightly inhibited by aldicarb and phorate initially, but soon overcame the effect. Thus, the increase in disease severity in the field may be attributable to some metabolic or physiological effect of the chemicals either on the host or on the infection process of the pathogen. Indiscriminate use of these insecticides should therefore be avoided in areas where root rot is prevalent but where insects are not a problem. 相似文献
3.
Rhizoctonia solani Kühn is an important pathogen of sugar beet (Beta vulgaris L.) that can cause damping-off and crown and root rot. Commercial cultivars which are highly resistant to the pathogen are not as high yielding as susceptible cultivars under low or absent disease pressure. These resistant cultivars often do not have resistance to other common pathogens such as Aphanomyces cochlioides, Cercospora beticola, and Fusarium oxysporum. Fungicides, such as azoxystrobin which belongs to the quinone outside inhibitors (QoI) class, are necessary for controlling Rhizoctonia solani, but there are concerns about the buildup of fungicide-resistant strains in the targeted pathogen population. There is a need to find effective fungicides from different chemical groups so they can be rotated with the current widely-used azoxystrobin to manage R. solani. The objective of this greenhouse study was to evaluate the efficacy of penthiopyrad, a succinate dehydrogenase inhibitor (SDHI), in managing R. solani on sugar beet using three different application methodologies. Penthiopyrad effectively controlled R. solani on sugar beet when applied at 210, 280, 420, or 550 g a.i./ha in-furrow at planting and as a soil drench at the 4-leaf stage. However, foliar application of penthiopyrad failed to provide disease control. These trials indicated that penthiopyrad needs to be in close proximity or direct contact with R. solani in the soil to provide effective control. Penthiopyrad has the potential to be used as an effective alternate partner with azoxystrobin for controlling R. solani and to help in mitigating the development of fungicide resistant isolates of R. solani. 相似文献
4.
In a 2-year assessment carried out on tomato crops of Central and Southern Italy, a high incidence of Rhizoctonia solani and Sclerotium rolfsii was found. These fungal pathogens attack horticultural crops and are responsible for severe crown and stem rot. Because of technical, economical and environmental issues their chemical control is an arduous task. To find alternative and eco-compatible control methods, the effectiveness of two new antagonistic bacterial isolates (Burkholderia cepacia, T1A-2B, and Pseudomonas sp., T4B-2A), previously selected from suppressive organic amendments, were tested on tomato plants grown under both growth chamber and field conditions. The potential antagonists were compared with two commercial biofungicides, based on Bacillus subtilis (BSF4) and Trichoderma asperellum (TV1), and four synthetic fungicides (tolclofos-methyl, azoxystrobin, fosetyl-Al and fosetyl-Al + propamocarb). In 2-year field experiments carried out on tomato plants, the biocontrol bacteria as well as the other treatments were applied to the soil, proximal to the plant crowns and main roots, by means of an effective and specific system of drip irrigation. In all the experiments the novel selected biocontrol bacteria significantly reduced both incidence and severity of the diseases caused by S. rolfsii or R. solani, with results demonstrating effectiveness equal to TV1, better than BSF4 and comparable with the synthetic fungicides, except for tolclofos-methyl which was the most effective treatment. In field experiments, carried out for two consecutive years, isolate T1A-2B reduced up to 58.33% and up to 63.8% the severity of the diseases caused by S. rolfsii and R. solani respectively; whereas isolate T4B-2A gave reduction of S. rolfsii and R. solani diseases severity up to 73.2% and up to 62.7%, respectively. 相似文献
5.
Rhizoctonia solani causes economically important root and hypocotyl diseases in common bean throughout the world. Root health is a vital factor in plant development and root diseases would negatively influence water and nutrient uptake as well as cause direct stand reduction and root rot damage to the crop. An efficient common bean screening method to evaluate damping-off and early root/hypocotyl damage from R. solani was developed and used to identify dry bean lines with levels of resistance to this disease. Two sets of 163 and 111 lines previously evaluated for drought tolerance in Nebraska and Puerto Rico were evaluated for damping-off resistance and early root/hypocotyl damage under greenhouse conditions. Disease severity on plants was identified based on above-ground symptoms, seedling survival and root lesions using a rating scale of 1 (resistant) to 9 (susceptible). In the first set of lines representing commonly grown dry bean cultivars, germplasm and sources of damping-off resistance, the Rhizoctonia mean rating ranged from 1.7 to 3.9; Phaseolus vulgaris lines PI 310668 and PI 533249 had the highest damping-off resistance. In the second set of the best lines from a drought tolerance shuttle breeding program the Rhizoctonia mean rating was between 2.6 and 5.7. The availability of drought tolerant dry bean lines allowed the testing of the hypothesis that there was a correlation between selecting for drought tolerance and R. solani damping-off resistance. No correlation between mean disease rating and drought tolerance was found, but adapted dry bean lines such as NE14-08-176 released as SB-DT1, and NE14-08-225 were identified with moderate damping-off resistance and drought tolerance. Lines with both traits and other attributes will facilitate development of resistant bean cultivars to manage damping-off caused by R. solani. 相似文献
6.
《Crop Protection》1987,6(1):49-55
A soil in which sugar beet had been monocultured for several years was treated with the fungicide captafol to investigate the effect of controlling nematophagous fungi on populations of Heterodera schachtii in the field and in pots. In the field trial, nematode populations failed to increase on sugar beet in the first 2 years in untreated soil, only increasing (×3·9) in the third. However, in captafol-treated soil, populations increased in all three years (x 3·0, x1 · 7 and x 6 · 5). In the pot experiment using the same soil and equivalent rates of captafol, greater multiplication occurred in captafol-treated pots. This was caused by an increase in lateral root weight which provided more invasion and feeding sites for the nematode, and by a reduction in fungal parasitism of female nematodes. Most of the natural control in the untreated soil operated on the second generation of the nematode. Cylindrocarpon destructans was the fungus isolated most frequently from infected females; Verticillium chlamydosporium and Fusarium spp. were also identified, but half of all isolates were diverse unidentified fungi. Fungal pathogens in beet monoculture did not cause H. schachtii populations to fall below the damage threshold, but might usefully be integrated with other measures, such as nematicides, to limit nematode increase. 相似文献
7.
Some secondary metabolites of plants function as antimicrobial products against phytopathogens and constitute an increasingly important class of pesticides. In the present study, the essential oil of Asarum heterotropoides var. mandshuricum was analyzed by GC/MS and its antimicrobial activity was evaluated against five phytopathogenic fungi. Major components of the oil were methyleugenol (59.42%), eucarvone (24.10%), 5-allyl-1,2,3-trimethoxybenzene (5.72%), and 3,7,7-trimethylbicyclo(4.1.0)hept-3-ene (4.93%). The essential oil and the most abundant component, methyleugenol, were separately assayed for inhibition of 5 pathogens: Alternaria humicola, Colletotrichum gloeosporioides, Rhizoctonia solani, Phytophthora cactorum and Fusarium solani. Both the oil and methyleugenol strongly inhibited the growth of the test pathogens (IC50 values <0.42 μg ml−1) except F. solani, with the best activity against P. cactorum (IC50 values = 0.073 and 0.052 μg ml−1, respectively). It is concluded that the essential oil of A. heterotropoides var. mandshuricum has a broad antiphytopathogenic spectrum, and that methyleugenol is largely responsible for the bioactivity of the oil. The mode of action of methyleugenol against P. cactorum is discussed based on changes in the mycelial ultrastructure. 相似文献
8.
Application of Trichoderma harzianum, to soil or by coating tomato fruits, reduced Rhizoctonia solani fruit rot by up to 43% and 85%, respectively, under laboratory conditions. When mixed with naturally infested soil, Trichoderma reduced R. solani inoculum potential by 86% in field trials. It also significantly reduced fruit rot by 27–51%. 相似文献
9.
Harsh Garg Chhaya Atri Prabhjodh S. Sandhu Balvir Kaur Michael Renton Shashi K. Banga Hardeep Singh Charandeep Singh Martin J. Barbetti Surinder S. Banga 《Field Crops Research》2010
Sclerotinia rot caused by the fungus Sclerotinia sclerotiorum is one of the most serious and damaging diseases of oilseed rape and there is keen worldwide interest to identify Brassica genotypes with resistance to this pathogen. Complete resistance against this pathogen has not been reported in the field, with only partial resistance being observed in some Brassica genotypes. Introgression lines were developed following hybridization of three wild crucifers (viz. Erucastrum cardaminoides, Diplotaxis tenuisiliqua and E. abyssinicum) with B. napus or B. juncea. Their resistance responses were characterized by using a stem inoculation test. Seed of 54 lines of B. napus and B. juncea obtained from Australia, India and China through an Australian Centre for International Agricultural Research (ACIAR) collaboration programme were used as susceptible check comparisons. Introgression lines derived from E. cardaminoides, D. tenuisiliqua and E. abyssinicum had much higher levels (P < 0.001) of resistance compared with the ACIAR germplasm. Median values of stem lesion length of introgression lines derived from the wild species were 1.2, 1.7 and 2.0 cm, respectively, as compared with the ACIAR germplasm where the median value for stem lesion length was 8.7 cm. This is the first report of high levels of resistance against S. sclerotiorum in introgression lines derived from E. cardaminoides, D. tenuisiliqua and E. abyssinicum. The novel sources of resistance identified in this study are a highly valuable resource that can be used in oilseed Brassica breeding programmes to enhance resistance in future B. napus and B. juncea cultivars against Sclerotinia stem rot. 相似文献
10.
Ana Piedra-Buena José A. López-PérezMiguel Á. Díez-Rojo Lee RobertsonIván Castro-Lizazo Antonio Bello 《Crop Protection》2011,30(2):134-140
The susceptibility of three sweet potato cultivars (Ipomoea batatas L.) C4, TIS 3290 and TIS 9162 was evaluated against 156 isolates of Meloidogyne spp. with the aim to include resistant/tolerant sweet potato cultivars in a crop rotation scheme for the management of root-knot nematodes. The nematode isolates corresponded to races 1, 2 and 3 of Meloidogyne arenaria (n = 7), races 1, 2, 3 and 4 of M. incognita (n = 131) and Meloidogyne javanica (n = 18). Also, the isolates of M. incognita were differentiated in virulence groups: Pepper (n = 35), Pepper-Mi (n = 25), Tomato (n = 41) and Tomato-Mi (n = 30), depending on their ability to parasitize resistant pepper and tomato cultivars. The tested isolates of M. javanica parasitized C4 and TIS 3290, but not TIS 9162, whereas M. arenaria parasitized C4 and TIS 9162, but not TIS 3290, and M. incognita was able to parasitize the three sweet potato cultivars tested. C4 was the most susceptible cultivar to all nematode species tested, especially M. incognita, TIS 3290 was the most resistant and TIS 9162 was in between (7.2, 62.9 and 26.9% of resistant plants, respectively). Susceptibility of the sweet potato cultivars showed slight variations depending on the race or virulence group of M. incognita. The results suggest that sweet potato cultivars TIS 3290 and TIS 9162 may be used as rotation crops in fields where root-knot nematodes are present, their selection depending on the Meloidogyne isolates present. The use of resistant sweet potato cultivars would be preferably combined with other management practices to avoid virulence selection in nematode isolates. 相似文献
11.
The soil-borne pathogen Rhizoctonia solani AG 8 causes major yield losses in wheat (Triticum aestivum. L) production worldwide. Plant tissues of Brassicaceae species contain glucosinolates that are hydrolyzed in the presence of the enzyme myrosinase into products with pesticidal properties. Growth chamber studies were conducted to determine the effect of the Brassicaceae seed meals (SMs) from Brassica juncea, Brassica napus and Sinapis alba on the suppression of the R. solani AG 8 infection of winter wheat. Pasteurized sandy soils were amended with intact and denatured SMs of rape seed and mustard at a rate of 0.5% by soil weight. Regardless of the glucosinolate type and content, all intact and denatured Brassicaceae significantly reduced the infection of winter wheat seedlings by R. solani AG 8 compared to the un-amended control. However, soils amended with S. alba SMs had the lowest severity of Rhizoctonia root rot relative to other amended soils. Phytotoxicity arising from the use of Brassicaceae SMs was observed particularly in soils amended with high glucosinolate-containing SMs. These studies demonstrate that Brassicaceae SMs can be used to manage disease caused by R. solani AG-8. However, future studies will need to focus on strategies for diminishing the crop growth-reducing effects associated with Brassicaceae SM amendment to fully maximize these fungicidal benefits. 相似文献
12.
Vernalization requirement, photoperiod response and earliness per se (EPS) of bread wheat cultivars are often determined using controlled environments. However, use of non-field conditions may reduce the applicability of results for predicting field performance as well as increase the cost of evaluations. This research was undertaken, therefore, to determine whether field experiments could replace controlled environment studies and provide accurate characterization of these three traits among winter wheat cultivars. Twenty-six cultivars were evaluated under field conditions using two natural photoperiod regimes (from different transplanting dates) and vernalization pre-treatments. Relative responses to vernalization (RRVGDD) and photoperiod (RRPGDD) were quantified using the reciprocal of thermal time to end of ear emergence, whereas earliness per se was estimated by calculating thermal time from seedling emergence until end of ear emergence for fully vernalized and lately planted material. An additional index based on final leaf numbers was also calculated to characterize response to vernalization (RRVFLN). To test whether the obtained indices have predictive power, results were compared with cultivar parameters estimated for the CSM-Cropsim-CERES-Wheat model Version 4.0.2.0. For vernalization requirement, RRVGDD was compared with the vernalization parameter P1V, for photoperiod (RRPGDD), with P1D, and for earliness per se, EPS was compared with the sum of the component phase durations. Allowing for variation in EPS in the calibration improved the relation between observed versus simulated data substantially: correlations of RRPGDD with P1D increased from r2 = .34 (p < .01), to .82 (p < .001), and of RRVGDD with P1V, from r2 = .88 (p < .001), to .94 (p < .001). In comparisons of observed versus simulated anthesis dates for independent field experiments, the estimated model coefficients resulted in an r2 of .98 (p < .001) and root mean square error of 1d. Overall, the results indicated that combining planting dates with vernalization pre-treatments can permit reliable, quantitative characterization of vernalization requirement, photoperiod response and EPS of wheat cultivars. Furthermore, emphasize the need for further study to clarify aspects that determine EPS, including whether measured EPS varies with temperature or other factors. 相似文献
13.
Sudden death syndrome, caused by Fusarium virguliforme, and the soybean cyst nematode, Heterodera glycines, combined cause the highest yield losses in soybean. The objective of this study was to determine the effectiveness of corn rotated annually with soybean on reducing severity of sudden death syndrome (SDS) and if such crop rotation is beneficial to soybean root health and thus improves disease management strategies. Experiments were conducted from 2003 to 2006 through two cycles of a corn–soybean rotation on two commercial fields in Indiana. With one exception, the rotation of soybean with corn did not provide yield benefits compared to monoculture of soybean. Severity of foliar and root symptoms of SDS in rotation plots were never less than in soybean monoculture plots. At one location, soybean monoculture resulted in suppression of SDS compared to the corn–soybean rotation, while H. glycines reproduced freely. At the other location, monoculture of soybean resulted in suppressiveness against H. glycines, while SDS was limited in all treatments. The data suggest that soil suppressiveness can independently impact the pathogens that are important in SDS development. Because H. glycines can increase SDS symptoms, its suppression may also reduce severity of SDS. Current production systems consisting of yearly rotation of soybean with corn are highly vulnerable to the development of severe soil-borne disease complexes. The simple year-to-year rotation of corn and soybean is not considered sustainable. While monoculture of soybean resulted in some disease suppression in these trials, reliance on monoculture may be detrimental due to other environmental considerations beyond the scope of these trials. Including other crops may be beneficial in improving the sustainability of soybean and corn production systems. 相似文献
14.
Peanut fields are monitored for pod rot, which is typically caused by Pythium spp. and Rhizoctonia solani, in order to determine need, and the type and timing of fungicide applications. Pod rot can lead to damaged peanut kernels and when damage exceeds 2.49%, substantial price reductions occur. Nine fields or tests were sampled weekly for pod rot during the 2009 through 2012 growing seasons. The sampling was conducted on fields treated uniformly with fungicides for pod rot or within large research plots with various fungicide treatments. Pythium myriotylum was the most frequently identified pathogen species, although Rhizoctonia spp. were also recovered from diseased pods at all sites. Pod rot incidence was related to percent damaged kernels at harvest in 3 of 5 sites. Collection of 304 samples (sample unit = 46 cm of row) in a field was required to estimate 1% pod rot accurately (CV = 20%). There was a linear relationship between average % pod rot in a field, and the percentage of sampling units (absence/presence) with pod rot at low disease incidences. Scouting for pod rot of peanuts to make in-season fungicide applications will be hampered by high sample number, destructive sampling of plants, frequent sampling (due to rapid increase of disease), and the poor relationship between disease during the season and kernel damage at harvest. Making one preventative application at 60–70 days after planting may be a better practice than timing the initial fungicide application based on sampling for disease. 相似文献
15.
Nguyen Thi Thu Cuc Nguyen Thanh Son Tran Minh Trung Nguyen văn Trang Lâm Minh Đang Marc Pilon 《Crop Protection》2010
Polianthes tuberosa is a commercially valuable flower crop in the Mekong Delta of Vietnam that is propagated by the harvesting and planting of bulbs. Cultivation of P. tuberosa is infected by an endemic Aphelenchoides besseyi nematode that damages a high proportion of plants and persists within the bulbs. Here we report on the comparison of hot water and pesticide treatments as control methods to protect P. tuberosa from A. besseyi damage, and conclude that a hot water treatment consisting of soaking bulbs in water for 30 min at 57 °C is the most efficacious method to produce healthy flowers in a cost effective manner. 相似文献
16.
Two antimicrobial alkaloids, palmatine and jatrorrhizine, were isolated from tubers of traditional Chinese medicinal plant Tinospora capillipes using activity-guided isolation method and chromatography. Their antimicrobial activity was determined in vitro. The results showed that palmatine and jatrorrhizine had inhibitory activity against plant pathogens Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. niveum, Mycosphaerella sentina, Pestalotia mangiferae, Cercospora kaki, Gymnosporangium haraeanum, Rhizoctonia solani and Colletotrichum graminicola, with the EC50 values of 0.0348-0.8356 g L−1 and 0.0240-0.8649 g L−1, respectively. Palmatine and jatrorrhizine also exhibited inhibition against animal pathogens Bacillus cereus, Bacillus megaterium, Bacillus subtilis, Staphyloccocus aureus, Staphylococcus epidermidi, Micrococcus lysodeikticus, Proteus vulgaris, Salmonella typhi and Escherichia coli, with the MIC values of 0.1-0.8 g L−1 and 0.1-0.6 g L−1, respectively. These results suggested that palmatine and jatrorrhizine showed relatively broad spectrum antimicrobial activity against plant and animal pathogens. 相似文献
17.
Paola Lax Juan C. Rondan DueñasNorma B. Coronel Cristina N. GardenalPaula Bima Marcelo E. Doucet 《Crop Protection》2011,30(11):1414-1420
The existence of races within the species Nacobbus aberrans sensu Sher has been confirmed; however, there is no consensus on a consistent system for race determination. Four plant species previously used as differential hosts in some N. aberrans race tests (tomato, pepper, sugarbeet and potato) were tested for susceptibility to seven nematode populations from Argentina. Plants were inoculated with second-stage juveniles and kept under glasshouse conditions at 21 °C for 90 days. The parameters evaluated (root gall index, egg mass index, and reproduction factor) in different nematode populations and plants showed significant differences. The reproductive fitness of the nematode populations differed among the plants that showed some degree of susceptibility. The results showed that N. aberrans comprises populations differing in host preference. Based on the nematode populations’ behaviour on these hosts, two groups were distinguished: i) populations that multiplied on all hosts, ii) populations that did not multiply on potato. The present work contributes to the analysis of criteria for developing a differential host test. 相似文献
18.
Rita Maggini Letizia TozziniSilvia Pacifici Andrea RaffaelliAlberto Pardossi 《Industrial Crops and Products》2012,35(1):269-273
In separate experiments conducted in 2007 and 2008, growth and accumulation of selected caffeic acid derivatives (CADs; i.e., caftaric acid, chlorogenic acid, echinacoside, caffeic acid, cynarin, p-coumaric acid, ferulic acid and cichoric acid) were determined in Echinacea angustifolia DC. var. angustifolia seedlings grown in hydroponic culture (floating raft system) at a density of 122 plant m−2 (at planting). Plants were harvested 11 (2007) or 16 (2008) weeks after transplanting (i.e., 15 or 20 weeks after sowing). In both years, plants grew vigorously and at harvest approximately half of the plants under observation had developed one to three inflorescences. In 2008, the root yield (2940 kg ha−1) harvested in nearly eight months from two consecutive hydroponic cultures was within the yield reported in the literature for field cultivations lasting two to four years. None of the selected CADs was found in the leaves, while the inflorescences (stem and capitulum) contained only caftaric acid and echinacoside at concentrations higher than the detection limits (0.05 mg g−1 dry weight). Echinacoside, cynarin and chlorogenic acid were found in root tissues at concentrations ranging from 0.36 to 5.25 mg g−1 dry weight. In all plant samples, echinacoside, which is the marker compound for E. angustifolia material, did not reach the minimum quality standard (10 mg g−1 dry weight) for the production of standardized extract. We concluded that short-cycle, high-density greenhouse hydroponic culture stimulates plant growth and root production in E. angustifolia, but it does not ensure sufficient CADs accumulation in dried roots. 相似文献
19.
Yenny Adriana Gómez-Aguirre 《Industrial Crops and Products》2012,36(1):188-195
Castilleja tenuiflora is a highly valued medicinal plant that grows in pine-oak woods in Mexico. In this study, we identified for the first time verbascoside and isoverbascoside as the major phenylethanoid glycosides (PhGs) in C. tenuiflora. These compounds have proven biological activities, including anti-inflammatory, antioxidant, and cytotoxic activities, which may be related to the traditional uses of this plant. We developed a reverse-phase high-performance liquid chromatography (RP-HPLC) procedure to analyze PhGs, and determined their concentrations in various different tissues of wild plants. Verbascoside accumulated mainly in roots and inflorescences (9.23 and 7.88 mg g−1 dry biomass, respectively), while isoverbascoside accumulated mainly in the roots (7.13 mg g−1 dry biomass). To provide an alternative source of material for production of bioactive compounds, we established in vitro adventitious root cultures in which roots were grown in B5 medium containing either 10 μM indole 3-acetic acid (IAA) or 10 μM α-naphthaleneacetic acid (NAA). The greatest dry biomass yield (30 g L−1) was achieved at 30 days after transfer of roots into IAA-containing medium. The highest specific yields of PhGs were also obtained using this auxin; the maximum level of verbascoside was 14.62 mg g−1 dry root biomass (438.6 mg L−1) at 30 days after root transfer, and the maximum yield of isoverbascoside was 37.32 mg g−1 dry root biomass (522.48 mg L−1) at 23 days after root transfer. Adventitious root cultures of C. tenuiflora are a promising system for further studies on scale-up and phenylethanoid glycosides biosynthesis. 相似文献
20.
The current revision of pesticides in the EU, including those for soil disinfection, will necessitate the introduction of alternative integrated methods for the control of weeds and parasites in tobacco production in Italy. The present study compared the effect of some soil fumigants, biocontrol agents, cover crops and mulching for the control of tobacco weeds and root parasites. The results show that the different soil fumigants had an important role in increasing tobacco yield, due to their ability to control weeds and the nematodes Meloidogyne incognita and Meloidogyne javanica. In particular, a typical nematicide like 1,3-dichloropropene did not control only nematodes but also Portulaca oleracea, a common weed in Italian tobacco fields. Fenamiphos, although showed a certain efficacy in controlling root-knot nematodes, did not generally have a satisfactory activity at the dose of 40 g m−1; cover crops like Trifolium squarrosum and Eruca sativa and a commercial formulation composed by the endomycorrhizal fungi Glomus spp., the antagonistic fungi Trichoderma spp. and bacteria including Pseudomonas, Bacillus and Streptomyces (Micosat F, CCS Aosta, Italy), were not able to control root tobacco diseases. The investigations confirmed that a prolonged monoculture causes a reduction of black root rot. Soil fumigation and the use of Good Agricultural Practices (GAP), influencing the inoculum density of Chalara populations, can contribute to the maintenance or to the establishment of particularly unfavourable conditions for the saprophytic growth of the pathogen, leading to a lower development of the disease. 相似文献