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1.
Aspergillus flavus, Alternaria alternata and Fusarium oxysporum were found to be the pathogenic fungi mostly reducing cereal (barley, sorghum and wheat) seedlings. The pathogens have the ability to produce aflatoxin B1 and G1, diacetoxyscirpenol, kojic acid and tenuazonic acid that reduced seedling viability. The inhibition dose for 50% reduction (LD50) was recorded by aflatoxins at 0.83 mg L-1 for barley, 1.74 mg L-1 for wheat and 2.75 mg L-1 for sorghum. Diacetoxyscirpenol produced its inhibition at 1.26 mg L-1 for barley, 3.98 mg L-1 for wheat and 10 mg L-1 for sorghum. Kojic acid induced 50% inhibition at 63 mg L-1 for barley, 105 mg L-1 for wheat and 251 mg L-1 for sorghum. However, tenuazonic acid was less toxic where, the toxicity was ranged between 79-550 mg L-1. The inhibition in germination was more pronounced in barley followed by wheat and negligible in sorghum to all tested mycotoxins. This inhibition attributed to the reduction in seedling amylase activity. Amylase was also reduced in the same trend: barley > wheat > sorghum. Grain treatment with carboxin-captan and thiophanatemethyl-thiram at 1 g kg-1 grain increased seedlings vigour of wheat in sterilized soil by 45 and 22%, barley by 24 and 33% and sorghum by 15 and 30%, respectively. These fungicides have also a positive effect on cereal when soil was inoculated with A. flavus, A. alternata and F. oxysporum. 相似文献
2.
Fifty-seven of 87 isolates of Alternaria alternata (Fr) Keissler grown on autoclaved, moist corn-rice substrate and fed to rats were lethal. The major toxin produced was isolated and characterized as tenuazonic acid. Twenty of 23 toxigenic Alternaria isolates examined produced tenuazonic acid. No tenuazonic acid could be detected in either of the field samples of sorghum or blackeyed peas, which were heavily invaded by Alternaria. 相似文献
3.
Summary Immature zygotic embryo has been the widely used explant source to develop embryogenic callus lines, cell suspensions and
protoplasts for transformation of cereal crops including maize, wheat, rice, oat, barley, sorghum, and millet. However, the
lack of competence of immature embryos in certain elite lines is still a barrier to rontine production of transgenic cereal
crops in certain commercial cultivars. In addition, a great deal of effort is required to produce immature embryos, manipulate
cultures, of immature embryos or their cell suspensions, and cryoperserve cultures for further use. In addition, undifferentiated
cells may have reduced regenerability after a few months, of in vitro culture. Alternative explants and regeneration systems for efficient transformation of cereal crops are needed to avoid or
reduce the above limitations. During the past decade, scientists have successfully manipulated the shoot apical meristerms
from seedlings of maize oat, sorghum, millet, wheat, and barley in an effort to develop a less genetype-dependent and efficient
cereal regneration system that can be maintained in vitro for long pertiods of time without the need for cryopreservation. Furthermore, apical mesistem regeneration systems were used
to stably transform maize, wheat, rice, oat, barley, sorghum, and millet. 相似文献
4.
This study was aimed to evaluate the effectiveness of the aqueous and ethanolic extracts of fruits of Syzygium cumini, against the mycelial growth of Alternaria alternata and Fusarium oxysporum. The results showed that ethanolic extract at the concentrations of 7.5 and 9?mg/ml completely inhibited the mycelial growth of A. alternata and F. oxysporum, respectively. While the aqueous extract at a highest tested concentration (37.5?mg/ml) exhibited only 27.86 and 37.23% inhibition of mycelial growth of A. alternata and F. oxysporum, respectively. The spore germination assay also showed the complete inhibition of spore germination of A. alternata and F. oxysporum by ethanolic extract at 50 and 60?mg/ml concentrations, respectively. Minimum inhibitory concentration was recorded as 0.039 and 0.156?mg/ml in ethanolic extract and 20 and 6.25?mg/ml in aqueous extract against A. alternata and F. oxysporum, respectively. Phytochemical analysis also showed the presence of high amount of phenolics, tannins, flavonoids, alkaloids and saponins. 相似文献
5.
Summary Thidiazuron (TDZ) is a substituted phenylurea which has been shown to be an efficacious regulator of in vitro morphogenesis of many dicot plant species. However, information regarding the effect of TDZ on in vitro regeneration of monocot species is limited. We investigated the effects of TDZ on in vitro regeneration of barley ( Hordeum vulgare L.) and wheat ( Triticum aestivum L.) and found that it promoted shoot regeneration from callus in these two important cereal species. Plant regeneration from
calluses derived from immature embryo culture of barley and wheat was observed in regeneration media with a wide range of
TDZ concentrations (0.045–45 μ M). Shoot regeneration from barley calluses was the highest (38.3% for cv. Golden Promise) at 4.5 μ M (1 mg l −1) TDZ, while the optimal TDZ level for wheat regeneration seemed to be 0.9 μ M (0.2 mg l −1) (87% for cv. Bob White and 49.4% for cv. Hi Line). Roots developed normally when the regenerated wheat and barley shoots
from TDZ-containing media were transferred to the rooting medium. Comparison with other plant growth regulators commonly used
in wheat and barley regeneration media suggested that TDZ was among the best for in vitro regeneration of wheat and barley.
Both authors contributed equally 相似文献
6.
Production of alternariol, alternariol mono-methylether and tenuazonic acid by Alternaría alternata was studied in competition with Aspergillus parasiticus and Bacillus subtilis on irradiated sunflower seeds at 0.90 a w.
In cultures co-inoculated with Alternaría alternata and Aspergillus parasiticus alternariol production decreased by 64%. Similar results were observed in cultures co-inoculated with Alternaría alternata and Bacillus subtilis. 相似文献
7.
Tenuazonic acid (TeA) is a putative phytotoxin obtained from Alternaria alternata, the organism that can cause brown leaf spot disease of Crofton weed ( Eupatorium adenophorum). It is demonstrated here that the tenuazonic acid inhibits the activity of photosystem II (PSII); the I50-value is 48 μg mL ?1. Evidences from chlorophyll fluorescence show that tenuazonic acid interrupts electron transport between Q A and Q B on the acceptor side of PSII. It does not have an effect on the antenna pigments, the oxygen-evolving complex (OEC) at the donor side of PSII. On the basis of the fluorescence induction kinetics and competition experiments with [ 14C]atrazine, it is shown that tenuazonic acid does not share the same binding environment with atrazine despite their common action target: the Q B-site. It is concluded that tenuazonic acid is a member of a novel class of PSII inhibitors. 相似文献
8.
The occurrence of mycotoxins in barley, sorghum, teff ( Eragrostis tef) and wheat from Ethiopia has been studied. Samples were analyzed for aflatoxin B 1 (AFB1), ochratoxin A (OTA), deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) using high performance liquid chromatography
(HPLC) and for fumonisins (FUM) using enzyme linked immunosorbent assay (ELISA). AFB1 and OTA were detected in samples of
all the four crops. AFB1 was detected in 8.8% of the 352 samples analyzed at concentrations ranging from trace to 26 μg kg −1. OTA occurred in 24.3% of 321 samples at a mean concentration of 54.1 μg kg −1 and a maximum of 2106 μg kg −1. DON occurred in barley, sorghum and wheat at 40–2340 μg kg −1 with an overall incidence of 48.8% among the 84 mainly ‘suspect’ samples analyzed; NIV was co-analyzed with DON and was detected
at 40 μg kg −1 in a wheat sample and at 50, 380, and 490 μg kg −1 in three sorghum samples. FUM and ZEN occurred only in sorghum samples with low frequencies at concentrations reaching 2117
and 32 μg kg −1, respectively. The analytical results indicate higher mycotoxin contamination in sorghum, which could be related to the widespread
storage of sorghum grain in underground pits leading to elevated seed moisture contents. This is the first report on the occurrence
of OTA in teff. 相似文献
9.
Alternaria alternata is isolated in high frequency in sunflower seeds both in the field and storage. This species produces several toxic metabolites among them alternariol, alternariol monomethyl ether and tenuazonic acid. The accumulation of mycotoxins is regulated by physical, chemical and biological factors and for their production in many commodities nothing is known with regards to these conditions. In sunflower seeds the optimal conditions of temperature and water activity for tenuazonic acid production are unknown. The aim of this work was to investigate the effect of temperature and water activity on tenuazonic acid production by Alternaria alternata ITEM 539 in sunflower seeds. The temperature conditions evaluated were: 20, 25, and 30 °C and the water activities were 0.97, 0.90, 0.87, 0.80. The tenuazonic acid determinations were carried out during the incubation period at intervals of 7 days. Under conditions of constant temperature 25 °C) and variable water activities, 0.90 was the optimal value for tenuazonic acid production. At this water activity of the optimal temperature for tenuazonic acid production was 25 °C. 相似文献
10.
Alloplasmic lines of common wheat with disomic substitution of chromosome 7D for telocentric chromosome 7H 1L mar of barley H. marinum subsp. gussoneanum Hudson were isolated from the plants of generation BC 3, produced as a result of backcrossing of barley-wheat hybrids H. marinum subsp. gussoneanum (2 n = 28) × T. aestivum (2 n = 42), Pyrotrix, cultivar, with 28 common wheat cultivars Pyrotrix 28 and Novosibirskaya 67. Chromosome substitution pattern
was determined using SSR analysis and C-banding. In preliminary genomic in situ hybridization experiments, telocentric chromosomes
were assigned to wild barley was established. In the BC 3F 8 generations of three alloplasmic lines with the 7H 1L mar(7D) substitution type the differences in fertility manifestation were observed: most of the L-32(1) plants were sterile,
in line L-32(2) only sporadic plants were sterile, and line L-32(3) was fertile. Simultaneously with these experiments, using
selfpollinated progeny of the hybrids obtained in crosses of common wheat cultivar Saratovskaya 29 (2 n = 41), monosomic for chromosome 7D, with common wheat cultivar Pyrotrix 28 with addition of pair of telocentric chromosomes
7H 1L mar (7D) of barley H. marinum subsp. gussoneanum, euplasmic wheat-barley ditelosomic substitution 7H 1L mar (7D) lines were isolated. The lines obtained had normal fertility. PCR analysis of the 18S/5S mitochondrial repeat (hereafter,
mtDNA sequence) in alloplasmic and euplasmic ditelosomic substitution lines 7H 1L mar(7D) was performed. In the plants from alloplasmic sterile line L-32(1), the sequences only of the barley (maternal) type
were revealed, while the plants from alloplasmic fertile lines L-32(2) and L-32(3) demonstrated heteroplasmy (the presence
of barley- and wheat-like sequences within one individual). In euplasmic ditelosomic substitution lines the presence of only
wheat-like 18S/5S mitochondrial repeat sequences was observed. The results indicate that the presence of barley-like mtDNA
sequences in alloplasmic substitution lines was not associated with the presence of barley chromosomes in their nuclear genomes. 相似文献
11.
The effects of root applications of gibberellic acid (GA 3) on growth and photosynthesis of 12 species of plants including C 3 monocots ( Triticum aestivum L., wheat, Hordeum vulgare L., barley and Avena sativa L., oat), C 3 dicots ( Vigna radiata L., mung bean, Cucurbita moschata L., squash and Capsicum annuum L., pepper), C 4 monocots ( Zea mays L., corn, Sorghum vulgare L., sorghum and Panicum ramosum L., millet) and C 4 dicots ( Amaranthus retroflexus L., pigweed, Kochia scoparis L., kochia and Gomphrena celosoides L., gomphrena) were evaluated. Relative growth rates (RGR) of barley, oat, squash, pepper, corn, sorghum, millet, pigweed and kochia were increased above the control by 12.7%, 9.9%, 11.3%, 10.7%, 19.2% 10.1%, 11.5%, 16.4% and 32.7% respectively, four days following optimum GA 3 treatments. There was no effect of GA 3 on RGR in wheat, mung bean, and gomphrena. Gibberellic acid decreased the chlorophyll content expressed on an area basis by 20.0%, 13.9%, 20.9%, 17.1%, 11.9% and 28.0% in barley, squash, pepper, sorghum, pigweed and kochia, respectively, while that of oat, wheat, mung bean, corn, millet and gomphrena remained unchanged. When photosynthetic rates were expressed per mg of chlorophyll, it showed that GA 3 could stimulate photosynthesis in barley, squash, pepper, sorghum, millet, pigweed and kochia by 20.4%, 20.6%, 16.5%, 17.4%, 10.4%, 24.2%, and 29.4%; while there was no effect in oat, wheat, mung bean, corn and gomphrena. An increase in leaf blade area and/or length of sheath were observed in GA 3 treated plants of oat, barley, mung bean, squash, pepper, corn, sorghum, millet and kochia. The transpiration rate remained unchanged following GA 3 treatment in all 12 species.This work was supported in part by the Fair Funds administered by the Pennsylvania Department of Agriculture. Contribution No. 39, Department of Horticulture, The Pennsylvania State University. Authorized for publications as paper no. 6886 in the journal series of the Pennsylvania Agricultual Experiment Station.Research assistant and assistant professor respectively. 相似文献
12.
Hydrous fuel ethanol (95%) and distiller's wet grain (DWG) were produced in a farm-scale plant (< 4 million liters ethanol year −1) from corn, wheat, and grain sorghum particles of various sizes, from corn combined with thin stillage-whey, and from various other cereal grains. These variations were made in a search to find the best set of conditions for maximizing the energy balance (energy output divided by energy input) and minimizing the cost of ethanol production. We found that the optimum hammermill screen size for corn, wheat, and grain sorghum was 1·59–2·38 mm. In tests with thin stillage and whey a higher energy balance (2·91) occurred when one part whey was mixed with three parts stillage, rather than the reverse (2·69). However, the reverse (three parts whey and one part stillage) gave a lower ethanol cost ($0.45 liter −1) than the original ($0.47 liter −1). Tests with various cereal grains (corn, oats, wheat, barley, rye, and grain sorghum) gave identical energy balance values (2·26) when 10% (v/v) ethanol beers were produced. However, rye ($0.50 liter −1), grain sorghum ($0.46 liter −1), and corn ($0.51 liter −1) yielded ethanol at the lowest net cost. Recommendations for farm-scale plants are also provided. 相似文献
13.
The development of infection structures, derived from urediospores of Puccinia recondita f.sp. trilici in nearisogenic lines of susceptible and resistant wheat, and in non-hosts (viz. maize, oat, sorghum and barley), was examined by fluorescence microscopy and scanning electron microscopy (SEM). The infection structure formation on and in five cereal species follows a similar pattern. In sorghum, fungal development is arrested at the stage of substomatal vesicle formation, while, in maize, most fungal structures collapse during the stage of primary hypha development. By contrast, in wheat, barley and oat, the fungus forms many branched infection hyphae and haustorial mother cells. 相似文献
14.
3 ) and sorghum (C 4) leaves for the measurements of osmotic volume change and metabolite uptake. We first investigated whether the silicone oil
layer filtering centrifugation method could be applied to the protoplasts. The density of the silicone oil was optimized ( ρ =1.026) and 0.5M betaine was chosen as an osmoticum in the protoplast suspending medium. By using [ 14C] sorbitol and [ 14C] inulin as the marker of the medium carried over into the pellet, protoplast osmotic or internal volume was estimated to
be 200–300 μl (mg Chl) −1, with the medium space in the pellet of 8–15 μl (mg Chl) −1. Lowering of the osmotic pressure of the medium induced protoplast swelling as expected. Light also induced swelling. Using
this system, we could detect light-enhanced uptake of ascorbate, glutamate and pyruvate in both barley and sorghum protoplasts.
Pyruvate uptake was far higher in barley than in sorghum and inhibited by various inhibitors, showed saturation kinetics and,
therefore, seemed to be mediated by a translocator protein.
Received 10 August 1999/ Accepted in revised form 6 December 1999 相似文献
15.
Grey mould, caused by the fungus Botrytis cinerea, is one of the most destructive diseases in greenhouses for which serious fungicide resistance has developed. Between 2003 and 2005, 213 isolates of B. cinerea from two geographical regions were characterised for baseline sensitivity to kresoxim‐methyl. In the absence of salicylhydroxamic acid (SHAM), the mean 50% effective concentration (EC 50) values were 6.67 ± 0.61 (mean ± SD) and 0.37 ± 0.10 mg L ?1 during growth and germination, respectively. In the presence of 100 mg L ?1 SHAM, baseline sensitivities were distributed as unimodal curves with mean EC 50 values of 2.38 ± 0.21 and 0.28 ± 0.09 mg L ?1 for inhibiting growth and inhibiting germination, respectively. The mixture of kresoxim‐methyl and boscalid showed good control efficacy against strawberry grey mould disease. After the mixture was extensively used on strawberry for 2 years, 50 isolates were collected and determined for their sensitivity to kresoxim‐methyl and boscalid, respectively. The mean EC 50 of germination inhibition by boscalid was 0.39 ± 0.08 mg L ?1. The mean EC 50 of germination inhibition by kresoxim‐methyl was 0.26 ± 0.07 mg L ?1 in the presence of 100 mg L ?1 SHAM. Sensitivities of B. cinerea to both kresoxim‐methyl and boscalid did not show any significant decrease. These results suggest that their mixture is a satisfactory alternative candidate for management of grey mould disease in greenhouses. 相似文献
16.
One major problem encountered with cereal anther culture is that some genotypes are low or non-responders to the technique. The objective of this study was to improve anther culture efficiency of recalcitrant barley ( Hordeum vulgare L.) genotypes. Reciprocal F 1s between the two low responsive cultivars, Morex and Steptoe, were used. These were chosen because doubled haploids (DH) were required from these genotypes for the North American Barley Genome Mapping project. Ficoll 400 at 200 g l –1 in the induction medium significantly increased green plant production compared to four other media formations containing different gelling/viscosity modifying agents. Cold pretreatment of donor spikes of 28 vs 14 d resulted in an increase in embryoid, total plant and green plant production. Anther culture response in these experiments was little influenced by donor plant growth conditions. Indole-3-acetic acid (1 mg l –1) or 1-naphthaleneacetic acid (2 mg l –1) in the induction medium did not affect anther culturability or plant regeneration. Based on this research, the negative genotypic effect for doubled haploid production could be diminished, which is desirable for practical application.Abbreviations BAP
6-benzylaminopurine
- IAA
Indole-3-acetic acid
- LS
Linsmaier & Skoog
- NAA
1-naphthaleneacetic acid
- DH
doubled haploid 相似文献
17.
Tritordeum is a fertile amphiploid derived from durum wheat ( Triticum turgidum L. conv. durum) × a wild barley ( Hordeum chilense Roem. et Schultz.). The organic nitrogen content of tritordeum grain (34 mg g -1 DW) was significantly higher than that of its wheat parent (25 mg g -1 DW). Leaf and root nitrogen content became higher in tritordeum than in wheat after four weeks of growth, independently of
the nitrogen source (either NO 3
- or NH 4
+). Under NO 3
- nutrition, tritordeum generally exhibited higher levels of nitrate reductase (NR) activity than wheat. Nitrite reductase
(NiR) levels were however lower in tritordeum than in its wheat parent. In NH 4
+-grown plants, both NR and NiR activities progressively decreased in the two species, becoming imperceptible after 3 to 5
weeks of growth. Results indicate that, in addition to a higher rate of NO 3
- reduction, other physiological factors must be responsible for the greater accumulation of organic nitrogen in tritordeum
grain. 相似文献
18.
Necrotrophic fungal pathogens produce toxic compounds that induce cell death in infected plants. Often, the primary targets of these toxins and the way a plant responds to them are not known. In the present work, the effect of tenuazonic acid (TeA), a non–host‐specific toxin of Alternaria alternata, on Arabidopsis thaliana has been analysed. TeA blocks the Q B‐binding site at the acceptor side of photosystem II (PSII). As a result, charge recombination at the reaction centre (RC) of PSII is expected to enhance the formation of the excited triplet state of the RC chlorophyll that promotes generation of singlet oxygen ( 1O 2). 1O 2 activates a signalling pathway that depends on the two EXECUTER (EX) proteins EX1 and EX2 and triggers a programmed cell death response. In seedlings treated with TeA at half‐inhibition concentration 1O 2‐mediated and EX‐dependent signalling is activated as indicated by the rapid and transient up‐regulation of 1O 2‐responsive genes in wild type, and its suppression in ex1/ex2 mutants. Lesion formation occurs when seedlings are exposed to higher concentrations of TeA for a longer period of time. Under these conditions, the programmed cell death response triggered by 1O 2‐mediated and EX‐dependent signalling is superimposed by other events that also contribute to lesion formation. 相似文献
19.
Mature embryos of einkorn (Triticum monococcum ssp. monococcum) and bread (Triticum aestivum L.) wheat were used for callus induction on media containing four different doses (0, 1, 2 and 4 mg L?1) of 2,4-D and dicamba supplemented with five different boron concentrations (0, 6.2, 12.4, 24.8, and 37.2 mg L?1). The obtained callus was transferred to culture media with three (0, 0.5, and 2 mg L?1) different BAP doses with five boron concentrations for further regeneration. The maximum callus weight in einkorn wheat was in culture media with 1 mg L?1 dicamba and 6.2 mg L?1 (3.71?±?0.13 g). Bread wheat had the maximum callus weight on culture media with 4 mg L?1 dicamba and 12.4 mg L?1 (3.46?±?0.40 g). The highest plantlet numbers were in only 2 mg L?1 BAP (2.92?±?0.88) for einkorn wheat and 0.5 mg L?1 BAP supplemented with 6.2 mg L?1 boron (3.71?±?1.12) for bread wheat. This indirect regeneration protocol using mature embryos of einkorn and bread wheat under boron stresses expected to be useful for future wheat breeding studies. 相似文献
20.
Increasing atmospheric CO 2 concentration has led to concerns about potential effects on production agriculture as well as agriculture's role in sequestering C. In the fall of 1997, a study was initiated to compare the response of two crop management systems (conventional and conservation) to elevated CO 2. The study used a split‐plot design replicated three times with two management systems as main plots and two CO 2 levels (ambient=375 μL L ?1 and elevated CO 2=683 μL L ?1) as split‐plots using open‐top chambers on a Decatur silt loam (clayey, kaolinitic, thermic Rhodic Paleudults). The conventional system was a grain sorghum ( Sorghum bicolor (L.) Moench.) and soybean ( Glycine max (L.) Merr.) rotation with winter fallow and spring tillage practices. In the conservation system, sorghum and soybean were rotated and three cover crops were used (crimson clover ( Trifolium incarnatum L.), sunn hemp ( Crotalaria juncea L.), and wheat ( Triticum aestivum L.)) under no‐tillage practices. The effect of management on soil C and biomass responses over two cropping cycles (4 years) were evaluated. In the conservation system, cover crop residue (clover, sunn hemp, and wheat) was increased by elevated CO 2, but CO 2 effects on weed residue were variable in the conventional system. Elevated CO 2 had a greater effect on increasing soybean residue as compared with sorghum, and grain yield increases were greater for soybean followed by wheat and sorghum. Differences in sorghum and soybean residue production within the different management systems were small and variable. Cumulative residue inputs were increased by elevated CO 2 and conservation management. Greater inputs resulted in a substantial increase in soil C concentration at the 0–5 cm depth increment in the conservation system under CO 2‐enriched conditions. Smaller shifts in soil C were noted at greater depths (5–10 and 15–30 cm) because of management or CO 2 level. Results suggest that with conservation management in an elevated CO 2 environment, greater residue amounts could increase soil C storage as well as increase ground cover. 相似文献
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