Microflora of Barley Kernels

Numbers and kinds of microflora were determined in 160 samples of barley grown in different regions of the United States; microflora were more abundant in the grains grown in the central states than in those grown in the western states. During steeping and germination in micromalting equipment, the number of colonies of filamentous fungi increased from two to five times, colonies of yeasts from five to ten times, and bacteria from 50 to more than 100 times the numbers present in the grain before malting. Kiln drying according to a commercial schedule reduced the number of all types of microflora below the number present before kilning, but all were present in larger numbers in the kilned malt than in the original grain. In barley stored at room temperature and at a moisture content of 15 to 18%, members of the Aspergillus glaucus group increased with increasing time and increasing moisture content, and germination percentage of the seeds decreased. Stored free of storage fungi at room temperature, barley with a moisture content just over 15% retained a high germination percentage for 5 months, but at a moisture content of 16% the germination decreased to zero.     

Biological,physical and chemical changes in stored wheat

Six lots of wheat from six farmers' bins in Manitoba were adjusted to a range of 5 moisture contents, held at 6 temperatures and sampled at 6 times during storage. After sampling, seeds were surface sterilized with mercuric chloride and subsamples plated on Czapek's agar, on filter paper moistened with water, or on filter paper moistened with a 7.5% sodium chloride solution. The microflora on the seed was determined, germination counts were made, and the seed was examined by government inspectors for its condition and grade. A total of 1192 samples were examined. In addition, 180 samples were subjected to a fat acidity test. Deterioration for each combination of temperature and moisture, the fungi involved, and the consequent effect on condition, grade and fatty acid content were observed. The effect of high moisture content (>20%) and low temperatures (3–10 ° C) on infection of seed by Penicillium and the consequent effect on germination, condition, grade and fatty acid value are stressed. The interrelationship among fungi, and among fungi and temperature, moisture, storage time, fat acidity values and germination are indicated by correlation coefficient matrices.Deceased July 25, 1982.     

The performance of carrot seeds in relation to their viability

The germination and emergence characteristics, and early seedling growth, of carrot seeds cv. Chantenay red-cored from different sources with a range of germination from 54–94%, was compared. Seeds from protected crops (mean temperature of growth 21°C, r.h. 45–70%) gave higher percentage germination than those from crops grown outdoors (mean temperature 15°C, 70–100% r.h.). Germination was also higher from mature (seed moisture content at harvest 20% or lower) than immature seed (seed moisture content at harvest between 20 and 60%). High percentage germination (>90%) was associated with low mean germination times and low spreads of germination times whilst the reverse was true for low percentage germination. Similar relationships were found for seedling emergence characters in the field although a lower proportion of the viable seeds produced seedlings from slowly than rapidly germinating seed lots. In general, seed lots having a low percentage germination gave greater variability in plant weight than those of higher percentage germination. There was no effect of seed source on radicle or shoot relative growth rates or on post-emergence seedling growth rates.     

Principal component analysis of interrelations in stored-wheat ecosystems infested with multiple species of insects

Principal component analysis (PCA) was used to determine the effects of infestation of bulk stored wheat by multiple species of insects at 30±2°C for 60 wk. Eight 204-liter drums containing wheat at 15.5% moisture content were used as three distinct man-made ecosystems: (a) Control system (2 drums), insect-free; (b) RST system (3 drums), artificially infested with Rhyzopertha dominica (F.),Sitophilus oryzae (L.), and Tribolium castaneum (Herbst ); and (c) COT system (3 drums), infested with Cryptolestes ferrugineus (Stephens ),Oryzaephilus surinamensis (L.), and Tribolium castaneum. The variables measured tri-weekly within each system included carbon dioxide, oxygen, temperature, grain moisture, seed damage, grain weight and volume, dust weight and volume, fat acidity values (FAV) of the wheat, seed germination, microflora including Alternaria alternata(Fr.) Keissler ,Aspergillus glaucus group, Aspergillus candidusLink , and bacteria, insects and the mite Tarsonemus granariusLindquist . PCA provided multivariate synopsis of the data quantifying several important relationships among the variables monitored. Tri-weekly and cumulative 60-wk analyses of each system showed that high bacterial counts were associated with high FAV levels;Tarsonemus numbers were positively related to Aspergillus; Alternaria and seed germination were negatively related to FAV, bacteria and grain damage; and that the number of insects was related to the presence of Aspergillus and negatively related to the presence of bacteria. Seed germination and Alternaria infection often decrease rapidly presumably because of infection by fungi of the Aspergillus glaucus group. The combined action of R. dominica and Aspergillus spp. enhanced seed damage and increased grain moisture content thus promoting bacterial growth which in turn inhibited insect and mold growth. Fat acidity values increased with time unless seed damage and bacterial infection were extensive as in the RST system.     

The effects of re-use of polyethylene glycol priming osmotica upon the development of microbial populations and germination of leeks and carrots

Three batches of leek seeds were osmotically primed successively in the same polyethylene glycol solution in a bubble column at a seed concentration of 100 g/litre for seven days at 15°C. Three batches of carrot seeds were similarly primed in a separate solution for six days at 15°C. The concentration of microorganisms in the solutions increased rapidly during priming of the first seed batch for both seed types, but increases during priming of the second and third batches were small. The seeds were the main source of the microorganisms; priming reduced the numbers of colonies of filamentous fungi and increased those of bacteria and yeasts. The priming treatments improved the percentage germination of the three seed batches of primed carrots and reduced the mean time to germination in both species and the mean time to emergence in compost. Percentage emergence was not affected by priming except in the third batch of primed carrot seed. The presence of large numbers of microorganisms in the priming solutions did not greatly affect seed performance when the same osmoticum was used three times with leeks and twice with carrots. Priming did not affect the number of abnormal seedlings.     

Effects of crop residues in soil on phymatotrichum root rot of cotton

The effects of cropping pea or barley and the decomposition of their residues on Phymatotrichum root rot of cotton were studied for five years. Little or no changes occurred in pH, content of carbon or moisture in the soil, but there were significant increases in populations of competitive microflora. Best control was obtained in infested soil which was cropped to either pea or barley in winter or in soil which received the higher tonnage of Papago pea plants. Reduction in incidence of root rot may be attributed to premature germination of overwintering propagules making hyphae vulnerable to the chemicals of decomposition and to competition of microflora in the soil.Former Graduate Assistant in Research, Associate Professor, Professor, and Former Professor of Plant Pathology     

The microflora of ripening barley grain and the effects of pre harvest fungicide application

Newly-emerged ears of barley soon became colonised by micro-organisms with numbers increasing to 5·8 × 10⁵ viable propagules/g dry weight by harvest. Bacteria were numerically predominant throughout. Yeasts and yeast-like fungi were also numerous during the early stages of grain development but were exceeded by propagules of filamentous fungi during ripening, with Cladosporium spp., Alternaria alternata, Epicoccum purpurascens and Verticillium lecanii most abundant. Numbers of most micro-organisms were greatest in a wet season but Alternaria was equally abundant in hot dry weather. Application of fungicides at or after anthesis modified the grain microflora. Captafol was most effective overall in decreasing numbers of fungi. However, benomyl decreased Cladosporium inoculum more than catpafol but was ineffective against Alternaria which became more numerous on benomyl-treated grain than on untreated. Yield increases of up to 4% were obtained by late fungicide treatment, least in a hot, dry year. Germination was also increased by some treatments by up to 5%.     

Methods of Examining Damp Grain at Harvest and After Sealed and Open Storage: Changes in the Microflora of Damp Grain during Sealed Storage

S ummary . Methods are described for enumerating the micro-organisms occurring on damp grain (18–35% moisture content) after harvesting and after sealed and open storage.
The microflora of 41 samples of damp grain at harvesting and 137 samples after sealed storage on farms have been examined. The latter included 25 samples from experimental storage, including polythene bags, and 51 samples from stores where spoilage had occurred or advice was sought.
A remarkably consistent population level of bacteria, moulds and yeasts was found on damp grain at harvesting. This information was used as a convenient basis for comparisons with results from grain after storage. Bacteria were initially present at 1–10 × 10⁶/g, but the level generally diminished during anaerobic storage. Also coli-aerogenes bacteria died out but lactobacilli increased. Strict anaerobes ( Clostridium spp.) did not develop. Moulds originally present in small numbers normally decreased but while total yeasts often remained at the ingoing number, there was a change from non-myceliated to myceliated species, numbers of which sometimes increased further.
If thermophilic yeasts and moulds or Streptomycetaceae were present in large numbers, the grain had been subjected to aeration and had heated. Sometimes mould growth appeared to cause binding of the grain, but in other instances myceliated yeasts were implicated.     

The microbiology of moist barley storage in unsealed silos

The microflora of moist barley grain and whole-crop barley silage stored in top-unloading, unsealed concrete-staved silos on six farms in England depended on the initial water content of the grain (23–58%), method of covering the grain, and the rate at which it was unloaded. Fungi and actinomycetes were fewest when the initial water content was more than 30%, and the grain was covered first with a layer of wilted grass, and then a plastic sheet. During unloading, the uppermost layer of grain remained in good condition provided 7.5 cm was removed daily. With an inefficient top-seal, the top grain heated and became mouldy, as it also did when unloading was slow. As the rate of unloading slowed, heating increased, and a characteristic succession of fungi and actinomycetes developed. With unloading at 7.5 cm/day or more, only yeasts, chiefly Endomycopsis chodatii Wickerham and Hansenula anomala (Hansen) H. & P. Sydow, were abundant, but at slightly slower rates of unloading Penicillium spp. also became common. Both these groups became less common as unloading was slowed further and were replaced, first by Absidia spp. and Mucor pusillus Lindt, then Aspergillus fumigatus Fres., Humicola lanuginosa (Griffon & Maublanc) Bunce, Micropolyspora faeni Cross, Maciver & Lacey, and Thermoactinomyces vulgaris Tsiklinsky as the heating increased. The number of spores (including bacterial cells) that could be removed from samples by blowing air ranged from 0.4–428 times 10⁶/g dry weight of grain. Whole-crop barley silage contained 2.9–132 times 10⁶spores/g dry weight. Similar species were isolated from whole-crop silage as from grain. Little moulding occurred deeper than 30 cm below surface of the grain. Concentrations of airborne spores were estimated periodically during two seasons. There were always more airborne spores than is usual in outdoor air. Without disturbance the silos contained 10⁶-10⁷ spores/m³ air, but when mouldy grain was unloaded concentrations increased to a maximum of 2860times10⁶ spores/m³ air; more than half of these were bacteria and actinomycetes and a quarter Aspergillus flavus Link. Potentially pathogenic fungi and actinomycetes were frequent, particularly when they also occurred in the grain or capping materials for spontaneous heating. Some probably survived in dust deposits and were resuspended during unloading. Airborne spores were frequent around the silos when grain was unloaded and rolled. Workers should wear efficient dust respirators at these times and while inside silos.     

Dormancy, ABA content and sensitivity of a barley mutant to ABA application during seed development and after ripening.

Assessment of dormancy inception, maintenance and release was studied for artificially dried immature seeds harvested throughout seed development in the barley cv. Triumph and its mutant line TL43. Each was grown in Spain and Scotland under low and high dormancy inducing conditions, respectively. Both TL43 and Triumph followed a similar pattern of release from dormancy across the seasons, although seeds of TL43 were able to germinate at an earlier seed development stage. Abscisic acid (ABA) content was also studied in immature grains throughout the seed development period. Total amount of ABA in seeds of Triumph and TL43 was higher in plants grown in Scotland than in Spain. However, no clear genotypic differences in ABA pattern in the course of grain development could be detected whilst significant genotypic differences were observed for germination percentage (GP). Endogenous ABA content alone throughout grain development did not explain genetic differences in GP within environments. Environmental and genetic differences in dormancy were also observed on mature seeds throughout the after-ripening period. The initial germination (GP(0)) played a key role in the sensitivity to ABA of post-harvest mature seeds. For the same after-ripening stage, TL43 was more insensitive to exogenous ABA than Triumph. However, ABA responses in seeds of the two genotypes with similar GP(0) at different after-ripening stages were comparable. Therefore, differences in exogenous ABA sensitivity of post-harvest mature grain of these two genotypes seemed to be determined by, or coincident with, the initial germination percentage.     

Growth, yield and grain quality of barley (Hordeum vulgare L.) in response to nitrogen uptake. II. Plant development and rate of germination

A nutrient culture system supporting stands of barley was used to examine the effect of nitrogen supply on plant development and germination rate. Two contrasting cultivars of barley were grown for two seasons with nitrogen supplied at an optimal rate and at one-third that rate. Mature grain was dissected from ears by grain position; stored until out of dormancy, weighed, and the time from inhibition to germination estimated for different ear positions. A parallel set of samples was analysed for grain nitrogen concentrations. A systematic increase in germination time was observed from the bottom to the top of the ear. This effect was in addition to and of the same order as the effect of grain size on germination time. Although there was significant variation in nitrogen concentration by grain position, these effects were smaller than the variations in grain weight within the ear and were not related to germination rate. These results are discussed in relation to plant development and events at the onset of germination.Keywords: Barley, germination, grain size, ear position, nitrogen.      

紫花苜蓿种子对逆境贮藏条件的反应

以陇东紫花苜蓿 (MedicagosativaL .cv .“Longdong”)种子为材料 ,在室温、35℃和 35℃ +10 %的种子含水量 (SMC) 3种贮藏、接种或不接种燕麦镰刀菌 (Fusariumavenaceum (Fr.)Sacc .)的条件下 ,1年贮藏期内对各逆境处理的种子每隔 6 0d进行 1次标准发芽试验 ,2 0℃恒温、第 10d统计种子的发芽率和死亡率 ,试验结束时计测种子幼苗的长度和感病率 ;在大田条件下观测各处理种子的出苗率 ,确定催腐 (CD)与各种贮藏条件下的苜蓿种带真菌种类和检出率 .结果表明 ,随着贮藏温度和种子含水量等逆境贮藏条件胁迫的加剧 ,苜蓿种带真菌检出率逐渐增高 ,从室温、35℃条件下的 10 %上升到CD +35℃ +10 %SMC条件下的 2 9% ;抗病性逐渐减弱 ,35℃ +10 %SMC条件下幼苗的感病率和种子死亡率显著 (P <0 .0 5 )高于室温和 35℃下的感病率和种子死亡率 ;室内种子发芽率和田间出苗率逐渐下降 ,35℃ +10 %SMC条件下的种子的发芽率和田间出苗率显著 (P <0 .0 5 )低于在室温和 35℃下的发芽率和田间出苗率 ;幼苗生长受到抑制 ,35℃ +10 %SMC条件下的苗长和根长显著 (P <0 .0 5 )低于在室温和 35℃下的幼苗长度 .随着贮藏时间的延长 ,种子真菌检出率和田间出苗率下降 ,幼苗感病率增加 .与未接种的对照相比 ,接种燕麦镰刀菌的种子     

Analysis and simulation modelling of population dynamics and bioenergetics ofCryptolestes ferrugineus (Coleoptera: Cucujidae) in stored wheat

The consequences of infestation of stored wheat by the rusty grain beetle, Cryptolestes ferrugineus (Stephens) was determined for 222 d at 30°C in 70-1 drums containing wheat at 13.5% moisture content. Temperature, grain moisture, seed damage, germination and weight, dust weight, fat acidity values (FAV), published data on growth, reproduction, survival and cannibalism rates and energy budget were used to develop a computer simulation model to simulate the population dynamics of C. ferrugineus at 30°C. In the insect-free control system, the fungi, Alternaria alternata decreased, Aspergillus glaucus group and Penicillium spp. increased, probably causing a rise in FAV of the grain. In the insect-infested system, C. ferrugineus could only eat the wheat germ of kernels that had a broken bran layer; 35.7% of the wheat germ or 914.6 J per 100 kernels was consumed. Within two generations after initial introduction, C. ferrugineus reached a peak in numbers and biomass polluting the ecosystem with excreta and remains, and accelerating the deteriorative process observed in the insect-free control system by increasing respiration temperature, FAV and reducing grain germination. After 87 d, the insect population declined to low levels. The simulation model provided a close match between the observed and predicted numbers of insect life stages and bioenergetic variables during the insect population growth phase. Simulation trials suggested that cannibalism of larger compared with smaller immature stages would be more wasteful of developmental time and energy, reducing the number of individuals reaching reproductive age, and that density-dependent fecundity was probably not an important regulatory mechanism of C. ferrugineus population dynamics in this study.     

Moisture content,mould invasion and seed germinability of stored melon

The variation in seed moisture, mould content and seed germination of two species of melon,Citrullus lanatus L. andCitrullus vulgaris Shrad. stored in jute bags was monitored at intervals of 2 months for one year. Seed moisture decreased in the first 6 months of storage followed by a gradual increase in the rainy months. The field fungi predominated immediately after harvest and disappeared completely after 6 months of storage. The storage fungi increased in both species and abundance throughout the storage period.Citrullus lanatus maintained high germination percentage for the first 4 months,C. vulgaris for the first 2 months, thereafter seed germinability decreased with prolonged storage.     

Dormancy of Paddy Seeds of a 'Non-dormant' Variety

Seeds of a non-dormant rice variety, Satika, were studied underdifferent natural and controlled humid conditions of storageat room temperature. Just after harvest the germination andpercentages of grain moisture were 9.2 and 30.0 respectively.Under humid conditions of storage (94 per cent) there was onlypartial break of dormancy after 42 d (32.8 per cent ger mination)with high grain moisture (23.8 per cent); in all other treatmentswhere the grain moisture varied from 4.4 to 16.4 per cent thegermination percentages were over 96 per cent after 42 d. This delaying effect of high moisture contents on the breakingof dormancy became very pronounced at about 26 per cent. Itis suggested that high moisture content may inhibit dormancy-breakingreactions possibly by interrupting air-diffusion inside theseeds.     

贮藏因素对超甜玉米种子活力及抗氧化指标的影响

本试验主要采用标准发芽实验与抗氧化指标测定等方法,研究了贮藏条件和含水量对绿色超人、超甜414两个超甜玉米品种种子活力与抗氧化指标的影响.结果表明,随着贮藏时间的延长,甜玉米种子发芽率均逐渐下降,绿色超人较超甜414种子易发生劣变;室温贮藏较低温贮藏易发生劣变;高含水量(12.5％)较低含水量(10.0％)易发生劣变....     

Ability of ectomycorrhizal fungi to utilize starch and related substrates

Basidiomycetous fungi of 55 strains of 33 species in 15 genera which are thought to be ectomycorrhizal were grown on starch and related substrates as a sole carbon source, and their ability to utilize these substrates was determined. Mycellial weights of the fungi grown on agar media containing starch and amylose varied between the strains from 1.1 to 94.9 mg/flask and from 0.4 to 93.3mg/flask, respectively. Mycelial growth rates ranged from 0 to 1.17 mm/d on barley grain medium and from 0 to 2.03 mm/d on rice grain medium; the highest rate corresponded to about half of the average of reference wood-rotting fungi. Most of the mycorrhizal fungi that grew well on amylose gave higher growth rates on barley. Several strains inLyophyllum, Hebeloma, Sarcodon, andTricholoma grew well on both glucose and starch media.     

Storage fungi and seed health of rice: A study in the Philippines

Fifty seed samples of different rice varieties stored in warehouses for varying periods (1–28 months) were collected and screened for their fungal flora, using standard blotter and agar plate methods, resulting in the isolation of 36 fungal forms. The samples were also studied for moisture content, germinability, and seedling abnormalities. Significant correlations were found among the numbers of fungi, storage period, and germinability. Fourteen samples, seven each of IR64 and IR66 were studied with regard to moisture content, germination test, abnormal seedlings, speed of germination, conductance of leachates, total dehydrogenase activity, total free amino acids, total soluble sugar, fat acidity, gelatinization temperature, gel consistency, amylose content, translucency, and per cent whiteness. Significant relationships were found between the fungi and the parameters studied.     

The floristic composition of moulds growing on walls of food and drink processing factories

Samples were taken from heavily moulded walls at a range of food and drink processing plants. Quantitative estimates of the number of moulds, yeasts and bacteria were made and the moulds were identified. The floristic diversity of the germination areas and kilns of several maltings establishments was also investigated. The most commonly isolated organisms were Penicillium spp. although each environment appears to have its own characteristic flora with more than 50% of the total colony forming units isolated at each site being accounted for by three or fewer species. The results are discussed in relation to the microflora of mouldy walls in other environments.Several of the fungi associated with the maltings establishments were not found at any other sites. The origin of these fungi is discussed in relation to the flora associated with grain and processing of malt.     

Germination of Cistus ladanifer seeds in relation to parent material

Variability in seed germination behaviour of Cistus ladanifer L. (rockrose), a Cistaceous species widely distributed in the Mediterranean Basin, was studied in a central Spanish population under controlled conditions. No correlation between seed moisture content and germination was found. Great variability in germination was found among seeds of the population studied, not only between seeds belonging to different mother plants, but also between those collected from different capsules on the same plant. In most cases, seeds preheated at 100 °C for 30 minutes showed a significant increase in germination. This germination behaviour is related to fire regimes as this plant is a typical shrubby element of the mediterranean shrublands. Percent germination did not vary significantly after several months of seed storage at room temperature. In the same way, no difference was found in final germination percentage of seeds stored under room temperature vs. seeds stored under cold conditions.