Fresh Weight Sample Research Articles

Microwave pretreatment allows accurate fatty acid analysis of small fresh weight (100 g) dried alfalfa, ryegrass, and winter rye samples

Accurate analysis of forage fatty acid (FA) profile and content, particularly polyunsaturated FA (PUFA), such as alpha-linolenic acid (ALA) and linoleic acid (LA), is vital for ongoing research optimizing the desired FA content of ruminant-derived foods. Lyophilization (i.e., freeze-drying) is regarded as the gold standard for preserving labile constituents, such as PUFA, in fresh forage samples. This method, however, is expensive, time consuming, and generally impractical for the large number and size of forage samples in agronomic studies.The objective of the first experiment was to evaluate the efficacy of a brief (1 min) microwave pretreatment prior to forced hot air drying (FHA) for preserving alfalfa (Medicago sativa L.) and Italian ryegrass (Lolium multiflorum L.) forage samples, relative to both a freeze-drying control and FHA drying alone. In a second experiment, similar drying methods were examined in winter rye (Secale cereale L.), as well as the decline of ALA proportion of total FA in ground samples stored 72 weeks.In the first experiment, small fresh weight samples (100 g) receiving 1 min microwave pretreatment before FHA drying were found equivalent to freeze-dried samples in FA content and profile, and both were greater in ΣPUFA than samples that received FHA alone. Large fresh weight samples (400–500 g) receiving FHA alone, a common practice in agronomic studies, contained 1.5–2.5 fold lower total ALA content and 1.3–1.6 fold lower LA content than the freeze-dried control, while large fresh weight samples (400–500 g) receiving 1 or 2 min microwave pretreatment contained 1.2–2.2 fold lower total ALA content and 1.1–1.5 fold lower LA content than the freeze-dried control. The second experiment revealed a reduction in ALA proportion of total FA of stored samples over a long period of time regardless of preparation method; however, FHA samples had a greater rate of reduction.This study confirms that FHA drying alone is not adequate for forage sample preservation for FA analysis, and may lead to a significant underestimation of ALA, the principal FA in plants. This distorts measurements of other FA reported on a proportional basis (g 100 g−1 total FA). In conclusion, a simple and inexpensive 1 min microwave pretreatment prior to FHA drying results in FA analysis comparable to freeze-dried samples, provided that samples are of a small fresh weight (100 g).

Additive biomass equations based on complete weighing of sample trees for open eucalypt forest species in south-eastern Australia

The aboveground biomass and carbon stock of less commercialized Eucalyptus open forests of south-eastern Australia are not well-known due to a lack of accurate biomass equations for even the prevalent species in these forests. To improve biomass and carbon estimates of these forests, a total of 245 trees of 11 eucalypt species with DBH (diameter overbark at the breast height of 1.3m above ground level) up to 139cm and height up to 39m were destructively sampled across three broad study sites in north-central Victoria. Trees were sampled as the four aboveground components of lower stem, upper stem, crown, and dead attached stem and branch materials. All four components were weighed completely in the field. To determine the dry to fresh weight ratio for each of the four components, 90 of these trees were further subsampled for moisture content. General linear models were used to relate dry to fresh weight ratio to site, species and tree size and the parameters of the models were estimated through generalized estimating equations. The model-estimated dry to fresh weight ratios were used to convert fresh weight to dry weight for all biomass components of fresh weight sample trees. Using the derived dry weight data, two systems of nonlinear additive biomass equations for stem, crown and total tree biomass were developed for each of the 11 species, with DBH as the independent variable in one system and the combined variable of DBH and tree height in another. Residual error variances and approximate confidence bands containing about 90% of the observed data about the mean curve of predicted biomass were estimated and derived for all biomass components of each species. In addition to the species-specific equations, two sets of site-specific biomass equations were developed using pooled biomass data from each site regardless of species. These systems of additive biomass equations will improve the accuracy of biomass and carbon estimation of open eucalypt forests in south-eastern Australia.

The Role of Cosmotic Adjustment On Drought Stress of Some Olive Cultivars

Generally native genotypes of Olives have different reaction against drought stress. The current research was conducted in order to determine the metabolic index under drought stress conditions in olive cultivars (Nabali, Gordal, Arbequine, Zard, Roghani and Feshomi). It was designed on a RCBD experiment based on factorial with full irrigation and drought stress treatments in three replicates. The evaluated parameters in this research were several metabolic solutions, including, sucrose, starch, proline, and betaine. There were significant differences between control treatment and drought stress in different cultivars for the evaluated parameters. The amount of sucrose in three continual experiments showed significant differences between two control treatments and drought stress. Highest Sucrose was measured in Gordal (40.83 mg/g -1 ) and lowest amount was measured in Roghani cultivar (18.88 mg/g -1 ) in the fresh weight samples. Sucrose content increased under drought stress intensity and starch content decreases under water stress condition (20.83 and 37.75 mg/g -1 respectively). Proline content increased under drought stress conditions in the cultivars which is Nabali; 12.33 and Arbequine; 9.64 Micro mol/g -1 in the fresh weight samples respectively), however, it's the reason for differences of physiological and bio-chemical behaviors in these cultivars. Betaine content increased under water stress conditions (101.342 Micro mol/g -1 in fresh weight samples), so far that contrary to the metabolic solutions betaine is not quickly metabolized after drought stress and it may be considered as an indices of previous stress inside the plant, and it could be concluded that Gordal and Nabali were the best cultivars compared to Arbequine, Zard, Roghani and Feshomi due to drought resistance levels.

The Role of Cosmotic Adjustment On Drought Stress of Some Olive Cultivars

Generally native genotypes of Olives have different reaction against drought stress. The current research was conducted in order to determine the metabolic index under drought stress conditions in olive cultivars (Nabali, Gordal, Arbequine, Zard, Roghani and Feshomi). It was designed on a RCBD experiment based on factorial with full irrigation and drought stress treatments in three replicates. The evaluated parameters in this research were several metabolic solutions, including, sucrose, starch, proline, and betaine. There were significant differences between control treatment and drought stress in different cultivars for the evaluated parameters. The amount of sucrose in three continual experiments showed significant differences between two control treatments and drought stress. Highest Sucrose was measured in Gordal (40.83 mg/g-1) and lowest amount was measured in Roghani cultivar (18.88 mg/g-1) in the fresh weight samples. Sucrose content increased under drought stress intensity and starch content decreases under water stress condition (20.83 and 37.75 mg/g-1 respectively). Proline content increased under drought stress conditions in the cultivars which is Nabali; 12.33 and Arbequine; 9.64 Micro mol/g-1 in the fresh weight samples respectively), however, it’s the reason for differences of physiological and bio-chemical behaviors in these cultivars. Betaine content increased under water stress conditions (101.342 Micro mol/g-1 in fresh weight samples), so far that contrary to the metabolic solutions betaine is not quickly metabolized after drought stress and it may be considered as an indices of previous stress inside the plant, and it could be concluded that Gordal and Nabali were the best cultivars compared to Arbequine, Zard, Roghani and Feshomi due to drought resistance levels. Keywords: Olive –Drought Stress –Proline–Trehalose –Betaine

Determination of alkaloids and oxalates in some selected food samples in Nigeria.

The amount of alkaloids and oxalates present in some selected Nigerian food samples were determined. The samples include Solanum tuberosum L., Ipomea batatas L., Discorea alta, Discorea rotundata, Colocasia esculents L., Triticum vulgare, Soja hispida and Amarathus sp. The percentage alkaloids present in the samples ranged from 11.4 - 29.5% while that of oxalates range from 20 - 92 mg per 100 g of fresh weight sample. Sol. tuberosum L. has the highest alkaloid content while Amarathus sp. has the highest oxalate content. There is a positive correlation between the alkaloid content and oxalate content in the food samples analyzed.

A direct ultratrace determination of platinum in environmental, food and biological samples by ICP-SFMS using a desolvation system

The purpose of this study was to develop a robust, reliable and accurate method that allows measurements of platinum in the sub-ppt range in environmental, food and biological samples. The quantification of platinum was performed with digested samples, exploiting the high sensitivity of inductively coupled plasma sector field mass spectrometry (ICP-SFMS) in low resolution mode. The hafnium oxide interference affecting the determination of platinum was investigated. A desolvation device in combination with a membrane unit was used as the sample introduction system, in order to minimize the oxide formation. A HfO+/Hf+ ratio of 0.01% was obtained (50 times lower than with a standard inlet system), thus interferences were strongly reduced and no mathematical corrections were necessary in most samples. The platinum value found in the reference material road dust BCR 723 agreed with the certified value (within the 95% confidence limit). Additionally, recovery tests in spiked peat and hay samples confirmed the accuracy of this technique at an acceptable precision from 3.5% to 15.5% (RSD). The method was applied to the measurement of environmental and food samples from two locations, one near a well-frequented motorway, one from an alpine site. The higher platinum concentrations measured at the first site confirmed the polluting effect of the traffic. Swiss diet samples, urine samples and corresponding reference materials, SRM 1548 and SRM 2670 for total diet and urine, respectively, were measured as well. The method was successfully applied to the determination of trace and ultratrace levels of platinum in the samples, with very low limits of detection of 4.5 ng kg−1 in dry environmental and food samples, corresponding to 0.2–1.8 ng kg−1 in fresh weight samples and of 0.5 ng L−1 in urine samples.

Isolation of an endophytic diazotroph, Klebsiella oxytoca, from sweet potato stems in Japan

The population density of endophytic bacteria in the stem of field-grown sweet potato cultivars (Beniotome [BO], Koganesengan [KS], and Shiroyutaka [SYD in Miyakonojo, Miyazaki, Japan, ranged from 102 to 104 cells g−1 fresh weight sample using a semi-solid nitrogen-free medium. Eleven strains were isolated from the stems and two isolates, BO-1 and BO-5, showed a positive reaction in the acetylene reduction activity (ARA) test. BO-1 and BO-5 were isolated from cv. Beniotome in September 1999 and 2000, respectively. Morpho-physiological characterization of these isolates revealed that BO-1 and BO-5 showed a similar colony color in potato sucrose agar slants, produced bubbles in a modified semi-solid medium, acidified the medium, and displayed similar characteristics using the API 20NE rapid diagnostic kit. Partial sequence analysis of 16S rRNA from BO-1 revealed a 100% similarity (491 bp) to that of Klebsiella oxytoca. The other 9 isolates showed a negative reaction in the ARA test, slightly acidified or did not acidify the medium. Partial sequence analysis of the 16S rRNA revealed that the isolate SY-2 corresponded to Methylobacterium sp. (99.3% similarity for 1,241 bp), BO-3 to Pantoea agglomerans (99.1% similarity for 469 bp), and BO-8 to Sphingomonas sanguinis (98.8% similarity for 419 bp).

Isolation and partial characterization of endophytic diazotrophs associated with Japanese sugarcane cultivar

Endophytic bacteria were isolated from the juice of a 6 month-old sugarcane cv. NiF-8, which was collected from Miyako, Okinawa and planted in a field lysimeter in Tsukuba, Ibaraki, Japan. The most probable number of N2-fixing endophytes was 4.5 × 105 cells per gram of fresh weight sample and 21 isolates have a positive reaction for ARA in an N2-free semi-solid medium with 10% crystallized sugarcane sugar and 0.5% sugarcane juice. Analyses of some of the biochemical properties of the N2-fixing isolates indicated that 13 isolates were putative strains of Acetobacter diazotrophicus, 4 isolates showed similar characteristics to those of Herbaspirillum seropedicae, and 4 isolates consisted of Herbaspirillum rubribalbicans-like strains. This study confirmed the existence of N2-fixing endophytic bacteria in the Japanese sugarcane cv. NiF-8.

Evaluation of Bacterial Antagonists for Reduction of Summer Patch Symptoms in Kentucky Bluegrass

Ten bacterial strains previously identified for their ability to control soilborne pathogens on agronomic crops were evaluated for their ability to suppress summer patch disease caused by Magnaporthe poae in Kentucky bluegrass (Poa pratensis L). Bacterial strains varied in the ability to inhibit the growth of M. poae in agar plate bioassays, although most strains inhibited the fungus to some degree. Three strains originally isolated from wheat, Pseudomonas fluorescens 2-79, P. fluorescens 13-79, and Bacillus subtilis D-39Sr, and two strains originally isolated from cotton, Enterobacter cloacae EcH-1 and EcCT-501, significantly reduced summer patch symptoms by between 29 and 46% compared to untreated control plants after a 5-week period in the growth chamber. The five strains did not reduce summer patch disease in field trials in 1990. However, in 1991, B. subtilis D-39Sr and E. cloacae EcH-I reduced summer patch severity by 53 and 49%, respectively, over the entire season compared to untreated control plots. In 1994, both B. subtilis D-39Sr and E. cloacae EcH-1 also reduced summer patch severity over the entire season by up to 39 and 34%, respectively, compared to the untreated control in field plots. All five bacteria that reduced summer patch in growth chamber studies were present in the rhizosphere of greenhouse/growth chamber grown turfgrass at 10 4 to 10 6 CFU/g of fresh weight sample 2 weeks after application to plants. A single sampling of field plots during 1991 and four separate samplings of field plots during 1994 indicated that introduced bacteria were present within the turf at populations above 10 3 CFU/g of sample.

Development of Soybean Fresh and Dry Weight Relationships for Real Time Model Calibration

AbstractMeasurements of dry weight and crop phenology are normally used to validate comprehensive growth models. To reduce this requirement in applications such as large area yield forecasting, the present research was conducted to study the change of dry matter concentration (ratio of dry weight to fresh weight) of the vegetative and reproductive plant components of soybean (Glycine max (L.) Merr.]. The paper evaluates the usefulness of simple statistical equations that relate dry matter concentration to developmental stages for the specific purpose of growth model calibration. During the 1984 through 1985 seasons, five cultivars of soybean were grown in five locations throughout the soybean producing regions of the U.S. Soil type, planting date, plant population, and irrigation management varied from site to site. Plant samples were taken at 1‐ to 2‐wk intervals during the growing season for fresh weight and dry weight of vegetative parts and pods, and counts of reproductive sites. In most of the field locations, dry matter concentration of different soybean parts was found to follow a predictable pattern. The pattern was explained for most locations by a simple relation of developmental stage and vegetative dry matter concentration, using data collected until the beginning of pod fill. A second model explained the course of pod dry matter concentration over developmental stage, using data collected after the beginning of seed growth. Insignificant differences among regression lines of extreme locations suggest that the course of dry matter concentration may be of an inherent nature, with minor impact due to differences of cultivar, or weather. The equations developed in this paper to estimate dry weight data will reduce the effort of calibrating and/or validating soybean comprehensive growth models by requiring only the collection of fresh weight samples at known phenological events.

A simplified method for determining 1-aminocyclopropane-1-carboxylic acid (ACC) in plant tissues using a mass selective detector

A sensitive and specific method is described for the routine assay of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) in 100–200 mg fresh weight samples of green or etiolated tissue. The method involves high performance liquid chromatography (HPLC) and gas chromatography linked to mass spectrometry (GCMS) and uses 14C-labelled ACC as an internal standard, N-benzoyl n-propyl ACC as an easily prepared derivative for HPLC and GCMS, and N-benzoyl isobutyl ACC as an internal standard for GCMS. The procedure is faster and safer than an existing GCMS method and more specific and reliable than indirect assays widely in use. The method has been used to measure ACC in maize roots, young leaves of cucumber, and aerobic or anaerobic seedlings of rice.

Procyanidins (Condensed Tannins) in Green Cell Suspension Cultures of Douglas Fir Compared with Those in Strawberry and Avocado Leaves by Means of C18-Reversed-phase Chromatography

The procyanidins (the most common type of proanthocyanidin or condensed tannin) from cell suspension cultures derived from cotyledons of Douglas Fir have been compared with those isolated from leaves of strawberry and avocado. Seventy per cent methanol (v/v) extracts from 100 milligrams fresh weight samples were analyzed by a combination of C(18)-reversed-phase columns with high-performance liquid chromatography, and normal phase paper chromatography. (-)-Epicatechin and its oligomers were generally retarded longer on C(18) columns than the corresponding units made of (+)-catechin when eluted with solvents made up of 5% acetic acid alone or mixed with methanol up to 15% (v/v). Douglas fir preparations contained the most complex set of procyanidins and consisted of oligomers of catechin and epicatechin, whereas strawberry and avocado contained mainly (+)-catechin and (-)-epicatechin derivatives, respectively.

TOLERANCE AND RESIDUE STUDIES OF TRIALLATE IN LENTILS

The tolerance of lentils (Lens culinaris Medic.) to both preplant and postplant spring incorporation of the wild oat herbicide triallate [S-(2,3,3-trichloroallyl) diisopropyl-thiocarbamate] was studied at two locations. Seed yield, maturity and stand density were not affected by application rates considered adequate for effective wild oat (Avena fatua L.) control. An analytical method for determining triallate residues in lentil green tissue and mature grain was developed. Using electron-capture gas chromatographic detection, the limit of detection, based on a 1-g fresh-weight sample, was 20 ppb. Recoveries were in the order of 75% at the 50 ppb fortification level. Triallate residues did not exceed 20 ppb in any of the samples.