排序方式： 共有22条查询结果，搜索用时 31 毫秒
1.
Drought is a lack of moisture in nature, consistent or unnatural. The term consistent refers to a state of shortage, and unnatural refers to the deviation from an index of the regional natural condition. The objective of this research was to examine and forecast the intensity, duration, frequency and extent of droughts in Fars province. For this purpose, and in order to survey droughts in the province, a standard precipitation index (SPI) was determined as a selective index, considering its capacity to facilitate accurate positional analysis between various regions of the drought extent. For this, precipitation data within the same statistical period of 32 years (1968 to 1999) in 5 time scales of 3, 6, 12, 24 and 48 months from some 26 stations located within and out of the province were used, and the trends were assessed by using a time series analysis. At the next stage, RUN theory and Markov Chain were combined, on this basis to create transition probability and a steady matrix, and then the conditions of long term droughts in the province in terms of number and duration were forecast for the subsequent 10 years. The characteristics of the extent of drought were determined by using the Geographic Information System (GIS) with the help of geo-statistical methods. The results of the drought station surveys for the mentioned characteristics showed that the highest drought intensity (in terms of % deviation from normal) was at the Gozoon station and the longest duration of drought in months was at the Polkhan station; droughts both of long duration and with the highest frequency during the statistical period were observed at the Jahrom and Darshahy stations. The map of the extent of droughts showed higher intensity in the south and central regions of the province, while northern parts of the province were less sensitive to the effects of droughts. Also, the results of the maps of drought duration in various periods showed that droughts in the south of the province were of higher intensity and longer duration than elsewhere. 相似文献
2.
Figueroa-Espinoza MC Poulsen C Borch Søe J Zargahi MR Rouau X 《Journal of agricultural and food chemistry》2004,52(13):4240-4249
The overall objective of this research was to find a new way to valorize rye bran, by producing a gellifier from the enzymatic solubilization of arabinoxylans (AX). The effects of three pure endo-xylanases from Aspergillus niger (Xyl-1), Talaromyces emersonii (Xyl-2), and Bacillus subtilis (Xyl-3) and of Grindamyl S100 (GS100), a commercial enzyme preparation containing a Xyl-1 type endo-xylanase, were tested on rye bran to study the solubilization of water-unextractable arabinoxylans (WUAX). Eight different extrusion-treated rye brans were also used as substrates to find the best physical treatment to facilitate enzymatic arabinoxylan (AX) solubilization. Arabinoxylans were better solubilized from the bran extruded at high temperature using Xyl-3. This enzyme was then tested in combination with pure (1,4)-beta-d-arabinoxylan arabinofuranohydrolase (AXH) and endo-beta-d-glucanase or ferulic acid esterase (FAE), from A. niger. Only beta-glucanase in combination with Xyl-3 improved the AX extraction, but it did not have a marked effect on the viscosity of the extracts. Xyl-3 was then tested on a high-shear-treated rye bran, and results were compared to those obtained with the high-temperature-extruded rye bran. The high-shear treatment did not improve the bran AX enzymatic solubilization. The combination of FAE with Xyl-1 or Xyl-3 did not improve the AX extraction from untreated and high-shear-treated rye bran. Finally, to study the gelation capacity of the enzymatically solubilized AX, the effect of the hydrogen peroxide/horseradish peroxidase (H(2)O(2)/POD) was tested on the Xyl-3 high-temperature-extruded bran extracts. Solubilized AX did not gel in the presence of the oxidizing system. 相似文献
3.
Moazenzadeh Kadusa Islami Houman Rajabi Zamini Abasali Soltani Mehdi 《International Aquatic Research》2017,9(1):25-35
International Aquatic Research - This study investigated the effect of dietary Zn levels on growth performance, feed utilization, and hematological parameters of juvenile Siberian sturgeon... 相似文献
4.
Effects of Dietary Ascorbic Acid on Growth Performance,Body Composition,and Some Immunological Parameters of Caspian Brown Trout,Salmo trutta caspius 
下载免费PDF全文
下载免费PDF全文 A 9‐wk feeding experiment was conducted to investigate the effect of dietary ascorbic acid (AA) on growth performance and tissue compositions of Caspian brown trout. The fish (9.64 ± 0.62 g) were held in tanks at a density of 40 fish per tank. Five experimental diets were prepared by providing of 9.8, 43.8, 89.4, 188.5, and 384.2 mg AA equivalent/kg diet, respectively. At the end of the trial, an increasing trend was found on growth performance with the increase of AA supplementation. Fish fed diet supplemented with more than 188.5 mg/kg AA also had significantly higher bone collagen than fish fed diets containing 9.8 mg/kg AA (P < 0.05). According to the broken line, the dietary AA requirement of Caspian brown trout fingerlings was 177.24 mg AA/kg diet based on the weight gain, 186.97 mg AA/kg diet based on the protein tissue, and 163.95 mg AA/kg diet based on the bone collagen. Serum lysozyme and alternative complement pathway activities were also influenced by graded level of AA supplementation to the diet. The present research clearly indicated that AA is required for normal growth and enhancement of immune response in Caspian brown trout fingerlings. 相似文献
5.
Mohammadi Yasaman Mesbah Mehrzad Dezfoulnejad Mojdeh Chelemal Mehrgan Mehdi Shamsaie Islami Houman Rajabi 《Aquaculture International》2021,29(6):2751-2767
The present study investigated the effects of monovalent and bivalent vaccines against Streptococcus iniae and Vibrio harveyi on growth performance, blood biochemical parameters, immune system, and antioxidant defense of Asian seabass (Lates calcarifer) fingerlings. Fish were exposed to seven experimental groups containing phosphate buffer saline (control), S. iniae vaccine by injection, S. iniae vaccine by immersion method, V. harveyi vaccine by injection, V. harveyi vaccine by immersion method, S. iniae/V. harveyi vaccines by immersion method, and S. iniae/V. harveyi vaccines by injection in triplicate for 60 days. Vaccination resulted in a significant alteration of the final weight (FW), feed conversion ratio (FCR), daily weight gain (DWG), relative growth rate (RGR), glucose, lysozyme, and complement levels at 60 days post-vaccination. Also, serum glutathione activity significantly increased in group SVIM (S. iniae/V. harveyi vaccines by immersion method) compared to the control group at 60 days post-vaccination. The level of MDA in serum was significantly decreased in SIN (S. iniae vaccine by injection) and SVIM groups compared to the control group 60 days post-vaccination where the value of this parameter was significantly higher in VIM (V. harveyi vaccine by immersion method) and SVIN (S. iniae/V. harveyi vaccines by injection) groups. The results of this study suggest that exposure to monovalent and bivalent vaccines against S. iniae and V. harveyi could alter the growth performance, nonspecific immune response, and antioxidant defense of Asian seabass fingerlings.
相似文献6.
Seed is an important input in production of field crops. The successful production of sugar from sugar beet depends on high
yielding varieties, optimum plant establishment after sowing and good agricultural practices. Therefore, seed with the highest
germination ability and vigour is necessary to ensure an early and high level of field emergence. Knowledge of the genetic
control of seed characters may help breeders to efficiently select for improved germination. In this research, variance components
and inheritance of sugar beet seed characteristics were studied. Five monogerm diploid O-Type lines were crossed with 15 monogerm,
diploid cytoplasmic male sterile (CMS) lines on the basis of North Carolina Design II (Factorial Design), and 75 F1 hybrids
(single crosses) were produced. The hybrids were then compared in three completely randomized designs of 25 entries each.
Eight seed traits of F1 hybrids were evaluated in the laboratory in three replications. Based on genetic analysis, the additive
variance for rootlet length, hypocotyle length, uniformity of germination and 1,000-germ weight was significant at 5% probability
level. Also, the dominance variance was significant at 1% probability level for all the seed traits measured except for germination
percentage. Narrow-sense heritabilities of rootlet and hypocotyle lengths were significant at 5% probability level. Correlation
analysis showed that germination speed and hypocotyle length were positively and negatively correlated with germination uniformity,
respectively, at 1% probability level. These results indicated that there was a remarkable genetic variation for the seed
traits which could be exploited by selection and heterosis breeding. 相似文献
7.
8.
Improved water use efficiency (WUE, the ratio of dry matter produced to water used) can potentially result in yield improvement
in water-limited environments. Genetic variation in WUE can be exploited by carbon isotope discrimination (Δ) in C3 species. In order to improve WUE and its associated traits, it is necessary to understand the genetic systems controlling
the expression of these traits. A full diallel analysis carried out on five inbred lines selected from a previous field experiment
revealed that Δ, WUE and specific leaf weight (SLW, the ratio of leaf dry weight to leaf area) had high narrow-sense heritability
(Hn, the ratio of additive variance to phenotypic variance) and were controlled largely by additive gene effects indicating that
these traits can be improved by selection in early generations. In contrast, maternal effects had a large influence on phenotypic
expressions of total dry matter yield, total water use, chlorophyll content and leaf area suggesting the important role of
selection of female parent for improvement of these traits. The parental line R49 was found to be the best general combiner
for all of the traits. Genetic variation in SLW was strongly associated with Δ (R
2 =0.49, P < 0.01). This implies that SLW could be used as an inexpensive alternative measure for Δ to assess genotypes during the early
phases of breeding programmes. 相似文献
9.
Kadusa Moazenzadeh Houman Rajabi Islami Abasali Zamini Mehdi Soltani 《Aquaculture Nutrition》2020,26(4):1108-1118
An 8‐week feeding trial was conducted to quantify dietary copper (Cu) requirement of juvenile Siberian sturgeon, Acipenser baerii. Five isonitrogenous diets were formulated to provide actual dietary copper values of 1.8, 5.7, 10.1, 15.9 and 28.3 mg Cu per kg diet. Experimental diets were fed to the Siberian sturgeon (27.57 ± 0.24 g) in triplicate to apparent satiation for 8 weeks. At the end of experiment, weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) were significantly increased with increasing dietary Cu level up to 10.1 mg/kg and then decreased with further increases in dietary Cu level (p < .05). The Cu concentration in the liver and cartilage was positively correlated with the respective concentrations in the diet (p < .05), while muscle and serum Cu concentrations remained significantly unchanged (p > .05). Superoxide dismutase and glutathione peroxidase had the highest activities in serum of fish fed with 15.9 and 28.3 mg Cu per kg diet, respectively. Analysis by the broken‐line regression of SGR, crude protein content and superoxide activity demonstrated that the optimum dietary Cu requirements in juvenile Siberian sturgeon were 9.51, 9.58 and 16.10 mg/kg diet, respectively. 相似文献
10.
Journal of Crop Science and Biotechnology - It is of special importance to track the fertility restoring alleles in plants such as sugar beet in which cytoplasmic male sterility (CMS) is used to... 相似文献