首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   32篇
  免费   6篇
林业   1篇
农学   1篇
  15篇
综合类   2篇
农作物   6篇
水产渔业   6篇
畜牧兽医   2篇
园艺   2篇
植物保护   3篇
  2022年   2篇
  2021年   3篇
  2020年   4篇
  2019年   2篇
  2018年   9篇
  2017年   2篇
  2016年   3篇
  2015年   4篇
  2014年   2篇
  2013年   3篇
  2012年   1篇
  2011年   2篇
  2006年   1篇
排序方式: 共有38条查询结果,搜索用时 31 毫秒
11.
The aim of this experiment was to evaluate the impact of colonization with arbuscular mycorrhizal (AM) fungus Glomus constrictum on the biomass production, flower quality, chlorophyll content, macronutrients and heavy metals content of marigold (Tagetes erecta L.) planted under uncontaminated soil and watered with various rates of sewage water. Sewage water utilization significantly decreased biomass production, characters of flower, nutrient concentration and rates of mycorrhizal colonization of mycorrhizal (M) and non-mycorrhizal (NM) marigold as compared to control untreated plants especially at the higher rates, but the reduction rate was proportionally higher in non-AM treatments. Mycorrhizal plants had significantly greater yield, relative chlorophyll content, leaf area, flower quality and element (P, N, K and Mg) content compared to non-inoculated marigold plants irrigated with or without sewage water. Furthermore, AM inoculation had highly decreased heavy metal (Zn, Co, Mn, Cu) content in tissues as compared to equivalent non-inoculated plants grown under sewage water application. Growing marigold with AM inoculum can reduce toxicity of heavy metals and enhance biomass production and P uptake. The results support the view that AM have a protective function for the host plant, hence playing a potential function in soil polluted immobilization processes, and thus are of assessing the potential of phytoremediation of heavy metals in sewage water contaminated soil.  相似文献   
12.
Supercritical fluid extraction (SFE) technique was applied and optimized for temperature, CO2 pressure and ethanol (modifier) concentration using orthogonal array design and response surface methodology for the extract yield, total phenols and antioxidants from grape (Vitis labrusca B.) seeds. Effects of extraction temperature and pressure were found to be significant for all these response variables in SFE process. Optimum SFE conditions (44?~?46 °C temperature and 153?~?161 bar CO2 pressure) along with ethanol (<7 %) as modifier, for the maximum predicted values of extract yield (12.09 %), total phenols (2.41 mg GAE/ml) and antioxidants (7.08 mg AAE/ml), were used to obtain extracts from grape seeds. The predicted values matched well with the experimental values (12.32 % extract yield, 2.45 mg GAE/ml total phenols and 7.08 mg AAE/ml antioxidants) obtained at optimum SFE conditions. The antiradical assay showed that SFE extracts of grape seeds can scavenge more than 85 % of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The grape seeds extracts were also analyzed for hydroxybenzoic acids which included gallic acid (1.21?~?3.84 μg/ml), protocatechuic acid (3.57?~?11.78 μg/ml) and p-hydroxybenzoic acid (206.72?~?688.18 μg/ml).  相似文献   
13.
Synthetic herbicides are posing problems owing to the development of weed resistance and emerging debate on their associated health hazards and ecological threats. Allelopathic manipulations are evolving as applicable substitutes for weed management in agroecosystems. In order to assess the efficacy of potential allelopathic water extracts from different plant species, field experiments were conducted during 2010 and 2011. Sorghum bicolor L., Helianthus annuus L., Brassica napus L., Oryza sativa L., Zea mays L. and Morus alba L. aqueous extracts in different combinations alone or along with a reduced dose of herbicide were evaluated for weed suppression in a maize crop. A weedy check and two herbicidal treatments, S‐metolachlor + atrazine (pre‐emergence) and atrazine alone (early postemergence), were included for comparison. Sorghum, brassica or sunflower tank‐mixed with 25% of the recommended dose of atrazine significantly suppressed the total weed density and dry biomass, along with a concomitant decrease in the crop resistance indices and treatment efficacy indices over the control. The weed density and dry biomass that were recorded at 60 days after sowing showed a strong negative correlation, while the leaf area index, crop growth rate, dry matter accumulation and net assimilation rate predicted a strong positive correlation, with the stover and grain yield of maize.  相似文献   
14.
As their natural prey, copepods are considered the ideal diets for hatchery culture of fish larvae. However, intensive cultivation of copepods has proven difficult and low culture productivity is the norm, which severely limits their use in aquaculture. This study investigated the effects of algal diets on a range of productivity‐related parameters, including egg production, hatching success, naupliar and copepodite survival, post‐embryonic development time, population growth and sex ratio of a small‐sized tropical copepod, Parvocalanus crassirostris, which has been identified as a high potential species for aquaculture. The diets tested included three live algal diets: Isochrysis sp. (T‐Iso), Pavlova 50 (Pav) and the diatom Chaetoceros muelleri (Cht); two algal paste diets: Isochrysis sp. (P‐Iso) and Thalassiosira weissflogii (P‐TW), as well as four mixed algae treatments composed of three binary algae diets (T‐Iso + Pav, T‐Iso + Cht and Pav + Cht) and a tri‐algal diet (T‐Iso + Pav + Cht). All parameters examined except sex ratio were significantly affected by the diets. The binary algal diet T‐Iso + Cht produced significant higher total egg production over female lifespan (121.0 ± 5.9 eggs) than all other treatments (P < 0.05). Survival during naupliar and copepodite stage was significantly superior when P. crassirostris were fed either the mixed diet of T‐Iso + Cht or the monoalgal diets of Cht or T‐Iso (P < 0.05) than other diets. These three treatments also had the fastest time of development to adults (ranging from 6.2 to 6.7 days). With an initial 100 adults, the T‐Iso + Cht treatment produced the highest population growth over a 15‐day cultivation period, which was significantly higher than other treatments (P < 0.001). In contrast, the algal paste treatments, including (P‐Iso) produced overall the worst results for various parameters examined. However, the sex ratio of P. crassirostris was not significantly affected by diets and was always heavily skewed towards females (>84% were females) across all treatments. Based on the results of this study, T‐Iso + Cht is recommended for intensive cultivation of P. crassirostris.  相似文献   
15.
Microbes in marine ecosystems are known to produce secondary metabolites. One of which are carotenoids, which have numerous industrial applications, hence their demand will continue to grow. This review highlights the recent research on natural carotenoids produced by marine microorganisms. We discuss the most recent screening approaches for discovering carotenoids, using in vitro methods such as culture-dependent and culture-independent screening, as well as in silico methods, using secondary metabolite Biosynthetic Gene Clusters (smBGCs), which involves the use of various rule-based and machine-learning-based bioinformatics tools. Following that, various carotenoids are addressed, along with their biological activities and metabolic processes involved in carotenoids biosynthesis. Finally, we cover the application of carotenoids in health and pharmaceutical industries, current carotenoids production system, and potential use of synthetic biology in carotenoids production.  相似文献   
16.
Increasing temperature due to global warming has emerged one of the gravest threats to rice production. This study examined the influence of high temperature and exogenously applied plant growth regulators on pollen fertility, anther dehiscence, pollen germination and metabolites synthesis in pollens of two rice cultivars (IR‐64 and Huanghuazhan (HHZ)). Plants were subjected to high day temperature (HDT), high night temperature (HNT) and control temperature (CT) in controlled growth chambers. Four different combinations of ascorbic acid (Vc), alpha‐tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA) and triazoles (Tr) were used along with a nothing applied control. Our results depicted that high temperature severely reduced the pollen fertility, anther dehiscence, pollen retention, germination and metabolites synthesis in pollens of both rice cultivars. Nonetheless, exogenous application of various plant growth regulators assuaged the adverse effects of high temperature and Vc + Ve + MeJA + Br was found the best combination than the other treatments for every studied characteristic. The HNT posed more negative effects than the HDT. Variations were also apparent between cultivars and HHZ performed better than IR‐64 under high‐temperature stress, with higher pollen fertility, better anther dehiscence, and greater pollen retention and germination rates. The greater tolerance of HHZ to high temperature was related with the higher synthesis of metabolites in this cultivar.  相似文献   
17.
18.
Abstract

This study intends to assess the effect of compost types and rates on lettuce growth. A pot experiment was conducted at the greenhouse of the College of Agriculture and Veterinary Medicine experimental station, Saudi Arabia. Three types (chicken residues, animal residues, and mixed organic residues) and four rates (1%, 2%, 4%, and 6%) were added to sandy soil. Lettuce seeds were sown in a nursery. After two weeks, each seedling was transplanted to a pot that contained 15?kg of soil. The lettuce plants were irrigated regularly for 60?days, then harvested following dry weight (DW) and chemical analyses. The results showed great variation in the DW, nutrient content, and heavy metals concentrations between the different compost treatments. It noted that DW of lettuce decreased with increasing rates of compost in certain treatments. Moreover, no plant growth occurred in some treatments derived from the mixed organic residue with higher application rates. The nutrient status of lettuce tissues varies greatly among different types of compost. The concentration of heavy metals and microelements present within the lettuce tissues was significantly affected by the types of compost. Copper (Cu), Zinc (Zn), Lead (Pb), Cadmium (Cd), and Nickel (Ni) concentrations in lettuce tissues ranged between 7.4 and 9.6, 81.5 and 104, 23.3 and 28.2, 3.7 and 5.8, and 27 and 30?mg kg?1, respectively. It revealed that heavy metals concentration increased in lettuce tissues with an increasing application rate of composts. The content of Zn, Pb, Cd, and Ni in lettuce plants were higher and did not meet the requirement set by national standards.  相似文献   
19.
A sand culture experiment was conducted to study the effect of saline water on the growth and fruit quality of processing tomato (Lycopersicon esculentum Mill.) Seedlings of five tomato cultivars were transplanted in quartz‐sand pots in a greenhouse at the Agricultural Experiment Station of Sultan Qaboos University. There were four saline nutrient solutions and a control consisting of half‐strength Hoagland solution. Salinity treatments were: 50 raM NaCl + 3 mM K2SO4 (EC 6.75), 50 mM NaCl + 1.5 mM orthophosphoric acid (EC = 7.18), 50 mM NaCl + 1.5 mM orthophosphoric acid + 3 mM R2SO4 (EC 7.29), and 50 mM NaCL (EC = 5.6). Treatments were applied daily commencing two weeks after transplanting. Data were collected on growth, and fruit yield and quality. Partitioning of mineral elements was determined in the vegetative tissue. The results obtained clearly show that concentrations of total soluble solids were increased in fruits treated with saline nutrients. Dry matter content of fruits exposed to salinity were higher than those from the control plants. Fruit acidity was increased with salinity, possibly due to a lower water content and increased organic acid accumulation. In the saline treatments, sodium (Na) content was decreased when potassium (K) was applied with NaCl but Na was higher in stems followed by root and leaf tissues. The partitioning of K followed a trend opposite to that for Na but with higher content in leaves. A similar situation was observed for calcium (Ca) and magnesium (Mg). Accumulation of phosphorus (P) was the lowest among all the ions. These results indicated that survival under saline conditions was accompanied by high ion accumulation. The study confirmed that saline nutrients are important for improving fruit quality of processing tomatoes.  相似文献   
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号