Participatory evaluation of Guinea yam (Dioscorea cayenensis Lam.–D. rotundata Poir. complex) landraces from Benin and agro-morphological characterization of cultivars tolerant to drought,high soil moisture and chips storage insects     

Y. L. Loko  A. Adjatin  A. Dansi  R. Vodouhè  A. Sanni 《Genetic Resources and Crop Evolution》2015,62(8):1181-1192

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Digestive Enzyme Activity during Larval Development of Black Snook,Centropomus nigrescens          下载免费PDF全文

Carlos Yanes‐Roca  Mayra E. Toledo‐Cuevas  Lizbeth J. Sánchez  Ana Born‐Torrijos  Nicole Rhody  Kevan L. Main 《Journal of the World Aquaculture Society》2018,49(3):612-624

Black snook, Centropomus nigrescens, have been identified as a promising candidate for aquaculture although, like many of the Centropomid species, high mortality associated with early larval stages presents a significant bottleneck to their commercialization. The digestive capacity of black snook larvae throughout the first 37 d after hatch (d.a.h.) was evaluated by quantifying digestive enzyme activities using biochemical techniques. Results showed that black snook larvae have alkaline proteases at hatching, which are known to be important during the first days of feeding for digestion. Toward the end of the study, acid proteases concentration increased (37 d.a.h.). Enzymes for lipid digestion, pancreatic lipase and bile salt‐activated lipase, were already present in the larvae before exogenous feeding commenced, and their activity increased with age and growth (length). Intracellular digestion, measured as the activity of leucine‐alanine peptidase, was high early on (5 d.a.h.) and decreased as development progressed (next 32 d). In contrast, alkaline phosphatase activity was lowest at first feeding and subsequently increased with age. Overall patterns in enzyme activity suggest the possibility of live feed weaning before 32 d.a.h. if artificial diets can be properly balanced.  相似文献   

Fucoidan and Cancer: A Multifunctional Molecule with Anti-Tumor Potential     

Farzaneh Atashrazm  Ray M. Lowenthal  Gregory M. Woods  Adele F. Holloway  Joanne L. Dickinson 《Marine drugs》2015,13(4):2327-2346

There is a wide variety of cancer types yet, all share some common cellular and molecular behaviors. Most of the chemotherapeutic agents used in cancer treatment are designed to target common deregulated mechanisms within cancer cells. Many healthy tissues are also affected by the cytotoxic effects of these chemical agents. Fucoidan, a natural component of brown seaweed, has anti-cancer activity against various cancer types by targeting key apoptotic molecules. It also has beneficial effects as it can protect against toxicity associated with chemotherapeutic agents and radiation. Thus the synergistic effect of fucoidan with current anti-cancer agents is of considerable interest. This review discusses the mechanisms by which fucoidan retards tumor development, eradicates tumor cells and synergizes with anti-cancer chemotherapeutic agents. Challenges to the development of fucoidan as an anti-cancer agent will also be discussed.  相似文献   

Differences in growth,fillet quality,and fatty acid metabolism-related gene expression between juvenile male and female rainbow trout     

Meghan L. Manor  Beth M. Cleveland  P. Brett Kenney  Jianbo Yao  Tim Leeds 《Fish physiology and biochemistry》2015,41(2):533-547

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Tissue distribution of olive flounder VDAC2 and its expression in fish cell lines     

Aijun Lü  Xiucai Hu  Li Li  Chao Pei  Chao Zhang  Xianglin Cao  Xianghui Kong  Guoxing Nie  Xuejun Li  Jingfeng Sun 《Fish physiology and biochemistry》2015,41(4):899-907

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Combined application of nitrogen and phosphorus to enhance nitrogen use efficiency and close the wheat yield gap on varying soils in semi‐arid conditions     

Therese M. McBeath  Vadakattu V. S. R. Gupta  Rick S. Llewellyn  Sean D. Mason  Christopher W. Davoren  Raymond L. Correll  Ben Jones  Anthony M. Whitbread 《Journal of Agronomy and Crop Science》2019,205(6):635-646

A primary driver of the wheat yield gap in Australia and globally is the supply of nitrogen (N) and options to increase N use efficiency (NUE) are fundamental to closure of the yield gap. Co‐application of N with phosphorus (P) is suggested as an avenue to increase fertiliser NUE, and inputs of N and P fertiliser are key variable costs in low rainfall cereal crops. Within field variability in the response to nutrients due to soil and season offers a further opportunity to refine inputs for increased efficiency. The response of wheat to N fertiliser input (0, 10, 20, 40 and 80 kg N ha^‐1) under four levels of P fertiliser (0, 5, 10 and 20 kg P ha^?1) was measured on three key low rainfall cropping soils (dune, mid‐slope and swale) across a dune‐swale system in a low rainfall semi‐arid environment in South Australia, for three successive cropping seasons. Wheat on sandy soils produced significant and linear yield and protein responses across all three seasons, while wheat on a clay loam only produced a yield response in a high rainfall season. Responses to P fertiliser were measured on the sandy soils but more variable in nature and a consistent effect of increased P nutrition leading to increased NUE was not measured.  相似文献   

The priority of management factors for reducing the yield gap of summer maize in the north of Huang-Huai-Hai region,China          下载免费PDF全文

Yue-e LIU  Yu-xin LI  Tian-fang LÜ  Jin-feng XING  Tian-jun XU  Wan-tao CAI  Yong ZHANG  Jiu-ran ZHAO  Rong-huan WANG 《农业科学学报》2021,20(2):450-459

Understanding yield potential, yield gap and the priority of management factors for reducing the yield gap in current intensive maize production is essential for meeting future food demand with the limited resources. In this study, we conducted field experiments using different planting modes, which were basic productivity(CK), farmer practice(FP), high yield and high efficiency(HH), and super high yield(SH), to estimate the yield gap. Different factorial experiments(fertilizer, planting density, hybrids, and irrigation) were also conducted to evaluate the priority of individual management factors for reducing the yield gap between the different planting modes. We found significant differences between the maize yields of different planting modes. The treatments of CK, FP, HH, and SH achieved 54.26, 58.76, 65.77, and 71.99% of the yield potential, respectively. The yield gaps between three pairs: CK and FP, FP and HH, and HH and SH, were 0.76, 1.23 and 0.85 t ha~(–1), respectively. By further analyzing the priority of management factors for reducing the yield gap between FP and HH, as well as HH and SH, we found that the priorities of the management factors(contribution rates) were plant density(13.29%)fertilizer(11.95%)hybrids(8.19%)irrigation(4%) for FP to HH, and hybrids(8.94%)plant density(4.84%)fertilizer(1.91%) for HH to SH. Therefore, increasing the planting density of FP was the key factor for decreasing the yield gap between FP and HH, while choosing hybrids with density and lodging tolerance was the key factor for decreasing the yield gap between HH and SH.  相似文献   

DNA条形码技术在中药领域的应用     

吕小旭  关鉴茹  樊敏  赵小荣 《中兽医医药杂志》2021,(1):42-45

DNA条形码技术可对物种进行快速自动鉴定,具有鉴定准确、结果稳定、操作简便、适用广泛等特点,目前在中药领域应用较多。从DNA条形码技术在中药材鉴定、种植、流通、市场监管、中成药鉴定和药用植物种质资源调查等中药领域的多个方面进行综述,并探讨DNA条形码技术在中药领域的优势和不足,以期为DNA条形码技术在中药领域的研究提供新的思路。  相似文献   

Time‐lapse monitoring of soil water content using electromagnetic conductivity imaging          下载免费PDF全文

J. Huang  E. Scudiero  W. Clary  D. L. Corwin  J. Triantafilis 《Soil Use and Management》2017,33(2):191-204

The volumetric soil water content (θ) is fundamental to agriculture because its spatiotemporal variation in soil affects the growth of plants. Unfortunately, the universally accepted thermogravimetric method for estimating volumetric soil water content is very labour intensive and time‐consuming for use in field‐scale monitoring. Electromagnetic (EM) induction instruments have proven to be useful in mapping the spatiotemporal variation of θ. However, depth‐specific variation in θ, which is important for irrigation management, has been little explored. The objective of this study was to develop a relationship between θ and estimates of true electrical conductivity (σ) and to use this relationship to develop time‐lapse images of soil θ beneath a centre‐pivot irrigated alfalfa (Medicago sativa L.) crop in San Jacinto, California, USA. We first measured the bulk apparent electrical conductivity (EC_a – mS/m) using a DUALEM‐421 over a period of 12 days after an irrigation event (i.e. days 1, 2, 3, 4, 6, 8 and 12). We used EM4Soil to generate EM conductivity images (EMCIs). We used a physical model to estimate θ from σ, accounting for soil tortuosity and pore water salinity, with a cross‐validation RMSE of 0.04 cm³/cm³. Testing the scenario where no soil information is available, we used a three‐parameter exponential model to relate θ to σ and then to map θ along the transect on different days. The results allowed us to monitor the spatiotemporal variations of θ across the surveyed area, over the 12‐day period. In this regard, we were able to map the soil close to field capacity (0.27 cm³/cm³) and approaching permanent wilting point (0.03 cm³/cm³). The time‐lapse θ monitoring approach, developed using EMCI, has implications for soil and water use and management and will potentially allow farmers and consultants to identify inefficiencies in water application rates and use. It can also be used as a research tool to potentially assist precision irrigation practices and to test the efficacy of different methods of irrigation in terms of water delivery and efficiency in water use in near real time.  相似文献   

Soil physical changes and maize growth in a structurally fragile tropical soil due to mulching and duration between irrigation intervals          下载免费PDF全文

E. G. Moura  V. R. A. Macedo  V. G. L. Sena  L. S. Campos  A. C. F. Aguiar 《Soil Use and Management》2017,33(4):631-638

Under tropical meteorological conditions, the volume of soil explored by plant roots is crucial for crop growth as it allows increased water and nutrient use efficiency. We hypothesized that, under different irrigation intervals, leguminous mulch can extend the duration between irrigation events but maintain crop performance, because decreased evaporative fluxes also reduce constraints to root exploration imposed by mechanical stress. We evaluated the combined effects of leguminous mulch and irrigation intervals on soil physical properties to determine whether the growth and productivity of maize were modified in a structurally fragile tropical soil. The experiment involved the following treatments: 4‐day irrigation intervals with soil mulched (4C) or bare (4S), 6‐day irrigation intervals with soil mulched (6C) or bare (6S), 8‐day irrigation intervals with soil mulched (8C) or bare (8S) and 10‐day irrigation intervals with soil mulched (10C) or bare (10S). Mulch decreased soil penetration resistance and increased to 4 days the favourable time for root development in drying soil. Relative to bare soil, mulch with a 6‐day irrigation interval almost doubled nitrogen uptake post‐tasselling, which decreased nitrogen remobilization and increased the crop growth rate during this stage. These conditions had a positive effect on the transpiration rate and stomatal conductance as well as on the growth and yield of maize. A 6‐day irrigation interval with mulch compared to 4 days with bare soil resulted in similar conditions for root development, but greater uptake of nitrogen (102.73–78.70 kg/ha) and better yield (6.2–5.3 t/ha), which means greater efficiency in nitrogen and water use.  相似文献