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1.
A variety of slow release fertilizers, controlled release (availability) fertilizers (CAFs), and stability fertilizers have been developed in response to the serious drawbacks of the conventional fertilizers since the early 1960's. Of these fertilizers, CAFs which are coated with resin are consumed in the largest quantity in the world. Selecting CAFs with higher performance, the author will discuss about: 1) Innovation of agro-technologies for various field crops including new concepts of fertilizer application, 2) high yielding of field crops, 3) enhancing quality and safety of farm products, and 4) controlling the adverse effect of intensive agriculture on the environment.  相似文献   

2.

A variety of slow release fertilizers, controlled release (availability) fertilizers (CAFs), and stability fertilizers have been developed in response to the serious drawbacks of the conventional fertilizers since the early 1960’s. Of these fertilizers, CAFs which are coated with resin are consumed in the largest quantity in the world. Selecting CAFs with higher performance, the author will discuss about: 1) Innovation of agro-technologies for various field crops including new concepts of fertilizer application, 2) high yielding of field crops, 3) enhancing quality and safety of farm products, and 4) controlling the adverse effect of intensive agriculture on the environment.

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3.
Different field surveys have shown that sulphur (S) fertilization can increase the resistance of agricultural crops against fungal pathogens. The mechanisms of this sulphur-induced resistance (SIR) are, however, not yet known. Volatile S compounds are thought to play an important role because H(2)S is toxic to fungi. A field experiment was conducted to analyse the influence of S fertilization and the activity of H(2)S-releasing enzymes on fungal infections. Two levels of N and S fertilizers and two varieties of oilseed rape were investigated with respect to their potential to release H(2)S by the enzymatic activity of L-cysteine desulphydrase (LCD) and O-acetyl-L-serine(thiol)lyase (OAS-TL). LCD releases H(2)S during cysteine degradation, while OAS-TL consumes H(2)S during cysteine synthesis and free H(2)S is only released in a side reaction. All plots of the field trial showed an infection with Pyrenopeziza brassicae and leaf disc samples were taken from visibly infected leaf areas and apparently uninfected areas to investigate the reaction to the infection in relation to the treatments. Different S fractions and the activities of LCD and OAS-TL were measured to evaluate the potential to release H(2)S in relation to S nutrition and fungal infection. S fertilization significantly increased the contents of total S, sulphate, organic S, cysteine, and glutathione in the plants, but decreased LCD activity. Infection with P. brassicae increased cysteine and glutathione contents, as well as the activity of LCD. Therefore crops were able to react to a fungal infection with a greater potential to release H(2)S, which is reflected by an increasing LCD activity with fungal infection.  相似文献   

4.
In intensive cropping systems, mineral nitrogen (N) fertilizers represent the largest component of the N cycle because the indigenous N supply is not adequate. The requirement for mineral fertilizer may be reduced with the use of organic nutrient sources. A more realistic use of organic matter, particularly in sub-Saharan Africa due to limited amounts and availability, is the combined use of organic nutrient sources and mineral fertilizers. The beneficial effects of integrated use of inorganic fertilizers and organic manures on improved nutrient recoveries, soil moisture retention, cation exchange capacity, and erosion control have been reported. However, there are as many reports indicating negligible benefits or even disadvantages of combining nutrient sources on crop production. This is not surprising given the combination of organic residue sources, soils, climatic, crops, and management factors that influence nutrient dynamics. The most widely accepted function of organic materials is improving the nutrient availability to crops by supplying N. The key to both improving efficiency of N use and reducing N losses is synchronization of N supply from soil, biological N2 fixation, organic residues, and inorganic fertilizers with the crop N demand. Organic materials are not magic; N losses also result from their use. Controlling N release from organic sources depends on their nutrient content and quality, soil properties, and the environmental and management factors. This paper will synthesize the information generated from integrated nutrient management trials in sub-Saharan Africa and the Philippines. Management strategies based on an organic resources database and a dynamic soil-crop simulation model are used to identify organic sources as N fertilizers or soil amendments. The decision support tools are also used to attain optimum synchrony between release from organic sources and soils with crop N demand.  相似文献   

5.
Tumor progression requires the communication between tumor cells and tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are major components of stromal cells. CAFs contribute to metastasis process through direct or indirect interaction with tumor cells; however, the underlying mechanism is largely unknown. Here, we reported that autophagy was upregulated in lung cancer-associated CAFs compared to normal fibroblasts (NFs), and autophagy was responsible for the promoting effect of CAFs on non-small cell lung cancer (NSCLC) cell migration and invasion. Inhibition of CAFs autophagy attenuated their regulation on epithelial–mesenchymal transition (EMT) and metastasis-related genes of NSCLC cells. High mobility group box 1 (HMGB1) secreted by CAFs mediated CAFs’ effect on lung cancer cell invasion, demonstrated by using recombinant HMGB1, HMGB1 neutralizing antibody, and HMGB1 inhibitor glycyrrhizin (GA). Importantly, the autophagy blockade of CAFs revealed that HMGB1 release was dependent on autophagy. We also found HMGB1 was responsible, at least in part, for autophagy activation of CAFs, suggesting CAFs remain active through an autocrine HMGB1 loop. Further study demonstrated that HMGB1 facilitated lung cancer cell invasion by activating the NFκB pathway. In a mouse xenograft model, the autophagy specific inhibitor chloroquine abolished the stimulating effect of CAFs on tumor growth. These results elucidated an oncogenic function for secretory autophagy in lung cancer-associated CAFs that promotes metastasis potential, and suggested HMGB1 as a novel therapeutic target.Subject terms: Cancer microenvironment, Non-small-cell lung cancer, Metastasis, Translational research  相似文献   

6.
D. Alazard  M. Becker 《Plant and Soil》1987,102(1):141-143
The widely accepted application of the fertilizers via the irrigation stream (fertigation) has necessitated the development of suitable techniques to help research in estimating the fertilizer requirements of crops. This paper describes a simple, inexpensive, and precise system tested for three years in field experiments, in which various levels of a fertilizer could be supplied simultaneously. The same system could also be used when irrigating simultaneously various crops with different fertilizer requirements from a single concentrated fertilizer solution, using only one fertigator.  相似文献   

7.
Controlled release nitrogen (N) fertilizers have been commonly used in horticultural applications such as turf grasses and container-grown woody perennials. Agrium, a major N manufacturer in North and South America, is developing a low-cost controlled release urea (CRU) product for use in field crops such as grain corn, canola, wheat, and other small grain cereals. From 1998 to 2000, 11 field trials were conducted across western Canada to determine if seed-placed CRU could maintain crop yields and increase grain N and N use efficiency when compared to the practice of side-banding of urea N fertilizer. CRU was designed to release timely and adequate, but not excessive, amounts of N to the crop. Crop uptake of N from seed-placed CRU was sufficient to provide yields similar to those of side-banded urea N. Grain N concentrations of the CRU treatments were higher, on average, than those from side-banded urea, resulting in 4.2% higher N use efficiency across the entire N application range from 25 to 100 kg ha(-1). Higher levels of removal of N in grain from CRU compared to side-banded urea can result in less residual N remaining in the soil, and limit the possibility of N losses due to denitrification and leaching.  相似文献   

8.
通过田间试验,研究了硫膜和树脂膜控释尿素对小麦产量、品质和耕层土壤无机氮含量及氮素利用率的影响.结果表明:与普通尿素相比,硫膜和树脂膜控释尿素均能显著提高小麦籽粒产量和品质,增产幅度达10.4%~16.5%,小麦籽粒蛋白质和淀粉含量分别提高5.8%~18.9%和0.3%~1.4%;两种控释肥均能有效保持耕层土壤无机氮含量,且其氮素后移的功效满足了小麦生育后期对氮素的需求;有效提高了氮肥偏生产力,降低了土壤氮素依存率(降幅11.0%~17.3%),提高了氮素利用率(增幅58.2%~101.2%).其中,树脂膜控释尿素比硫膜控释尿素表现出更好的增产效应,实现了氮素的高效利用.  相似文献   

9.
In the context of radiotherapy, collateral effects of ablative doses of ionizing radiation (AIR) on stromal components of tumors remains understudied. In this work, cancer-associated fibroblasts (CAFs) isolated from freshly resected human lung tumors were exposed to AIR (1x 18 Gy) and analyzed for their release of paracrine factors. Inflammatory mediators and regulators of angiogenesis and tumor growth were analyzed by multiplex protein assays in conditioned medium (CM) from irradiated and non-irradiated CAFs. Additionally, the profile of secreted proteins was examined by proteomics. In functional assays, effects of CAF-CM on proliferative and migratory capacity of lung tumor cells (H-520/H-522) and human umbilical vein endothelial cells (HUVECs) and their tube-forming capacity were assessed. Our data show that exposure of CAFs to AIR results in 1) downregulated release of angiogenic molecules such as stromal cell-derived factor-1, angiopoietin, and thrombospondin-2 (TSP-2); 2) upregulated release of basic fibroblast growth factor from most donors; and 3) unaffected expression levels of hepatocyte growth factor, interleukin-6 (IL-6), IL-8, IL-1β, and tumor necrosis factor-α. CM from irradiated and control CAFs did not affect differently the proliferative or migratory capacity of tumor cells (H-520/H-522), whereas migratory capacity of HUVECs was partially reduced in the presence of irradiated CAF-CM. Overall, we conclude that AIR mediates a transformation on the secretory profile of CAFs that could influence the behavior of other cells in the tumor tissue and hence guide therapeutic outcomes. Downstream consequences of the changes observed in this study merits further investigations.  相似文献   

10.
Carcinoma-associated fibroblasts (CAFs) are critical in determining tumor invasion and metastasis. However the role of CAFs in the invasion of salivary gland adenoid cystic carcinoma (ACC) is poorly understood. In this study, we isolated primary CAFs from two ACC patients. ACC-derived CAFs expressed typical CAF biomarkers and showed increased migration and invasion activity. Conditioned medium collected from CAFs significantly promoted ACC cell migration and invasion. Co-culture of CAFs with ACC cells in a microfluidic device further revealed that CAFs localized at the invasion front and ACC cells followed the track behind the CAFs. Interfering of both matrix metalloproteinase and CXCL12/CXCR4 pathway inhibited ACC invasion promoted by CAFs. Overall, our study demonstrates that ACC-derived CAFs exhibit the most important defining feature of CAFs by promoting cancer invasion. In addition to secretion of soluble factors, CAFs also lead ACC invasion by creating an invasive track in the ECM.  相似文献   

11.
长期不同施肥方式对麦田杂草群落的影响   总被引:1,自引:0,他引:1  
蒋敏  沈明星  沈新平  戴其根 《生态学报》2014,34(7):1746-1756
以太湖地区农业科学研究所31a的长期肥料定位试验田为材料,分别于2011—2012年小麦苗期、拔节期和收获期进行了杂草群落调查,研究杂草类型与密度的分布、杂草多样性指数的变化,并对杂草种群分布与土壤养分因子进行冗余分析。结果表明:小飞蓬、看麦娘、大巢菜、稻槎菜、通泉草是本地区小麦生长期的主要杂草类型;随着小麦的生长以及氮肥、有机肥的施入,杂草密度呈下降趋势;施入有机肥降低了麦季杂草的群落多样性指数,在小麦生长的不同时期均衡施肥的CNPK处理以及不施肥的C0处理的群落各项多样性指数能维持在一个较高的水平。RDA分析显示土壤氮含量以及有机质含量与第一排序轴相关性大,是对杂草分布影响最大的两个土壤养分因子。太湖地区稻麦两熟制条件下,长期有机无机肥料单一或配合投入可显著影响麦田杂草的群落组成,其中氮肥和有机肥的施入能显著降低杂草密度;土壤养分的差异影响田面杂草密度和优势种群,均衡施肥能降低优势杂草种群的优势地位,抑制其发生危害程度,提高农田生态系统的生产力及稳定性。  相似文献   

12.
Cancer-associated fibroblasts (CAFs) play a crucial role in cancer progression and even initiation. However, the origins of CAFs in various cancer types remain controversial, and one of the important hypothesized origins is through epithelial-mesenchymal transition (EMT) from cancer cells. In this study, we investigated whether the HEp-2 laryngeal cancer cells are able to generate CAFs via EMT during tumor formation, which is now still unknown. The laryngeal xenografted tumor model was established by inoculating the HEp-2 laryngeal cancer cell line in nude mice. Primary cultured CAFs from the tumor nodules and matched normal fibroblasts (NFs) from the adjacent connective tissues were subcultured, purified, and verified by immunofluorescence. Migration, invasion, and proliferation potentials were compared between the CAFs and NFs. A co-culture of CAFs with HEp-2 cells and a co-injection of CAFs with HEp-2 cells in nude mice were performed to examine the cancer-promoting potential of CAFs to further verify their identity. Karyotypic analyses of the CAFs, NFs, and HEp-2 cells were conducted. A co-culture of NFs with HEp-2 cells was also performed to examine the expression of activated markers of CAFs. A pathological examination confirmed that the laryngeal xenografted tumor model was successfully established, containing abundant CAFs. Immunocytochemical staining verified the purities and identities of the CAFs and NFs. Although the CAFs manifested higher migration, invasion, proliferation, and cancer-promoting capacities compared with the NFs, an analysis of chromosomes revealed that both the CAFs and NFs showed typical normal mouse karyotypes. In addition, the NFs co-cultured with HEp-2 cells did not show induced expressions of activated markers of CAFs. Our findings reveal that the CAFs in the HEp-2 established laryngeal xenografted tumor are not of laryngeal cancer origin but of mouse origin, indicating that the HEp-2 laryngeal cancer cells cannot generate their own CAFs via EMT in this model.  相似文献   

13.
Roots of agricultural crops, including maize, are hosts of different microorganisms, many beneficial, like plant growth and health‐promoting arbuscular mycorrhizal fungi (AMF), as well as pathogens including Pythium, Polymyxa and Microdochium. To improve crop nutrition and health, profound knowledge is required regarding how agricultural practices affect field populations of root‐associated microorganisms. Hence, the objective of this work was to evaluate the effect of crop genotype and organic fertilizers on the plant growth performance of maize and their root‐associated microorganisms. The experiment was conducted as a fully factorial greenhouse pot experiment with maize cultivars (two land races and two hybrids) and organic fertilizers (green manure, cow manure and compost) as the two main factors. Plants were harvested 8 weeks after sowing. In general, the different maize cultivars responded similarly to the applications of the organic fertilizers. Cow manure and compost increased plant growth, whereas green manure had limited effect on plant growth. Root colonization with AMF was reduced by green manure with rape. Infection with the root pathogens Pythium and Polymyxa was reduced by all organic fertilizers, whereas in contrast, infection with Microdochium increased with the majority of the organic fertilizers applied. In conclusion, both maize genotype and organic fertilizers affect the abundance of AMF and root pathogens in maize, which should be considered when developing management strategies of these root‐inhabiting microorganisms.  相似文献   

14.
Effects of long-term application of various fertilizers and crops on soil microbiomes in a long-term field experiment were investigated using the library of the 16S rRNA gene sequences obtained by highthroughput sequencing of the total DNA. The communities exhibited high diversity, with 655 microbial genera belonging to 34 phyla detected (31 bacterial and 3 archaeal ones). For analysis of the effect of the studied factors on community structure, a linear model was developed in order to simplify interpretation of the data of high-throughput sequencing and to obtain biologically important information. Liming was shown to modulate the effect of mineral fertilizers on the structure of microbial populations. The differences in the structure and alpha-diversity of microbial communities were shown to depend more on the crops and liming than on the fertilizers applied. Interaction between the crop factor and liming expressed as an ambiguous effect of liming on the microbiome in the presence of different plants was reliably demonstrated. Thus, in the case of barley and clover, liming resulted in increased taxonomic diversity of the community, while in the case of potato and flax it had an opposite effect.  相似文献   

15.
Cancer-associated fibroblasts (CAFs) are involved in critical aspects of head and neck squamous cell carcinoma (HNSCC) pathogenesis, such as the formation of a tumor-permissive extracellular matrix structure, angiogenesis, or immune and metabolic reprogramming of the tumor microenvironment (TME), with implications for metastasis and resistance to radiotherapy and chemotherapy. The pleiotropic effect of CAFs in TME is likely to reflect the heterogeneity and plasticity of their population, with context-dependent effects on carcinogenesis. The specific properties of CAFs provide many targetable molecules that could play an important role in the future therapy of HNSCC. In this review article, we will focus on the role of CAFs in the TME of HNSCC tumors. We will also discuss clinically relevant agents targeting CAFs, their signals, and signaling pathways, which are activated by CAFs in cancer cells, with the potential for repurposing for HNSCC therapy.  相似文献   

16.
《Translational oncology》2022,15(12):101231
Communication networks in the tumor microenvironment (TME) play a crucial role in tumor progression. Cancer-associated fibroblasts (CAFs) are among the most abundant stromal cells in the TME. Bidirectional signal transduction between cancer cells and CAFs within the TME is important for cancer development and treatment responsiveness. Extracellular vesicles (EVs) carrying proteins, miRNAs, and other biomolecules are secreted into the extracellular matrix (ECM), which has been demonstrated to be an important communication medium between tumors and CAFs. Tumors regulate the activation of CAFs by secreting EVs. Conversely, CAFs can also affect tumor proliferation, metastasis, and therapeutic resistance through EVs. Here, we will classify EV cargoes and discuss the role of EV-mediated interactions between CAFs and tumors, reviewing current knowledge in combination with our confirmed results.  相似文献   

17.
《Translational oncology》2021,14(12):101231
Communication networks in the tumor microenvironment (TME) play a crucial role in tumor progression. Cancer-associated fibroblasts (CAFs) are among the most abundant stromal cells in the TME. Bidirectional signal transduction between cancer cells and CAFs within the TME is important for cancer development and treatment responsiveness. Extracellular vesicles (EVs) carrying proteins, miRNAs, and other biomolecules are secreted into the extracellular matrix (ECM), which has been demonstrated to be an important communication medium between tumors and CAFs. Tumors regulate the activation of CAFs by secreting EVs. Conversely, CAFs can also affect tumor proliferation, metastasis, and therapeutic resistance through EVs. Here, we will classify EV cargoes and discuss the role of EV-mediated interactions between CAFs and tumors, reviewing current knowledge in combination with our confirmed results.  相似文献   

18.
P. R. Warman 《Plant and Soil》1991,134(1):115-119
A field-size experiment was initiated in 1982 on an acid, low fertility Springhill silt loam to determine the effect of five unfertilized green manure crops (alsike clover, sweet clover, single- and double-cut red clover, and buckwheat) on subsequent oat production and soil fertility. The field was limed in 1982 and green manures were seeded (without fertilizer) in spring, 1983 in 1400 m2 strips randomly assigned within three treatment blocks. Plant tissue samples were taken from different locations in each plot in the fall of 1983 and all crops were incorporated. In 1984 the field was separated into an upper and lower section and each section received three rates of NPK fertilizer (0; 30-36-36; 60-72-72 kg ha-1) spread across the previous strips. Gary oats were seeded and at harvest were divided into grain and straw. The results indicated significant effects of field sample location, green manure type and fertilizer level on oat yields. Buckwheat significantly reduced oat production compared to the four clovers, while the highest fertilizer rate improved oat yields compared with the other levels of fertilizers. Elemental analysis of the green manure crops and soil fertility was compared with data of the same crops grown in more fertile, neutral soils.  相似文献   

19.
Micronutrient status and fertilizer use scenario in India   总被引:1,自引:0,他引:1  
India was dependent on external food supplies in the early 1960s. To meet the growing demand for food, fiber and fuel, high yielding cultivars were introduced. These high yielding crop cultivars were highly responsive to fertilizers. Thus, slowly the soils were exhausted of their nutrients. Application of major nutrients (nitrogen, phosphorus, potassium) became common, therefore the crops started responding to micronutrient fertilizers. Concerted efforts have been made through the All India Coordinated Research Project on Micronutrients to delineate the soils of India regarding the deficiency of micronutrients. At present about 48.1% of Indian soils are deficient in diethylenetriaminepentaacetate (DTPA) extractable zinc, 11.2% in iron, 7% in copper and 5.1% in manganese. Apart from the deficiency of these micronutrients, deficiencies of boron and molybdenum have also been reported in some areas. Areas with multi-micronutrient deficiencies are limited, thus simple fertilizers are sufficient to exploit the potential of crops and cropping systems. Based on the extent of deficiency, cultivated area, and crop removal, the micronutrient fertilizer demand in 2025 is projected using sufficiency and maintenance approaches.  相似文献   

20.
Bøckman  O.C. 《Plant and Soil》1997,194(1-2):11-14
Biological nitrogen fixation (BNF) has an assured place in agriculture, mainly as a source of nitrogen for legumes. Legumes are currently grown mostly as a source of vegetable oil and as food for humans and animals, but not as nitrogen source.Other crops with BNF capability may be eventually be developed eventually. Such crops will also need mineral fertilizers to maintain a good status of soil nutrients, but their possible effects to the environment is also a concern. Fertilizers, however, will remain a necessary and sustainable input to agriculture to feed the present and increasing human population. It is not a case of whether BNF is better or worse than mineral fertilizers because both plays an important role in agriculture.  相似文献   

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