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1.
The marine diatom Chaetoceros calcitrans f. pumilus has been examined for its potential source as live feed in aquaculture. The present study investigated effects of temperature (20, 25 and 30 °C), salinity (25 and 35) and carbon dioxide addition (air+CO2) on the growth and proximate composition of C. calcitrans under laboratory conditions. The growth and biomass of C. calcitrans were primarily affected by carbon dioxide addition, and to a lesser extent by temperature and salinity. In general, lipid and carbohydrate contents were higher at lower temperatures (20 and 25 °C), while the protein content was unaffected. Carbon dioxide addition increased protein, while lowering carbohydrates, but had no effect on lipid content. Carbohydrates were increased while lipids and protein decreased at the highest salinity (35±0.9). These results should be taken into consideration when evaluating the dietary value of this micro alga for aquaculture.  相似文献   
2.
Xylazine–ketamine combination was evaluated for its efficacy and safety after epidural administration in uraemic and healthy goats. The combination (xylazine 0.025 mg/kg and ketamine 2.5 mg/kg) was administered to uraemic (n = 6) and healthy (n = 6) animals in the lumbosacral epidural space. The combination was evaluated in terms of clinical, physiological, haematological and biochemical parameters. The onset of analgesia was faster in healthy animals than in uraemic animals. Xylazine and ketamine produced complete analgesia of tail, perineum, inguinal and thigh regions in all animals of both groups. However, healthy animals showed longer duration of complete analgesia than did uraemic animals. Greater ataxia was recorded in healthy animals than in uraemic animals. The heart rate showed a significant decrease in both groups; however, respiratory rate and rectal temperature did not show any significant changes. Haemoglobin, packed cell volume and total leukocyte count decreased non-significantly in both groups. Total leukocyte count was significantly higher in uraemic animals. A significantly higher value of urea nitrogen and creatinine was recorded in uraemic animals. The blood electrolytes (Na+, K+ and Cl) and blood gases (P o 2 and P co 2) did not show any significant changes in both groups; however, base excess was significantly higher in uraemic animals. The effects produced by the combination on different systems were transient and values normal as the effect of the drugs wore off. The results suggest that the combination when used epidurally in uraemic goats produced effective and safe surgical analgesia.  相似文献   
3.
Ca uptake by micropropagated ‘Norland’ potato plantlets was investigated in relation to cation and macroelement salt concentrations in modified Murashige and Skoog (1962) basal media. Increased Ca:specific cations, by lowering NH4, Mg, or K, had little effect on the Ca content of plantlets grown on these media. Increased Ca:total cation ratio, by raising Ca from 3 to 6 mM in the medium, promoted Ca content of micropropagated plantlets. At equivalent Ca:total cation ratio, macroelement dilution increased the osmotic potential of the medium, and had an even greater impact on plantlet shoot Ca content. Root pressure, which is sensitive to variations in salt concentration, was probably the primary Ca delivery method to developing tissues since transpiration was limited in vitro. In vitro systems appear ideal for studying some aspects of nutrient relationships of plants.  相似文献   
4.
Seventy Frankia spp. strains (nodulating N2-fixing actinomycetes) were isolated from root nodules of Casuarina equisetifolia from different localities of Tamil Nadu state, India. From these, four strains (UMCe12, UMCe23, UMCe35, and UMce55) were selected. Their potential use as biological control agents for Rhizoctonia solani root rot disease of C. equisetifolia seedlings and their relative efficiency in nodule production were investigated. Between the two inoculum broadcast systems tested, seed-coating with Frankia spp. cell suspension was superior to the soil application of cells as sand-vermiculite-basal ammonium propionate inoculum. UMCe12 was the promising strain, offering the highest level of disease protection (81.1%) and nodule production (88.1%) in the R. solani-infested soil, followed by UMCe23 (60.3 and 65.5% of disease protection and nodule production, respectively), UMCe55 (53.5 and 58.2%), and UMCe35 (45.4 and 44.5%). Further, a significant positive correlation was observed between the dose of Frankia spp. and efficiency in both disease control and nodule production.  相似文献   
5.
Solutions of ruthenium red (RR, 0.01 mM), ethylene glycol‐bis‐(ß‐aminoethyl ether)‐N,N,N’,N'‐tetraacetic acid (EGTA, 0.1 mM), calcium (Ca, 1 mM), and double‐distilled water (control) were fed through a bottom branch of soybean with (ST) and without (NS) water stress at the seed‐filling stage. The volume absorptions and transpiration rates were significantly higher for NS than for ST plants and decreased almost linearly with time for all treatments. The transpiration rates of Ca‐feeding ST plants and the control overlapped, while the NS plants approached the same rate of transpiration by the third week only. It is suggested that Ca was implicated in stomatal closure for the reduction of transpiration rates. The relative amounts of chlorophyll decreased with time but chlorophyll was least affected in Ca‐absorbing plants for both ST and NS plants. The use of RR (a Ca‐transport blocker) and EGTA (a Ca chelator) indicated the role of intracellular Ca concentrations on stomatal closure and foliar senescence at the end of the season.  相似文献   
6.
A series of experiments were conducted to evaluate the effects of diet, stocking density and environmental factors on the growth, survival and metamorphosis of short neck clam Paphia malabarica larvae. These experiments examined the following factors: diet [ Isochrysis galbana , Nannochloropsis salina and a mixture of I. galbana and N. salina (1:1 w/w)], stocking density (1, 3, 5 and 7 larvae mL−1), light intensity (unshaded, partially shaded and fully shaded) and water filtration (unfiltered and sand filtered). Results indicated that N. salina could replace 50% of I. galbana as a food source for the clam larvae with an increase in growth, survival (47.2%), metamorphosis (33.5%) and early settlement. Larval growth decreased significantly with increasing stocking density. A density of 1–3 larvae mL−1 appeared to be optimal for normal growth of clam larvae. Neither diet nor stocking density used in the study had a significant effect on larval survival. Under partially shaded (light intensity=1000–5000 lx) and fully shaded (light intensity <1000 lx) conditions, larval growth was significantly faster than under direct sunlight (unshaded). Larvae grew significantly faster in the unfiltered water than in the filtered water.  相似文献   
7.
The stromal microenvironment of tumors, which is a mixture of hematopoietic and mesenchymal cells, suppresses immune control of tumor growth. A stromal cell type that was first identified in human cancers expresses fibroblast activation protein-α (FAP). We created a transgenic mouse in which FAP-expressing cells can be ablated. Depletion of FAP-expressing cells, which made up only 2% of all tumor cells in established Lewis lung carcinomas, caused rapid hypoxic necrosis of both cancer and stromal cells in immunogenic tumors by a process involving interferon-γ and tumor necrosis factor-α. Depleting FAP-expressing cells in a subcutaneous model of pancreatic ductal adenocarcinoma also permitted immunological control of growth. Therefore, FAP-expressing cells are a nonredundant, immune-suppressive component of the tumor microenvironment.  相似文献   
8.
Ca deficiency disorders are common in micropropagated plantlets but little is known regarding the uptake of Ca in vitro. Ca uptake by in vitra-grown potato (Solanum tuberosum L. cvs. Bintje and Norland) plantlets was investigated when Ca levels were maintained but the total macroelement salts or just NH4, the major competing cation, were reduced in Murashige and Skoog (MS) medium. This increased the ratio of Ca:cations or Ca:NH4 as well as the osmotic potential of the medium. The increased Ca-cations improved Ca uptake of shoot tips, leaves, and stems while increased Ca:NH4 had no effect. MS medium macroelement dilution may improve Ca uptake by micropropagated plantlets and prevent Ca deficiency disorders.  相似文献   
9.
Implicit economic values of physical attributes of teak logs (girth, length, straightness and soundness) were estimated using hedonic regression. The influence of spatial and temporal variations on teak wood prices was also estimated. The auction prices of teak wood at various Timber Sales Depots of the Forest Department of Kerala State in India during the period 2006–2010 were used for the study. Traders ascribed over 80 % of variation in teak wood prices to girth, straightness and soundness of logs. A reduction in age at felling of teak plantations in forest areas is proposed. The study also underlines the need to continue tree improvement programs and silvicultural operations for the production of high quality teak wood and thereby increase the profitability of teak plantations.  相似文献   
10.
Summary The pre-and post-fertilization barriers in the interspecific crosses between Vigna umbellata and V. minima were investigated. In the reciprocal crosses (V. minima as the parent) the entry of pollen tubes into the ovary was delayed by about 4 h, and no seed set was observed. However, no pre-fertilization barriers were encountered in crosses involving V. minima as the parent and V. umbellata as the parent (normal cross). The delay/absence of divisions in the endosperm and the failure of embryo to divide were the post-fertilization barriers responsible for somatoplastic sterility in normal crosses which yielded a few hybrid seeds. The hybrid seeds showed poor germinability. The F1 hybrids were intermediate between the parents in most morphological characters, and are completely sterile for pollen. Backcrossing of F1 hybrid with both the parents did not restore fertility in the progenies. V. minima is considered as the tertiary gene pool of the rice bean.  相似文献   
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