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排序方式: 共有193条查询结果,搜索用时 46 毫秒
51.
S. V. K. Jagadish E. M. Septiningsih A. Kohli M. J. Thomson C. Ye E. Redoña A. Kumar G. B. Gregorio R. Wassmann A. M. Ismail R. K. Singh 《Journal of Agronomy and Crop Science》2012,198(5):360-373
Rice, with its wide geographic distribution extending from 50°N to 35°S, is expected to be the most vulnerable cultivated crop to future changing climates. Among the different abiotic stresses, extreme temperatures coinciding with critical developmental stages, increasingly frequent floods and drought spells, and worsening sea water inundation are some of the major threats to sustainable rice productivity. Following the successful implementation of molecular marker‐assisted backcrossing to introgress large‐effect QTL for submergence tolerance in rice mega varieties, rice breeding for drought, salinity and, recently, heat tolerance is employing the same approach. Although tolerance for combined submergence and salinity has been achieved, developing rice varieties with multiple tolerance for other abiotic and biotic stresses and finding the appropriate agronomic package to exploit their performance remain a challenge. The major bottleneck is the lack of unidentified large‐effect QTL for other abiotic stresses that are strongly influenced by genotype × environment (G × E) interaction. Rapid advances in the use of molecular tools, including a plethora of SNP markers, are expected to facilitate the development of major abiotic stress‐tolerant rice. In response to the actual farmer field situation, progress achieved in understanding and developing independent abiotic stress tolerance is being exploited to combine tolerances (for example, heat and drought; salinity and submergence) to address emerging environmental problems across a wide range of rice ecosystems. 相似文献
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Reiner G 《DTW. Deutsche tier?rztliche Wochenschrift》2006,113(2):65-69
Product quality in the pig is defined by the choice of lean meat including a reasonable intramuscular fat content and good water binding capacity, which can be produced and marketed at a reasonable price, based on good fattening performance and disease resistance. Traits of product quality are mostly of polygenic character, while some of these genes show larger effects. Genome analysis intends to identify the genetic basis of phenotypic trait variation and to complement conventional phenotypic selection criteria by direct regarding of the nucleotide level, thus marker assisted selection. The present paper describes the most important markers in use to improve product quality in swine, and shows perspectives of genome analysis in this regard, including positional and functional strategies. 相似文献
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Kaser-Hotz B Reiner B Hauser B Arnold P Lieb A Cordt I Lang J Blattmann H 《Schweizer Archiv für Tierheilkunde》2000,142(11):631-637
Two cats with large pituitary neoplasms (adenoma and adenocarcinoma) were treated with fractionated radiation therapy. Total doses of 40 Gy, respectively 36 Gy, were applied in 10 fractions of 4 Gy, and 3.6 Gy respectively. Side effects were minimal and transient. Anesthesia was well tolerated. Improvement of clinical signs could be observed during radiation therapy in both cats. One cat had a complete, the other a partial tumor response. One cat (suspicion of adenoma) was euthanized 1 3/4 years after therapy due to unrelated disease. No tumor was found on histopathology, however a small focal necrosis of brain tissue in the irradiated field was observed. The second animal with a pituitary adenocarcinoma was euthanized because of tumor recurrence 1 1/2 years after therapy. Radiation therapy was effective, despite the low total doses of radiation applied. 相似文献
59.
Rice plants play a pivotal role in different levels of the methane (CH4) budget of rice fields. CH4 production in rice fields largely depends on plant-borne material that can be either decaying tissue or root exudates. The
quantity and quality of root exudates is affected by mechanical impedance, presence of toxic elements, nutrient deficiencies,
water status of growing medium, and nitrogenase activity in the rhizosphere. CH4 oxidation in rice fields is localized in the rhizosphere where the concentration gradients of CH4 and oxygen overlap. CH4 oxidation capacity is a function of the downward transport of oxygen through the aerenchyma, which, in turn, also acts as
a conduit for CH4 from the soil to the atmosphere. The decisive step in the passage of CH4 through rice plant is the transition from root to stem. However, rice plants show an enormous variety of morphological and
physiological properties, including differences in root exudation and gas transfer capacity. Comparative studies on different
cultivars are deemed crucial for accomplishing a better understanding of the mechanisms of CH4 consumption in the rhizosphere and CH4 transport through the rice plant as well as the interaction of these processes. The results of such studies are considered
tools for devising mitigation options.
Received: 7 April 1999 相似文献
60.
Chang JT Palanivel VR Kinjyo I Schambach F Intlekofer AM Banerjee A Longworth SA Vinup KE Mrass P Oliaro J Killeen N Orange JS Russell SM Weninger W Reiner SL 《Science (New York, N.Y.)》2007,315(5819):1687-1691
A hallmark of mammalian immunity is the heterogeneity of cell fate that exists among pathogen-experienced lymphocytes. We show that a dividing T lymphocyte initially responding to a microbe exhibits unequal partitioning of proteins that mediate signaling, cell fate specification, and asymmetric cell division. Asymmetric segregation of determinants appears to be coordinated by prolonged interaction between the T cell and its antigen-presenting cell before division. Additionally, the first two daughter T cells displayed phenotypic and functional indicators of being differentially fated toward effector and memory lineages. These results suggest a mechanism by which a single lymphocyte can apportion diverse cell fates necessary for adaptive immunity. 相似文献