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玉米体细胞继代无性系核型分析 总被引：2，自引：0，他引：2
观察已选择培养４７次的玉米胚性细胞，发现细胞核、核仁、间期核染色中心和染色体数目等表现出广泛的变异，即细胞核类型多样化，细胞核仁加倍，间期核染色中心增多，细胞直径增大和染色体数混倍性。多样性细胞的出现可能与长时间继代培养过程中使用２，４－Ｄ等激素有关。 相似文献
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Brandon AD Humayun M Puchtel IS Leya I Zolensky M 《Science (New York, N.Y.)》2005,309(5738):1233-1236
Osmium extracted from unequilibrated bulk chondrites has isotope anomalies consistent with an insoluble s-process carrier, termed Os(i) here. Osmium from metamorphosed bulk chondrites does not have isotope anomalies, implying that the Os(i) carrier was destroyed by metamorphism. The isotopic homogeneity of metamorphosed bulk chondrites is consistent with extremely effective mixing of presolar grains from varied sources in the nebula. Osmium in the Os(i) carrier is likely from nucleosynthetic sites with a neutron density about two to four times as high as that of the average solar s-process Os. 相似文献
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植物生长调节剂对水稻光合速率和产量构成因素的影响 总被引：3，自引：1，他引：2
针对近年江淮地区水稻孕穗开花期间持续高温天气(7月中下旬气温≥35℃,持续5d)造成中稻空、瘪子率提高的现状,本试验在水稻孕穗期和抽穗期叶面喷施不同的植物生长调节剂,并通过对水稻生育进程、光合能力、产量结构等的测定分析,发现不同的植物生长调节剂对水稻剑叶光合生理的影响及对水稻结实灌浆的调控作用是不同的。喷施合适的植物生长调节剂,如萘乙酸(NAA-Na)、吲哚乙酸(IAA)、赤霉素(GA3)、细胞分裂素(6-BA)可提高稻株剑叶光合速率,延缓叶片衰老,改善水稻结实性状,该措施可作为一种补偿途径减轻前期高温对水稻的伤害,利于水稻的高产、稳产。 相似文献
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Background： Increasing the polyunsaturated fatty acid （PUFA） content and decreasing the saturated fatty acid （SFA） content of mutton can help to improve its nutritional value for consumers. Several laboratories have evaluated the effects of vitamin E on the fatty acid （FA） composition of muscle in sheep. However, little information is available on wool sheep, even though wool sheep breeds are an important source of mutton, especially in northern China where sheep are extensively farmed. The present study was designed to address the effects of vitamin E on muscle FA composition in male Aohan fine-wool sheep. Methods： Forty-two male Aohan fine-wool lambs （5 mo old） with similar initial body weight were randomly divided into seven groups and fed diets supplemented with 0 （control group）, 20, 100, 200, 1,000, 2,000, or 2,400 IU/sheep/d vitamin E for 12 mo. Three lambs from each group were slaughtered to measure vitamin E and FA content in the Iongissimus lumborum （LL） and gluteus medius （GM） muscles. Results： Vitamin E concentrations in the LL and GM increased significantly after 12 mo of vitamin E supplementation （P 〈 0.05）. However, this increase did not occur in a dose-dependent manner because the muscle vitamin E concentration was highest in the 200 IU/sheep/d group. Dietary vitamin E supplementation also caused a significant reduction in SFA content and an increase in monounsaturated FA （MUFA） content in the LL and GM （P 〈 0.05）. All six doses of vitamin E significantly increased cis9 tronsl -conjugated linoleic acid （cgtl -CLA） content in the LL compared with the control group （P 〈 0.05）. Conclusions： Dietary supplementation with vitamin E increased muscle vitamin E content and improved the nutritional value of mutton by decreasing SFA content and increasing MUFA and c9tl 1-CLA contents in Aohan fine-wool sheep. These effects were greatest in sheep fed a diet containing 200 IU/sheep/d vitamin E. 相似文献
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Irshad Ahmad Tasok Leya Neelam Saharan Babitha Rani Asanaru Majeedkutty Gaurav Rathore Adnan Hussain Gora Irfan Ahmad Bhat Ajit Kumar Verma 《Aquaculture Research》2019,50(10):2879-2887
Biofloc technology degrades waste into useful resources exploiting microbes and can be used in zero‐water exchange systems. To study the effect of different biofloc systems on haematological and metabolic response of Labeo rohita fingerlings, a 60‐days experiment was conducted using four long lasting carbon sources. Seven hundred and fifty fingerlings having mean weight of 4.80 ± 0.12 g were randomly distributed into 15 tanks (n = 50 per tank). Five experimental groups were set in triplicate; T1 (Tapioca), T2 (Wheat), T3 (Corn) T4 (Sugar bagasse) and control (clear water). In‐situ biofloc was developed in 300 L fibre‐reinforced plastic (FRP) tanks and a C/N ratio of 15 was maintained. Water quality variables indicated ammonia immobilization by heterotrophic bacteria, as the dominant mechanism for the removal of toxic‐nitrogenous compounds in the biofloc systems. Results exhibited significantly higher floc volume (53.33 ± 7.88 ml/L), haemoglobin content (6.61 ± 0.03 g/dl) and total leucocyte count (109.66 ± 0.06 thousand cells/mm3) in tapioca biofloc system. Furthermore, the digestive and anti‐oxidative enzymes activities were also significantly higher in tapioca biofloc system. The lactate dehydrogenase and malate dehydrogenase enzyme assays showed a decreased level in tapioca biofloc system as compared with other biofloc systems and control group. Our observations indicate that tapioca biofloc system could improve the water quality, haematological and anti‐stress responses of L. rohita fingerlings in biofloc systems and thus can effectively replace other carbohydrate sources for the biofloc system. 相似文献