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991.
992.
小麦对缺铁胁迫的适应性反应 总被引:1,自引:0,他引:1
采用溶液培养法,比较正常供铁和缺铁胁迫下小麦的生理生化指标,同时设置加氧和不加氧2个处理。结果表明,完全营养液加氧处理的小麦株高和穗长最大,达到51.0cm和7.5cm。缺铁处理降低了小麦的籽粒长、籽粒宽、籽粒厚和穗粒数。正常供铁条件下,小麦植株叶绿素a、叶绿素b和叶绿素总含量显著高于不供铁的小麦。加氧处理的小麦叶绿素含量高于无氧处理的小麦。根际Fe3+还原酶活性在缺铁胁迫条件下达到17.3μmol·g-1·(2h)-1。缺铁处理降低了小麦植株地上部的铁素含量,并且在加氧条件下更明显。Mn、Cu这两种元素和Fe元素之间存在某种拮抗关系。 相似文献
993.
F. M. Rueda J. A. López F. J. Martínez S. Zamora P. Divanach & M. Kentouri 《Aquaculture Nutrition》1997,3(3):161-165
The total fat content and the fatty acids of total lipids (TL), phospholipids (PL) and triacylglycerols (TAG) were analysed in white muscle from wild and reared red porgy, Pagrus pagrus (L.). The fat percentage was higher in reared (3.03 ± 0.57%) (mean ± SE) than wild (0.65 ± 0.03%) fish. The fatty acid pattern of reared porgy TL reflected the diet's lipid. Wild red porgy showed higher levels of ω3 and ω6 polyunsaturated fatty acids (PUFA) than reared, but both the atherogenic index and the index of thrombogenicity were very low for both wild and reared red porgy. The lipid fractions showed that the PL were composed of very high levels of PUFA, especially 22:6ω3, and their composition seemed to be better regulated than the composition of TAG. TAG showed greater differences between wild and reared fish, presumably because they reflected the dietary content of lipids. PUFA were the principal component of wild red porgy TAG. 相似文献
994.
Hai-ying Wang Yue-jun Wang Qing-yin Wang Chang-hu Xue Mi Sun 《Fish physiology and biochemistry》2006,32(2):179-188
Proteolytic activity in the different parts of the digestive tract of the turbot (Scophthalmus maximus L.) were studied in this work. One pure protease was isolated from turbot stomach and its behavior was studied. Results showed the optimum pH for proteases in the different parts of the digestive tract of the turbot were pH 2.0 for the stomach, pH 8.0 for the pylorus cecum, pH 8.0 for the foregut, pH 8.5 for the midgut, and pH 8.0 for the hindgut. The activity of proteases in the different parts of the digestive tract were in the sequence pylorus cecum protease > stomach protease > foregut protease > midgut protease > hindgut protease. The stomach protease was purified by ammonium sulfate precipitation and column chromatography on DEAE-Sepharose F.F. and Sephadex G-100. The purified enzyme gave a single band in SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Its molecular weight was found to be approximately 42,000 Da. The enzyme is stable at pH 1.0–9.0 and at temperatures below 40°C. Its activity was maximum at pH 2.0 and 40°C. When reaction time was prolonged the optimum temperature of the enzyme tended to decline. The enzyme was activated by Mn2+ and Cu2+ and inactivated by Fe3+. It was fully inhibited by pepstatin and partially inhibited by PMSF, TPCK, PCMB, and NBS. These results imply the enzyme is a pepsin. 相似文献
995.
Peculiarities of reproduction, early ontogeny, methods of egg incubation, and influence of temperature on development are compared in wolffish (Anarhichas lupus L.) and in salmonids, mainly Atlantic salmon (Salmo salar L.). Reproductive indices of females are similar in both species, but differ in males due to the small production of sperm in wolffish, a difference explained by internal fertilization in the latter species. The rate of embryonal development until the beginning of differentiation of fin fold at the same temperature is similar in both species, but the period from activation to hatching is more than twice as long in wolffish as in Atlantic salmon. Wolffish hatch at a more advanced stage with a small remnant of yolk sac and begin to feed shortly thereafter. As in Atlantic salmon, eggs and larvae of wolffish have a wide range of temperature resistance except before and after hatching. Based on the difference of life cycles in wolffish and salmon, technologies for their artificial breeding are compared. 相似文献
996.
为全面评价长江流域小麦品种区域试验精确度的发展水平,分析了2011—2021年度中国长江流域冬麦区单年单点和一年多点小麦区域试验的试验精确度和品种比较精确度,对产量、穗数、穗粒数、千粒重、生育期、株高、基本苗和最高茎数等性状的试验精确度差异进行了比较。结果表明,长江流域冬麦区单年单点品种试验精确度较好,试验误差变异系数(CEV)在5%和10%以下的试点数占比分别在60%和95%以上,但品种比较精确度(RLSD0.05)在3%以下的试验比例不到10%,长江上游和中下游单点品种试验RLSD0.05在10%以下的试点数分别占比约60%和90%。一年多点区域试验精确度和品种比较精确度显著优于单年单点试验,上游和中下游试验平均CEV分别在8%和5%以下。采用试点固定模型时,长江上游和中下游试验平均RLSD0.05分别为2.19%和1.49%,符合国家小麦品种审定标准对品种比较精确度的要求;但采用试点随机模型时,小麦品种试验尚无法鉴别出品种间3%的产量差异。试验对生育期、株高、基本苗、千粒重和穗数的RLSD0.05优于产量性状,而最高茎数和穗粒数的RLSD0.05较低。 相似文献
997.
998.
999.
1000.
The growth of two breeds of common carp, Cyprinus carpio L., was tested in ponds under the climatic conditions of South Bohemia. T?eboň scaly carp (TR) and Hungarian mirror carp (M2) were kept in both low and high stocking densities during the second growing season and then stocked together for communal testing during the third growing season. Before the communal testing, the mean initial weights of fish from low‐ and high‐density stocks differed significantly (374.1 vs. 227.7 g for the TR breed and 766.7 vs. 317.3 g for the M2 breed respectively, P<0.01). After communal testing, mean weights of fish from low‐ and high‐density stocks gained 761.8 vs. 543.8 g for the TR breed and 1339.7 vs. 706.7 g for the M2 breed respectively. These observed weights were also significantly different (P<0.01). However, the test of corrected weight gain, i.e. gain not related to the initial weight of fish, revealed insignificant differences (P>0.01) between the weight gains after correction, i.e. the effect of different initial weights was successfully eliminated. These results seem to confirm the applicability of this method for the assessment of growth of purebred common carp under the climatic conditions of Central European fish farms. 相似文献