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261.
Poor growth of lupins on calcareous soils may be attributed to a number of soil physical and chemical factors. Nutrient imbalances, such as deficiency of phosphorus (P) and micronutrients or calcium (Ca) excess have been reported to be responsible for the calcifuge behavior of the plants. In the present study we investigated the importance of nutrient imbalances for the growth reduction of lupins on a lime‐containing soil. Three lupin species (Lupinus luteus, Lupinus angustifolius, and Lupinus albus) were compared with lime‐tolerant Pisum sativum. Plants were cultivated in a sandy soil containing 0.2% or 10% magnesium (Mg) limestone and were fertilized with a complete nutrient solution except for iron (Fe). In each lime treatment, three of six pots per species were supplied with iron as FeEDDHA. Strong liming greatly decreased shoot growth, rate of leaf appearance, and shoot dry matter accumulation in all Lupinus species, but only marginally in P. sativum. All Lupinus species displayed chlorosis on the strongly limed soil, whereas on the slightly limed soil, only L. luteus did so. Shoot concentrations of P, potassium (K), Ca, Mg, manganese (Mn), zinc (Zn), and copper (Cu) were generally in the adequate range. Decreased shoot growth was not associated with increased Ca concentrations. FeEDDHA fertilization alleviated chlorosis in most cases, but was not able to restore shoot growth. Therefore it is concluded, that, at least in the juvenile stage, nutrient imbalances do not play a major role in growth limitation of lupins on calcareous soils. 相似文献
262.
M. J. Fuhr C. Stührk B. Münch F. W. M. R. Schwarze M. Schubert 《Wood Science and Technology》2012,46(4):769-779
The visualization and the quantification of microscopic decay patterns are important for the study of the impact of wood-decay fungi in general, as well as for wood-decay fungi and microorganisms with possible applications in biotechnology. In the present work, a method was developed for the automated localization and quantification of microscopic cell wall elements (CWE) of Norway spruce wood such as bordered pits, intrinsic defects, hyphae or alterations induced by white-rot fungus Physisporinus vitreus using high-resolution X-ray computed tomographic microscopy. In addition to classical destructive wood anatomical methods such as light or laser scanning microscopy, this method allows for the first time to compute the properties (e.g., area, orientation and size distribution) of CWE of the tracheids in a sample. This is essential for modeling the influence of microscopic CWE on macroscopic properties such as wood strength and permeability. 相似文献
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Annular moats and outer rises around large Venus coronae such as Artemis, Latona, and Eithinoha are similar in arcuate planform and topography to the trenches and outer rises of terrestrial subduction zones. On Earth, trenches and outer rises are modeled as the flexural response of a thin elastic lithosphere to the bending moment of the subducted slab; this lithospheric flexure model also accounts for the trenches and outer rises outboard of the major coronae on Venus. Accordingly, it is proposed that retrograde lithospheric subduction may be occurring on the margins of the large Venus coronae while compensating back-arc extension is occurring in the expanding coronae interiors. Similar processes may be taking place at other deep arcuate trenches or chasmata on Venus such as those in the Dali-Diana chasmata area of eastern Aphrodite Terra. 相似文献
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Functions of sodium (Na+) and potassium (K+) are closely associated. In some crops, Na+ is able to prevent or reduce considerably the occurrence of K+ deficiency. Sugar beet (Beta vulgaris L.) is a natrophilic crop, and positive effects of Na+ applications on yield were observed when K+ was sufficiently supplied. However, it is not known which specific function of K+ can limit the growth of sugar beet when K+ is substituted by an equivalent amount of Na+. Therefore, K+ substitution by Na+ was investigated for sugar beet in hydroponics. Surprisingly, no K+‐deficiency symptoms were observed. However, calcium (Ca2+) concentrations in the leaves were significantly decreased. Moreover, Ca2+ uptake and translocation through xylem sap were reduced in Na+‐treated plants. It is concluded that Ca2+ uptake by roots and its translocation via xylem sap primarily limit the possibility of K+ substitution by Na+ in sugar beet nutrition. 相似文献
268.
疾病是全球范围内危害畜禽健康的主要问题,解析免疫系统调控相关基因成为当前抗病分子育种的研究热点。为研究小鼠黑色素瘤模型功能异常CD8~+T细胞对免疫抗体处理的应答机制,通过基因调控网络方法筛选功能异常CD8~+T细胞在Ig G和PD1抗体处理的特定基因、转录因子和细胞表面受体。结果发现对照组、PD1抗体与Ig G抗体处理组分别有28、17、33个特定表达基因。与对照组相比,Ig G和PD1处理组有2个转录因子Zfx、Zfhx3关闭表达,PD1处理组细胞表面受体Raet1b表达。Raet1b基因的表达可能使小鼠黑色素瘤功能异常CD8~+T细胞恢复功能,结果为抗病育种的相关基因研究提供理论基础。 相似文献
269.
研究处理后的工业污水能否用于荒山绿化.在张家口市桥东区水泉沟瘠薄山地的典型地段设立了一个造林试验点,采用不同的灌溉措施,对臭椿、火炬树、四季玫瑰等3个树种进行了的植苗造林试验.结果表明:不同灌溉措施对不同树种当年的植苗造林成活率及其株高、地径和冠幅等指标的影响差异不显著,经过对土壤相关指标的测定,工业污水(50%)处理... 相似文献
270.
Site-specific management of limiting nutrients in peanut (Arachis hypogaea) on the Texas High Plains
Rolf Färe Chenggang Wang A. Michael Schubert Kevin F. Bronson Jeff Johnson 《Precision Agriculture》2009,10(4):331-341
Nutrient data obtained from soil chemical tests were analyzed in an activity analysis model to identify limiting factors in
peanut production on the Texas High Plains. A production function was estimated for the study field, and limiting factors
were identified at individual sites where the production function indicated that yield did not respond. The estimated production
function also enabled us to conduct a cost-return analysis of variable- and blanket-rate fertilizer applications. The results
showed that peanut yields did not respond to most of the nutrients included in the study, which confirmed conclusions from
previous studies in the study region. Calcium and nitrogen were the only two limiting factors identified in this study. Significant
economic returns could be obtained by site-specific fertilizer application. The average economic return from variable-rate
calcium fertilizer application was $27.84 ha−1 and from blanket-rate it was $10.73 ha−1. The return from variable-rate nitrogen fertilizer application was about $20 ha−1 and from a blanket-rate it was about $14 ha−1. There seems to be quite a strong economic incentive to adopt variable-rate application for calcium and nitrogen fertilizer
application.
相似文献
Jeff JohnsonEmail: |