排序方式: 共有44条查询结果,搜索用时 31 毫秒
11.
Teppei Komiyama Seiichi Niizuma Eiji Fujisawa Hiromasa Morikuni 《Soil Science and Plant Nutrition》2013,59(3):419-426
In the Japanese warm areas, as a result of intensive and repeated potato cropping, common scab, a soil-borne disease has become a serious problem. The soil moisture level has been shown to be an important factor affecting the incidence of common scab. That is, a high level of soil moisture reduces the severity of common scab. However, in this investigation, although during the spring cropping precipitation was abundant, a large number of tubers showing scab lesions were produced. The results indicate that the soil moisture level may not be an important factor affecting the incidence of potato scab in the humid region. To identify other factors which may affect scab severity, the relation between sugar content in the peel of potato tuber and the incidence of common scab was investigated. Generally, the amount of reducing sugar in the tuber peel increased gradually with the growth of the tubers, then reached a maximum level two weeks after the start of tuber formation, and thereafter declined. The period corresponding to the highest sugar content in peels coincided with the most susceptible period for scab infection. The content of reducing sugar in the peel of susceptible cultivars was higher than that of the resistant cultivars, throughout the tuber growth, and the critical value of the content was 2.0 mg per 100 g fresh peel. These results suggest that the content of reducing sugar in tuber peel may be an important factor affecting the incidence of common scab. 相似文献
12.
13.
用X射线衍射法测定木材纤维次生壁的平均微纤丝角 总被引:4,自引:0,他引:4
测定木材次生壁上的平均微纤丝角是研究木材细胞壁构造的关键环节,本文介绍了一种先进的X射线衍射测定法。 相似文献
14.
本文采用骨指数法监测骨营养代谢病的防治效果。以D=(A+B)/C×100为计算公式,试验前、中、后期分别测定骨指数,然后计算其骨指数差。试验Ⅰ、Ⅱ组为采用不同方法防治组,Ⅲ组为对照组。试验前各组的骨指数无明显差异,试验后Ⅰ组骨指数差均呈正值,平均增加+1.36,骨发育良好;Ⅱ组其骨指数差很小,个别出现负值,平均增加+0.39,骨发育一般;对照组骨指数差几乎均呈负值,平均为-2.67,为骨营养不良X线征。试验表明,骨病理X线影像分析及骨指数总的分析,不仅能诊断骨营养不良,而且是监测骨营养不良防治效果的可靠手段。 相似文献
15.
Boris Lazarević Craig J. Sturrock Milan Poljak Sacha J. Mooney 《Communications in Soil Science and Plant Analysis》2016,47(2):263-274
Root architectural traits are of fundamental importance for plant performance, especially under unfavorable soil conditions. This study examined the effect of aluminum (Al) toxicity in different growing media (nutrient solutions and soil) on root architecture of two wheat (Triticum aestivum L.) cultivars with different Al tolerances. Seedlings were grown in acidic and limed soil and in two contrasting nutrient solutions. Root systems of soil-grown plants were scanned using x-ray microcomputed tomography (µCT) while that of nutrient solution–grown plants were assesses using WinRhizo, 3 and 5 days after planting (DAP), respectively. Aluminum caused significant reduction of all examined root traits (number of seminal roots, root length, length of the longest seminal root, root surface area, and root volume). Growth in acidic soil caused significant reduction in root length, length of the longest seminal root, and root surface area at 5 DAP. Soil-grown plants produced a larger root system compared to plants grown in nutrient solutions. Aluminum toxicity–induced differences of root traits were also found between different nutrient solutions. Beside the well-known reduction of root length, Al toxicity had a profound effect on other root architectural traits. X-ray µCT has revealed root architectural changes under specific conditions of acidic, Al-toxic soil. Differences obtained in Al-induced effects on root architecture between different nutrient solutions as well as between different growing systems emphasize the need for further study of root architecture, especially under specific conditions of Al toxicity in acidic soils. 相似文献
16.
17.
通过直流电弧等离子体方法制备了氮化镓纳米晶,并研究了制备的样品的基本特性。使用N2和NH3的混合气体进行反应,并对样品进行了电子显微镜扫描(SEM),X射线衍射(XRD)和Raman散射分析。试验发现,样品为纤锌矿结构,平均大小为50nm左右,晶格常数为a=3.186,c=5.174。 相似文献
18.
本文利用X射线光电子谱(XPS)对Gd原子在Ba_2RCu_3O_(7+8)(R=Y, Ho)高温超导体表面上引起的化学反应进行了研究.实验发现,在该超导样品表面上蒸镀的Gd原子被氧化,超导体中对超导特性起重要作的Cu-O链遭到破坏,其中一部分处于Cu~(2+)态的Cu元素被还原,超导体内其它各元素也不同程度地受到了影响.当样品表面上Gd覆盖度达到22A(R=Y)和30A(R=Ho)时,界面上的化学反应不再继续 相似文献
19.
《Communications in Soil Science and Plant Analysis》2012,43(16):1998-2017
There is a paucity of information on the soil phosphorus (P) forms removed by alkaline and acidic reagents in Vertosols. The first aim of this study was to identify which soil phosphates are removed by a two-step sequential fractionation (0.1 M NaOH and 1 M HCl) and by a dilute acid extractant (0.005 M H2SO4; Bureau of Sugar Experiment Stations (BSES) soil P test) on an “untreated” Vertosol using P K-edge x-ray absorption near-edge structure (XANES) at the Australian Synchrotron. There was supporting evidence that the 0.1 M sodium hydroxide (NaOH), 1 M hydrochloric acid (HCl), and 0.005M sulfuric acid (H2SO4) extractants remove soil phosphates according to the chemical solubility of known P minerals. The XANES spectra revealed the 1 M HCl and 0.005 M H2SO4 extractants remove calcium (Ca) phosphates from Vertosols, suggesting the latter extractant could be used as an alternative for a rapid and cost-effective measure of Ca phosphates in Vertosols. 相似文献
20.
The structure and principle of double-channel elliptical crystal spectrometer are presented.The whole process of manufacturing dispersive element with natural muscovite is specified.The instrument was applied to diagnose plasma produced by laser on "XG-II" facility and the spectrum of flat Au was obtained.In order to analyze the reason of unsatisfactory pattern in which spectral lines interveined each other,X-ray diffraction experiment and observating surface of muscovite were conducted.The experimental results show that using such natural muscovite as dispersive element is the real reason for interlaced spectrum. 相似文献