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61.
在膜下滴灌条件下,棉花早衰问题严重。在对国内外关于棉花早衰研究成果及膜下滴灌条件特殊根区微环境深入分析的基础上,提出了膜下滴灌棉花早衰原因的合理假设,认为不合理的根系构型及其高蕾铃负荷是造成膜下滴灌棉花早衰的根本原因:膜下滴灌条件下棉花根系生长和构型分布发生的明显变化不利于棉花根系吸收土壤深层的水分和养分,抗逆性减弱,对环境的改变无法做出及时的反应,加之覆膜增温及优越的水肥供应,棉花地上部生长良好,蕾铃负担增加,一旦遇到逆境条件,在高蕾铃负荷前提下,即使对根系养分吸收功能最轻微的损害或者暂时的养分供应短缺均有可能造成对地上部养分供应的不足并发生早衰。因此,如何通过调控构建与地上部生长更为匹配的、构型分布更加合理的、抗逆性更强的棉花根系就成为解决膜下滴灌棉花早衰问题的关键。 相似文献
62.
The effect of partial substitution of dietary fish meal with a high‐value soybean meal (HVS) and a commercial soybean meal (CSM) on the growth performance in juvenile Japanese seabass (8.3±0.2 g body weight) was determined. Nine isonitrogenous (crude protein 44%) and isoenergetic (20 kJ g?1) practical diets replacing 0 (the control), 15%, 30%, 45% and 60% fish meal protein by soybean meal protein (HVS or CSM) were formulated. Each diet was randomly assigned to four replicate cages (1.5 × 1.5 × 2.0 m). Fish were fed twice daily for 10 weeks. Growth was significantly reduced with increased soybean inclusion in fish fed both the soybean sources. Independent of the soybean source used, increased inclusion of soybean meal decreased the growth performance. When the substitution level was 45% or more in CSM and 60% in HVS, the specific growth rate (SGR) and the feed efficiency ratio (FER) were significantly lower compared with the control. These results indicated that CSM protein could substitute for 30% fish meal protein, while the substitution level of HVS protein could be 45%, which did not influence the growth of juvenile Japanese seabass. The higher substitution level for HVS compared with CSM was probably due to better nutritional values. 相似文献
63.
The impact of genetically modified canola (Brassica napus) on biodiversity has been examined since its initial stage of commercialization. Various research groups have extensively investigated crossability and introgression among species of Brassicaceae. B. rapa and B. juncea are ranked first and second as the recipients of cross-pollination and introgression from B. napus, respectively. Crossability between B. napus and B. rapa has been examined, specifically in terms of introgression from B. napus to B. rapa, which is mainly considered a weed in America and European countries. On the other hand, knowledge on introgression from B. napus to B. juncea is insufficient, although B. juncea is recognized as the main Brassicaceae weed species in Asia. It is therefore essential to gather information regarding the direct introgression of B. napus into B. juncea and indirect introgression of B. napus into other species of Brassicaceae through B. juncea to evaluate the influence of genetically modified canola on biodiversity. We review information on crossability and introgression between B. juncea and other related Brassicaseae in this report. 相似文献
64.
Development of mediator-type biosensor to wirelessly monitor whole cholesterol concentration in fish
Mai Takase Masataka Murata Kyoko Hibi Ren Huifeng Hideaki Endo 《Fish physiology and biochemistry》2014,40(2):385-394
We developed a wireless monitoring system to monitor fish condition by tracking the change in whole cholesterol concentration. The whole cholesterol concentration of fish is a source of steroid hormones or indicator of immunity level, which makes its detection important for tracking physiological condition of fish. Wireless monitoring system comprises of mediator-type biosensor and wireless transmission device. Biosensor is implantable to fish body, and transmission device is so light, in that fish is allowed to swim freely during monitoring. Cholesterol esterase and oxidase were fixated on to the detection site of biosensor and used to detect the whole cholesterol concentration. However, cholesterol oxidase incorporates oxidation–reduction reaction of oxygen for detection, which concentration fluctuates easily due to change in environmental condition. Meanwhile, mediator-type biosensor enables monitoring of whole cholesterol concentration by using mediator to substitute that oxidation–reduction reaction of oxygen. Characteristic of fabricated mediator-type biosensor was tested. The sensor output current of mediator-type biosensor remained stable compared to output current of non-mediator-type biosensor under fluctuating oxygen concentration of 0–8 ppm, which implied that this sensor is less affected by change in dissolved oxygen concentration. That biosensor was then implanted into fish for wireless monitoring. As a result, approximately 48 h of real-time monitoring was successful. 相似文献
65.
Taosha Ou Mengyun Guan Yongrui Mai Peiyan Deng Yutang Xiao Dayi Deng 《Journal of Soils and Sediments》2017,17(8):2202-2213
Purpose
Surface sediments contaminated with high levels of multiple heavy metal(loid) species are very common environmental problems. Especially, the labile and bioaccessible fractions of heavy metal(loid)s in the sediments are posing serious risks to the biota and the overlaying water quality. This study aimed at developing a potential method to manage the activity of the labile fractions of heavy metal(loid)s in surface sediments.Materials and methods
This study assessed the feasibility of adding iron powder, a low-cost industrial by-product, to sediments containing high levels of Pb, As, and Cd to adsorb labile fractions of heavy metal(loid)s onto the sorbent surfaces and to retrieve the heavy metal(loid) laden powders by applying external magnetic field. In addition, the redistribution of Pb, Cd, and As in different sediment fractions, the dissolved fraction and the sorbent-adsorbed fraction, was also investigated and characterized.Results and discussion
The results indicate that the bioactive labile fractions (exchangeable and carbonate-bound fractions) of heavy metal(loid)s are prone to concentrating onto iron powders and can be selectively removed from the sediments by magnetic retrieval. In addition, iron addition induces conversion of labile fractions of heavy metal(loid)s into more stabilized fractions.Conclusions
Overall, the process can effectively minimize the activity of labile fractions of heavy metal(loid)s in surface sediments.66.
Hai Nguyen Tran Chung-Kung Lee Mai Thi Vu Huan-Ping Chao 《Water, air, and soil pollution》2017,228(10):401
Spherical biochar derived from saccharides (glucose, sucrose, and xylose) was prepared through two steps: pre-hydrothermal carbonization at 190 °C and calcination at low temperatures (200–325 °C). The spherical biochar was characterized by Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared spectroscopy, zeta potential, scanning and transmission electron microscopies, and X-ray diffraction. The result indicated that the spherical biochar exhibited low S BET (15–22 m2/g), but abundant superficial active oxygen-containing functional groups. The spherical biochar possessed a negatively charged surface within solution pH 2.0–11. The adsorption process of Pb2+, Cu2+, and methylene green 5 (MG5) was strongly dependent on the solution pH and reached fast equilibrium at approximately 60 min. The maximum Langmuir adsorption capacity (Q°max) exhibited the following order: glucose-biochar > sucrose-biochar > xylose-biochar prepared at 300 °C. The selective adsorption order of glucose-biochar was Cu2+ (0.894 mmol/g) > Pb2+ (0.848 mmol/g) > MG5 (0.334 mmol/g). The electrostatic attraction played a determining role in the adsorption mechanism of pollutant cations. The adsorption of anionic dye (acid red 1) on the spherical biochar was negligible because of electrostatic repulsion. The spherical biochar can serve as a newer and promising adsorbent to remove toxic pollutant cations from water media. 相似文献
67.
Seiichi Furuya Mai Mochizuki Seiya Saito Hironori Kobayashi Tsutomu Takayanagi Shunji Suzuki 《Pest management science》2010,66(11):1268-1272
BACKGROUND: The increasing occurrence of QoI fungicide resistance in Plasmopara viticola (Berk. & MA Curtis) Berl. & DeToni populations is becoming a serious problem in the control of grapevine downy mildew. In Japan, the existence of QoI‐fungicide‐resistant P. viticola was reported in 2009. RESULTS: The QoI fungicide resistance in P. viticola samples collected from vineyards in Japan in 2008 and 2009 was monitored. Resistant P. viticola were detected in the regions where QoI fungicides have been introduced in accordance with the pest management programme, whereas in Hokkaido vineyards, where QoI fungicides have not yet been introduced, QoI‐fungicide‐resistant P. viticola were not found. CONCLUSION: Japan comprises thousands of islands and is physically isolated from other countries by the sea. Monitoring the emergence, incidence and distribution of QoI fungicide resistance in P. viticola populations in Japan is necessary to improve pest management strategies for downy mildew disease in Japanese vineyards. Copyright © 2010 Society of Chemical Industry 相似文献
68.
温度势差驱动玉米去水试验研究 总被引:1,自引:0,他引:1
从能势转换的角度探讨谷物节能干燥工艺,即利用自然界自身存在的温度势差驱动谷物水分气化、迁移和扩散,达到去除高水分玉米水分和提高粮温的目的,并通过试验验证了该方法的可行性,为烘干机高效节能设计提供基础数据。 相似文献
69.
70.
Andrés Dieste Andreas Krause Carsten Mai Holger Militz 《Wood Science and Technology》2010,44(4):597-606
Beech wood (Fagus sylvatica L.) was modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU). The equilibrium moisture content (EMC) of wood modified
with DMDHEU calculated on a dry modified basis is reduced. Previous results have shown that the modification with DMDHEU does
not alter the capillary condensation; therefore, the reduction in EMC seems exaggerated. The equilibrium constants of the
Hailwood–Horrobin model (K
d and K
h) and the molecular weight of a hypothetical polymer of modified wood capable of adsorbing one molecule of water (W
i) were calculated from the EMC on a dry modified wood basis (M) and on a dry wood basis (M
R). The hypothetical polymer was also calculated by stoichiometry (W
c) and compared to W
i to estimate the number of operative OH groups. The number of operative OH groups decreased when M was used, in contradiction with the previously obtained results of differential heat of adsorption (∆H
s). Therefore, the use of M
R is recommended for the analysis of moisture sorption in wood modified with DMDHEU. 相似文献