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151.
Denitrification and fermentation in plant-residue-amended soil 总被引:1,自引:0,他引:1
Summary Nitrous oxide production (denitrification) during anaerobic incubation of ground-alfalfa-, red-clover-, wheat-straw-, and cornstover-amended soil was positively related to the initial water-soluble C content of the residue- amended soil. The water-soluble C concentration decreased in all treatments during the first 2 days, then increased in the alfalfa-, red-clover-, and wheat-straw-amended soil until the end of the experiment at 15 days. An accumulation of acetate, propionate, and butyrate was partly responsible for the increased water-soluble C concentration. Denitrification rates were much higher in the alfalfa-and red-clover-amended soil, but NO
3
–
was not fully recovered as N2O in these treatments. Supported by earlier experiments in our laboratory, we conclude that some of the NO
3
–
was reduced to NH
4
+
through fermentative NO
3
–
reduction, otherwise known as dissimilatory NO
3
–
reduction to NH
4
+
. Acetate, the primary product of anaerobic fermentation, accumulated in the alfalfa- and red-clover-amended soil in the presence of NO
3
–
, supporting previous observations that the processes of denitrification and fermentation occur simultaneously in C-amended soil. The partitioning of NO
3
–
between denitrification and fermentative NO
3
–
reduction to NH
4
+
depends on the activity of the denitrifying and fermentative bacterial populations. NO2 concentration may be a key in the partitioning of NO
3
–
between these two processes. 相似文献
152.
利用固液反应球磨技术制备了Al-Cu-Ni三元合金粉末.采用Ni球球磨wAl-33.2%wCu,wAl-54%wCu(Al2Cu)和wAl-70%wCu(AlCu)二元合金熔体,在893 K分别球磨wAl-33.2%wCu熔体12 h和24 h后均生成了Al7Cu4Ni粉末;在893 K球磨wAl-54%wCu12h后生成Al7Cu4Ni粉末,在993 K和1 123 K球磨wAl-54%wCu(Al2Cu)24 h后均生成Al0.28Cu0.69Ni0-粉末;在1 123 K球磨wAl-70%wCu(Al2Cu)24 h后生成Al0.28Cu0.69Ni0-粉末.同时,对Al-Cu-Ni三元合金相形成规律进行了研究,对固液反应球磨机理进行了探讨. 相似文献
153.
为探索烟叶成熟度对香味成分的影响,研究了烟叶成熟度与香气质量关系。利用同时蒸馏萃取装置提取不同成熟度烟叶样品的挥发性香味成分,经毛细管气相色谱法对烟叶中主要香味成分变化进行了定性定量分析。结果表明:(1)烟叶中主要香气成分的总量、醇类和酮类香味成分随烟叶成熟度的提高而增加(2)糠醇、5-甲基糠醛、6-甲基-5-庚烯-2-酮、苯甲醇、芳樟醇、β-苯乙醇、异佛尔酮、茄酮、大马酮、二氢猕猴桃内酯、金合欢基丙酮等香味成分等香气成分含量则随着成熟度的提高而持续增加,最大值出现在完熟阶段;(3)糠醛、苯乙酮、二氢大马酮、巨豆三烯酮、香叶基丙酮等香味成分在烟叶成熟时含量最高,之后其含量缓慢下降。 相似文献
154.
黄山栾树叶中具有清除自由基活性物质的分离和制备 总被引:4,自引:0,他引:4
在一次大规模的植物提取物清除自由基活性物质筛选中,发现黄山栾树(Koelreuteria bipinnata Franch.var.integrifoliola(Morr.)T Chen)鲜叶的甲醇提取物具有很强的清除DPPH有机自由基的活性,其IC50为46.37μg·mL-1.用甲醇成功地提取出该活性成分,同时用色谱等方法对该活性成分进行了分离和制备,并用高效液相色谱法和DPPH薄层试验对其纯度及活性进行了检验,得到了一个清除自由基活性很强的纯化合物.该化合物对1 mmol·L-1DPPH自由基的IC50为23.84μg·mL-1,其清除自由基活性高于抗坏血酸纯品. 相似文献
155.
稀土对烤烟生长和代谢的影响研究 总被引:2,自引:0,他引:2
烤烟叶面喷施稀土表明,600mg/L处理,移栽45天后。烟株干物重、光合强度、三磷酸腺苷、硝酸还原酶、过氧化氢酶分别比对照提高17.08%,34.46%,34.41%,24.51%和34.11%;移栽85天后,烟叶的干物重、K2O,总糖、总氮和蛋白质含量分别比对照提高49.62%,28.96%,12.00%,14.13%和25.84%。 相似文献
156.
植物抗氧化剂研究展望 总被引:13,自引:1,他引:13
总结了植物多酚、活性多糖、维生素、蛋白质和氨基酸等植物提取物的抗氧化活性主要成分,提出应在原料筛选,提取、分离方法创新,多组分协同作用机理和抗氧化活性成分的构效关系等方面深入研究 相似文献
157.
158.
Lamastra L Ferrari F Fait G Greco L Kennedy SH Capri E Trevisan M 《Pest management science》2011,67(11):1439-1445
BACKGROUND: 1,3‐Dichloropropene (1,3‐D, CAS No. 542‐75‐6) is a broad‐spectrum soil fumigant used to control numerous species of soilborne plant‐parasitic nematodes. 1,3‐D consists of two isomers, (Z)‐ and (E)‐1,3‐D. There are a number of low‐level chlorinated compounds that could potentially be produced as a part of the 1,3‐D manufacturing process. 1,3‐D and its metabolites, as well as potentially related chlorinated compounds, represent potential groundwater contaminants. RESULTS: This study has investigated the hydrolytic stability, under biotic and abiotic conditions in the laboratory, of an extensive representative list of 1,3‐D and potentially related chlorinated compounds in order to predict their environmental fate. All of these compounds showed intrinsic hydrolytic instability under both abiotic and biotic test conditions. Furthermore, a monitoring programme was carried out. Twenty‐five wells were monitored in five Italian regions characterised by historical and existing use of 1,3‐D. The parent compound, its two major metabolites and potentially related chlorinated compounds were not detected in the well water at > 0.1 µg L?1 at any sampling location. CONCLUSION: The soil fumigant (E,Z)‐1,3‐D, its metabolites and potentially related chlorinated compounds constitute a low risk to groundwater. Copyright © 2011 Society of Chemical Industry 相似文献
159.
160.
The simultaneous impact of three successive crops of wheat (Triticum aestivum L.) and of the earthworm (Lumbricus terrestris L.) on the mineralisation of 15N-labelled organic compounds adsorbed to different soil size fractions (sand and organic residues >50 μm; silt 50–2 μm; coarse
clay 2–0.2 μm and fine clay <0.2 μm) was studied under controlled conditions in the greenhouse. Unplanted soils (UPS) were
used as controls. In planted soils without earthworm (PS) total plant biomass decreased with each cropping by up to 50%. However,
in planted soils with earthworms (PES) the total plant biomass loss was only 17%. This pattern was explained by the earthworm
effect. Compared to the unplanted soils, the planted soils had an increased (mean +37%) mineralisation of 15N adsorbed onto fine clays and a partial transfer of 15N to silt and coarse clay. The quantities of 15N mineralised and transferred were higher in the planted soils with earthworms, indicating an amplification of the phenomenon
in the presence of earthworms. The simultaneous effect of the rhizosphere and the drilosphere did not lead to increased mineralisation
of N adsorbed onto coarse clays and silts but instead a greater transfer of N associated with the fine fractions towards the
coarser fractions.
Received: 25 April 2000 相似文献