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紫外线的Bt伴孢晶体的损伤和腐植酸的保护作用   总被引:4,自引:0,他引:4  
用SDS-PAGE电泳分析和生物测定等方法研究了紫外线对苏云金芽孢杆菌(Bacillus thuringiensis,简称Bt)伴孢晶体的损伤及腐植酸对Bt伴孢晶体的保护作用。结果表明,紫外线对Bt伴孢晶体有明显的损伤,伴孢晶体紫外线辐射3h后溶解性能及生物活性基本丧失。腐植酸对紫外线有较强的吸收作用,能有效地减轻紫外线对Bt伴孢晶体的损伤。  相似文献
2.
本文介绍了影响烯草酮降解的一些因素,明确了微生物,腐殖酸和单线态氧对土壤中烯草酮在降解影响,即施药后72h烯草酮在微生物,腐殖酸和单线态氧作用下,相对降解率分别为31%52.61%和18.15%,而水溶性中的烯草酮在光和腐殖酸的作用下,不产生降解。  相似文献
3.
阿尔泰山西北部垂直带谱中的土壤有机氮素,同土壤腐殖质一样表现为非连续性的特征转化系列。在干旱气候带,土壤的全氮量随海拔升高到黑钙土增加至10倍。土壤中酸不溶态氮相对含量也持续增加,而氨基酸和氨基糖态氮含量下降。胡敏酸中酸不溶态氮和氨基酸态氮也表现出类似的变化趋势。冷一湿气候带中土壤胡敏酸的未鉴定态氮相对含量明显地多于干旱气候带,而干旱气候带中土壤胡敏酸的酸不溶态氮量显著地高于冷—湿气候带。土壤和其胡敏酸中氮素形态分布,与垂直带谱中土壤的腐殖质化过程紧密相关,随腐殖质化度的增加,酸不溶态氮相对含量提高,而氨基酸态氮和氨基糖态氮量下降。胡敏酸中氨基糖态氮含量甚微。  相似文献
4.
Man CHENG 《干旱区科学》2015,7(2):216-223
 Revegetation is a traditional practice widely used for soil protection. We evaluated the effect of natural revegetation succession on soil chemical properties and carbon fractions (particulate organic carbon (POC), humus carbon (HS-C), humic acid carbon (HA-C) and fulvic acid carbon (FA-C)) on the Loess Plateau of China. The vegetation types, in order from the shortest to the longest enclosure duration, were: (a) abandoned overgrazed grassland (AbG3; 3 years); (b) Hierochloe odorata Beauv. (HiO7; 7 years); (c) Thymus mongolicus Ronnm (ThM15; 15 years); (d) Artemisia sacrorum Ledeb (AtS25; 25 years); (e) Stipa bungeana Trin Ledeb (StB36; 36 years) and (f) Stipa grandis P. Smirn (StG56; 56 years). The results showed that the concentrations of soil organic carbon, total nitrogen and available phosphorus increased with the increase of restoration time except for ThM15. The concentration of NH4-N increased in the medium stage of vegetation restoration (for ThM15 and AtS25) and decreased in the later stage (for StB36 and StG56). However, NO3-N concentration significantly increased in the later stage (for StB36 and StG56). Carbon fractions had a similar increasing trend during natural vegetation restoration. The concentrations of POC, HS-C, FA-C and HA-C accounted for 24.5%–49.1%, 10.6%–15.2%, 5.8%–9.1% and 4.6%–6.1% of total carbon, respectively. For AbG3, the relative changes of POC, HS-C and FA-C were significantly higher than that of total carbon during the process of revegetation restoration. The higher relative increases in POC, HS-C and FA-C confirmed that soil carbon induced by vegetation restoration was sequestrated by higher physical and chemical protection. The increases of soil C fractions could also result in higher ecology function in semiarid grassland ecosystems.  相似文献
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为研究腐殖酸对克服烤烟重茬障碍的效果,试验在田间试验条件下设置对照(B1),当地常规施肥(B2),腐殖酸复混肥(B3)3个处理,研究了烤烟氮积累与烟叶品质变化规律。结果表明:根系氮积累生育期内呈现出增加的趋势,收获期B3处于最高值,与B2相比提高32.62%;茎内氮积累成熟期B3比B2处理提高41.62%,差异显著;下部叶成熟期B3比B2处理提高35.37%;中部叶B3比B2处理提高14.61%,差异显著;上部叶B3比B2处理提高32.64%,差异显著;B3促进氮在茎内的分配,比B1和B2处理分别提高5.27%、1.84%;B3产量与产值分别比B2提高6.94%、7.94%,烟叶质量评分下部叶、中部叶、上部叶分别低于B2处理1.50分、2.00分、2.00分。综合分析认为,腐殖酸对提高烤烟氮积累量和产量效果最佳。  相似文献
6.
通过在北疆布设的3种肥料(腐植酸液体肥料HALF-A、HALF-B、HALF-C)5个施肥水平的田间试验,研究了黑液腐植酸肥料对棉花生长及土壤肥力的影响。结果表明:(1)与常规肥料比,应用不同黑液腐植酸液体肥料,增产幅度达到8.54%~10.80%,提高单铃重0.2~0.3 g,对衣分和单株有效成铃数影响不大;(2)施用腐植酸液体肥料能够推迟棉花成熟2~4 d;(3)腐植酸液体肥料施用量2250kg/hm2以上时显著促进了棉花花后干物质的累积;(4)三种腐植酸液体肥料施用量3 000 kg/hm2时对棉花氮素养分的吸收促进作用最大,HALF-B在施用量2250 kg/hm2,HALF-C在3 000 kg/hm2时促进了棉花磷素养分的吸收,腐植酸液体肥料施用量3 750 kg/hm2以上时显著促进了棉花钾素养分的吸收;(5)施用腐植酸液体肥料对当年收获后土壤肥力影响不大。  相似文献
7.
采用田间试验方法,以小麦新春38号作为供试品种,设置3个处理:空白对照、等养分复合肥和等养分棉粕腐植酸复合肥,研究了棉粕开发的腐植酸水溶性肥料对土壤团聚体、酶和养分的影响.结果表明:与不施肥处理相比较,腐植酸肥处理使土壤团聚体含量向2~0.25 mm和>2 mm粒级有显著转移;土壤脲酶活性、过氧化氢酶和碱性磷酸酶活性显著提高,对蔗糖酶活性差异不明显;可显著提高碱解氮、速效钾和有效磷含量,腐植酸肥处理能平均提高全生育期0~~20 cm 土层碱解氮37.27%、速效磷42.24%、速效钾37.02%,20~40 cm土层碱解氮提高15.55%、速效磷提高61.52%、速效钾提高57.36%.与等养分复合肥处理相比,腐植酸肥处理使不同土层土壤团聚体百分含量向2~0.25 mm和>2 mm粒级均有转移;前期抑制土壤脲酶活性,后期提高壤脲酶活性,提高过氧化氢酶和碱性磷酸酶活性,蔗糖酶活性差异不明显;可提高土壤中碱解氮含量,显著提高速效钾和速效磷含量,腐植酸肥处理可平均提高全生育期0~20 cm土层碱解氮5.92%、速效磷8.8%、速效钾4.29%,20~40 cm土层碱解氮提高1.9%、速效磷提高15.39%、速效钾提高8%.  相似文献
8.
Humic acid, a natural by-product from lignite coals, was evaluated for its potential to control root-knot nematode, Meloidogyne incogntia infecting banana. Hatching of M. incognita eggs was inhibited 50%–100% following incubation in 0.08%-2.0% humic acid in vitro. Exposure of juveniles (J2) of M. incognita to different humic acid concentrations significantly affected the mobility of J2 in vitro. The percent immobility of J2 increased with concentrations of humic acid up to 0.08%. In pot experiments, soil treatment with humic acid reduced the root galling in banana plantlets. All the humic acid tested concentrations (0.04%, 0.08%, 0.2% and 0.4%) significantly reduced the nematode soil density by 53.5%–56.7%, root infection by 61.9%–63.8%, egg population by 61.9%–63.8% and reproduction rate by 55.7%–56.6%. A significant improvement of growth of banana plantlets in terms of number of leaves, pseudostem height, girth, weight, root length and weight was noticed in humic acid treated pots. Humic acid did not suppress growth of the biocontrol agents Pseudomonas fluorescens and Trichoderma viride in vitro. Results suggest that soil treatment with humic acid at 0.04% not only offers significant nematode control but also improves growth of banana.  相似文献
9.
通过室内培养方法,研究外源磷不同用量及腐植酸施用方式对灰漠土有效磷含量的影响。结果表明:随外源磷用量增加,土壤有效磷含量先增大后减小,土壤固磷率先增后减再增大,有效磷含量在土壤中有一个极大值平衡点;腐植酸及外源磷施用方式对土壤有效磷含量影响较大,单施腐植酸或单施外源磷均可增加土壤有效磷含量,且效果显著;腐植酸与外源磷的合理搭配施用,使土壤有效磷含量大于单施外源磷和单施腐植酸的方式;在腐植酸与外源磷施用过程中,先施外源磷再施腐植酸,土壤有效磷含量增加速度最快、土壤有效磷含量最高,差异达到显著水平。  相似文献
10.
BACKGROUND: Clomazone is a herbicide used to control broadleaf weeds and grasses. Clomazone use in agriculturally important crops and forests for weed control has increased and is a potential water contaminant given its high water solubility (1100 µg mL−1). Soil sorption is an environmental fate parameter that may limit its movement to water systems. The authors used model rice and forest soils of California to test clomazone sorption affinity, capacity, desorption, interaction with soil organic matter and behavior with black carbon. RESULTS: Sorption of clomazone to the major organic matter fraction of soil, humic acid (HA) (Kd = 29–87 L kg−1), was greater than to whole soils (Kd = 2.3–11 L kg−1). Increased isotherm non‐linearity was observed for the whole soils (N = 0.831–0.893) when compared with the humic acids (N = 0.954–0.999). Desorption isotherm results showed hysteresis, which was greatest at the lowest solution concentration of 0.067 µg mL−1 for all whole soils and HA extracts. Aliphatic carbon content appeared to contribute to increased isotherm linearity. CONCLUSION: The results indicate that clomazone does not sorb appreciably to sandy or clay soils. Its sorption affinity and capacity is greater in humic acid, and consequently clomazone has difficulty desorbing from soil organic matter. Sorption appears to follow processes explained by the dual‐mode model, the presence of fire residues (black carbon) and a recently proposed sorption mechanism. Copyright © 2009 Society of Chemical Industry  相似文献
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