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1.
为明确侵蚀环境中长期施用化肥条件下农田土壤养分积累特征及其对流域面源污染的潜在威胁。在高塬沟壑区,分别采集塬面—坡地—沟道和川地—河漫滩—河道中土壤及泥沙样品,分析不同侵蚀地貌单元中团聚体粒级分布特征和不同团聚体中C、N、P含量变化及其潜在环境风险。结果表明:(1)沟道和河道等低洼地带＜63 μm粒级团聚体占比最高,川地—河漫滩—河道系统中＜63 μm粒径含量显著高于塬面—坡地—沟道系统;(2)塬面有机碳(SOC)、全氮(TN)、全磷(TP)、有效磷(Olsen—P)含量分别为8.49,1.19,1.23 g/kg和51.80 mg/kg,是80年代初的1.39,1.49,1.76,16.27倍;川地分别为6.80,1.00,1.07 g/kg和27.40 mg/kg,是80年代初的1.12,1.25,1.52,8.13倍,磷素积累最为明显。各粒级团聚体中SOC、TN、TP、Olsen—P含量由高到低依次为＞250 μm粒级,63~250 μm粒级,＜63 μm粒级;(3)无论是从塬面到沟道,还是从川地到河道,不同粒级团聚体中SOC、TN、TP、Olsen—P都呈现了显著降低趋势,但沟道和河道＜63 μm粒级团聚体中有效磷素含量已升高到塬面上世纪80年代初水平。易侵蚀迁移的团聚体(＜250 μm)分布特征和CaCl2—P的突变点问题突出,成为塬面和川地农田土壤养分积累影响水体环境的潜在风险源。因此,防治水土流失和改善施肥措施是确保黄河流域高质量发展的基础。 相似文献
2.
以洞头海区养殖的"洞头本地菜"和"浙东1号"2种坛紫菜品系为研究材料,测定其不同收割期叶状体长度、干质量、CNP含量等参数,核算了S值、产量及CNP固定效率等指标。结果显示:随着收割期延长,2种坛紫菜品系的叶状体长度逐渐下降,单条叶状体干质量与S值逐渐增加,产量先升后降,CNP固定效率整体呈上升趋势。一水至四水"洞头本地菜"的单条叶状体长度、干质量均高于"浙东1号",二水至四水"洞头本地菜"的产量、CNP固定效率均高于"浙东1号",2种坛紫菜品系S值之间无明显差异。一水至四水"洞头本地菜"CNP总固定效率分别为900.74 kg/hm~2、110.16 kg/hm~2和14.16 kg/hm~2,"浙东1号"CNP总固定效率分别为683.34 kg/hm~2、84.3 kg/hm~2和10.75 kg/hm~2。上述指标在不同收割期均呈极显著差异(P0.01),在不同品系间均无显著差异(P0.05),研究结果有助于进一步认知坛紫菜养殖的生长性状与生态效益。 相似文献
3.
HUANG Huayun LIANG Zhong LIU Longzhou ZHAO Zhenhua WANG Qianbao LI Chunmiao HUANG Zhenyang ZHANG Xin LI Shoufeng 《中国畜牧兽医》2007,47(11):3555-3562
The aim of this study was to investigate the regulatory effect and mechanism of C-type natriuretic peptide (CNP) on the proliferation,differentiation and lipolysis of intramuscular preadipocytes (IMPs) in breast muscle of chickens,and lay a foundation on further elucidating the molecular mechanism of intramuscular fat deposition in chickens.The IMPs of breast muscle in Yellow-feathered broilers were used as the model in vitro,the preadipocytes were induced by 10-7 mol/L CNP.The proliferation,differentiation and lipolysis of IMPs were observed by CCK8,Edu staining,Oil Red O staining and isopropanol extraction,respectively.The concentration of cGMP and glycerin were detected by cGMP and glycerin kit,respectively.The expression of NPRA,NPRB and NPRC genes mRNA was detected by Real-time quantitative PCR.The results showed that compared with control group,the cell proliferation in CNP treatment group was enhanced significantly at 1 and 3 d (P<0.05).The cell differentiation and lipid deposition were extremely significantly decreased at 3 and 6 d (P<0.01),the intracellular cGMP concentration and glycerin concentration in the medium at 3 and 6 d were extremely significantly increased (P<0.01).The expression of NPRB and NPRC genes mRNA in CNP treatment group was extremely significantly or significantly higher than control group (P<0.01;P<0.05),and the expression of NPRA gene mRNA had no significant difference (P>0.05).The results revealed that CNP regulated the lipid deposition of intramuscular adipocytes through NPRB/NPRC-cGMP pathway in chickens. 相似文献
4.
大兴安岭不同退化阶段土壤和植物C、N、P浓度及其化学计量特征 总被引：1，自引：0，他引：1
在大兴安岭加格达奇地区,选择处于不同退化阶段的蒙古栎林、灌丛、灌草丛和草丛,进行土壤和植物叶片C、N、P浓度及其化学计量比分析。结果表明,土壤全N、全P浓度随植被退化逐渐下降,而土壤全C浓度在灌丛达到最高。随着植被退化,各退化阶段植物群落的叶片C、N、P浓度逐渐降低,而N/P比值则逐渐增加。蒙古栎林、灌丛、灌草丛和草丛植物群落的叶片N/P比值分别为：7.35、8.04、9.36和13.61,均小于14。各退化阶段9个共有物种的叶片N/P比值,在蒙古栎林和灌丛群落中均小于14;在灌草丛群落中小于14的共有物种8个,在14～16之间的共有物种1个;在草丛群落中小于14的共有物种7个,大于16的共有物种2个。根据以往对N/P临界值的确定,可以认为该区各退化阶段的植物生长主要受N素的限制。 相似文献
5.
以福建省沙县官庄国有林场杉木第3代种子园为研究对象,在区分高中低产区的基础上,分析了各产量小区中CNP化学计量特征。结果显示,CNP元素的含量随着产量减少而减少,在高产小区表现为最大。CN比值和CP比值只在0～20cm土壤层中表现为高产显著大于中产或低产,其他化学计量比值在20～40 cm和40～60 cm土层中没有发现显著差异。CP比值的范围明显大于CN比值和NP比值。相对高的CP和NP比值说明杉木种子园土壤可能缺乏P元素。 相似文献
6.
Atmospheric emissions of fly ash and SO2 from lignite-fired power plants strongly affect large forest areas in Germany. The impact of different deposition loads on the microbial biomass and enzyme activities was studied at three forest sites (Picea abies (L.) Karst.) along an emission gradient of 3, 6, and 15 km downwind of a coal-fired power plant (sites Ia, II, and III, respectively), representing high, moderate and low emission rates. An additional site (site Ib) at a distance of 3 km from the power plant was chosen to study the influence of forest type on microbial parameters in coniferous forest soils under fly ash and SO2 emissions. Soil microbial biomass C and N, CO2 evolved and activities of l-asparaginase, l-glutaminase, β -glucosidase, acid phosphatase and arylsulfatase (expressed on dry soil and organic C basis) were determined in the forest floor (L, Of and Oh horizon) and mineral top soil (0-10 cm). The emission-induced increases in ferromagnetic susceptibility, soil pH, concentrations of mobile (NH4NO3 extractable) Cd, Cr, and Ni, effective cation exchange capacity and base saturation in the humus layer along the 15 km long transect significantly (P<0.05) reflected the effect of past depositions of alkaline fly ash. Soil microbial and biochemical parameters were significantly (P<0.05) affected by chronic fly ash depositions. The effect of forest type (i.e. comparison of sites Ia and Ib) on the studied parameters was generally dominated by the deposition effect. Alkaline depositions significantly (P<0.05) decreased the microbial biomass C and N, microbial biomass C-to-N ratios and microbial biomass C-to-organic C ratios. Microbial respiration, metabolic quotient (qCO2) and the activities of l-asparaginase, l-glutaminase, β-glucosidase, acid phosphatase and arylsulfatase were increased by long-term depositions from the power plants. Acid phosphatase had the highest specific (enzyme activities expressed per unit organic C) activity values among the enzymes studied and arylsulfatase the lowest. The responses of the microbial biomass and soil respiration data to different atmospheric deposition loads were mainly controlled by the content of organic C and cation exchange capacity, while those of enzyme activities were governed by the soil pH and concentrations of mobile heavy metals. We concluded that chronic fly ash depositions decrease litter decomposition by influencing specific microbial and enzymatic processes in forest soils. 相似文献
7.
An isolated, perfused gill pouch preparation and myography were used to determine responses of the branchial vasculature of a hagfish to the mammalian natriuretic peptides, rANP and CNP. In the isolated gill pouch preparation afferent perfusion pressures increased in the first 5 min of exposure to low concentrations (10–14 to 10–10M) of ANP and CNP and then decreased below starting values by 15 min. At higher concentrations the depressor response prevailed and natriuretic peptides switched the flow away from the efferent artery to the venous route, which would fill the peribranchial sinus in vivo. At low concentrations ANP increased circumferential tensions in afferent branchial arterial rings. At higher concentrations afferent and efferent branchial arteries relaxed in response to ANP and CNP. 相似文献
8.
Guanylyl cyclase stimulation by homologous and heterologous natriuretic peptides in salmonids 总被引：3，自引：0，他引：3
Will Callahan Hamish McWilliam Mark D. Powell Tes Toop 《Fish physiology and biochemistry》2002,26(2):129-138
A range of homologous (trout ANP, trout CNP, trout VNP) and heterologous (eel ANP, eel ANP-NH2, rat ANP, porcine CNP) NPs were tested for their effect on guanylyl cyclase in gill and kidney membrane preparations from
freshwater and seawater-acclimated rainbow trout and Atlantic salmon. All NPs stimulated guanylyl cyclase at 1 μmol l−1in all preparations. ANP was the most potent stimulator of kidney guanylyl cyclase and CNP the most potent stimulator of guanylyl
cyclase in gills. Some differences were apparent between the potencies of homologous and heterologous peptides at 1 μmol l−1: tANP was more potent than rANP in the SW trout kidney and tCNP was more potent than pCNP in FW salmon tissues. While eANP
was more potent than tANP in trout gills, it was less potent than tANP in FW salmon gills. However, there was no significant
difference between the potencies of eANP and eANP-NH2 in trout or salmon gills. Salinity did not affect guanylyl cyclase activity with the exception that trout ANP at 1 μmol l−1was more potent in SW trout kidneys than in FW trout kidneys. These results suggest a predomination of NPR-A in the kidney
and NPR-B in the gill. It appears that salmonid NPR-A and NPR-B are relatively promiscuous in their ligand affinity, with
few differences in the potencies of trout and mammalian NPs and only small differences in cGMP production where these differences
do occur.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
设置模拟氮沉降的控制试验,以NH4NO3作为外加氮源,设计CK(0kg N hm-2·a-1)、LN(50 kg N hm-2·a-1)、MN(100 kg N hm-2·a-1)、HN(150 kg N hm-2· a-1)4个处理,历时9个月,测定木荷(Schima superba)幼苗的光合特性、生物量和C、N、P含量及其分配格局对氮沉降的响应.结果表明:(1)木荷幼苗的最大净光合速率和光饱和点随着氮处理水平增加呈先增加后减小的特点,在中氮处理下极显著增加(P＜0.01).氮处理降低了幼苗的光补偿点和暗呼吸速率,光补偿点在低氮处理下显著降低(P＜0.05),暗呼吸速率在低中氮处理下极显著降低(P＜0.01),高氮处理下显著降低(P＜0.05).未见氮处理对表观量子效率产生显著影响.(2)氮处理促进了木荷的全株生物量以及各部分生物量的增长.随着氮处理水平的增加,叶重比呈升高的趋势,而根重比和根冠比呈降低的趋势,在高氮处理下叶重比的增加和根重比、根冠比的降低都达到了显著水平(P＜0.05).(3)氮沉降促进各器官N含量的增加,在高氮处理下根和茎中N含量极显著增加(P＜0.01),叶中N含量显著增加(P＜0.05).而各器官C含量随着氮沉降程度的增加呈先增加后降低的趋势,在中氮处理下根和茎中C含量极显著增加(P＜0.01),叶中C含量显著增加(P＜0.05).但各器官P含量变化趋势各不相同,随着氮的增加,根中P含量是呈先增加后降低的趋势,而茎和叶中P含量是呈降低的趋势.氮沉降一定程度上降低了木荷各器官的C/N比值而增加了N/P比值. 相似文献
10.
植物碳氮磷生态化学计量对非生物因子的响应 总被引：6，自引：0，他引：6
在不同的环境条件下,植物会进行不同的生理生化反应,通过植物调节碳（C）、氮（N）、磷（P）的代谢和循环,使其具有不同的含量和分布,最终表现出特定的元素生态化学计量学特征。因此,植物主要元素的生态化学计量学特征从另一个方面体现了其对环境变化的响应和适应性。本研究对影响植物生长的主要非生物因子（包括土壤营养、CO2、水分、光照和温度）变化下植物的C、N、P生态化学计量学特征及其可能的机制进行了综合分析,并讨论了其空间和时间变异性。 相似文献