盐碱胁迫下绒毛白蜡种子的萌发特性

将中性盐NaC l,Na2SO4和2种碱性盐NaHCO3,Na2CO3按不同比例混合,模拟出20种盐度、碱度各不相同的复杂盐碱逆境条件,进行绒毛白蜡种子发芽试验。测定其发芽率等6项指标,结果表明:在混合盐碱的胁迫作用下,绒毛白蜡种子的发芽受到明显的抑制,发芽率、发芽势、发芽指数、活力指数等指标呈下降趋势,并随盐碱度递增,下降趋势变大,高盐高碱的共同作用结果远远大于单纯的高盐或高碱,SOD的活性总体上有不同程度的增加,CAT在不同处理组间均呈现上升的趋势,在50,100mmol/L的组内呈上升趋势,但在200,300mmol/L组内则是先升后降。可见盐胁迫与碱胁迫是2种完全不同的胁迫,应将碱性盐胁迫称为碱胁迫,而通常所说的盐胁迫应仅指中性盐胁迫,而且两者具有明显的协同作用。     

影响信阳毛尖茶叶品质的因素

[目的]为了研究影响信阳毛尖茶叶品质的因素。[方法]通过测定不同级别信阳毛尖茶多酚、总糖、氨基酸、咖啡碱和水浸出物的含量,对影响信阳毛尖茶叶品质的因素进行了分析。[结果]茶叶品质越高,茶多酚类化合物含量也越高。茶叶品质高低与可溶性糖和氨基酸的含量呈明显的正相关。高品质信阳毛尖不但茶多酚的含量高而且总糖的含量也高,但酚糖比较低。各级别信阳毛尖咖啡碱的含量无明显的区别,水浸出物总量随茶叶品质降低而升高。[结论]信阳毛尖茶叶品质主要由茶多酚、糖类、氨基酸和咖啡碱的含量决定,但每一种物质的含量过高或过低对茶叶品质都不利。高品质信阳毛尖茶叶应具有较低的酚氨比(10%~13%),较低的酚糖比(9%~13%)和合适的酚碱比(17%)。     

滩涂盐碱土壤微生物生态特征的研究

采集江苏省滨海县滩涂盐碱地土壤,以菜园土壤作为对照,系统研究了微生物区系及生态、生理特征.结果表明,盐碱土壤微生物区系和对照相比发生了重大变化,除细菌数量与对照无显著差异外,真菌、放线菌、解磷菌及钾细菌数量分别比对照土壤低1.57倍、22.34倍、5.59倍及259.39倍,达极显著差异;盐碱土基础呼吸作用、微生物生物量碳分别比对照低1.01倍(达极显著差异)、0.94倍(达显著差异),但基础代谢商(qCO2)却和对照无显著差异;盐碱土过氧化氢酶活性比对照低1.19倍,而脲酶活性却比对照高0.41倍,均达极显著差异.     

酸预处理对水稻秸秆沼气发酵的影响

为了研究酸处理对水稻秸秆沼气发酵的影响,采用不同浓度的酸（2%、4%、6%、8%、10%）对水稻秸秆进行处理,并对处理后的水稻秸秆进行厌氧沼气发酵,分析了酸预处理组和对照组在沼气发酵过程中产气量、pH值、甲烷含量及发酵前后水稻秸秆组分变化情况。结果表明,与对照相比,酸处理能显著地改变水稻秸秆的生物降解产沼气的性质,提高了产气的效率。比较来看,酸处理浓度为6%的效果最好,其甲烷含量最高可达44.3%,单位总固体产气率为150 mL.g-1,比对照组高出99.8%。     

秸秆厌氧消化预处理技术综述

农作物秸秆是一种重要的富含有机质(80％～90％)的生物质能源,因其复杂的晶体结构,不能直接被厌氧菌群利用来生产沼气.因此以秸秆作为原料发酵时,需要进行预处理,使复杂的晶体结构得到破坏,从而易于被厌氧菌群利用.文章综述了国内外用物理法、化学法、生物法、物化法预处理秸秆的相关研究进展,考查了不同预处理方法对厌氧消化效果的影响.     

茶叶中7种有机氯和拟除虫菊酯类农药残留检测技术研究

本文对茶叶中7种有机氯类和拟除虫菊酯类农药残留检测的前处理技术进行了研究,对比了2种不同的提取溶剂对农药回收率、净化效果的影响,建立了丙酮∶正己烷(1∶1,V/V)提取,Florisil固相萃取小柱净化的方法。本方法回收率在82.3～109.8%之间,变异系数3.3～10.22%,最低检出浓度为0.001mg/kg。该种残留分析前处理方法具有操作简便、成本低、回收率高、精密度好的特点。     

不同施肥配比对宁夏盐碱土壤油用向日葵产量的影响

研究了不同施肥配比对宁夏盐碱土壤向日葵产量的影响,建立了一元二次肥料效应函数方程.结果表明:对碱化土壤施氮量达到10.56 kg/667m2时,产量达到最大值183.2 kg/667m2;当施磷量达到5.71 kg/667m2时,产量达到最大值156.9 kg/667m2;最高产量施肥配方氮磷钾配比为10.56∶5.7...     

生物质气化站玉米芯飞灰的特性及其综合利用

作为玉米生产加工过程的农业废弃物,玉米芯的产量巨大,生物质气化工业利用玉米芯原料制备生物质燃气的过程中将产生大量的玉米芯灰。为了全面认识这些废弃玉米芯灰的灰特性及可能的应用,通过激光粒度分析、X射线荧光(X-ray fluorescence,XRF)、X射线衍射(X-ray diffraction,XRD)、热重和差热分析(thermal gravimetric and differential thermal analysis,TG-DTA)、扫描电镜(scanning electron microscopy,SEM)、能谱分析(energy dispersive X-ray,EDX)等方法对其进行深入研究。结果表明:玉米芯灰的粒度较小且分布不均,平均粒径为12.96μm;灰的元素组成中K和Si所占的比重最大;富含K、Ca、S和Cl等元素使玉米芯灰可用作土壤改良剂,而且灰中大量的Si O2和Al2O3使其可以用来制备抗压强度较高的水泥混凝土;灰中存在多种含钾元素的KHCO3、KAl Si O4、KAl Si2O6、KCl和K2SO4等结晶相矿物成分;灰粒的形状极不规则,树枝状的团聚灰渣具有丰富的空隙,易逐级吸附小颗粒,灰粒表面存在大量弱粘结的絮状物,断面多为孔状结构;熔融灰粒表面存在富钾现象,且多以KCl形式存在;飞灰的热解具有分段机制,加热到1 200℃时,其总失重和最大失重速率均随着氧气浓度的升高而增加;氮气中620℃的吸热峰是由KCl熔融吸热所致,而有氧气氛中在630℃处的放热峰则是未燃尽的残碳继续燃烧或有机物分解放热所致。     

Growth and ion accumulation responses of four grass species to salinity

Ion inclusion or ion exclusion are the two main strategies developed by plants to tolerate saline environments. Shoot sodium (Na⁺), potassium (K⁺), and calcium (Ca²⁺) in four perennial grass species (tall wheatgrass, Nuttall's alkaligrass, creeping foxtail, and switchgrass) treated with nutrient solution salinity levels ranging from 2 to 32 dS m^?1 were measured. As the nutrient solution salinity was increased from 2 to 10 dS m^?1, tall wheatgrass, creeping foxtail and Nuttall's alkali grass had increased shoot Na⁺ and decreased Ca²⁺ concentration while maintaining growth suggesting that these species tolerated these changes in shoot ion concentration. In contrast, switchgrass excluded Na⁺ from the shoot and maintained K⁺ and Ca²⁺ concentrations but suffered dramatic shoot dry weight reduction. Thus, the Na⁺ exclusion mechanisms present in switchgrass were less efficient in maintaining growth under the 10 dS m^?1 nutrient solution treatment than the Na⁺ inclusion mechanisms used by the other three species.     

Quantitative Measurement of Organic Carbon in Mine Wastes: Methods Comparison for Inorganic Carbon Removal and Organic Carbon Recovery

The present study aims to evaluate carbon recovery and analytical precision of two methods based on dry combustion for organic carbon (OC) quantification in base metal mine tailings: (1) IC subtraction method (inorganic C(IC) measured and subtracted from total C) and (2) direct OC quantification after acid pretreatment. Results showed IC subtraction method effectively hydrolyzed a range of IC minerals [calcium carbonate (CaCO₃), magnesium carbonate (MgCO₃), dolomite, magnesite, calcite] with satisfactory IC (as CO₂ released) recovery (87–103 percent). In the direct OC quantification method, 5 M hydrochloric acid (HCl) pretreatment resulted in a satisfactory recovery (76–92 percent) of most organic compounds [ethylenediaminetetraacetic acid (EDTA), cellulose, plant litter, and charcoal], except for water-soluble OC (sucrose, 40 percent recovery). The precision of both methods declined when C levels were <5 g kg^?1 with RSD (Relative Standard Deviation) > 10 percent. The OC values in test samples of base metal mine tailings were comparable between the two methods. However, IC subtraction method is not applicable for tailings with low OC levels (<5 g kg^?1) until the precision is substantially improved. Moreover, compared to the IC subtraction method, OC values are significantly lower in direct OC quantification method for tailings with high OC levels.