生物有机类复合调理剂在设施叶菜障碍土壤上的应用效果

针对设施叶菜土壤次生盐渍化和酸化严重,研制生物有机类复合调理剂,并从改良土壤综合性状方面探明其改良机制,为研制生物有机类复合调理剂及其在设施障碍土壤中的应用提供技术支撑和科学依据。以植物源有机肥、生物炭和耐酸耐盐功能微生物为原料研制生物有机类复合调理剂1和调理剂2,市场购买生物有机类调理剂3,并以化肥处理为常规对照,在苏南苋菜和鸡毛菜大棚中进行小区试验。调理剂1和调理剂2降低了土壤铵态氮和硝态氮含量,降低了电导率7.2%~12.9%,并显著增加了产量11.7%~24.5%。调理剂3增加了土壤有效磷和速效钾含量,显著增加电导率9.8%~20.8%,降低了土壤pH值,增加1.8%苋菜产量,但减少3.0%鸡毛菜产量。土壤生物学性状方面,调理剂1和调理剂2能显著增加土壤酶活性和有益微生物数量及微生物活性和多样性,并增加7.8%~30.2%土壤细菌数量,减少8.0%~45.2%土壤真菌数量。调理剂3则对土壤酶活性和微生物数量影响不显著,但降低了微生物活性和多样性。统计分析显示,对于高养分酸化设施叶菜土壤,高生物活性调理剂1和调理剂2主要通过降低盐分含量和改善土壤生物学性状有效缓解连作障碍,进而达到增产。在盐渍化和养分过度积累的设施障碍土壤中,应施用养分适宜、生物活性高的有机类土壤调理剂。

设施蔬菜土壤养分状况分析及综合评价

综合运用主成分分析和模糊数学相结合的方法,分析了苏北地区设施蔬菜主产区土壤养分状况,对其土壤肥力进行综合评价。结果表明,苏北地区平均土壤有机质含量为2.6%,属中等水平,但盐城市土壤有机质含量不足。苏北地区的土壤pH平均值为7.2,但有34.2%土壤呈碱性,2.5%土壤呈酸性,淮安市的土壤碱化现象较为严重。土壤硝态氮、有效磷和速效钾平均含量分别为152.5mg/kg、152.5mg/kg、386.2mg/kg,均存在过量积累现象,但不同城市土壤中3种养分积累程度不同。利用因子分析法确定各土壤指标权重,结合隶属度计算出土壤综合肥力指数,发现苏北地区的土壤综合肥力平均指数为0.5,处于中等水平,有25.2%的土壤综合肥力<0.4,即土壤肥力差。土壤速效钾为苏北地区土壤肥力的主要限制因子。

连续施用有机肥下设施土壤碳氮磷化学计量学特征及其与土壤有效磷的关系

为阐明设施土壤中连续施用有机肥条件下土壤碳氮磷化学计量学特征的动态变化,并探讨碳氮磷化学计量比对土壤磷素有效性的影响,通过定位试验研究连续5季大棚辣椒栽培中不同处理(CK,空白对照;CF,单施化肥;OCF1,有机肥替代49%磷肥;OCF2,有机肥替代63%磷肥;OCF3,有机肥替代73%磷肥)对土壤碳氮磷化学计量比及不同形态磷的影响。结果表明,与单施化肥相比,3个施用有机肥处理均显著增加了土壤全碳、全氮和全磷含量。OCF1处理的土壤碳氮比在5季辣椒栽培中都显著高于CF处理,OCF3处理的土壤碳磷比仅在第5季中显著高于CF处理。不同处理间的土壤氮磷比差异不显著。此外,与CF处理相比,OCF3处理在第1季和第2季显著增加了土壤有效磷含量,在第5季中OCF2处理显著降低了土壤有效磷含量。相关性分析结果表明,土壤全磷含量、无机磷含量及其占比、总碳含量、全氮含量与有效磷含量呈极显著正相关关系(P<0.01),而有机磷占比、碳磷比和氮磷比与有效磷含量呈极显著负相关关系(P<0.01)。结果说明在设施蔬菜栽培中长期施用有机肥替代磷肥可能会降低土壤有效磷含量,其原因可能是提高了土壤的碳磷比,造成土壤中有效磷的生物固持。

农林废弃物堆肥产物复配黄瓜育苗基质配方筛选

以农林废弃物为主要堆肥原料,设置正常通气量[10.0 L/(m^(3)·min)]和低通气量[2.5 L/(m^(3)·min)]2种方式,进行为期5个月的堆肥试验,并将发酵4个月和5个月的堆肥产物分别用于复配制备育苗基质进行黄瓜育苗试验。结果表明,正常通气量堆体最高温度和高温时间均大于低通气量堆体,有机质降解程度更高。发酵5个月后,低通气量堆肥产物中铵态氮、硝态氮、总钾含量分别比正常通气堆肥高68.7%、8.2%、38.3%,总氮、总磷含量分别比正常通气量堆肥低6.7%、15.6%。堆肥产物复配菜园土后的基质pH、电导率(EC值)、总养分含量和速效养分含量比单纯堆肥低,但容重增加。主成分分析结果表明,复配基质中堆肥产物添加比例越高,基质综合性能越好;发酵5个月的堆肥产物复配基质优于发酵4个月堆肥产物复配基质。好氧发酵产物与菜园土按3∶1体积比配比对黄瓜育苗效果较好,可作为其穴盘育苗的推荐配方。降低堆肥通风量制备的堆肥产物可以获得与正常通风水平下的堆肥产物及商品基质同等育苗效果。

贵州寒武纪杷榔动物群的古生态学初探

贵州剑河辣子寨村辣子寨剖面杷榔组的杷榔动物群是近期发现的一个化石丰度较大的产地。目前已发现了海绵动物、刺细胞动物、曳鳃动物、腕足动物、软舌螺动物、节肢动物、棘皮动物、藻类等8大类群的化石代表,计有63属80种。本文依据辣子寨剖面杷榔化石库下化石层的生物组合及各类群的生态特性、埋藏特征,探讨杷榔动物群的生态系及生活环境。杷榔动物群的生物群落,包括了底栖固着、内栖钻孔、表栖游移、漂游和游泳的生物类群,且生物群生活在赤道地区以北开阔海盆的透光区至弱透光区、水域含氧、海底有氧—弱氧、盐分正常、快速沉积事件频发的陆棚较深水环境。其古生态特点为:生物种类丰富,具有滤食、食草、食泥、食肉和食腐的动物;而捕食-被捕食的食物网的关系较为复杂,具有明显的金字塔型的营养结构。

贵州剑河寒武纪杷榔动物群中的海绵化石组合

贵州寒武纪杷榔动物群的海绵动物是近年在剑河辣子寨村发现的新类群。辣子寨剖面的海绵动物组合多样性高,化石保存好。经鉴定有普通海绵纲细丝海绵科的Leptomitus tereticusculus Chen et al.,1989,Leptomitus cf.L.conicus García-Bellido et al.,2007和Paraleptomitellasp.,斗篷海绵科的Choiaellacf.C.ovataZhao and Yang in Yang et al.,2003和Choiasp.;六射海绵纲的Saetaspongiasp.,计有5属6种和一些属种待定的海绵化石。剑河辣子寨村杷榔组海绵类群的发现丰富了杷榔动物群的组成面貌,扩展了寒武纪第四期海绵动物的古地理分布区,增加了寒武纪第四期海绵动物分异演化的信息,为海绵动物分类学、古生态学和埋藏学研究提供了新材料。

贵州寒武纪杷榔组古蠕虫类埋藏特征及意义

贵州剑河寒武纪杷榔组辣子寨剖面含有丰度较高的古蠕虫类化石。化石鉴定为Wronascolex geyiensis,主要保存在三个层位。在对三个层位的岩石、沉积特征、化石成因及埋藏特征探讨分析后,证实W.geyiensis化石保存于快速的沉积事件导致的浊流沉积层内,而化石埋藏的完美程度受到成岩过程中埋藏位置、沉积物中矿物结晶和充填方式的影响,这些后期的成岩、成矿作用对先期形成的化石精细结构产生了直接和间接的破坏作用。本文通过对W.geyiensis化石体上黏土矿物、草莓状黄铁矿、自形–半自形黄铁矿的成因分析后,获得最适合保存软躯体化石的环境应该为缺氧且生物体与孔隙水中的硫酸盐无接触的原地和近原地埋藏条件。

Different effects of isoflurane and sevoflurane on cytotoxicity in primary cortical neurons of rats

Background Isoflurane, a commonly used inhaled anesthetic, induces apoptosis in primary rat cortical neurons of rat in a concentration- and time-dependent manner by an unknown mechanism. We hypothesized that isoflurane induced apoptosis by causing abnormal calcium release from the endoplasmic reticulum （ER） via activation of inositol 1,4,5-trisphosphate （IP3） receptors. Sevoflurane has a reduced ability to disrupt intracellular calcium homeostasis and is a less potent cytotoxic agent. This study examined and compared the cytotoxic effects of isoflurane and sevoflurane on rat primary cortical neurons and their relationship with disruption of intracellular calcium homeostasis and production of reactive oxygen species （ROS）.Methods Primary rat cortical neurons were treated with the equivalent of 1 minimal alveolar concentration （MAC） of isoflurane and sevoflurane for 12 hours. MTT reduction and LDH release assays were performed to evaluate cell viability. Changes of calcium concentration in the cytosolic space, [Ca^2＋]c, and production of ROS were determined after exposing primary rat cortical neurons to isoflurane and sevoflurane. We also determined the effects of IP3 receptor antagonist xestospongin C on isoflurane-induced cytotoxicity and calcium release from the ER in primary rat cortical neurons.Results -Isoflurane at 1 MAC for 12 hours induced cytotoxicity in primary rat corticai neurons, which was also associated with a high and fast elevation of peak [Ca^2＋]c. Xestospongin C significantly ameliorated isoflurane cytotoxicity in primary cortical neurons, as well as inhibited the calcium release from the ER in primary cortical neurons. Isoflurane did not induce significant changes of ROS production in primary rat cortical neurons. Sevoflurane, at equivalent exposure to isoflurane, did not induce similar cytotoxicity or elevation of peak [Ca^2＋]c in primary rat cortical neurons.Conclusion These results suggested that isoflurane induced elevation in [Ca^2＋]c, partially via elevated activity of IP3 receptors, which rendered cells vulnerable to isoflurane neurotoxicity. ROS production was not involved in isoflurane-induced neurotoxicity. Sevoflurane, at an equivalent exposure to isoflurane, did not induce similar elevations of [Ca^2＋]c or neurotoxicity in primary cortical neurons of rat.

Humic-Like Substances from Different Compost Extracts Could Significantly Promote Cucumber Growth

The effects of direct extracts of compost (DEC), aerated fermentation extracts of compost (AFEC) and non-aerated fermentation extracts of compost (NAFEC) on cucumber growth and the action mechanisms were evaluated based on the structure and activity analysis of humic-like substances. AFEC increased cucumber growth most significantly, followed by DEC and NAFEC, which was insignificant compared to the control treatment. Humic-like substances from compost extracts played an important role in promoting cucumber growth. Application of humic-like substances stimulated auxin-like activity and increased chlorophyll content and nitrogen accumulation in plants. The positive auxin-like activity of humic-like substances could be attributed to the relative distribution of special carbon groups, such as those with a large amount of peptidic and carbohydratic groups or with a low content of phenolic groups. In conclusion, the best growth promotion by application of AFEC was mainly attributed to the humic-like substances in the AFEC.

Effects of minimal lipopolysaccharide-instilled lungs on ventilator-induced lung injury in rats

Mechanical ventilation （MV） may aggravate lung injury induced by a variety of injuries, including intratracheal hydrochloric acid instillation, intratracheal lipopolysaccharide （LPS） instillation with or without concurrent saline lavage, intravenous LPS, or intravenous oleic acid. However, the mechanism for this detrimental effect of MV is unclear. The purpose of the present study was to determine the effect of MV on lung injury induced by minimal LPS-instillation and on the LPS receptor CD14 in the lung.