作物残茬与生物篱组合对减轻土壤风蚀的作用

为了探究中国北方农牧交错带冬春风蚀季节生物篱与作物残茬组合对间作裸露秋翻地的防护作用,采用风蚀圈和野外移动式风洞试验的方法对研究区土壤风蚀情况进行监测,利用PC-3型自动气象站进行风速测定。结果表明,油葵秆生物篱减小了间作裸地近地面风速,提高了地表粗糙度;从防风蚀效果看草谷子茬优于油葵秆生物篱;在距油葵秆生物篱或草谷子茬下风向裸地不同位置处,土壤风蚀量基本呈先增加后减小的单峰曲线变化趋势,在4 m左右土壤风蚀量最大,在篱和茬的双重保护下,距茬5 m处发生了风积现象;土壤风蚀量降低率基本呈“V”字型分布;土壤风蚀模数随风速增大而增加,在生物篱的保护下5～15 m/s风速时土壤风蚀降低率为5.03%～20.53%。因此,油葵秆生物篱具有防风蚀作用,而且与草谷子残茬组合对间作裸地会起到更好的固土防蚀作用。     

黑龙江林业的发展应该关注森林碳汇问题

森林生态系统在全球碳循环与平衡中具有极为重要的和不可替代的地位和作用,随着《京都议定书》正式生效,森林碳汇问题已经越来越受到世界各国的重视。黑龙江省森林资源丰富,是我国最主要的林区,巨大的“碳汇”既具有重要的生态功能,也蕴藏着潜在的巨大经济利益,因此,研究我省应对《京都议定书》生效、开展森林碳汇项目的对策研究是极为必要的。     

不同沙土配比对约书亚树幼苗生理特征的影响

为了确定适宜培育约书亚树幼苗的沙土配比条件,以获得更适应恶劣、干旱环境的壮苗,在温室环境下,利用人工配比栽培土壤培育约书亚树幼苗,并利用LI-6400型光合仪测定2年生幼苗的净光合速率(Pn)、蒸腾速率(Tr)及其环境因子,同时测定幼苗体内渗透调节物质及酶活性指标,研究不同沙土配比对约书亚树幼苗生理特征的影响.结果表明:不同沙土配比对约书亚树幼苗的光合作用及渗透调节物质影响显著,但对幼苗抗氧化酶活性的影响不大.随着土壤环境的旱化,幼苗净光舍速率降低,水分利用效率升高.较其它处理,沙土配比为5:5左右的幼苗水分利用率最高(7.366 μmol·m-2·s-1),该处理幼苗体内脯氨酸的质量分数(4.886 μg·g-1)及可溶性蛋白质的质量分数(15.554 mg·g-1)均较高,分别为最低值的2.8、1.2倍.除抗氧化酶CAT活性随配比土壤中沙量的增加呈递减趋势外,SOD、POD、APX、CR活性差异不显著.     

公众参与农村闲置宅基地整理的研究综述

农村闲置宅基地整理是我国土地整理中的重要组成部分,有效的公众参与可以使农村闲置宅基地整理成为真正的"民心工程"。文章分析了以德国和荷兰为代表的国外土地整理中公众参与的研究进展,并与我国公众参与农村闲置宅基地整理的现状进行了对比,针对我国公众参与在农村闲置宅基地整理的方式和法律保障等方面的问题提出了建议。     

俄罗斯森林资源与木材生产分析

根据俄罗斯森林资源与木材生产发展状况, 探讨了俄罗斯森林资源的特点, 总结了俄罗斯木材生产面临的主要问题, 提出了俄罗斯林产品的品种和产量走势, 分析了俄罗斯森工行业和木材生产的发展机遇, 展望了中俄森林资源合作开发与林产品贸易和林业双边合作的发展前景。     

The dynamics of bacterial community in a polyculture aquaculture system of Penaeus chinensis,Rhopilema esculenta and Sinonovacula constricta

Polyculture with Chinese shrimp Penaeus chinensis, jellyfish Rhopilema esculenta and razor clam Sinonovacula constricta (S.J.R) is a common aquaculture system in Dandong, China. Investigation on the composition and function of microbial communities and their relationship with environmental factors in aquaculture systems have crucial implications. Therefore, the sequencing of 16S rRNA gene was applied to profile the bacterial community composition of water and sediment in S.J.R polyculture system in the present study. Proteobacteria was the dominant phylum in S.J.R polyculture ponds following with Actinobacteria and Bacteroidetes in water; in contrast, more diverse phyla were detected in sediments. Water temperature, pH and dissolved oxygen were determined the bacterial community composition in the S.J.R polyculture systems. Specially, Planktomarina, PS1 clade, Candidatus Aquiluna and Fibrobacteres, which can resist the phytoplankton blooms or degrade the cellulose, were more abundant in water at the early stage of cultivation in the S.J.R polyculture system. Moreover, the functions of bacterial communities in water were mainly associated with cell communication mediated, while the functions related to basal metabolism were enriched in sediments. The findings of this study allowed us to better understand the bacterial community in the S.J.R polyculture system and accumulated data for the improvement of cultural management.     

基于GIS的鲁东南典型丘陵平原区农田土壤养分空间变异特征及影响因素研究

以鲁东南丘陵平原区的某镇为例,利用采集的200个农田表层土壤样点数据,运用地统计学方法研究了土壤中有机质(SOM)、全氮(TN)、碱解氮(AN)、速效磷(AP)和速效钾(AK)含量的空间变异特征及其影响因素.结果表明:SOM、TN、AN、AP和AK的平均含量分别为13.52g/kg、0.75g/kg、87.27mg/k...     

dusp1敲降对低温诱导斑马鱼ZF4细胞凋亡的作用

为了研究双特异性磷酸酶(dual-specificity phosphatase 1,dusp1)基因与鱼类低温诱导的细胞凋亡之间的关系,本研究经Eco RI和Age1酶切构建plko.1-dusp1-sh RNA1,plko.1-dusp1-shRNA2,plko.1-negative control(nc),plko.1-EGFP的重组质粒,并分别与慢病毒包装质粒pCMV-DR8.9.1、pCMV-VSVG共同转染至293T细胞中,经293T细胞包装的病毒,感染斑马鱼(Danio rerio)胚胎成纤维样细胞(zebrafish embryos fibroblast like cell line,ZF4),RT-PCR检测表明dusp1成功被敲降。经嘌呤霉素筛选获得稳定表达细胞系,将细胞于28℃培养(正常对照组)或经10℃低温处理10 d,使用annexin V-FITC/Propidium lodide(PI)双色标记流式细胞术检测ZF4细胞凋亡情况。结果显示:低温胁迫下dusp1敲降的细胞凋亡(dusp1-shRNA1敲降,dusp1-kd1;dusp1-shRNA2敲降,dusp1-kd2)比例较nc组显著上调,其中早期凋亡和晚期凋亡细胞比例dusp1-kd1显著高于nc组,并且dusp1-kd1活细胞数显著低于nc组(P0.05),进一步证明dusp1参与鱼类冷应激过程,并在低温情况下保护细胞。该研究为后期对斑马鱼细胞低温胁迫实验奠定了基础,其中dusp1基因沉默型斑马鱼细胞在10℃低温处理10 d凋亡数显著大于对照组,证明dusp1在细胞凋亡信号通路中起到重要调控作用,为低温下研究斑马鱼基因的分子机制提供新的思路。     

Replacement of fish meal by meat and bone meal in diets for large yellow croaker, Pseudosciaena crocea

A growth experiment was conducted to investigate the effects of replacement of fish meal (FM) by meat and bone meal (MBM) in diets on the growth and body composition of large yellow croaker (Pseudosciaena crocea). Six isonitrogenous (43% crude protein) and isoenergetic (20 kJ g^− 1) diets replacing 0, 15, 30, 45, 60 and 75% FM protein by MBM protein were formulated. Each diet was randomly allocated to triplicate groups of fish in sea floating cages (1.0 × 1.0 × 1.5 m), and each cage was stocked with 180 fish (initial average weight of 1.88 ± 0.02 g). Fish were fed twice daily (05:00 and 17:30) to apparent satiation for 8 weeks. The water temperature ranged from 26.5 to 32.5 °C, salinity from 32 to 36‰, and dissolved oxygen content was approximately 7 mg l^− 1 during the experimental period. Survival decreased with increasing dietary MBM and the survival in the fish fed the diet with 75% protein from MBM was significantly lower than other groups (P < 0.05). There were no significant differences in specific growth rate (SGR) among the fish fed the diets with 0 (the control group), 15, 30 and 45% protein from MBM. However, SGR in the fish fed the diets with 60 and 75% protein from MBM were significantly lower than other groups (P < 0.05). No significant differences in feeding rate were observed among dietary treatments. The digestibility experiment showed that the apparent digestibility coefficients (ADC) of dry matter, protein, lipid and energy of MBM were significantly lower compared with those of FM (P < 0.05). Essential amino acid index was found to be correlated positively with SGR in the present study, suggesting that essential amino acid balance was important. Body composition analysis showed that the carcass protein and essential amino acids were not significantly affected by dietary MBM. The lipid and n-3 highly unsaturated fatty acid (n-3 HUFA) in fish muscle, however, significantly decreased with increasing dietary MBM. These results showed that 45% of FM protein could be replaced by MBM protein in diets of large yellow croaker without significantly reducing growth. It was suggested that the reduced growth with higher MBM was due to lower digestibility and imbalance of essential amino acids.     

北京市土壤侵蚀监测方法探讨

 为了科学定量评价北京市土壤侵蚀状况,通过北京市地面水土流失监测网络,开展水土流失定点观测,研究北京市土壤侵蚀监测的评价方法。结果表明：利用大量实测资料,基于美国通用土壤流失方程建立的北京土壤流失方程,可以作为北京市土壤侵蚀调查的模型工具;基T GIS和降雨侵蚀力模型的年度土壤侵蚀量推算方法,可作为从小区尺度转换到区域尺度的一种方法;由于网格法没有考虑水土保持措施因子,调查得到的土壤侵蚀量结果比采用抽样调查法得到的结果偏大。北京市土壤侵蚀监测方法的研究可为区域水土流失定量评价和动态监测提供借鉴作用。