我国耕地数量变化与保护政策关系的实证分析

以耕地数量的统计数据耕地、保护政策的颁布和实施为基础,借助经济计量学理论以及Eviewes5.1软件,运用协整分析、Granger因果关系检验和脉冲响应等分析方法,分析了改革开放以来我国耕地数量变化与耕地保护政策之间的互动关系。结果显示:耕地数量变化与耕地保护政策之间存在一种长期均衡关系,说明二者之间存在着某种机制在制约着变量的运动,使二者之间短期内的偏离不会太远,长期则会走向均衡;耕地数量变化与耕地保护政策之间存在单向的因果关系,即耕地数量变化与是耕地保护政策的Granger原因,而耕地保护政策不是耕地数量变化的Granger原因;脉冲响应以及方差分解表明,耕地数量变化对耕地保护政策具有较为持续的促进作用,且作用程度随着滞后期的加大而加强;耕地保护政策具有较强的惯性,主要受其自身以前水平的影响,因此耕地保护政策对耕地保护政策的促进作用不太显著。这也从一个侧面佐证了Granger因果检验的结果。因此,应制定长期而非短期的策略,强化耕地保护政策理论研究,加大耕地保护政策的制定、执行和监督力度,这是解决耕地过快减少问题的重要途径。     

Apoptosis of Granulosa Cells: A Review on the Role of MAPK-signalling modules

Recent studies suggest that ovarian follicular atresia is associated with DNA fragmentation and degeneration of granulosa cells, the hallmark of programmed cell death or apoptosis. Apoptosis of granulosa cells play a major role in follicular atresia. These studies have also demonstrated the involvement of tumour suppressors, apoptotic proteins and survival factors. These factors contribute to the developmental decision as to whether the ovarian follicles mature or undergo atresia. However, the precise temporal and molecular events involved in the apoptotic pathways in this process need to be elucidated. The present report summarizes the role of Jun N‐terminal kinase (JNK), p38 mitogen activated protein kinase (p38 MAPK), and extracellular‐signal regulated kinase (ERK)‐signalling module in the regulation of pro‐ and anti‐apoptotic factors of the granulosa cells in regulating follicular atresia. The findings presented here suggest that the loss of tropic hormone support is translated into the attenuation of Raf‐1‐MAPK/ERK kinase (MEK)‐ERK‐signalling pathway of the granulosa cells and this results in the decreased phosphorylation of the pro‐apoptotic BAD.     

山苍子（Litsea cubeba）可培养内生细菌的多样性

【目的】研究山苍子可培养内生细菌的多样性。【方法】利用添加植物组织浸提液的营养琼脂培养基分离山苍子根、茎、叶及果实中的可培养内生细菌,采用16S rDNA序列鉴定法对分离获得的山苍子可培养内生细菌进行鉴定。同一组织内,对16S rDNA序列及形态完全一样的菌株合并冗余,用Clustalx对分离得到的菌株16S rDNA进行排序,构建NeighborJoining系统进化树,并计算Jaccard指数和多样性指数。【结果】 共分离得到52株山苍子可培养内生细菌（根23株、茎8株、叶7株、果实14株）,分属于芽孢杆菌属（Bacillus）、类芽孢杆菌属（Paenibacillus）、Paenochrobactrum、普罗威登斯菌属（Providencia）、假单胞菌属（Pseudomonas）、鞘氨醇单胞菌属（Sphingomonas）和Lysinibacillus共7个属的16个种,其中芽孢杆菌属细菌40株,与Bacillus tequilensis、解淀粉芽孢杆菌（Bacillus amyloliquefaciens）、苏云金芽孢杆菌（Bacillus thuringiensis）3个种最接近的内生细菌占分离细菌株数的69.2%;根及果实中的可培养内生细菌数量及种属均最丰富,其多样性指数高于茎、叶;叶与果实可培养内生细菌的Jaccard指数最高,达0.56,其余均较低。【结论】山苍子可培养内生细菌在植株内部的分布既有种属特异性,又有器官相似性。     

Molecular mapping of greenbug (Schizaphis graminum) resistance gene Rsg1 in barley

The greenbug, Schizaphis graminum (Rondani) is an extremely damaging aphid pest of barley (Hordeum vulgare L.) particularly in the southern Great Plains of the USA. The simply inherited, dominant resistance gene Rsg1 is in all greenbug‐resistant US barley cultivars. In this study, we conducted molecular mapping of Rsg1 using an F_2:3 population derived from a cross between the greenbug‐resistant Post 90*4/R015 and susceptible CI2260 inbred lines. Segregation of host responses to greenbug biotype E infestation confirmed that a single dominant gene is responsible for greenbug resistance in Post 90*4/R015. Simple sequence repeat (SSR) markers evenly distributed along the seven barley chromosomes were employed for the construction of a framework genetic map. Linkage analysis placed the Rsg1 locus in the long arm of chromosome 3H (3HL) flanked by SSR markers Bmag0877 and GBM1420 that were 35 cM apart. Polymorphic single‐nucleotide polymorphism (SNP) markers in 3HL were identified from an Illumina GoldenGate SNP assay and used for targeted mapping to locate Rsg1 to an 8.4‐cM interval. Comparative analysis identified syntenic genomic regions in Brachypodium distachyon chromosome 2, in which 37 putative genes were annotated including a NB‐LRR‐type resistance gene homologue that may be a potential candidate gene for the Rsg1 locus of barley. Results from this study offer a starting point for fine mapping and cloning of this aphid resistance gene in barley.     

Enzymological,histological, and serum biomarker responses of snubnose pompano on complete replacement of fishmeal using cottonseed meal supplemented with lysine and methionine in the diet

Fish Physiology and Biochemistry - In a feeding experiment, cottonseed meal (CSM) was used to replace fishmeal (FM) in the diet of snubnose pompano, Trachinotus blochii, supplemented with lysine...     

四种植物生长调节剂对玫瑰香葡萄无核化及果实品质的影响

【目的】用不同浓度及配比的植物生长调节剂对玫瑰香葡萄进行无核化处理,研究植物生长调节剂对玫瑰香葡萄无核化及果实品质的影响,为广西玫瑰香葡萄生产提供有效的无核化处理技术。【方法】以4种不同浓度、配比的植物生长调节剂赤霉素（GA3）、吡效隆（CPPU）、脱落酸（ABA）和氯毗脲（KT-30）对玫瑰香葡萄进行无核化处理,试验共设7个植物生长调节剂处理,以清水为对照。选取长势一致的花序,于花前2d对花穗进行第1次浸泡处理,15d后再浸泡一次。葡萄成熟后测定单果重、颗粒大小、果形指数、果实硬度、无核率、可溶性固形物含量等指标。【结果】7个植物生长调节剂处理均不同程度地提高了玫瑰香葡萄的无核率,其中以处理1的效果最好,果实无核率达86．0％;7个植物生长调节剂处理均能获得与常规有核栽培大小及品质基本一致的果实。【结论】生产上宜在玫瑰香葡萄开花前2d用20mg／LGA,处理花穗,15d后再用10mg／LGA,＋2mg／LKT-30＋10mg／LABA处理一次,能获得与常规有核栽培大小及品质基本一致的无核化果实。     

Immunomodulation and interferon gamma gene expression in sutchi cat fish,Pangasianodon hypophthalmus: effect of dietary fucoidan rich seaweed extract (FRSE) on pre and post challenge period

A 45‐days feeding trial was conducted to study the immunomodulatory effect and interferon gamma gene expression of dietary fucoidan rich seaweed extract (FRSE) from Sargassum wightii on Pangasianodon hypophthalmus fingerlings. One hundred and eighty fingerlings were distributed into six experimental groups in triplicates. Each group was stocked with 10 fish and fed to satiation with iso‐nitrogenous (34.96 ± 0.09–35.18 ± 0.03 CP%) and iso‐caloric (368.65 ± 0.86–375.09 ± 0.26 Kcal/100 g) purified diets containing either 0% FRSE (control), 1% FRSE (TF₁), 2% FRSE (TF₂), 3% FRSE (TF₃), 3% seaweed powder (TS₃) or 6% seaweed powder (TS₆) in the feed. After feeding trial the experimental fish were challenged with Aeromonas hydrophila. Immunological parameters like respiratory burst activity, lysozyme activity, phagocytic activity and total leukocyte count (TLC) were increased with the increasing level of dietary FRSE, whereas serum Albumin/Globulin (A/G) ratio and blood glucose level exhibited decreasing trend (P < 0.05). Increased TLC, blood glucose level, respiratory burst activity, serum A/G ratio, lysozyme and phagocytic activities were recorded during the post‐challenge period. Maximum expression of interferon gamma (IFN‐γ) gene was recorded in FRSE fed groups than the control group both in pre and post challenge condition. After challenged with A. hydrophila the highest survival was observed in TF₂ and TF₃ groups whereas lowest survival was observed in the control group. Hence, dietary supplementation of FRSE at an optimum level of 2% reduced the stress and improved the immune status of P. hypophthalmus fingerlings.