Interactions between bacteria and ectomycorrhizal fungi

Interactions between eight ectomycorrhizal fungi and eight bacteria were tested on five laboratory media and in the rhizoplane of Pinus radiata. Depression of growth of the fungi by the bacteria in laboratory media was dependent on the medium and bore little relation to effects in the rhizoplane. In the rhizoplane, different bacteria could depress, have no effect or even stimulate growth of mycorrhizal fungi. Competition and antagonism are suggested as mechanisms for depression of the fungi. Some bacteria gave protection against the depressive effects of other bacteria. Considerable differences occurred between ectomycorrhizal fungi in their colonization of the rhizoplane in the absence of bacteria and also in their presence. The common mycorrhizal fungi Rhizopogon luteolus and Thelephora terrestris generally colonized roots well but the strain of Pisolithus tinctorius studied colonized poorly. Direct microscopy showed the percentage cover of the root by microorganisms was usually only 10–20%.It is proposed that interactions of ectomycorrhizal fungi with soil organisms are important in determining the successful introduction and persistence of inoculated ectomycorrhizal fungi. Fungi should be selected for compatibility with a wide range of soil microflora as well as efficiency in plant stimulation.     

The penetration of soil by mycelial strands of ectomycorrhizal fungi

Soil factors affecting growth of mycelial strands from ectomycorrhizas into surrounding soil were studied experimentally. Treated soil cores were inserted into root boxes for 4–6 weeks, then infiltrated with gelatin, sectioned, and mycelial strands harvested. Very large differences in mycelial strand growth (measured by weight) occurred between different soils, some soils completely inhibiting growth of strands of the mycorrhizal fungus Rhizopogon luteolus. Compaction of soil reduced mycelial strand penetration greatly e.g. by 80 per cent in one experiment. Soil sterilization ameliorated compaction effects. High soil phosphorus tended to increase strand growth but nitrogen level and Pseudomonas fluorescens. a common soil bacterium, had small or inconsistent effects.     

吉林省西部盐碱地综合开发多情景模拟与水资源效应

[目的] 盐碱地综合开发利用是提高农业生产力、践行大食物观的必然选择。但受限于开发利用模式单一、耗水压力较大,亟待探索多元化治理模式并依据其水资源效应开展优化调控。[方法] 以吉林省西部地区为研究区,采用FLUS模型预测2030年盐碱地资源在自然发展、粮食安全、粮饲综合开发和生态安全4种情景下的开发利用格局,并对不同情景下的产水量变化进行评估。[结果] (1)2000—2020年研究区开发利用盐碱地1 540.18 km²,主要被恢复为草地或开垦为耕地,但其中旱地次生退化风险较高。(2)不同情景下盐碱地开发均以耕地利用为主。粮食安全情景下水田和旱地开垦面积占比分别为67.48%,4.23%。相较于自然发展情景,粮饲综合开发情景下盐碱地恢复为草地的面积增加139.18 km²,生态安全情景下生态用地规模显著提高。(3)至2030年,4种发展情景下研究区产水量较基期均有所下降,生态安全情景下降幅度最大,达到3.71×10⁸ m³。相比之下,粮饲综合开发情景充分保障粮食和饲草生产,同时缓和盐碱地治理所导致的水资源压力。[结论] 松嫩平原盐碱地开发利用应充分考虑粮饲综合开发模式,统筹粮食和饲草供应,协调粮食和生态安全,以大食物观引领国土空间生态修复和退化土地的开发利用。     

人工养殖西伯利亚狍肠道微生物组成的雌雄差异

肠道微生物是一个复杂的生态系统,与宿主的健康、疾病以及其他因素有着密切的关系。目前,关于肠道菌群结构和功能的研究较多,但是对西伯利亚狍肠道菌群的研究还未见报道。西伯利亚狍(Capreolus pygargus)属于反刍动物,有独特的消化特性和微生物群来帮助它们适应高纤维的食物。本研究利用高通量测序技术在Illumina MiSeq平台上对14只狍肠道微生物进行16S rRNA基因分析。结果表明:个体样本中门类组成的差异,雌性个体JY3和雄性个体JY9除Firmicutes,Bacteroidetes,Proteobacteria这3类菌群外,其他门类菌群所占比例都很低。在科水平上,雌性个体中Ruminococcaceae在JY7和JY13肠道内含量相对较少,Bacteroidaceae在JY7,JY10和JY13中含量较高。雄性个体中Ruminococcaceae在JY11和JY14肠道内含量较少,Prevotellaceae在JY4中含量较少。在属水平上,雌性个体特有的菌属为Roseburia,Alloprevotella,Lachnospiraceae_incertae_sedis和Coprococcus;雄性个体特有的菌属为Fusobacterium,Succiniclasticum,Streptococcus和Clostridium sensu stricto。Alpha多样性分析表明,Ace指数范围2128.93—772.98,Chao1指数范围2128.89—785.27,Shannon指数范围5.44—3.78,Simpson指数范围0.07—0.01。在不同物种分类水平上,雌雄狍肠道内的优势菌群有些不同。PCoA(principal co-ordinates analysis)分析显示,狍样本几乎混在一起,没有明显差异。     

ZigBee技术在农林业中的应用研究

设计一个基于ZigBee技术的农林业生产环境监测系统。系统采用太阳能电池供电,利用ZigBee技术将传感器采集到的与农林业生产环境相关的数据通过无线网络传输给上位机。该系统的应用可为农林业环境质量评价、农林业环境质量变化趋势预测提供实时、准确的数据。     

具有中国大豆遗传背景的7S与11S多亚基缺失型大豆新品系的创制

利用我国高油大豆品种东农47与日本引进多亚基缺失型育种材料日B,采用回交、三交的育种方法,综合系谱选择,通过SDS-PAGE技术分析亚基组成,在BC₁、BC₃及三交种F₈群体内,选育到(α+11S groupⅡa)-缺失型、(α′+11S groupⅡa)-缺失型、[(α′+α)+11S groupⅡa、Ⅱb]-缺失型、[(α′+α)+11S groupⅡa]-缺失型、[(α′+α)+11S groupⅡb+X₁X₂]-缺失型、[(α′+α)+11S groupⅡb]-缺失型和(α′+11S groupⅠ、Ⅱa)-缺失型共7种具有中国大豆遗传背景的7S球蛋白α′、α亚基与11S球蛋白groupⅠ(A_1aB_1b,A₂B_1a,A_1bB₂)、groupⅡa(A₄A₅B₃)和groupⅡb(A₃B₄)不同亚基缺失组合新种质。测定优良品系的综合农艺性状及氨基酸组成、含量,结果表明,与对照相比,各种缺失突变体的各种氨基酸组分含量普遍提高,蛋白总量普遍高于轮回亲本,精氨酸含量特别是游离精氨酸的含量大幅提高。其中亚基组成为(α+11S groupⅡa)-缺失型品系G2-2-3的17种氨基酸含量、氨基酸总量、蛋氨酸含量均显著高于轮回亲本东农47,特别是游离精氨酸含量高出7.27mg/g。以上结果表明,7S与11S多亚基缺失型优良品系在有效去除致敏蛋白的同时,可以提高大豆蛋白氨基酸含量, 改善大豆蛋白氨基酸组分配比。各种致敏蛋白缺失型大豆优良新品系的获得,大大丰富了我国蛋白质组分改良育种的种质基础。     

东北地区螽斯总科调查报告

通过近4a的调查,初步摸清了东北地区螽斯总科的种类与分布,包括硕螽科3种、露螽科6种、螽斯科23种、草螽科10种,共计17属42种2亚种。其中:拟寰螽属Paratlanticus为国内新记录属;长白山拟寰螽Pa-ratlanticus palgongensis、对马拟寰螽Paratlanticus tsushimensis、乌苏里拟寰螽Paratlanticus ussuriensis和乌苏里姬螽Metrioptera ussuriana为国内新记录种。并对一些种中存在的问题进行了分析和讨论。     

环氧树脂-水性聚酰胺改性豆粕胶黏剂压制胶合板的研究

本文采用环氧树脂和水性聚酰胺对豆粕进行复合改性制备无醛胶黏剂,对豆粕胶黏剂的性能指标和胶合板的胶合强度进行了研究.通过正交试验得出以下最佳工艺参数:当热压温度为120℃、环氧树脂与水性聚酰胺改性豆粕溶液的质量比为20:80、热压时间600 s时胶合板的胶合强度最高,为0.7628 MPa,达到国家标准GB/T 9846...     

布鲁菌介导细胞自噬的研究进展

布鲁菌是布鲁菌病的病原体,在世界范围内给养殖业带来巨大损失.自噬是细胞的一种代谢方式,细胞在自噬相关基因的调控下清除细胞内病原微生物和吞噬降解受损、衰老细胞器及大分子物质,以维持机体内环境平衡.布鲁菌入侵细胞后,能够诱发细胞自噬,而这一复杂的过程需要很多细胞因子的参与,探究布鲁菌引发的细胞自噬已成为揭示布鲁菌致病机制的...