黑斑蛙养殖模式对稻田土壤肥力、土壤酶活性的影响及其经济效益

对两种黑斑蛙养殖模式即黑斑蛙精养和稻蛙共生进行田间对比试验,旨在比较分析两种模式下的稻田土壤肥力、生物酶活性变化特征,并与水稻单作进行经济效益比较.试验结果表明,与黑斑蛙精养田相比,进行稻—蛙共生的稻田土壤全磷、全钾、碱解氮、速效钾均有所增加,增幅分别为87.5%、28.4%、10.0%、120.7%,而全氮、有效磷、有机质却低于精养田(p<0.05),分别减少了41.6%、66.7%、41.3%;但两种模式的C/N无明显差异.在土壤生物酶活方面,精养田土壤中的中性磷酸酶、脱氢酶和脲酶均明显高于稻蛙田(p<0.05),分别提高43.4%、65.9%、62.6%.水稻单作模式一般利润为1650元/公顷左右,而两种黑斑蛙养殖模式的经济效益显著高于水稻单作,其利润分别为297750、119250元/公顷,三者的产投比分别为1.99、1.60、1.18.从经济效益看,精养模式明显高于稻蛙共生模式,但从养殖管理和风险管控而言,稻蛙共生模式操作更为稳当,且经济效益较水稻单作仍较为可观,可在确保粮食安全前提下,有效提高农民生产积极性,实现保产增收、提质增效.     

汉寿县稻鸭共生绿色生态高效种养模式思考与应用

剖析了汉寿县稻鸭共生绿色生态种养的现状与生产中存在的问题,提出了政府推动促扩张、规范技术保效益、突出主体攻带动和产销对接强效益的创新思路,确保稻鸭生态种养持续扩展.     

3种细菌对小球藻生长和脱氮除磷效率的影响

鉴于水资源日益紧缺且水污染问题日渐加剧的现状,藻菌共生系统作为一种节能环保的污水处理方式,有助于提高污水处理效率。通过人工模拟城市污水,选取3种污水处理中常用细菌地衣芽孢杆菌(Bacillus licheniformis)、枯草芽孢杆菌(Bacillus subtilis)和沼泽红假单胞菌(Rhodopseudomonas palustris)与小球藻构建藻菌共生系统,探究了不同细菌对蛋白核小球藻(Chlorella pyrenoidosa FACHB-5)生长以及污水脱氮除磷效率的影响。结果显示,在3种藻菌共生系统中,地衣芽孢杆菌为小球藻促生长菌,而枯草芽孢杆菌对小球藻生长有抑制作用,沼泽红假单胞菌对小球藻生长无显著影响(P>0.05),且沼泽红假单胞菌的生长受到小球藻的显著抑制(P<0.05)。在3个共生系统中,地衣芽孢杆菌-小球藻共生系统中小球藻生物量最高,第2天水体的总氮和总磷去除率分别达到79.84%和83.48%,显著高于小球藻单独培养试验组(P<0.05)。研究表明,3种藻菌共生系统中,细菌与微藻间的关系具有特异性,应选择适宜的促生菌与微藻共培养,合适的藻菌共生系统可提高水体总氮和总磷的去除率。     

Partitioning of above and below ground costs during phosphate stress in Medicago truncatula

Phosphate (P) availability for plant uptake can limit the yield of natural and agricultural systems. Under P limited conditions, the P-requirement of symbiotic nodules of legumes may exacerbate the P stress of host plants. Adaptations to survive under P stress may vary between different functioning tissues. This study investigated the physiological adaptations to P stress in above and below ground organs of nodulated Medicago truncatula Gaertner. Seedlings were inoculated with Sinorhizobium meliloti in quartz sand and fed nutrient solution with either 0.01?mM or 0.5?mM P concentrations. P-stressed nodulated plants showed compromised photosynthetic responses. Alternative growth allocation during stressed conditions was observed between different organs. The concentration of inorganic P, carbon, and nitrogen were lower during stressed conditions. The above ground tissues scavenged P and lowered their dependence on adenosine-triphosphate required for metabolism. Whereas the below ground tissues recycled phosphate from phosphate monoesters in the cell.     

正红菇的生长环境研究

对正红菇生态环境各因子调查研究表明,具有食、药用价值的正红菇是一种主要与壳斗科林木共生的外生菌根野生真菌,其子实体产生的生态条件为:1～3cm厚枯枝落叶层,林木郁密度0 7以上,土壤富含腐殖质、疏松、通气、保水性好以及40%以上含水量,80%～100%的空气湿度,25～27℃的气温;正红菇每年发生2茬,其菌丝可与直径0 05～0 8cm的活树根结成共生体,干旱、森林火灾、采伐林木严重影响正红菇出菇量。并对其共生体与形态特征进行了综述。     

米糠碱溶性非淀粉多糖的酶解研究

研究了多糖主链降解酶(纤维素酶、木聚糖酶、果胶酶)与多糖侧链降解酶(阿拉伯呋喃糖苷酶、β半乳糖苷酶、乙酰木聚糖酯酶)在降解米糠碱溶性非淀粉多糖过程中的协同作用。用DNS法测定酶解生成的还原性当量作为评价降解效果的指标。研究表明,多糖主链酶分别与α-L阿拉伯木聚糖酶、β-半乳糖苷酶存在协同作用,而与乙酰木聚糖酯酶协同作用不明显。     

Cleaner fishes and shrimp diversity and a re‐evaluation of cleaning symbioses

Cleaning symbiosis has been documented extensively in the marine environment over the past 50 years. We estimate global cleaner diversity comprises 208 fish species from 106 genera representing 36 families and 51 shrimp species from 11 genera representing six families. Cleaning symbiosis as originally defined is amended to highlight communication between client and cleaner as the catalyst for cooperation and to separate cleaning symbiosis from incidental cleaning, which is a separate mutualism preceded by no communication. Moreover, we propose the term ‘dedicated’ to replace ‘obligate’ to describe a committed cleaning lifestyle. Marine cleaner fishes have dominated the cleaning symbiosis literature, with comparatively little focus given to shrimp. The engagement of shrimp in cleaning activities has been considered contentious because there is little empirical evidence. Plasticity exists in the use of ‘cleaner shrimp’ in the current literature, with the potential to cause significant confusion. Indeed, this term has been used incorrectly for the shrimp Infraorder Stenopodidea, involving three families, Stenopodidae, Palaemonidae and Hippolytidae, and to represent all members of Lysmata and Stenopus. Caution is expressed in the use of grey literature and anecdotal observations to generate data on cleaning interactions, due to the presence of species complexes. Interest in cleaning organisms as biological controls in aquaculture is increasing due to their value as an alternative to various chemical ectoparasite controls. Reports of the importance of cleaner organisms in maintaining a healthy reef ecosystem has also been increasing and we review the current biological knowledge on cleaner organisms, highlighting areas that are understudied.     

一株南海柳珊瑚共附生细菌的鉴定及其产活性物质的培养条件优化

对一株南海柳珊瑚共附生微生物菌株(中科院南海海洋研究所,菌种编号00856)进行了分类,并对其所产的生物活性物质特性进行了研究。依据形态及16SrRNA基因序列分析,海洋细菌00856归于芽孢杆菌属(SCSIO 00856)。利用所选择的细菌培养基,在一定的培养条件(28℃,pH 7.0)下,该菌株的次级代谢产物对酿酒酵母、金黄色葡萄球菌有一定程度的抑制活性。同时,在培养6d时,该菌产生的生物活性物质对酿酒酵母抑菌效果最好。利用滤纸片法测定产物活性,以抑菌物质高产为目标,利用正交试验的方法优化了培养基的配比。结果表明,用酿酒酵母作为指示菌,以海盐素26.25g/L、葡萄糖12g/L、酵母浸粉3g/L、磷酸二氢钾3g/L、麦芽浸粉5g/L为培养基发酵培养6d,海洋细菌00856产抑菌活性物质最多。     

Symbiosis between fungi and the hybrid <Emphasis Type="Italic">Cymbidium</Emphasis> and its mycorrhizal microstructures

Tissue culture seedlings of the hybrid Cymbidium were inoculated with six different fungal strains, isolated from the roots of different wild terrestrial orchids. About three months later, the average increment of fresh weight of seedlings inoculated with strains CF1, CF3 and CF12 were respectively 130.26%, 345.65% and 153.34% while that of the control was only 88.40%. The differences between the three treatments and the control were statistically significant （α = 0.05）, highlighting the treatment with strain CF3 （α = 0.01）. In addition, the three strains were obtained by re-isolating. Pelotons, regarded as typical structures of orchid mycorrhiza, were also found in the inoculating roots under a microscope. It seems that the strains of CF1, CF3, and CF12 are associated with the hybrid Cymbidium and supplied the orchid with nutrition. It can be confirmed that the three strains are beneficial for the seedlings of this hybrid.     

毛萼田菁茎瘤菌共生状态下吸氢与固氮关系的研究

不同瘤龄、不同光照和生长周期的毛萼田菁,其茎瘤的吸氢活性和固氮活性均呈正相关。绿色的茎瘤,无论在数量上还是固氮及吸氢活性上为最高。Ａ．ｃｏｕｌｉｎｏｄａｎｓＯＲＳ５７１菌、Ｈｕｐ突变株和含Ｒ．ｊａｐｏｎｉｃｕｍ５．９ｋｂ ｈｕｐ结构基因质粒的转移接２合子回接实验的结果表明,Ａ．ｃａｕｌｉｎｏｄａｎｓ具吸氢活性的菌株对植株生长有益,茎瘤的固氮活性高于根瘤的２倍以上;吸氢活性亦高,转移接合子在无选择压