长江流域农业生态研究现状与展望

长江流域农业生态研究现状与展望徐琪（中国科学院南京土壤研究所,２１０００８）ＣｕｒｒｅｎｔＳｉｔｕａｔｉｏｎａｎｄＰｒｏｓｐｅｃｔｏｆＡｇｒｏ－ｅｃｏｓｙｓｔｅｍＲｅｓｅａｒｃｈｉｎｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＢａｓｉｎ．￥ＸｕＱｉ（ＩｎｓｔｉｔｕｔｅｏｆＳｏｉｌＳｃｉｅｎｃｅ,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｎａｎｊｉｎｇ２１０００８）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｒ,１９９３,１２（２）：２５－２６．Ｔｈｅｃｕｒｒｅｎｔｓｉｔｕａｔｉｏｎｏｆａｇｒｏ－ｅｃｏｓｙｓｔｅｍｒｅｓｅａｒｃｈｉｎｔｈｅＹａｎｇｔｚｅＲｉｖｅｒｂａｓｉｎａｒｅｂｒｉｅｆｌｙｉｎｔｒｏｄｕｃｅｄａｎｄｔｈｅｆｕｒｔｈｅｒｍａｉｎｒｅｓｅａｒｃｈｆｉｅｌｄｓａｒｅｐｒｏｐｏｓｅｄｆｒｏｍｔｈｅｖｉｅｗｏｆａｇｒｉｃｕｌｔｕｒａｌｓｕｓｔａｉｎａｂｉｌｉｔｙ．Ｋｅｙｗｏｒｄｓ：ａｇｒｏｅｃｏｓｙｓｔｅｍ,ＹａｎｇｔｚｅＲｉｖｅｒｂａｓｉｎ,ａｇｒｉｃｕｌｔｕｒａｌｓｕｓｔａｉｎａｂｉｌｉｔｙ．１土地资源概况长江流域既是古老农业地区,也具有丰富的土地资源类型,为大农业发展提供了广阔的前景。在生态农业建设中典型甚多,并正在     

草基—鱼塘生态系统中能量转化与经济效益分析

草基－鱼塘生态系统中能量转化与经济效益分析王德建,徐琪,刘元昌（中国科学院南京土壤研究所,２１０００８）Ｇｒａｓｓｄｙｋｅ－ＦｉｓｈｐＯｎｄＥｃｏｓｙｓｔｅｍ──ＩｔｓＥｎｅｒｇｙＣｏｎｖｅｒｓｉｏｎａｎｄＥｃｏｎｏｌｎｉｃＢｅｎｅｆｉｔ￥．ＷａｎｇＤｅｊｉａｎ;ＸｕＱｉ;ＬｉｕＹｕａｎｃｈａｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＳｏｉｌＳｃｉｅｎｃｅ,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｎａｎｊｉｎｓ２１０００８）．ＣｈｉｎｅｓｅＪｏｕｍａｌｏｆＥ－ｃｏｌｅｇｙｌ１９９３,１２（２）：２９－３０．Ｕｓｉｎｇｓｉｍｕｌａｔｉｏｎｔｅｓｔｍｅｔｈｏｄ,ｔｈｅｅｎｅｒｇｙｃｏｎｖｅｒｓｉｏｎｉｎａｇｒａｓｓｄｙｈｅ－ｆｉｓｈｐｏｎｄｅｃｏｓｙｓｔｅｍｉｓｓｔｕｄｉｅｄ,ａｎｄｗｉｔｈａｐｒｏｄｕｃｔｉｖｅｓｙｓｔｅｍａｓｃｏｎｔｒｏｌ,ｔｈｅｅｃｏｎｏｍｉｃｂｅｎｅｆｉｔｏｆｔｈｅｅｃｏｓｙｓｔｅｍｉｓａｎａｌｙｚｅｄ．Ｔｈｅｒｅｓｕｌｔｓｓｈｏｗ：１．ｔｈｅｕｔｉｌｉｚａｔｉｏｎｒａｔｅｏｆｓｏｌａｒｅｎｅｒｇｙｂｙｇｒａｓｓｉｓ０．６％,ａｎｄｔｈｅｃｏｎｖｅｒｓｉｏｎｅｆｆｉｃｉｅｎｃｙｆｒｏｍｇｒａｓｓｔｏｆｉｓｈｉｓ     

湿地农田生态系统的特点及其调节

所谓湿地,系一个笼统的名称,直到目前并没有确切的定义。通常认为凡受地下水与地表水影响的土地均可称为湿地。它又可区分为两大类,即自然湿地与人工湿地,区别在于受不受人为活动干扰及其干扰程度。湿地包括沼泽型土壤、草甸型土壤与稻田土壤,稻田土壤在我国早期的土壤分类系统中也归为湿地族。近年来,国外对湿地研究十分活跃,从已有文献看其概念也欠确切,且因目的不同而有一定出入。例如在W.Z.Mitsh所著《湿地》一书中就引用了如下几种概念: 1.湿地系为浅水或间歇浅水层所淹没的低地,包括有植被着生的浅水湖区。2.水位接近或高于地表的土地,或者由于长期水分饱和形成的湿地,或者是具有水成土过程的土地,包括水成土以及适于水生植物     

太湖地区两种稻麦轮作制中营养元素的循环——Ⅱ.常规稻田生态系统中大量元素的循环状况

本文在太湖流域研究了平原地区三个不同试验点上小麦-水稻和元麦-水稻-水稻两种轮作方式下常规稻田生态系统中氮、磷、钾、钙、镁等五种大量营养元素的循环及表观平衡状况。所考虑的输入途径有施肥、灌溉、降雨、播种及移栽;输出途径有作物收获、田面排水和渗漏淋溶。此外,氮素的输出还包括了氨挥发及硝化与反硝化脱氮。三试验点两种熟制的稻田生态系统中各元素的表观平衡状况基本一致,在土壤养分库中磷、氮有盈余,钾、镁和钙有亏损。     

Evolution of funnel-revolver flowers and ornithophily in nasa (loasaceae)

Floral morphology, distribution, and flower visitors for 60 taxa of Nasa are investigated and compared to molecular trees inferred both from a combined marker analysis (ITS1 and trnL (UAA)) and from a single marker (ITS1). Flowers conform to two different floral types: Firstly, "tilt-revolver flowers", with spreading to reflexed, white to yellow petals and small, brightly coloured floral scales contrasting with the petals and firmly enclosing the nectar (Saccatae and Carunculatae); secondly, "funnel-revolver flowers", with half-erect to erect, orange to red petals and floral scales not contrasting with the petals, or enclosed in the corolla, and nectar freely accessible by funnel-shaped floral scales ( Alatae, Grandiflorae, and N. venezuelensis species group). Phylogenetic analysis shows that "tilt-revolver flowers" represent the plesiomorphic condition by outgroup comparison. The two groups with tilt-revolver flowers in Nasa are not monophyletic ( Saccatae are paraphyletic, Carunculatae are polyphyletic). Most Saccatae fall into two monophyletic assemblages, the N. poissoniana species group and the N. triphylla species group. The remainder of Saccatae group either with Grandiflorae ( N. insignis species group) or with Alatae ( N. laxa species group). The clades retrieved in the molecular analysis contradict the traditional classification, but are congruent with vegetative morphology, details of the flower morphology, and biogeography. "Funnel-revolver flowers" represent the derived condition, but molecular data suggest a convergent development (at least twice independently), since the corresponding species do not constitute a monophyletic group. "Tilt-revolver flowers" are visited and pollinated by bees (especially Colletidae), whereas "funnel-revolver flowers" are mostly visited by hummingbirds. The transition from melittophily to ornithophily may have been the license for the colonization of, and the diversification in, both cloud forest and high Andean habitats.     

Mx is dispensable for interferon-mediated resistance of chicken cells against influenza A virus

The type I interferon (IFN) system plays an important role in antiviral defense against influenza A viruses (FLUAV), which are natural chicken pathogens. Studies of mice identified the Mx1 protein as a key effector molecule of the IFN-induced antiviral state against FLUAV. Chicken Mx genes are highly polymorphic, and recent studies suggested that an Asn/Ser polymorphism at amino acid position 631 determines the antiviral activity of the chicken Mx protein. By employing chicken embryo fibroblasts with defined Mx-631 polymorphisms and retroviral vectors for the expression of Mx isoforms in chicken cells and embryonated eggs, we show here that neither the 631Asn nor the 631Ser variant of chicken Mx was able to confer antiviral protection against several lowly and highly pathogenic FLUAV strains. Using a short interfering RNA (siRNA)-mediated knockdown approach, we noted that the antiviral effect of type I IFN in chicken cells was not dependent on Mx, suggesting that some other IFN-induced factors must contribute to the inhibition of FLUAV in chicken cells. Finally, we found that both isoforms of chicken Mx protein appear to lack GTPase activity, which might explain the observed lack of antiviral activity.     

Phytochemistry and the systematics and ecology of Loasaceae and Gronoviaceae (Loasales)

A screening for iridoid compounds of 78 of 315 species from all major groups in Gronoviaceae and Loasaceae has been carried out. The results were compared to the systematic concepts in the family and distribution and ecology of the taxa. Iridoids are present in at least some species of all genera screened. Some simple, monomeric compounds (e.g., loganin, sweroside) are found in all major groups of the two families and represent the basic iridoid inventory. Other compounds are restricted to certain taxonomic groups: nine-carbon iridoids (e.g., deutzioside) are restricted to Mentzelia (Loasaceae subfam. Mentzelioideae), hetero-oligomeric iridoids (e.g., tricoloroside methyl ester, acerifolioside) are restricted to two small groups in Loasa (Loasa ser. Macrospermae and ser. Floribundae, Loasaceae subfam. Loasoideae), and oleosides (e.g., 10-hydroxyoleoside dimethyl ester) are restricted to the large genus Caiophora sensu Weigend). The distribution of certain iridoid compounds thus confirms some of the generic limits. Iridoid phytochemistry does not correlate with systematic entities above the generic level nor does it in any way correlate with the morphological evolution of taxa. Conversely, the amount and complexity of iridoid compounds present in taxa correlate positively with the aridity of their habitat and the extent of mammalian herbivore pressure.     

试论三峡工程对农业生态系统的影响

本文探讨了三峡工程对长江流域农业生态系统的影响。这些影响可分为2类:(1)淹没土地,移民搬迁,在已脆弱的库区生态环境中又增加了环境压力,属突变性;(2)随着水文水势的改变,可增加中下游地区低洼稻田的沼泽化与潜育化潜在威胁,三角洲地区土壤盐渍亦有加重趋势。为此,需封山育林,保水保土,合理安排农林用地,强化治水改土,以及防治土壤沼泽化潜育化等措施,方能改善流域生态系统,提高土地承载能力。     

细胞因子对鸡胚胎原始生殖细胞（EPGCs）增殖的影响

采用MTT法分别检测mLIF、bFGF、hSCF、hIL-11四种细胞因子协同作用对体外培养的第19、28期鸡EPGCs生长的影响。结果表明：与对照组相比较,19期的EPGCs体外培养72h后, mLIF、hSCF、bFGF、hIL-11对鸡EPGCs的增殖影响显著（P<0.05）。mLIF的最佳作用剂量是10~20ng/ml,hSCF的最佳作用剂量是15~20ng/ml,bFGF的最佳作用剂量是10～20ng/ml。hSCF、bFGF的联合使用优于单因子作用的结果（P<0.05）。单独使用hIL-11时,细胞的增殖情况比其他三因子单独使用的效果较差,但OD均值有随剂量增高而上升的趋势。在与其他因子联合使用的情况下, hIL-11的最佳作用剂量为0.10~0.20ng/ml。