Das kleine Gr?serbuch

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Das kleine Gräserbuch

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Hauptprobleme der forstlichen Entomologie in Dänemark (mit besonderer Berücksichtigung der Verhältnisse seit 1923)

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Untersuchungen zur Koloniegründung der PharaoameiseMonomorium pharaonis (L.)

Zusammenfassung Die Koloniegründung der Pharaoameise,Monomorium pharaonis, wurde untersucht. Erfolgreich waren Ansätze von begatteten Jungweibchen mit (1) Arbeiterinnen und Brut, mit (2) Arbeiterinnen allein und (3) mit Brut allein. Einzelne begattete Weibchen isoliert zogen aus eigenen Eiern wenige kleine Arbeiterinnen auf, waren aber zur Grü ndung einer dauerhaften Kolonie nicht fähig.Versuche mit unbegatteten Weibchen waren erfolglos, obwohl in einigen Fällen Männchen produziert wurden.Begattete und unbegattete Weibchen beginnen 9 bis 14 Tage nach dem Schlüpfen mit der Eiablage. Beide nehmen Nahrung auf, tragen Futter ein und pflegen Brut.Die normale Form der Koloniegründung ist sicher die Abspaltung von Tochtervölkern aus der polygynen Mutterkolonie. Das Verhalten der begatteten Weibchen deutet jedoch auf eine ursprünglich selbständige Koloniegründung durch einzelne Weibchen unter Nahrungssuche hin.

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Summary Colony foundation of Pharaoh's Ant,Monomorium pharaonis, was investigated. Experiments with (1) fertilized young females, workers and brood, (2) young females and workers, and (3) young females and brood were successful. Isolated fertilized females bred some small workers out of their eggs, but they were unable to start an established colony.Attempts with unfertilized females were unsuccessful, although in some cases males were produced.Fertilized and unfertilized young females start egg laying 9–14 days after eclosion. They both take up food.Foraging, food storage and efficient brood tending could be observed. Surely the normal type of foundation is the splitting of daughter colonies from a polygynous mother colony.The behaviour of our fertilized females however indicates an earlier independant colony foundation by isolated queens, which had to forage for their brood.

     

Analysis of Competitive Ability among Clones of the Palisade Grass, Brachiaria brizantha (Hochst. Ex. A. Rich.) Stapf.

Four clones of palisade grass, Brachiaria brizantha (Hochst. Ex. A. Rich.) Stapf., were studied in a diallel competition trial to investigate their competitive relationship in clonal mixtures. Clone X associate interactions were observed for plant height, number of tillers per plant and dry matter yield per plant. Both general and specific competitive abilities were observed for tiller number and dry matter yield. Clone X associate interaction for plant height was mainly due to the specific competitive ability of individual combinations. The most competitive clone observed was CIAT 6387. Competitive abilities of local clones were low compared to the imported clones. Local clones (RU 127 and RU 139) yielded more than imported clones (CIAT 6387 and PI 292185) under low competitive stresses. General and specific competitive abilities should be taken into consideration when mixing clones of palisade grass.     

The effect of lupins as compared with peas and oats on the yield of the subsequent winter barley crop

New high yielding early maturing cultivars of lupins have been introduced in north-west Europe as grain protein crops in crop rotations. This paper reports on a comparative study of lupins with peas and oats, and of their effect on yield of subsequent winter barley crops. These crops were given five levels of N under irrigated and non-irrigated conditions on sand and loam. Under rain fed conditions the grain yield of pea, oat and lupin varied between 24–36, 34–53 and 18–37 hkg DM ha⁻¹, respectively. Supplemental irrigation raised grain yield of oat to 50–60 hkg DM ha⁻¹, while grain yield in pea was not affected and grain yield in lupin in most cases decreased due to gray mould attack and excessive vegetative growth in the indeterminate lupin variety. Under rain fed conditions, the grain nitrogen content of pea, oat and lupin varied between 137–172, 61–80 and 189–226 kg N ha⁻¹, respectively, and was significantly higher in lupin as compared with pea. On sandy soil, similar low-root densities were found for pea, oat and lupin below 30 cm depth. On sand, at final harvest the residual soil-N of lupin and pea, as measured in a subsequent winter barley crop not supplied with N fertilizer, was 15 and 8–10 kg N ha⁻¹ higher than in winter barley following oat, respectively. The nature of the probably more N-root residues of lupin is discussed. On loam, the residual N of lupin and pea was similar, 18–27 kg N ha⁻¹. On sand, under rain fed conditions preceding lupin and pea as compared with oat, increased the barley grain yield at zero N-application 77 and 49%, respectively; the effect of lupin was significantly higher than that of pea until the highest N-level 120 kg N-application ha⁻¹. On loam under rain fed conditions preceding lupin and pea increased the barley grain yield at zero N-application by 36 and 62%, respectively, as compared with oat; at N-application>60 kg N ha⁻¹ the grain yield was similar after all three crops. For both soil types the same level of effect was found under irrigated conditions. Conclusions: Supplemental irrigation might result in lower grain yield in lupin due to gray mould attack and excessive growth if indeterminate lupin varieties are used. Grain nitrogen yield of lupin is significantly higher than that of pea. On sand, the effect of lupin on the subsequent winter barley grain yield is significantly higher than that of pea, probably due to greater N-root nitrogen residues. On loam, lupin and pea have similar effects on the subsequent winter barley crop.     

近35年苏南典型地区的城镇扩展动态研究——以1966～2001年常熟市为例

利用常熟市不同时期 (1 966、1 984、1 992、1 999、2 0 0 0、2 0 0 1年 )、不同类型卫星遥感影像 (Corona、TM、SPOT、ETM )进行多波段合成 ,图像增强处理与精校正 ,建立不同影像城镇用地解译标志 ,通过人机交互判读 ,获得不同时期的各乡镇城镇用地矢量图的方法。统计出 35年来常熟市城镇建设用地扩大近 6 .4倍。城镇扩展空间上受到地貌条件和城市经济水平以及政策决策影响 ,城镇多数沿河流或交通线方向扩展 ,各城镇间扩展数量和相对速率有明显差异 ,且存在一定地理分布规律。结合社会经济的统计资料 ,分析发现城镇扩展与不断增加的城镇人口、GDP极显著相关 ,各乡镇单位城镇面积创造的GDP有较大的差异。     

Effects of lactoferrin, phytic acid, and EDTA on oxidation in two food emulsions enriched with long-chain polyunsaturated fatty acids

The influence of the addition of metal chelators on oxidative stability was studied in a milk drink and in a mayonnaise system containing highly polyunsaturated lipids. Milk drinks containing 5% (w/w) of specific structured lipid were supplemented with lactoferrin (6-24 muM) and stored at 2 degrees C for up to 9 weeks. Mayonnaise samples with 16% fish oil and 64% rapeseed oil (w/w) were supplemented with either lactoferrin (8-32 muM), phytic acid (16-124 muM), or EDTA (16-64 muM) and were stored at 20 degrees C for up to 4 weeks. The effect of the metal chelators was evaluated by determination of peroxide values, secondary volatile oxidation products, and sensory analysis. Lactoferrin reduced the oxidation when added in concentrations of 12 muM in the milk drink and 8 muM in the mayonnaise, whereas it was a prooxidant at higher concentrations in both systems. In mayonnaise, EDTA was an effective metal chelator even at 16 muM, whereas phytic acid did not exert a distinct protective effect against oxidation. The differences in the equimolar effects of the metal chelators are proposed to be due to differences in their binding constants to iron and their different stabilities toward heat and low pH.     

Influence of liquid cattle manure on reduction processes in soil

Summary Reduction processes in cultivated soil during the decomposition of liquid cattle manure were studied in laboratory experiments. Anoxic slurries of soil and manure in different proportions or alone were followed over 5 weeks. Upon NO _inf3 ^sup- depletion, ferrous Fe appeared in solution in soil-manure slurries. Sulfide levels were generally low in the presence of both soil and manure, probably because of precipitation by Fe²⁺; Fe thereby counteracted the production of free hydrogen sulfide. Methane formation was the quantitatively most important electron sink under prolonged anoxic conditions. When extra sulfate was added to soil-manure slurries, the concentration of Fe²⁺ remained low and less methane was produced. The detection of Fe²⁺ was examined in a model system with a gel-stabilized soil-manure mixture sandwiched between two soil phases with a water content near field capacity. Large methodological problems made it impossible to quantify Fe²⁺ in this oxic-anoxic environment, but the results indicated that reducing conditions were maintained in the manure-saturated zone for the 20-day period of this experiment.