Einfluß von Stickstoff- und Cytokiningaben auf die Entwicklung des Fahnenblattes und der Karyopsen von Weizen

Influence of nitrogen and cytokinin applications on the development of flag leaves and grains of wheat In two experiments spring wheat cv. Solo was grown in hydroculture under greenhouse conditions. The influence of cytokinin applications during grain filling period (Cy: 0 – 100 μg BA/l nutrient solition) combined with different nitrogen supply (N: 0, 0.25, 0.50 and 4.0/1.3 mMol/l) was studied in regard to the development of flag leaves and grains. As to flag leaf, only N was capable to increase specific fresh and dry matter and delay the decrease during development. Similar changes in the chlorophyll content, photosynthesis and N-content of leaves and grains, resp., could be induced by either N or Cy. Grain growth and grain N-content was favoured by N, with the first effect becoming visible early and the second late in the grain filling period. At maturity Cy gave the same effects, but time course was slightly modified. At high doses of N (4.0/1.3 mMol/l) Cy-applications reduced chlorophyll content, photosynthesis and N-content of leaves and grains. This gave rise to the conclusion that cytokinins limit the corresponding physiological processes only if nitrogen nutrition is low.     

Der Einfluß der Expositionszeit auf die Höhe der Bodenatmung bei Anwendung der Lundegardhmethode

The influence of exposure time on the magnitude of soil respiration under employment of the Lundegardh-procedure To assess the role of carbon-rich soils under a potential climate change much more data are needed then currently available. These have to be collected also under conditions, where only limited technical and personal resources are available. Therefore the easy to be accomplished Lundegardh-procedure, which is accepted as a standard procedure for exposure times up to 24 hours (Anderson, 1982), was tested for its suitability to longer periods of exposure. For this purpose six Lundegardh-traps were installed on seven consecutive days (treatment B), and the means of the six repetitions added to a weekly value. In the immediate vicinity to the former, six Lundegardh-traps were installed for periods from one to seven days (treatment A) This was done during the warm season as well as in the winter. The comparison of the treatments A and B revealed a linear correlation, which allows to substitute cumulated daily values by values of traps, that have been installed for several days. However, the “chamber-effect”, an overestimation of respiration by the traps installed for more than 24 hours found by Tesarova and Gloser (1976) has to be considered. In the summer, the same degree of overestimation (16%) was found as reported by Tesarova and Gloser (1976). In the winter, far lower absolute values and therefore higher statistical importance of extremes led to an overestimation of 46%.     

Einfluß langjähriger Düngung mit verschiedenen N-Formen auf die Phosphat-Dynamik einer Ackerbraunerde

Influence of long-term application of different nitrogen sources on the dynamics of phosphate in an arable brown earth In a long-term field experiment parameters of the soil phosphate status were determined after 53 years. Soil characteristics of the arable brown earth are: sandy silt loam; pH 5,9–6,6; total carbon 0,9%; CEC 13–15 meq/100 g soil; effective field capacity 160 mm unto 150 cm. The following results were obtained: Total P content was slightly higher in the plots without mineral N and with farm manure (90 and 93 mg P/100 g soil resp.) than in the plots with mineral N supply (Ø 85 mg P/100 g soil). Application of farm yard manure and ammonium sulfate caused higher proportions of ?Fe and Al phosphates”? (56–57% of inorganic phosphate) whereas calcium cyanamide, calcium nitrate and ammonium sulfate with annual liming led to higher a content of Ca-phosphate (52–56% of inorganic phosphate). When pH was brought to 6,5 by liming, P uptake of rye grass and green oats/green rape-seed in a pot experiment depended on the soil content of ?Fe- and Al-phosphates”?. Without liming, P uptake was lower in the plot with ammonium sulfate, however, in the calcium cyanamide plot P uptake was higher than expected from the content of ?Fe- and Al-phosphate”?.     

Der Einfluß langjähriger Düngungsmaßnahmen auf die Dynamik der Bodenstruktur

The influence of a long term fertilizer experiment on the dynamic of soil structure In a long term manurial experiment at Dikopshof the dynamic of the structure of a Luvisol from loess during the growing seasons 1981 and 1982 was investigated. Farmyard manure effected the greatest variations in pore volume, amount of pores > 50 μm, air and water permeability, aggregate stability and dehydrogenase activity. Higher amounts of mineral fertilizer, that is additional mineral fertilization equivalent to the mineral contents of farmyard manure, could change the soil structure only for a short period. The yield of winter wheat was in close relation to the pore volume, the amount of pores > 50 μm and the dehydrogenase activity of the topsoil.     

Untersuchungen zum Einfluß des Kinetins,des Cycloheximids und des Chloramphenicols auf die lösliche Proteinfraktion von Karottengewebekulturen

Influence of kinetin, cycloheximide and chloramphenicol on soluble protein of carrot tissue cultures An application of chloramphenicol indicated that the influence of kinetin on cell division activity depends on the synthesis of proteins in cell organelles. Concurrently with the application of chloramphenicol an accumulation of proteins with relatively high electrophoretic mobility, synthesized in the cytoplasm, was observed. These protein components are preferentially synthesized after kinetin application. The influence of cycloheximide seems to be directed to the action mechanisms of IAA and inosit in the explants.     

Vergleich deutscher und schweizer Regensimulatoren - Einfluß der Regeneigenschaften auf die Bodenoberflächenrauhigkeit

Comparison of German and Swiss Rainfall Simulators - Influence of Rainfall Characteristics on Soil Surface Roughness Six different field rainfall simulators were compared. Soil surface roughness was tested by a simple field method before and after rainfall simulation. Preparation of the test site with a rotary cultivator inadvertently entailed spatial variability of roughness and aggregate size. Thus, the plots with finer seedbed showed higher runoff and soil loss. The relative decrease of roughness could best be correlated with the total kinetic energy as well as with the R factor of the different simulators (r = 0.87 resp. 0.91). Thus, the degree of soil surface leveling was shown to be due to the rainfall characteristics of the different simulator types. However, there was no relation between change of soil surface roughness and runoff. The relative classification of the kinetic energy of the rainfall simulators explained the leveling of the soil surface better than the classifications previously used in many studies (r = 0.91 as against r = 0.73).     

Einfluß der Frucht auf Photosynthese und Atmung

Fruit Effect on Photosynthesis and Respiration Several investigations about fruit effects on photosynthesis and respiration, mainly of Citrus madurensis (Lour.) and Solanum melongena (L) plants are reviewed. Fruiting plants had higher photosynthetic rates (mg CO₂ · dm^?2 · h^?1) than non fruiting ones, particularly during stages of most intensive fruit growth. The photosynthetic rates could be stimulated by increasing fruit temperatures. No differences in dark respiration rates of fruiting and non fruiting plants were observed. However photorespiration was considerably higher in non fruiting plants as compared to fruiting ones. Leaves of non fruiting plants accumulated more sugars and starch in the leaves during the light periods than fruiting ones. The gaseous diffusive resistance of leaves was higher in non fruiting as compared to fruiting ones. The higher photosynthetic efficiency of fruiting plants is probably controlled by several mechanisms, some of which were discussed in the paper.     

Einfluß der Fließstreckenlänge auf die Bodenumlagerung innerhalb einer erosionsgeschützten Kleinparzelle

Dependence of erosion from flow length within an erosion-protected plot On an Udalf derived from loess different micro-reliefs were formed to reduce erosion. Their effects on the spatial distribution of sand contents on bare soil after one vegetation period are described. At first erosion caused residuals of sand on unflooded areas and corresponding accumulation of finest material on flooded ones. Beds without flow barriers showed reduced clay and silt contents in the upper layer of about 2 mm. On beds with small dams there were no soil losses from the catchment areas between these flow barriers visible. Secondly the enriched sand was moved, too. This occured widely on flat beds. Within catchment areas there were only very small deposits of removed sand in front of the dams. In conclusion: Within the limits of a chosen risk, artificial microreliefs reduce completely erosion damages.     

Einfluß langjähriger Düngung mit verschiedenen Phosphatdüngerformen auf die Phosphatverfügbarkeit in der Rhizosphäre von Raps

Influence of long-term application of different P-fertilizers on phosphate availability in the rhizosphere of rape The residual P effect was investigated in soils from a 10 years' lasting field trial (North of Hessia, Alfisol-Udalf, pH 5.7) in which different P-fertilizer types had been applied with a rate of 111 kg P₂O₅ ha^?1 a^?1. Soil analysis showed that basic slag phosphate had increased the content of CAL-, H₂O- and EUF extractable P in the soil to a higher extent than Novaphos (partially acidulated phosphate rock) or Hyperphos (phosphate rock). In the latter treatment the highest content of DL soluble P was found as compared with the other P-fertilizer types. Pot experiments with rye-grass, rape and maize showed that P recovery was highest from the soil with the basic slag treatment and lowest in the treatment with Hyperphos, Novaphos taking an intermediate position. This finding demonstrates that the DL-method does not provide a reliable information on the P-availability of a soil, if treated with rock phosphate. The level of water soluble P in the rhizosphere of rape was investigated with a particular technique (Kuchenbuch and Jungk, 1982). It could be shown that the P level in the rhizosphere of the Hyperphos treatment was only slightly higher than the P level of the P₀ treatment (without P fertilizer) while in the Novaphos – and particularly in the basic slag treatment much higher levels of soluble P were found. It thus becomes evident that even in the rhizosphere the solubility of Hyperphos was poor. The levels of water soluble P in the rhizosphere followed a depletion curve. The steepest gradient was found for basic slag, followed by the Novaphos-, Hyperphos- and the P₀ treatment.     

Der Einfluß der Fauna auf die Stoffverlagerung sowie die Homogenität und die Durchlässigkeit von Böden

The influence of the fauna on displacement and on homogeneity and permeability of soils The influence of the most important soil animals (mammals, ants, termites, woodlice and earthworms) on displacement and on homogeneity and permeability of soils is discussed in reference to both older and more recent literature. Nearly all soil animals cause displacement of organic and mineral soil particles. The quantity, intensity and direction of this activity depends upon the morphological characters of the species involved. The homogeneity of soils is positively influenced only by the earthworms (and related forms) whereas the activity of the other soil fauna mostly has a contrary effect as far as shorter periods are concerned. The permeability of soils increases in different dimensions due to the activity of all species discussed. Permanent vegetation and non-tilling for the most part favour the activity of the soil fauna. Recent field experiments dealing with minimum or zero tillage have made this fact fairly evident.     

Einfluß der Bodeneigenschaften auf die Freisetzung der gelösten organischen Substanz (DOM) aus dem Oberboden

Influence of Soil Properties on the Release of Dissolved Organic Matter (DOM) from the Topsoil A percolation experiment over a period of three month with small monoliths from forest and grassland soils varying in their anthropogenic changes was carried out to identify, to weigh and to quantify important soil properties for DOM release from the topsoil. Quality of soil organic matter determines the amount of DOM released from the topsoil if the soils have a low ability to adsorb and to precipitate DOM. Favorable conditions for high DOC concentrations in the soil solution are wide C/N ratios in the soil and in the hot water soluble fraction, a high soil content of hot water soluble organic carbon and a high portion of hot water soluble organic carbon in the total organic carbon content. Anthropogenic changes of the soils are effective to DOM release via changing quality of soil organic matter. Long dry periods and large water fluxes can further increase DOM release. The effects of soil organic matter can be disguised in soils with a high DOM retention capacity (high CEC, high content of exchangeable bases, Fe_ox and Fe_d). Then adsorption and precipitation determine DOM release from the topsoil and contribute to a decrease of DOM release.     

Einfluß von Natriumchlorid und Mycostatin auf den Mineralstoffgehalt im Blattgewebe und die Feinstruktur der Chloroplasten

Effect of Sodium Chloride and Mycostatin on the Mineral Content of Leaf Segments and on the Fine Structure of Chloroplasts Leaf segments of bean, barley and sugar beet were treated for several hours with 25 meq NaC1 or with the antibiotica mycostatin. The effect of these treatments on the content of potassium, sodium, calcium, magnesium and chloride in the leaf segments and on the fine structure of chloroplasts was studied. In bean sodium chloride treatment induced strong efflux of potassium and swelling of the chloroplasts. Sodium sulfate or mycostatin had the same effect. Despite of the strong efflux of potassium the content of calcium and magnesium in the segments was practically unaffected. Addition of 1 meq calcium to the external solution prevented the effect of sodium chloride on efflux of potassium as well as on the fine structure. In barley sodium chloride or mycostatin also induced efflux of potassium and swelling of the chloroplasts. These effects, however, were less pronounced than in bean. Again the content of calcium and magnesium in the segments was practically unaffected, and the addition of 1 meq calcium compensated the effect of sodium chloride. In sugar beet both mycostatin and sodium chloride did not induce efflux of potassium, despite of a strong influx of sodium in the sodium chloride treatment. In both treatments no change in the fine structure of the chloroplasts was observed. It was proved by isolation of chloroplasts that the typical sodium chloride induced differences in efflux of potassium from the leaf segments is also reflected in efflux of potassium from the chloroplasts. The results indicate the causative connection between efflux of potassium and change in the fine structure of the chloroplasts. Differences between the three plant species with respect to efflux of potassium induced by sodium chloride or mycostatin are reflections of different membrane properties. The presence of calcium in the external solution is much more important for the membrane stability of bean than it is for sugar beet e. g. The results obtained with leaf segments are a good reflection of the different tolerance of these three plant species to high sodium chloride concentrations under field conditions.     

Einfluß der Löslichkeit verschiedener Phosphatdüngemittel auf die Phosphataufnahme und den Ertrag von Sommerweizen

Solubility of various phosphate fertilizers in a brown podzolic soil and their effect on phosphate uptake and yield of spring wheat. The solubility of various phosphate fertilizers (Superphosphate, Rhenaniaphosphate, Novaphos, Carolonphosphate and Hyperphosphate) was studied in an incubation experiment, and P uptake and yield effect of these fertilizers were investigated in a pot experiment. The soil used was a carbonate free brown podzolic earth (C horizon) with a neutral pH and low in available phosphate and humus. The quantities of P extracted from the soil by the EUF technique were the lower, the higher the amount of non processed phosphate of the incubated P fertilizers. This clear differentiation in the solubility of the various P-fertilizers was not obtained by the DL extraction. The P uptake of plants was highly correlated with the P quantities extracted by EUF (r = 0,95***), while the correlation between P uptake and the P of the DL extract was less narrow (r = 0,64*). The yield, particularly the grain yield, decreased with an increase of the non processed P in the fertilizers tested. Grain yield and EUF extractable P were highly correlated (r = 0,86***); while the relationship between grain yield and the DL extractable P was poorer (r = 0.62*). The experiments have shown that mainly the easily soluble phosphate is of decisive importance for the yield formation.     

Der Einfluß des Wassergehaltes auf den Atrazin-Abbau im Boden

The influence of water-content on atrazine degradation in soil In samples of the standard soil 2.2 (loamy sand, 3 % C, pH 7,0) and of a Luvisol (Ap-horizon, loam 1,4 % C, pH 5,2), the degradation of [ethyl-1-¹⁴C]atrazine was investigated in dependence of the soil water content. The experimental conditions were choosen in accordance with the methods proposed by the Biologische Bundesanstalt to study the degradation of pesticides in the soil. The soil water content was varied to simulate the moisture conditions observed in a soil during plant growth. Therefore, besides a steady water content of 20, 40, 60, and 80 % of the maximum water holding capacity of the soils, the soil water contents were fluctuated by 20 to 60 % of the maximum water holding capacity by passing dry air through the soil. At a concentration of 10mg atrazin/kg of soil between 4 and 6 % of the ethyl-1-carbonatom of the atrazine molecule was mineralized to CO₂ within 71 days at a constant soil temperature of 22°C. In the standard soil 2.2 the mineralization in total was reduced to 2/3 compared to the degradation in the Luvisol. With decreasing water content increasing hydroxilated metabolites were formed. About 30–40 % of the applied radioactivity was determined as non-extractable residue in the soil. In general the degradation processes were more enhanced and more intense in the Luvisol as compared to the Standard soil 2.2 which again unterlines that for this type of experiments a fresh soil should be used. In conclusion, the variation of the soil water content did not have a pronounced influence on the mineralization rates of atrazine, but did influence the metabolism and the formation of certain metabolite fractions.     

Einfluß des Calcium-Angebotes auf Wachstumsrate und Calcium-Gehalt von Kartoffelknollen

Effect of calcium supply on growth rate and calcium content of potato tubers. . Using potato plants in water culture with a constant calcium supply to the roots, a study was made of the influence of additional supply of calcium to the tuber surface on growth rate and calcium content of the tubers. Under conditions of high relative humidity around the tubers the calcium nutrition of the tubers was exclusively dependent on the calcium supplied to the tuber surface (?exogenous calcium”?). With a high level of exogenous Ca the growth rate of the tubers was high and the rate of uptake of Ca was proportional to the tuber growth. With a low level of exogenous Ca the growth rate declined to a lower but constant value. In absence of exogenous supply of Ca the growth rate of the tubers declined gradually until growth ceased. Cessation of tuber growth occurred when the Ca content decreased below 0,36 mg Ca per g dry matter for smaller tubers and below 0,14 mg Ca per g dry matter for larger tubers. Severe Ca deficiency in potato tubers causes necrosis at the tuber apex.     

Der Einfluß von Bormangel und von mechanischer Zerstörung des Spitzenmeristems auf die Zellteilung bei Sonnenblumen

Influence of boron deficiency and destruction of the apical meristem on the cell division in sunflowers With a severe, nearly absolute boron deficiency metabolism and formation of tissues are so disturbed that the primary symptom of boron deficiency can not be recognized with certainty. Investigations here had to clarify if cutting the tops or destruction of the apical meristem with a red-hot needle will induce symptoms similar to those of boron deficiency or how symoms develop under mild boron deficiency. With the red-hot needle technique, it was possible to obtain cambial enlargement in plants with a normal boron nutrition. Cutting off the tops also, induced an enlargement of the hypocotyl. In this case the enlargement was however due to an enlargement of the cortex by formation of an aerenchymlike tissue. A boron supply near the deficiency level caused development of deficiency symptoms in growing plants (chlorosis, inhibited enlargement of the stem, small deaf' blades, small-celled xylem, malformed and discoloured cell walls and appositions on the young cell walls). As long as the shoot apex displayed growth, enlargement of the cabium did not appear as a rule. This symptom seems to be a secondary symptom of boron deficiency caused by damage to the shoot apex and, thus disturbed auxin metabolism.     

Einfluß von Ammonium- und Nitratstickstoff auf die Entwicklung von Buchenjungpflanzen

Influence of ammonium and nitrate nitrogen on the growth of young beech plants Young beech plants were grown in aerated nutrient solutions with NH₄ or NO₃ nitrogen for a period of 12 weeks. pH-changes caused by the source of nitrogen were corrected every second day. Absorption of NH₄-N was higher than of NO₃-N. NH₄-N was superior for shoot growth and development of lateral roots, NO₃-N for growth of the main root. Nutrient solution containing both sources of nitrogen was the most favorable.