摘要:

AbstractChemical fixation and critical point drying of plant tissue prior to scanning electron microscopy often degrades the outermost layer of the specimen, i.e. the epicuticular wax. Knowledge of the unaltered wax, including its morphology, is important because the wax constitutes the interface between the plant and its surroundings. Having worked previously with barley leaves (anatomy, infection biology of pathogens), we found it of interest to examine and describe the wax morphology on barley leaves and to determine whether or not there were differences between cultivars. Hence, the morphology of the epicuticular wax on the first leaf of two spring barley cultivars has been studied by scanning electron microscopy following cryofixation.The wax on both cultivars consists chiefly of scales with a small proportion of rods and granules. There is little variation in wax morphology over each leaf side, and only minor differences between the abaxial and adaxial sides of the same leaf. Distinct differences are, however, observed between the two cultivars, especially regarding the thickness and the shape of the wax scales. The wax bodies cover the entire surface of a leaf except for parts of trichomes and guard cells, and some scattered wax free areas.The morphology and distribution of wax are discussed in relation to studies made on barley leaves using different techniques. Also, the implications of wax morphology for disease resistance are briefly discussed.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01107.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractConcentrations and amounts of macro‐nutrients (N, P, K, Ca, Mg, S) in shoots, vegetative and generative plant parts inB. napusandB. junceaand nutrient inflow per unit root length inB. napuswere studied in a field experiment at Uppsala, Sweden. Concentrations in vegetative plant parts were, except for Ca inB. napus,highest at the beginning of the season, and N and K were higher inB. napusthan inB. juncea.The higher N concentration in vegetative parts (leaves, stems and pods) inB. napuswas probably due to differences in growth pattern between the species. Seed concentrations of N, P, Ca, Mg and, most pronounced of all, S were higher inB. juncea.Nutrient amounts were, with the exception of K, throughout the season higher inB. junceathan inB. napusdue to a higher dry matter production. Nutrient inflow per unit root length inB. napuswas highest during the rosette stage for all nutrients. During flowering, the inflow decreased for N and K and increased for P and Ca. After root growth had stopped, no net inflow of K and S was found and inflow rates of other nutrients were at very low level

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01108.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTo establish the exact duration of critical periods for plant water stress during the reproductive growth stage of soybeans it is necessary to draw correlations between daily leaf water potential values and crop growth and yield. Different sets of daily leaf water potential values can be induced by different sets of irrigation applications. It is, however, imperative that water stress values are available for each day over the growing season of a large number of irrigation treatments. Since these values were not available, it was decided to calculate it by establishing a relationship between leaf water potential as determined by potential evapotranspiration and soil water content as well as soil water potential for various layers of the root zone. The most reliable regression formula was found to be:

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01109.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn a field experiment with fertilized and irrigated winter wheat the above‐ground crop was sampled once a week. Phenological development, plant density and canopy height were recorded and the green surface areas of leaves, stems and ears were measured. Soil mineral nitrogen was sampled and the field climate monitored. There were four treatments. The daily irrigated/fertilized (IF) and daily irrigated (I) treatments were both irrigated by a drip‐tube system. Liquid fertilizer was applied to IF following a logistic function according to calculated plant uptake. A total of 200 kg N ha−1was applied. Treatment I, control (C) and drought (D) were all fertilized once in spring with 200 kg N ha−1. In treatment D transparent screens were used to divert rainwater. Dry matter production ranged between 1400 in D and 2352 g m−2in IF. The corresponding amount of nitrogen uptake ranged between 15.8 and 24.6 g m−2. After harvest, soil mineral nitrogen was lowest in IF.An increase in the availability of nitrogen and water enhanced total biomass production as well as grain yield and leaf area. The daily supply of nitrogen according to crop demand delayed nitrogen uptake and increased total uptake. The results suggest that when the nitrogen is supplied in accordance with crop demand, the efficiency with which the applied fertilizer is utilized increases and the risk for nitrogen leachin

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01110.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTechnical treatments of slurry and their effects on intensively managed permanent grasslandSince 1987, seven different technical methods for slurry treatments were compared at a permanent grassland sward in South Germany. The effects on botanical composition of the grassland sward, dry‐matter yield and soil nutrient parameters were registered. The experiment includes the variants: mixing with a special slurry pump, separation (liquid and solid phase and composted solid phase), aerification and anaerobic fermentation in a biogas plant. Only slight effects of different treated slurry on the botanical composition could be shown. Comparing with mineral fertilization, the slurry variants had higher proportions of legumes and forage herbs. The dry‐matter yield was not influenced by slurry treated differently. The utilization of slurry nitrogen could be increased on average to 90 % during the experimental period compared to mineral nitrogen. Separation of slurry and fertilization in the liquid phase increased the utilization of nitro

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01111.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractTo determine the effect of different preceding crops and crop rotations on the grain yield of oil‐seed rape, a long‐term rotation experiment was conducted at the Hohenschulen experimental station in Kiel, NW Germany. Additional factors included the nitrogen fertilization and the fungicide application. The results reported herein are based upon the harvest years 1988 to 1993.Averaged over the different rotations and husbandry treatments, the grain yields in the 6 experimental years varied between 2.71 t ha−1and 3.99 t ha−1. In contrast, the effect of the different husbandry treatments was smaller and non significant. Averaged over 6 years, only the fungicide application caused small yield increase of 0.2 t ha−1.The highest grain yields of 3.77 t ha−1or 3.65 t ha−1occurred when oil‐seed rape was directly following peas. Low yields between 3.15 tha−1and 3.33 tha−1were obtained when oil‐seed rape was grown after oilseed rape. The lowest grain yield of 3.13 t ha−1was produced with oil‐seed rape grown in monoculture only. In rotations with oil‐seed rape following a preceding cereal crop (wheat or barley), the grain yields averaged between 3.22 tha−1in a two course rotation and up to 3.44 tha−1in a four course rotation. In general, the yields of oil‐seed rape increase with the length of the rotation and the length of the break between two oilseed rape crops. The yield component number of seeds per m2was affected by the previous cropping accordingly, whereas the thousand seed weight did not respond to the cropping history.Based upon disease assessments in the first years of this experiment, we argue that an increase in the incidence of fungal diseases has considerably contributed to the yield decrease of

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01112.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractEffects of tillage on the appropriate fertilizer N applications needed to achieve maximal grain yield are poorly denned. The study objective was determination of relative corn grain yield response to N application rate for four tillage practices: no‐tillage (NT), ridge tillage (RT), fall chisel plowing (CP) and fall moldboard plowing (MP). Maize (Zea maysL.) grain yield and N accumulation were monitored over a 6 year period with the same tillage treatment and the same fertilizer N rate applied each year to each plot. Two hybrids, differing in relative maturity rating, were planted each year. Fertilizer N rates ranged from 10 to 190 kg ha−1and consisted of 10 kg ha−1of liquid starter N applied at planting with varying amounts of fall applied anhydrous ammonia. With only starter fertilizer, grain yields increased with tillage intensity in the order NT ≤ RT ≤ CP ≤ MP. With ≥ 55 kg total applied Nha−1, 6 year average grain yields were unaffected by tillage. Total N removed in grain annually with only starter fertilizer ranged from 25–85 kg ha−1Maximal amounts of N removed, about 145 kg N ha−1, occurred with 100–145 kg applied N ha−1for all tillage treatments under the more favorable climatic conditions. Several interactions affecting grain yield appear climatically sensitive with exception of tillage by fertilizer N interactions. Because of variability in climate, planting dates varied by almost 4 weeks. Relative yield loss due to planting delay were Fertilizer N (mean change ≅−124 –−275 kg ha−1day−1)>Starter N only and MP (mean ≅− 259 kg ha−1day−1)>other tillages in general. Yield loss due to delayed planting ranged from 0.0–275 kg ha−1day−1. Grain yield gains due to early spring soil temperatures were 16.0–21.8 kg ha−1index‐degree−1with MP tillage and averaged 2.7– 16.7 kg ha−1ind

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01113.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractFodder sorghum (M. P. Chari) was grown at varying populations to examine its influence on light interception, leaf area index and biomass production. DMY, CGR and IPAR depending on LAI reached maximum at LAI 5 of 150 000 plants ha−1stand and thus yielded higher biomass. Therefore, physiological potential of fodder sorghum crop was found to be maximum at a population density of 150 000 plants ha−1. Further increases in population developed mutual shading and adversely affected the crop growth rate and dry matter accumulation. Significant linear relationships of dry matter yield with IPAR, plant population densities, LAI and CGR clearly indicate the interdependence of these charact

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01114.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY