摘要:

Symptoms of manganese toxicity in beans (Phaseolus vulgaris L)In water culture experiments with bush bean plants (Phaseolus vulgaris L.var. „Red Kidney”︁) the macro‐ and micro‐symptoms of manganese toxicity had been studied.Typical symptoms of Mn toxicity are small distinct blackish‐brown spots, first at the older leaves and at more severe toxicity also at the petals and stems. Using the autoradiographic technique on54Mn‐distribution and comparing this with corresponding light microscopic studies it could be demonstrated that the blackish‐brown spots in the leaves resemble Mn‐precipitations.These precipitations are Mn‐compounds of higher oxidated form and are primarily localized in the walls of cells in vicinity of the vessels. The extend to which these precipitations occur is not only a function of the Mn‐content of the leaves but also of their age. At comparable Mn‐content the extend of the precipitation increases with the leaf age.As secondary symptom of Mn‐toxicity under certain conditions (presence of silicon e.g.) induced Fe deficiency (chlorosis of the youngest leaves) and Ca deficiency („crinkle leaf”︁) may occur.It is assumed that the process of Mn precipitation within the leaves is enzymatically regulated. The severe reduction in the growth of leaf blades at Mn toxicity is presumably related to an interference

ISSN:0044-3263    

DOI:10.1002/jpln.19781410202

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Determination of trace elements in dilute aqueous solutions by X‐ray fluorescence spectrometry after preconcentration on cellulose ion exchangersDifferent methods dealing with the X‐ray fluorescence analysis of solutions are reviewed. Cellulose ion exchangers were found to be a medium for the preconcentration of traces of elements in aqueous solutions. The enrichment is carried out by filtering 11 water containing μg‐amounts of different ions through a column. After drying, the cellulose ion exchangers are pressed into pellets and analysed by X‐ray fluorescence.For the collection step strong acid SE‐ (sulfoethyl‐) cellulose and strong basic DEAE‐(diethylaminoethyl‐) cellulose are used having an exchange capacity of 0,2 meq./gram and 0.85 meq./gram, respectively. The accuray of the method is about ± 10%. Detection limits (theoretical values) are in the range of 1–5 μg.Variations of the method referring to preparation of pellets, sensitivity and column dime

ISSN:0044-3263    

DOI:10.1002/jpln.19781410203

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Investigations on the N‐metabolism and N‐transport in decapitated rootsExperiments were carried out on roots and bleeding sap of decapitated pumpkin plants supplied with nitrate‐N to investigate the nitrogen metabolism and transport of nitrogen in relation to the time after decapitation.1. Up to two hours after decapitation absorbed nitrate was metabolized into organically bound nitrogen. The rate at which this occurred decreased with time and subsequently the turnover was strongly depressed.2. 30 free amino acids were detected in the bleeding sap. These amounted to 25% of the organically bound nitrogen. Amino acids of the glutamate family dominated, especially glutamine and arginine. In the course of the first hour, the relative proportion of glutamine‐N increased; at the same time the total concentration of amino acids was slightly reduced. More pronounced shifts in this fraction were observed after two hours, indicating the occurrence of catabolic processes.In the root neither the total concentration of free amino acids nor the composition of this fraction was altered within the two hour period. However, the composition differed substantially from that of the bleeding sap.3. By aid of gel filtration, compounds in the bleeding sap were detected with molecular weights from 200 to 5000 and with free NH2‐groups.4. Up to the end of the two hour period the activities of nitrate reductase, glutamate‐dehydrogenase and glutamate‐oxalacetate‐transaminase remained almost fully functional. A slight and reversible decrease in the activity of nitrate reductase in the roots in the first half hour proved to be coincident with rising rates of nitrate accumulation and strongly decreasing rates of organically bound N accumulation.The results are discussed in relation to the interruption of carbohydrate supply to the root following decapitation. In addition, differences are pointed out between the contents of nitrogen compounds in the roots and in t

ISSN:0044-3263    

DOI:10.1002/jpln.19781410204

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Effect of potassium fertilization on K‐availability in potassium fixing soils over the vegetative periodThe effect of potassium fertilization on the K‐availability over the course of the vegetative period was tested on nine potassium fixing soils over two years.The availability of potassium fertilized at the beginning of vegetative period falls (on a soil with 50% clay) to half of the original amount within one month. The availability decreases especially during the time without vegetation. Only after fertilization with 1200 kg K2O/ha are substantial amounts of potassium available for the plants until the end of the vegetative period (determined by electroultrafiltration).An annual application of 300 kg K2O/ha only slightly increased the CAL‐K and exchangeable K in comparison with the unfertilized plots, although the plants showed marked yield responses. A significant improvement in potassium supply was not obtained with less than 600 kg K2O/ha.The potassium wet fixation values are relatively constant on the plots without or with low K‐fertilization: after high potassium application they show considerable fluctuation. The fixation potential is considerably reduced with an annual application of 1800 kg K2O/ha, but is not completely removed.Potassium can be removed by repeated extraction with a dilute CaCl2‐solution but the rate at which it is released into the soil solution is too slow compared to the needs of rapidly growing crop plants. The rise in the level of available potassium by fertilization is reverse to the clay content.There was considerable variation between the different available potassium forms over the vegetative period on the highly fertilized plots; consequently a soil test made annually can only give a rough idea of the K‐level in potassium f

ISSN:0044-3263    

DOI:10.1002/jpln.19781410205

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Investigation of the soil gas regime in a tillage experiment: 2. Apparent diffusion coefficients as a measure of soil structureIn a soil tillage experiment with nursery stock on three different soils the apparent diffusion coefficients for CO2were measured using soil cores of different depths at different times. Not‐tilled, herbicide treated plots were compared with rototilled plots.The relationship between the relative apparent diffusion coefficient and the air content may be described by an exponential regression function Ds/Da= 0.0085 · e6.8EL, if all measurements are taken into the calculation. By dividing into different soil textures different regressions are obtained for the three studied soils: a sand, a silt and a clay loam. In many cases it is possible to show by the changing Ds(EL) regression changes of the soil structure with depth or as a result of tillage. In all these cases the soil of the not tilled plots turns out to be better structurized than that of the tilled ones, demonstrated by higher Ds‐values at equal EL.The interpretation of the differences is being tried with the aid of soil pore tortuousity and continuity. Finally the measured Ds(EL) relationships are applied to characterize the soil gas regime for two seasons, using CO2concentration profiles of the soil air on a day in summer and fall, respectively. It is shown, that CO2production reaches farther down in summer than in

ISSN:0044-3263    

DOI:10.1002/jpln.19781410206

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractHumic acid, the principal component of soil organic matter, contains the surface active substances peptizable with alkali and non‐lixiviable with benzene, ethanol and benzene‐ethanol mixture. The surface tension of the decantate of suspension is below that of pure water being a few (<10) erg cm−2before peptization, and up to 30 erg cm−2after peptization.According to the surface tension values of the decantates of suspensions, the soils can be in the following order: non‐lixiviated

ISSN:0044-3263    

DOI:10.1002/jpln.19781410207

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Die Wirkung von Emulsionszusätzen bei BodenverbesserungDie Bodenverbesserungswirkung von Polymeremulsionen, ausgedrückt durch Kohäsion und Wasserstabilitätsexperimente, wird besonders beeinflußt durch die Teilchengröße: kleine Teilchen bewirken gute Wasserstabilität, aber geringe Kohäsion. Diese antagonistische Wirkung der Teilchengröße wird eliminiert entweder durch Verwenden von Copolymeren oder durch Zufügen von Zusätzen. Menge und optimale Konzentration jedes Zusatzes muß im Laboratorium be

ISSN:0044-3263    

DOI:10.1002/jpln.19781410208

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Degradation of monolinuron in different soil typesThe degradation of14C‐methyl, ‐ureido‐ and ‐phenyl‐labelled monolinuron was studied in laboratory experiments with different soil types. Mineralization of the ureido‐group was followed by two methods. It was found, that the mineralization rate depends on the soil. For the herbicide monolinuron there was a definite degradation characteristic. The release of14CO2from the methyl‐ and ureido‐group was faster than from the phenylring. In soil extracts monolinuron was found together with one or two radioactive substances not yet identified. Soil respiration was unchanged after the application of monolinuron. In a sterile soil no degra

ISSN:0044-3263    

DOI:10.1002/jpln.19781410209

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

On the determination of gypsum in soilsThe (020) X‐ray reflection of gypsum at 7,56 Å is nearly specific and may be used for detection and quantitative measurement of the mineral in soil samples. By X‐ray powder diffractometry gypsum can be detected as far down as 0,5% by weight. This limit may be extended down to 0,005% by concentration in the density fraction 2,1–2,5 g/cm3. For quantitative measurements references may be prepared from sample parts by dehydration of the original gypsum and adding known quantities of this mineral. So it is possible to compare samples of nearly identical grain size distribution, and mineral contents. This is important in the powder‐diffractometrical quantitative measurement of a mineral with low hardness and good cleavage where mechanical stress during homogenisation lowers the intensities of X‐ray reflections. Under comparable conditions for sample and reference, gypsum contents can be determined in the range of 0,5 to 20% by weight with an accuracy of ± 3%

ISSN:0044-3263    

DOI:10.1002/jpln.19781410210

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Die Wirkung von P‐Form, Zeit, Wassergehalt und pH auf die Bewegung von Cd im BodenDer Einfluß von P‐Form, Zeit, Wassergehalt und pH auf die Cd‐ und P‐Bewegung in einem sandigen Lehmboden, dem Cd‐P‐Mischungen zugegeben waren, wurde untersucht. Im Vergleich zu Cd allein verringerten die P‐Formen die Cd‐Diffusion in der Reihenfolge: Diammoniumphosphat (DAP)>Monocalciumphosphat (MCP)>Natriummetaphosphat (SMP)>Monoammoniumphosphat (MAP).Zeit und Wassergehalt hatten praktisch keinen Einfluß auf die Cd‐Wiedergewinnung mit DAP‐Cd‐Mischung, während im Fall von MAP‐Cd‐Mischung Zeit und Wassergehalt die Cd‐Diffusion erhöhten. Die Cd‐Bewegung im Boden wurde durch steigendes Boden‐pH mit beiden P‐Formen erniedrigt. Der Einfluß von Zeit, Wassergehalt und pH auf die

ISSN:0044-3263    

DOI:10.1002/jpln.19781410211

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY