摘要:

AbstractThe effect of four seedling densities developed soon after the emergence and two shading materials were studied in order to elucidate the response of seedling growth of tobacco. Germination and seedling emergence was better in beds under greycloth than under polythene. In contrast, shoot and root growth of tobacco seedlings was superior under polythene at all densities. This observation is attributed to optimal environmental conditions under polythene. The study also revealed that the highest shoot and root growth was at the lowest density. High plant densities hindered plant growth. Well developed plants were seen at the plant density of 165 plants per 0.1 m2under polythene.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00827.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractInteractive effect of NaCl salinity and gibberellic acid (GA3) on seedling growth and carbohydrate metabolism of rice was studied for five days. NaCl reduced the embryo axis growth and the rate of hydrolysis of starch in the endosperm. Parallel to this reduced rate of reserve carbohydrate mobilization, a decreased activity ofα‐amylase,β‐amylase, maltase and invertase was also found in the endosperm of sale stressed seeds. Presoaking treatment of seeds with GA3(10 mg l−1), however, increased the growth of seedlings and enhanced the hydrolysis of starch as well as the activities of said enzymes. Electrophoretic analysis revealed that NaCl inhibits the synthesis of amylase isozymes which, in turn, reversed considerably by GA3appl

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00828.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractTracer studies using32P labelled superphosphate and rock phosphate were conducted in microplots in a field experiment on rice‐rice‐greengram cropping system. The trial revealed that in all the rice crops studied, P uptake and P use efficiency were higher in superphosphate treated plots than in rock phosphate applied ones. P uptake was improved with organic manuring through application of green manure or crop residues like long rice stubbles. While superphosphate performed well either with or without organic manuring, rock phosphate performed fairly well only with organic manuring. Fairly good P use efficiency could be obtained in the system when green manuring and rock phosphate application in the first crop was followed by superphosphate and long stubble incorporation in the second crop. Apparent recovery values also showed nearly the same results. But tracer studies were found to be definitely superior in the evaluation of fertiliz

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00829.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSeedlings of four rice cultivars differing in salt tolerance were raised in sand cultures under increasing levels of NaCl salinity and metabolic levels of total polyamines, spermidine, spermine, agmatine and the diamine putrescine were determined in roots and shoots during 5‐20 days growth period. Salinity caused a remarkable increase in total polyamines level in rice seedlings. At similar level of salinity roots as well as shoots of salt sensitive cvs.RatnaandJayashowed higher level of total polyamines than tolerants. Salinity of 14 dSm−1NaCl caused more than 2 times polyamine level in shoots of sensitive cultivars compared to tolerants. Accumulation of polyamines was greater in salt stressed shoots than roots. In nonsalinized seedlings there appeared a gradual increase in putrescine level during 5 to 20 days growth period. Salt treatment caused sharp increase in putrescine level in all cultivars, however under similar level of salinization salt stressed seedlings of sensitive cultivars had higher putrescine level than tolerants. In nonsalinized seedlings of sensitive cultivars spermidine level increased gradually during 5 to 20 days growth period whereas a decline in the level was observed in seedlings of tolerant cultivars during this period. Higher level of salinity caused marked increase in spermidine level in sensitive cultivars. Specially during 5 to 10 days of growth salinity caused increase in spermine level in seedlings of sensitive cultivars. In all cultivars salt stressed seedlings had higher agmatine level compared to non‐stressed. Salinity led to greater accumulation of certain unidentified polyamines in seedlings of sensitive cultivars. Increased levels of total polyamines, putrescine, spermidine and unknown polyamines in rice seedlings under salinization suggest their possible role in combating the adverse effects of salinity s

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00830.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe influence of sowing date, seed rate, and variety on agricultural characteristics of winter wheat in a low external input systemGrowth conditions of winter wheat in agricultural low external input systems, e.g. ecological agriculture, are very different compared to conventional agriculture (mineral nutrition, impact of diseases, competition of weeds). In 1986, 1987, and 1988 the influence of sowing date and seed rate on crop development and grain production was studied with two varieties of winter wheat in field experiments in Northern Hessia.Drilling after the first decade of October decreases grain yield of both varieties significantly. The decrease was due to poor emergence, low plant densities, and low grain weights. Tillering could not compensate low plant densities, presumably because of low mineralization of nutrients in cold soils during respective growth stages.Variation of seed rate (350, 500, and 650 viable seeds/m2) had little influence on grain yield. Low plant densities and low numbers of ears per nr after sowing in the end of October could not be improved satisfactorily by increased seed rates.The ability of varieties of winter wheat to compensate unfavourable growth conditions due to “late” sowing varies considerably. Cultivars which are able to develop a high plant density seem to be more suitable for delayed sowing dates, as compared to varieties which own a high grain weight.Further investigations concerning wheat production are needed to optimize agricultural low external input systems. Especially sandy soils with quick response to increased ambient temperature, and sites with favourable growth conditions in late autumn and early spring should be conside

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00831.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe performance of three spring faba bean (Vicia fabaL.) cultivars Stella, Danas, and Minden in monocultures were compared with mixtures of Stella + Minden, and Danas + Minden sown as within row mixtures, alternate row mixtures, and as composites.Mixtures of both cultivar combinations, whether mechanical or composites, had net increases in seed yield per plot ranging from 10.5 % to 20 % above the means of the component cultivars grown in monoculture. Cultivars grown in mixtures in alternate rows had slightly greater seed yield than when they were grown alternately within rows. A further yield enhancement was obtained from growing composites.Data for total plant dry weight were similar to those for seed yield. The number of podded nodes per plant was the major yield component responsible for the increased yields of the component cultivars in mixtures. The ecological aspects of these results are discussed.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00832.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractYield components in old and new german winter wheat varieties with respect to the storage and remobilization of fructan in the wheat stemYield components and changes in carbohydrate content of four old german winter wheat varieties, bred before 1950, were compared with six new varieties over two years in field trials. In both years the old varieties built up more biomass than the new varieties. In the latter a better harvest‐index (0,56) as compared to the old varieties (0,43) was obtained, resulting in higher grain yields for the new varieties. Changes in water‐soluble carbohydrate (WSC) content were mainly due to variations in fructan content. Maximum of fructan content was mostly reached at the stage of early milk ripeness. In the new varieties a faster and more complete remobilization of fructan occurred; especially in the year with the short grainfilling per

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00833.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractTwo greenhouse experiments were conducted to evaluate the performance of selected soybean‐Bradyrhizobiumcombinations in a soil having low P‐high aluminum stresses under controlled conditions. Growth parameters such as plant height, nodule numbers, dry weight, nitrogenase activity and seed yield were used as an index. Three selected acid (low P‐high Al) tolerant (Essex, TracyandBedford) and three sensitive (Peking, HillandMcNair 600) soybean (Glycine max) varieties were sown in each pot. Three of the most tolerant strains ofBradyrhizobium(USDA 6, 110, 122), a mixture of these strains, and a commercial inoculant (Nitragin) were used to inoculate the Hartselle sandy loam soil. The results indicated that soil acidity significantly affected the soybeanBradyrhizobiumsymbiosis. The combination of varietyTracyplus Nitragin (mixed‐strain) produced the highest and varietyPekingplus mix‐strain Nitragin the lowest plant height at all pH levels. Plants inoculated with Nitragin had higher shoot dry weight and seed yields. VarietyEssexin combination with Nitragin produced the highest seed yields at all pH levels. Plants inoculated with Nitragin developed significantly more nodules than the other strains except for varietyPeking.There was no significant difference in total nodule numbers between tolerant and sensitive soybean varieties at all soil pH levels except for Nitragin. Shoot total N did not increase by increasing the pH level or by using different variety‐strain c

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00834.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA greenhouse study was conducted to determine the effect of nitrogen supply (30, 100 or 170 ppm N) and raceme position on the fatty acid composition of oil extracted from erucic acid‐free summer rape seed (Brassica napuscv.Callypso). The seven fatty acids analyzed for include palmitic, palmitolcic, stearic, oleic, linoleic, linolemc, and eicosenoic acids; of which oleic (59.54–64.84 %) and palmitoleic (0.36–0.4 %) acids were the highest and lowest levels respectively. Generally, N nutrition influenced fatty acid pattern only to a little extent. Palmitic, palmitoleic and stearic acid levels were increased by 170 ppm N, depending on raceme position, but oleic and linolenic acids were unaffected. Similarly, 170 ppm N produced the highest fatty acid levels in seeds on the lower portions of racemes, with the exception of oleic acid. This was also true in the case of the upper portions of racemes, except that 30 ppm N produced the highest levels of oleic and linoleic acids in rape seeds. Under the optimum N supply level (i.e. 100 ppm N), position of raceme on the rape plant did not greatly influence the levels of different fatty acids in l

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00835.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Books Reviewed in this Article:Fülgraff, G. (Hrsg.): Lebensmittel‐ToxikologieWagner, F., und G. Prediger: Der Feldversuch, Durchführung und Technik.Samson, R. A., H. C. Evans, and J. P. Latgé: Atlas of Entomopathogenic Fungi.Harrison, A. F.: Soil Organic Phosphorus. A Review of World Literature.Kumada, K., 1987: Chemistry of Soil Organic Matter Developments in Soil Sci

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00836.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY