摘要:

AbstractStarch and amylose synthesis in seeds of garden and field peasIn seeds of garden and field peas (Pisum sativum, ssp. medullareandssp. sativum) the synthesis of starch, amylose, amylopectin and sugar was investigated during seed development in plants differing in potassium nutrition. Seed growth started about 2 weeks after flowering and was terminated 5 weeks later.At the beginning of seed growth synthesis of amylose and amylopectin was very low in both pea species with a small surplus of amylopectin. After the first third of seed development, however, synthesis of amylose and mainly of amylopectin was improved at different rates. While both species exhibited an almost analogous increase in amylose synthesis, synthesis of amylopectin differed widely in garden and field peas. In garden peas it fell behind amylose production, yielding an amylose/amylopectin ratio of 2: 1 in mature seeds. In field peas amylopectin synthesis greatly exceeded amylose production resulting in an amylose/amylopectin ratio of 1:2.The 50 % higher starch content in seeds of field peas was mainly due to the more intensive rate of amylopectin synthesis. This shows that starch production via amylopectin synthesis is probably the more effective metabolic pathway.Sugar contents were highest in the middle of the generative phase. Until maturity they rapidly declined to one quarter of the maximum level. At each stage of seed development sugar content in garden peas was twice as high as in field peas. Potassium nutrition had only a very small influence on the carbohydrates examined.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00761.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA greenhouse experiment was conducted to study the effect of N nutrition (30, 100 or 170 ppm N) on the concentrations and distribution of P, K, Ca, and Mg in oilseed rape (Brassica napusL.). Leaf K concentration increased with increasing N supply up to 100 ppm N, as did leaf Mg after the bloom stage. Leaf Ca decreased with increasing N nutrition but P concentration was unaffected. Lower leaves had higher P concentrations than did the upper leaves. P, Ca and Mg concentrations in the roots at 34 days before bloom (DBB) declined when N supply was increased but K concentration was unaffected. At 10 and 44 days after bloom (DAB) P concentrations in the roots, stem and branches increased with N supply; whereas K, Ca and Mg concentrations did not respond. Concentrations of P in the pods increased with N nutrition up to 100 ppm N but those of K, Ca and Mg in the pods, hull and seeds were unaffected by N nutrition. P concentrations in the hull and in the seeds also increased with N supply. Most of the K and Ca were in the leaves while the least were in the seeds. Most of the P accumulated in the seeds and roots; whereas the hull contained the least. Of the four nutrients analyzed for, P concentrations were generally the lowest in the various plant parts and K concentrations the highest. Ca/Mg ratios for the hull and branches were increased by 100 ppm N and the ratios for the leaves, pods and seeds were unaffected by N nutrition.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00762.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractMetabolic status of total and individual free amino acids were studied in endosperms and embryoaxes of four rice cultivars differing in salt tolerance, growing under increasing levels of saline stress. At all saline treatment levels and in controls salt tolerant cultivars had higher levels of total free amino acids in germinating seed parts than sensitives. Individual free amino acids which always maintained higher levels in germinating tolerant seeds over sensitives were aspartic acid, arginine, glycine and leucine. Salinity caused accumulation of free amino acids in germinating seed parts in all cultivars. Maximum accumulation was of arginine followed by leucine, alanine, valine, glutamine and proline. Individual amino acids accumulated greatly in tolerant cultivars than sensitives. Increased salinity caused decrease in the levels of aspartic acid, serine, glutamic acid, glycine, lysine and histidine in growing embryoaxes. Results suggest possible relationship between levels of free amino acids arginine, leucine, alanine, valine, glutamine and proline and degree of salt tolerance in rice. These all amino acids should be considered in combination as indices for salt tolerance in rice.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00763.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTwo field trials under irrigated conditions were conducted in red sandy loam soils of Palathurai series (Typic Haplustalf) at Coimbatore to evaluate the changes in physical properties when intercropping was introduced to a pure crop system. The results of the first crop indicated that intercropping of sorghum (CSH 5)‐lab lab (CO 9) system was found to improve the physical properties such as hydraulic conductivity, total porosity, aggregate stability and stability index when compared to pure crop of either sorghum or lab lab. The results of the second crop indicated that the bulk density of soil was not significantly altered by intercropping. When a legume was introduced as an intercrop to a cereal crop the physical properties such as total porosity, hydraulic conductivity, aggregate stability and stability index were not affected but when the cereal was introduced to a legume, the above parameter significantly improve

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00764.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractGrain yield was largely governed by non‐additive (SCA) type of gene action with the significant existence of additive (GCA) type of gene action. GCA variance due to females was significant whereas due to males was non‐significant under all environments. SCA variance was highly susceptible to the changing environments as compared to GCA component of females, whereas GCA component of males was not at all interacting with environments. Proportion of SCA and GCA variances distorted on pooling the data and was contradictory. Such distortion of the proportion on pooling was observed due to large amount of g x e interactions. Impact of interaction of genetic variance components with environments, its proportion, utility and breeding approaches are discus

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00765.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effect of plant density and component frequency was examined in mixtures of two spring faba bean (Vicia fabaL.) cultivarsDonasandMindengrown in a replacement series experiment in the field. There were two densities, 44 and 25 plants m−2.At low density mixtures yielded significantly more (+ 22.5 %) than the mean of the components grown in monoculture. The advantage was considerably reduced (+ 7.8 %) at high density. A frequency dependent advantage was observed when the proportion of the components in mixtures was varied. At high density and when averaged over the two densities, the greatest yield advantages were obtained whenDanas, the high yielding component represented 75 % of the mixture, whilst at low density the greatest advantage was achieved at 50 : 50 mixture. Such gains were either due to component co‐operation or complementation type interactions.Mixtures produced greater total dry weights and more podded nodes per plant than the mean of the components. The remaining characters had values which were more or less similar for monocultures and mixtu

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00766.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAnalysis of Competitive Interactions in Grassland Stands by a Population Dynamical ModelThe potential yield of permanent grassland is highly influenced by dynamical interactions within its plant species. The possibility to recognize and to quantify these interactions opens a wide field of applications in grassland management. A mathematical simulation model was chosen to meet this aim. The base of the model is a simple population dynamic arrangement. The competition between the species or species groups is described by a linear function. A long time trial is used as a data base. The productivity and the floristic changes in this trial were recorded for 12 years. By reason of the limited data base the species were aggregated into 5 groups consisting of species with similar behaviour. The model proofed to be useful, to simulate the important interactions between the species groups and to quantify their significance with regard to the dynamic development of the grassland. Because of the small data set used in the sample, the model is limited in its validity. The model can be improved by incorporation of a larger data base.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00767.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00768.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractNitrogen inputs into rice fields can be increased by cultivation of green manure crops. ManySesbaniaspecies have been generally grown by the rice farmers in India and these green manures are capable of contributing significant amount of nitrogen in 45 to 90 days period by their association with the nitrogen fixing symbiotic bacterium –Rhizobium. Field experiments conducted at the Tamil Nadu Agricultural University, Coimbatore, India, during Dry and Wet seasons in 1987–88 with medium duration (145 days) rice variety CO 43.Sesbania rostrataproduced higher biomass on 60th day after sowing and accumulated higher percentage of nitrogen. Application of fertilizer nitrogen withS. rostratahave increased the nitrogen uptake and yield of r

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY