摘要:

AbstractEffects of salinity on the isozyme activities ofα‐amylase in germinating sorghum seeds were studied under laboratory conditions. Seeds were imbibed in NaCl solutions at concentrations ranging from 0–500 nM (osmotic pressure: 0–2.28 MPa) for 0–24 h and the isozymes activities were estimated after disc‐gel electrophoresis.Seed germination of sorghum was not affected by NaCl concentrations less than 100 nM (0.46 MPa). Germination was reduced by 50% at 300 nM NaCl (1.31 MPa), and completely inhibited at 500 nM (2.28 MPa). Theα‐amylase activity in the treated seeds followed a similar pattern to that of germination.At least five isozyme patterns of a‐amylase were observed in germinating sorghum seeds. The activities of the respective isozymes were enhanced with increasing duration of imbibition in distilled water. When treated with 100 nM NaCl, the activities of isozymes 2 and 5 decreased, but this was compensated by the increased activity of isozyme 1. The sensitivity of isozymes to the salinity treatments varied where isozyme 1 was the most tolerant. The isozyme activities were completely inhibited by 500 nM NaCl.The results indicate that sorghum seeds could germinate well in saline environments up to 0.46 MPa. Higher osmotic pressure or saline concentrations could be detrimental to the seed germination of sorghum. The salinity tolerance could be attributable to the compensation of loss of activities of certain isozymes ofα‐amylase

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01115.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this study, the correlation and path coefficients between ear characters and grain yield per plant were determined in triticale under Mediterranean climatic conditions.Weight of grains per ear and number of ears per plant were the most important direct components of yield. Characters like ear length and the number of spikelets per ear were not found to be the important component characters of grain yield. It could be concluded that among ear characters in triticale, the number of ears per plant and the weight of grains per ear are the most important yield contributing characters and these characters should get due consideration in future triticale breeding programmes.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01116.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe study aimed at: i) assessing the agronomic value of the pure stand (PS), of the complex mixture (CM) and of the binary mixture with each of six white clover genotypes (MWC) of eight grass varieties belonging to four species and contrasting for earliness of flowering; and ii) investigating the relationships of competitive abilities in CM and MWC with some morpho‐physiological traits of the grass varieties. CM showed a 24 % dry matter yield (DMY) advantage over mean value of PS but did not outyield the pure stand of the best yielding component. For grass‐white clover associations, the DMY advantage as Relative Yield Total over PS of the components averaged 43 %. DMY of the grass varieties averaged across MWC conditions was related positively to total DMY (r = 0.99) and negatively to associated clover DMY (r = ‐ 0.96). Competitive abilities as Relative Yield of the grass varieties in CM and in MWC correlated (r = 0.84) and were both positively associated to DMY, canopy height and inclination of leaves in PS. The results suggested that association of white clover with a grass of moderately high vigour, intermediate earliness and relatively erect leaves may provide the best option for rotational meadows in the experiment enviro

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01117.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractMost methods used to estimate N status require collection, processing and analysis of soil and/or plant tissue samples. In this study, leaf chlorophyll content of cereals, determined in the field with a portable chlorophyll meter (Minolta SPAD‐502), was used to predict N availability of wheat (Triticum aestivumL.), barley (Hordeum vulgareL.), oats (Avena sativaL.) and rye (Secale cerealeL.). The results indicated that accurate nitrogen (N) fertilizer recommendations based on chlorophyll content have both environmental and economic advantages. Determination of leaf chlorophyll content with a chlorophyll meter accurately indicated plant N status allowing N fertilizer requirement to be accurately determined and resulting in increased N uptake efficiency. Applying N fertilizer on this basis improved production economics and improved physical input‐output ratio during grain yield formation. Using a chlorophyll meter, responsive and non‐responsive categories can be determined at the stage of maximum number of florets per ear primordium (Zadoks' GS 37‐41) and at pollination (i.e. pollen grains on well‐developed stigmatic hairs,

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01118.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractInfluence of high temperature stress on photosynthesis and allocation of carbon into different biochemical fractions in mature leaves of Indian mustard [Brassica juncea(L) Czern] was investigated. Heat stress reduced14CO2fixation and inhibited the translocation of carbon from the leaves. Allocation of14C into starch and residue fractions was significantly lower in heat stressed plant leaves. Starch content was significantly reduced in heat stressed plants.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01119.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractField experiments with silage maize were conducted in 1987 and 1988 on a loess‐derived Luvisol in southwest Germany. Four nitrogen fertilizer treatments were compared: application of preplanting NH4N (plus a nitrification inhibitor, dicyandiamide as Didin) and preplanting NO3‐N, split application of NO3‐N (preplanting and side dressed 45 days after planting) and a control without nitrogen fertilizer in 1987 and with 64 kg N ha−1as calcium ammonium nitrate in 1988. The total amounts of soil mineral nitrogen (Nmin+ fertilizer N) were 200 kg N ha−1in 1987 and 240 kg N ha−1in 1988. Suction cups and tensiometer were installed at five depths and samples were taken in regular intervals.Nitrate concentrations in the suction solution steeply increased at 15 cm and 45 cm soil depth 3‐4 weeks after fertilizer application (1987 up to 160mgNl−1; 1988 up to 170mgN l−1) and steeply decreased up to 75 cm depth with the onset of intensive N uptake at shooting. Ammonium concentrations in the suction solution were very low (0‐0.16 mg N l−1). Compared to preplanting NCyN application, preplanting NH4‐N and split NO3‐N application decreased nitrate concentrations in the suction solution in spring 1987. In 1988, however, nitrate concentrations in the suction solution of preplanting NH4‐N and split NO3‐N application plots did not fall below 50mgNl−1at 15 cm depth during the growing season. Nitrate concentrations of split NO3‐N application increased again in autumn 1988 and hence doubled the calculated N losses by leaching during the winter months compared to preplanting N applications. At shooting, plants of the preplanting NH4‐N treatment had lower nitrate concentrations in leaf sheaths compared to plants of preplanting NO3‐N application. Total N uptake of maize between shooting and early grain filling of preplanting NH4‐N and split NO3‐N application tended to be higher compared to preplanting NO3‐N application, reflecting the higher N availability in the soil later in the season. However, final dry matter yields and N uptake were not significantly affected by N form or time of N application. Since N losses by nitrate leaching between N application and onset of N uptake by plants were negligible on the experimental site, preplanting NH4‐N application and split NO3‐N application showed no agronomic advantages. High amounts of side dressed NO3‐N may increase nitrate leaching during the winter months, especially

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01120.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractNitrogen management for production of bread quality wheat (Triticum aestivumL.) in eastern Canada has received little research attention. An experiment was conducted for 2 years at each of two sites in Québec to study the effect of level and timing of nitrogen (N) fertilizer application on grain protein concentration, protein content per seed, non‐protein seed dry matter, grain protein yield and nitrogen harvest index (portion of plant N in the grain) of four hard red spring wheat cultivars known to have potential as bread wheats in eastern Canada. The soil types were Bearbroock clay (fine, mixed, non‐acid, frigid, Humaquept) and Ste‐Rosalie clay (typic, non‐acid, frigid, Humaquept). The experiment was a 4 × 4 × 2 factorial. Four cultivars were used: Columbus, Katepwa, Max and Hege 155–85. In both years 0, 60, 120 and 180 kg Nha−1were applied either all at seeding or 60 % at seeding and 40 % at heading. Grain protein concentration and grain protein yield increased consistently with increasing N fertilizer and with split N application. Nitrogen harvest index was not increased by increasing applications of N fertilizer. Protein content per seed was more critical in determining grain protein concentration than non‐protein seed dry matter content. The western Canadian cultivars Columbus and Katepwa generally had greater grain protein concentration than the European cultivars Max and Hege 155–85, With reasonable N fertility the grain protein concentration of spring wheats grown in eastern Canada are sufficient fo

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01121.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractForty‐five accessions of sunflower collected from different countries were screened for salinity tolerance after 2 weeks growth in sand culture salinized with 150 meq l−1of NaCl2+ CaCl2(1:1 ratio equivalent wt. basis) in half strength Hoagland's nutrient solution. The results for plant biomass of 45 accessions show that there was considerable variation in salinity tolerance.In a further greenhouse experiment, the salinity tolerance of three tolerant (HO‐1, Predovik, Euroflor) and two sensitive (SMH‐24, 9UO‐985) lines (selected on the basis of their performance in the seedling experiment) was assessed at the adult stage to evaluate the consistency of salinity tolerance at different growth stages. All three salt tolerant accessions produced significantly greater plant biomass, seed yield and seed oil content than the salt sensitive accessions. The tolerant accessions accumulated less Cl−and more K+in the leaves under saline conditions compared with the salt sensitive accessions. The salt tolerant accessions also maintained relatively high leaf K:Na ratio and K+versus Na+selectivity. Although statistically nonsignificant, all three tolerant accessions had greater soluble carbohydrates, soluble proteins, total free amino acids and proline in the leaves than the sensitive accessions. A field trial conducted in a salt‐affected field confirmed the greenhouse results of the selected accessions.This study shows that salinity tolerance of sunflower does not vary with stage of plant cycle, so selection for increased salt tolerance can be carried out at the initial growth stage. Secondly, it is found that there is great variation of salt tolerance in sunflower. Low uptake of Cl−, high uptake of K+, and maintenance of high K:Na ratios and K+versus Na+selectivity in the leaves and possibly the accumulation of organic osmotica such as soluble carbohydrates, soluble proteins, proline and free amino acids seem to be the important components of salt toleran

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01122.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY