摘要:

Soybeans accumulate N in vegetative tissues up to pod initiation after which total vegetative N may remain constant during early phases of pod development. Eventually much of the vegetative N is mobilized to the pods. The mobilization of N from vegetative tissue to pods during the first few days of pod development is poorly understood but is important to an overall understanding of soybean N nutrition. The vegetative tissues of field grown soybeans were labelled with15N and sampled weekly during the reproductive phase of plant growth. Three foliar applications of (15NH4)2SO4were made prior to pod initiation at a combined rate of 3.3 kg N/ha. To immobilize soil N and to increase soybean dependance on N2‐fixation, sawdust was applied at a rate of 52 t ha‐1. Irrigation was required almost weekly because of a shallow soil profile and below normal summer precipitation. Mobilization of vegetative N began immediately upon pod initiation and continued at a linear rate through pod development. It appeared that N2‐fixation was able to provide approximately half of the N in pods during early podfill. Nitrogen content of vegetative tissue declined as soon as pods began developing.

ISSN:0190-4167    

DOI:10.1080/01904168209363043

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

In a lysimeter experiment the overall amino acid concentration in dry matter of ryegrass (Lolium perenne) increased in response to nitrogen application. Lack of water reduced the overall concentration of most amino acids in dry matter except proline the concentration of which was increased. Nitrogen application as well as lack of water significantly affected the overall amino acid composition, and in particular the relative concentration of glutamic acid and proline, respectively, which might be attributed to variations in the free amino acid composition, and resulting in a decreasing overall ratio essential/not essential amino acids.

ISSN:0190-4167    

DOI:10.1080/01904168209363044

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Incorporation of [14C] tyrosine into protein of lettuce seedlings was utilized to determine:

ISSN:0190-4167    

DOI:10.1080/01904168209363045

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Deep seeding of wheat, a common practice when soil moisture is deficient, causes poor seedling emergence and stand establishment. We investigated whether increasing seed protein content by nitrogen fertilization of parental plants might increase emergence rate and vigor of winter wheat seedlings from deep‐planted seeds. Four seeding depths, three cultivars, and three seed protein contents were compared in different soil mixtures and fertility regimes. Under all treatments, emergence rate and dry weight of seedlings markedly decreased as seeding depth was increased. Increasing protein content of seeds sometimes, but not always, increased seedling emergence rate and commonly increased seedling dry weight regardless of soil mixture or fertility regime. Differences were greatest at 4.8‐ and 12‐cm seeding depths; seedlings failed to emerge from 16‐cm depth under any treatments. We concluded that increasing seed protein content by nitrogen fertilization of parent plants is an economic and efficacious method of enhancing wheat establishment when seed must be deeply planted.

ISSN:0190-4167    

DOI:10.1080/01904168209363046

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Objectives of our studies were to quantify effects of salinity on growth and nitrogen metabolism of wheat and to measure variation in response of different cultivars, hybrids, and classes. Methods and criteria for identifying resistance to salinity in wheat, particularly effects on nitrogen metabolism also were tested. Variation in response to salinity was measured by subjecting seedlings of six wheats to one control treatment (‐0.1 bars) and two stress treatments (‐3.5 and ‐10.4 bars) from NaCl, MgSO4, and MgCl2in hydroponic solutions. Both stress treatments retarded growth; wheats significantly varied at ‐3.5 bars but not at ‐10.4 bars. Stress decreased root and shoot nitrate N and total N contents. Studies with one wheat cultivar showed that salinity decreased activity of nitrate reductase enzyme and stimulated accumulation of proline. Salinity more adversely affected vegetative stages than reproductive stages of plants grown to maturity. We concluded that salinity affected wheat by both osmotic effects and antagonism of nitrate metabolism from chloride. Absolute growth and relative growth at different stress levels were superior to differences in nitrogen metabolism as selection criteria for salinity tolerance.

ISSN:0190-4167    

DOI:10.1080/01904168209363047

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The relative response of poppy(Papaver somniferumL.) and eight crop and vegetable species to excess manganese was investigated in a glasshouse, solution culture experiment. Plant yields and manganese concentrations were measured after two and six weeks growth at five levels of manganese (10–800 μM).

ISSN:0190-4167    

DOI:10.1080/01904168209363048

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Various concentrations of Mg, NH4, and K in the root solution were studied on uptake of radiophosphorus by the root mass, movement to the xylem sap, and accumulation in the top of intact bean plants. Cation levels ranged from 0.02 to 30.0 mM. Potassium had little effect on radiophosphorus in all three measurements, regardless of the level of cation in the root solution. Magnesium and NH4, on the other hand, increased isotope in the root mass, plant top, and xylem sap. Magnesium was more effective in this respect than NH4. In all cases the increases in radiophosphorus occurred as an asymptote of cation level in the root solution.

ISSN:0190-4167    

DOI:10.1080/01904168209363049

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0190-4167    

DOI:10.1080/01904168209363042

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor