摘要:

Winter legumes can benefit subsequent crops by improving soil and water conservation, and by providing N. The amount of N produced is influenced by soil pH, fertility level and other factors. Maximum N is essential for returns which will offset production costs. A two year study was conducted on a Norfolk fine sandy loam, (Typic Paleudult) to determine the effects of lime and P on nodulation and N production by winter annual legumes. Treatments consisted of 0, 123, and 246 Kg P/ha; 0 and 4.5 Mg lime/ha; and arrowleaf clover (Trifolium vesiculosumSavi), crimson clover (Trifolium incarnatumL.) and common vetch (Vicia sativaL.). The initial soil water pH was 5.1 and Mehlich No. 1 extractable P was 6 kg/ha.

ISSN:0190-4167    

DOI:10.1080/01904168609363511

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Eighty‐five maize lines were evaluated in a primary screen for differences in uptake rate at 1 mM KNO3; 15 were statistically separable into either “high”; or “low”; populations. Kinetic parameters were determined by iterative, least‐squares regression using a model combining both a saturable and a linear component. Using the inbred B73 as an arbitrary standard, it was determined that the saturable component had a Km of 224 μM and a Vmax of 0.107 μmolNO3/mg root dry weight/hr. The ,linear component had a first order rate constant of 6.1 × 10‐2μmol NO3/mg root dry weight‐hr/mM. These values compared favorably with other published determinations of nitrate uptake kinetic parameters for saturable systems. No other constants have been reported for a linear component of nitrate uptake in higher plants.

ISSN:0190-4167    

DOI:10.1080/01904168609363512

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A compound has been isolated from sterile iron‐free hydroponic culture of soybeans (Glycine max(L.) Merr. cv. Amsoy 71) which, following thin‐layer chromatography, gives a brown reaction with Fe3+, a violet reaction with VO3‐, is ninhydrin positive, and tests positively for hydroxylamine nitrogen, but does not support growth ofArthrobacter flavescensJG‐9. The compound is produced in greater amounts in iron‐free than in complete nutrient culture. It is suggested that the compound is a siderophore produced by the plant in response to iron stress.

ISSN:0190-4167    

DOI:10.1080/01904168609363513

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Root cation exchange capacity (CEC) was analyzed for four cotton cultivars (Pima S‐5, Stoneville 825, Deltapine 41 and Auburn 56) within tvo species (Gossypium barbadenseandG.hirsutum) grown in control (O Al) and Al (1.5 mg/l) solution. Pima S‐5, aG.barbadensevariety, had significantly (P < 0.10) lower root CEC thanG.hirsutumcultivars in control (O Al) solution. Root CEC of Stoneville 825 was numerically but not significantly lower than Auburn 56 and Deltapine Al in control solution. Root CEC was significantly reduced in all cultivars when grown in Al solution. Compared to controls, Pima S‐5 and Stoneville 825 had either numerically or significantly less reduction in root CEC than Auburn 56 or Deltapine 41 in Al solution. Aluminum content of roots after CEC analysis was numerically greater in the former cultivars than the latter.

ISSN:0190-4167    

DOI:10.1080/01904168609363514

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Greenhouse grown sour orange (Citrus aurantiumL.) seedlings were pruned back to 1/3 of the original height or 8 cm tall. One treatment removed 70% (+L) and the other 100% (‐L) of the original foliage. In addition, stem was girdled to remove bark strips encircling 1/3, 2/3, or 3/3 of the stem circumference. At 0–2/3 girdling, the ‐L pruning treatment resulted in less new shoot growth and dry matter production and increased leaf levels of N, K, Mg, Ca, Zn, and Cu compared to the +L pruning treatment. Increases in leaf N, K, Mg, and Ca at ‐L pruning treatment were accompanied by lower levels of those elements in roots and/or stems indicating that retranslocation within the plant could have been responsible for elevated leaf N, K, Mg, and Ca levels. Increased absorption in relation to dry matter production was responsible for higher leaf Zn and Cu levels. Mineral nutrient uptake was reduced in plants completely girdled due to the shortage of energy in roots and possibly also a shortage of a shoot produced hormones. Partial girdling of the stem had a negligible effect on seedlings growth and nutrient status since the remaining bark at the site of girdling increased in thickness and probably compensated for that removed.

ISSN:0190-4167    

DOI:10.1080/01904168609363515

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The cation exchange capacity of roots (CECR) has been measured according to three different methods : titration of H‐roots with NaOH in the presence of CaCl2, MgCl2, or NaCl 0.1 N, saturation of roots with mixed Ca‐Mg‐Na solutions of eight different compositions and extraction of the adsorbed cations with copper, saturation of roots with Cu‐ions and extraction with HC1. Two types of roots were studied : roots of ryegrass(Lolium multiflorumLm.) and roots of clover (Trifolium pratense L.)

ISSN:0190-4167    

DOI:10.1080/01904168609363516

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The effects of transpiration rate on B uptake by roots and translocation to shoots of table beet (Beta vulgarisL. cv. Red Ace) plants were studied under conditions of environmental control. Plants grown under high or low relative humidities (RH) had low or high rates of transpiration, respectively. Dry weights and B contents of shoots and roots were higher among plants grown at 80% RH and B concentrations of roots were lower compared to plants grown at 30% RH. Shoot B concentrations were not affected by RH. Rates of growth and B accumulation in shoots were closely correlated for plants grown in 30% or 80% RH. These parameters were not closely correlated in roots.

ISSN:0190-4167    

DOI:10.1080/01904168609363517

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0190-4167    

DOI:10.1080/01904168609363510

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor