摘要:

Root elongation of corn(Zea mayscv. Hycorn 82) and mungbean(Vigna radiatacv. Berken) seedlings was measured in dilute complete nutrient solutions to which varying amounts of lanthanum (La) or cerium (Ce) had been added. The nutrient solutions were aged for 9 d prior to conducting the root elongation experiments and solution samples ultra‐filtered to 0.025 μm before chemical analyses for La or Ce, and phosphorus (P). Concentrations of La up to 10 μM and concentrations of Ce up to 8 μM remained in solution in the presence of 5 μM P at pH 4.5, but substantial losses of these elements and P occurred at pH 5.5. The relative root elongation of both plant species decreased with increasing concentrations of La or Ce in solution. Mungbean was much more sensitive than corn. Cerium was more toxic than La to mungbean, the concentrations associated with a 50% reduction in root elongation being 0.9 μM Ce and 3.1 μM La. Lanthanum was more toxic to corn than Ce, the concentrations corresponding to a 50% reduction in root elongation being 12.2 μM Ce and 4.8 μM La at pH 5.5, or 7.1 μM La at pH 4.5.

ISSN:0190-4167    

DOI:10.1080/01904169509365037

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Corn(Zea mayscv. Hycorn 82) and mungbean(Vigna radiatacv. Berken) plants were grown for 14 d in dilute nutrient solutions containing constant lanthanum (La) concentrations from 0 to 1.37 μM. Solutions were maintained at pH 4.5 to prevent precipitation of La. Lanthanum at 0.63 μM increased the root growth of corn by 36% and 0.19 μM La increased mungbean root growth by 21% relative to controls. However, no beneficial effects of La on the total dry matter yield of either plant species were demonstrated; that of corn was unaffected, whilst that of mungbean was reduced by over 30% at solution La concentrations greater than 0.19 μM.

ISSN:0190-4167    

DOI:10.1080/01904169509365038

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Corn(Zea mayscv. Hycorn 82) and mungbean(Vigna radiatacv. Berken) plants were grown for 16 d in dilute nutrient solutions containing constant cerium (Ce) concentrations from 0 to 1.31 μM. Corn root growth was increased approx. 2 fold at Ce concentrations 0.63 μM. However, the total dry matter production of corn was not significantly increased by Ce addition. With mungbean, the addition of as little as 0.19 μM Ce to the nutrient solution caused significant reductions in the dry weight of root (26%), shoot (48%) and total plant (44%). The youngest leaves of mungbean plants in the treatments containing 0.63 μM Ce displayed symptoms of manganese (Mn) deficiency. These leaves contained deficient Mn concentrations (5 mg/kg). Tissue concentrations of other nutrients in mungbean and all essential elements in corn were within ranges where healthy growth would be expected.

ISSN:0190-4167    

DOI:10.1080/01904169509365039

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Incorporation of bicarbonate (HCO3‐) by the roots of tomato seedlings resulted in an increase in biomass production and changed the chemical composition of xylem sap. In the xylem sap of seedlings grown on a medium enriched with HCO3‐(5.68 mM dm‐3, series II) compared with the control (series I) the element content increased by about 27% and 33% for cations and anions, respectively. Potassium was the major cation in the xylem sap and constituted 69% of the total concentration of all the inorganic cations determined. Calcium attained 19% of this amount. The anionic load in the xylem sap was chiefly nitrate, constituting about 90% of the content of all the inorganic anions. The exudate was analysed for seven organic acids. In general, malic (MA), maleic, and citric (CA) occurred in xylem exudate at greater concentrations, constituting about 95% of the total content of organic acids. Cultivation of seedlings on the medium enriched with HCOJ brought about an increased content of organic acids, exceeding the control by about 60%. The concentration of MA increased by about 104% and that of CA and maleic acid exceeded the control by about 40% and 14%, respectively. Twenty amino acids were identified in tomato xylem sap. Glutamic, aspartic and y‐arninobutyric acid, and particularly the amides aspargine and glutamine occurred in greater amounts. Their total concentration was about 60% and 70% of the total amino acid content in series I and II, respectively. The remaining amino acids occurred at concentrations ≥ 90 μM. The cultivation of plants on the medium containing HCO3‐resulted in an increase in amino acid content in xylem sap by about 28% as compared with the control. The ratio of amino acid to organic acid content was 2: 2.5 and 2: 3 for series I and II, respectively. The similar value of the ratio in the two series suggests that the synthesis of both groups of compounds be equally favoured by the carbon source (endogenous in the control and from the medium enriched with HCO3‐in series II). The increased level of elements and organic compounds in xylem sap in the case of plants supplied with HCO3‐is discussed in the work in respect of metabolic processes of roots.

ISSN:0190-4167    

DOI:10.1080/01904169509365040

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A greenhouse experiment was carried out in order to study the influence of three calcium (Ca)/potassium (K) ratios (0.25, 0.50, and 1.00) in the nutrient solution on nutrient uptake, mineral composition, and productivity of bean plants grown in sand culture. Nitrate consumption and nitrogen (N) plant levels were lower when the Ca/K ratio in the nutrient solution was 0.25. Calcium and K consumption and the corresponding concentrations in the plants were directly related with the Ca/K ratio in the nutrient solution. Magnesium (Mg) consumption decreased as the Ca/K ratio increased. The highest yields were obtained when the Ca/K ratio in the nutrient solution was 1.00.

ISSN:0190-4167    

DOI:10.1080/01904169509365041

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The objective was to establish a model of vegetative regrowth of plant matter in a stand of cocksfoot and tall fescue according to their nitrogen status. For three years (1989–1991), at the end of each spring, we studied regrowths in relation to differing supplies of nitrogen (120 kg/ha or low supply or nil). The herbage nitrogen status (IN) was estimated from the nitrogen concentration in the herbage and the above ground dry matter. The accumulated above ground dry matter was related to the amount of photosynthetic active radiation intercepted (PARi). The two parameters of the model, PARi (resulting from incident radiation and LAI) and the radiation use efficiency (RUE) depended on the herbage nitrogen status. For LAI, the parameters a, b, c of the model (LAI = a + b*T + c*T*IN) were not significantly different for the two species, (T = accumulated daily temperatures from the beginning of regrowth). On the other hand, RUE was about 15% higher for tall fescue in relation to a higher net photosynthesis activity. For other regrowths than those used for model calibration, measured above ground biomasses and LAI data were in good agreement with simulated data.

ISSN:0190-4167    

DOI:10.1080/01904169509365042

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In order to study the iron (Fe) distribution pattern in bean plants with different Fe nutritional status, french bean(Phaseolus vulgarisL.) seedlings were precultured in a complete nutrient solution with 8x10‐5M FeEDTA for five days. Thereafter, plants were further supplied with 8x10‐5M FeEDTA (Fe‐sufficient) or with only 2x10‐6M FeEDTA (Fe‐deficient) for another eight days. At this stage, the Fe‐deficient plants had much lower chlorophyll contents and lower dry weight of the leaves but higher reducing capacity of the roots compared with the Fe‐sufficient plants. For studies on short‐term distribution of Fe, the Fe‐sufficient plants were supplied 8x10‐5M59FeEDTA (specific activity 9.9 GBq/mol) and the Fe‐deficient plants 1x106M59FeEDTA (specific activity 98.8 GBq/mol). The plants were harvested after 4 and 24 hours. Despite a much lower supply of59FeEDTA/(factor 80), the Fe‐deficient plants took up significantly more59Fe but translocated less to the shoots (14.6% after 24 h) compared with the Fe‐sufficient plants (29.4% after 24 h). However, regardless of the Fe nutritional status of the plants, the majority of59Fe was translocated in the primary leaves. Our results demonstrate a similar distribution patterns of root‐derived59Fe in the shoots of Fe‐sufficient and Fe‐deficient plants, and thus, no preferential direct translocation of Fe to the shoot apex in the Fe‐deficient plants.

ISSN:0190-4167    

DOI:10.1080/01904169509365043

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Glomus aggregatumandAcacia mangiumwere interacted in an acid manganese (Mn)‐rich oxisol unamended or amended with hydrated lime [Ca(OH)2] or gypsum (CaSO4) at soil phosphorus (P) concentrations considered optimal for mycorrhizal host growth. Vesicular‐arbuscular mycorrhizal fungal (VAMF) colonization as well as VAMF function was significantly curtailed if soil was unamended with gypsum or lime. The highest mycorrhizal inoculation effect (MIE) was observed in the soil treated with gypsum at the rate of 0.32 g of calcium (Ca)/kg followed by the limed soil. Higher concentrations of gypsum deleteriously affected VAMF infectivity and effectivity. The first increment of gypsum compensated for part of the VAMF colonization and for all of the mycorrhizal inoculation effect that was lost due to low pH. The better MIE observed in the gypsum treated soil compared to that which was amended with lime suggests that the sensitivity of the acacia‐VAMF association to soil acidity was more a function of Ca inadequacy than it was of pH or associated increases in Mn concentration.

ISSN:0190-4167    

DOI:10.1080/01904169509365044

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A selection process for an ideal cover crop for yarn, maize, and cassava was initiated in 1993 cropping season in Makurdi, Nigeria. Four types of food legume crops grown locally were selected for the trials. The yield potentials of akidi(Phaseolus vulgaris),ground akidi(Sphenostylis stenocarpa),odudu(Phaseolus lunatus),and kafanji(Vigna unguiculata)were evaluated in two cropping seasons and under conditions where either no fertilizers, 50 kg nitrogen‐potassium‐phosphorus (NKP)/ha or 21 kg P/ha from single superphosphate (SSP) source were applied. The crops were planted in April and repeated in August of the same year in a 4 x 3 factorial in a split‐plot design. Fertilizer NKP generally increased the grain yield of all the crops significantly. The yield differences due to P fertilizers for odudu and akidi were not statistically significant (P=0.05). The P fertilizer resulted in significant increases in the grain yield of kafanji (from 1.113 to 1.7 mt/ha) and ground akidi (0.97 to 1.27). The biomass, root systems, and nodule yields were also increased proportionally by P application for all the legumes. No significant yield differences was observed between early and late crops in grain yield when no fertilizer was used. However, the crops produced about 30–40% less nodules, biomass, and root yield due to late planting (August).

ISSN:0190-4167    

DOI:10.1080/01904169509365045

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Young maize plants, grown hydroponically, were supplied with different amounts (7.5,0.75,0.15, 0.075, and 0 mg Fe/L) of iron (Fe). At 14, 21, and 28 days,in vitroactivities of catalase, peroxidase and nitrate reductase in leaves were determined. Strong and complete Fe deficiency resulted in decreased enzyme activities. Under moderate Fe deficiency—often a restoration of the normal activity after an initial reduction—was observed. The rapidity and the degree of reaction to Fe deficiency depended on the enzyme. The ratio peroxydase/catalase activity can not be applied as a reliable tool for diagnosis of Fe deficiency.

ISSN:0190-4167    

DOI:10.1080/01904169509365046

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor