摘要:

Alyssum pintodasilvaeDudley is a nickel (Ni) hyperaccumulator endemic to serpentine soils of north‐east Portugal. In one experiment, the effects of cadmium (Cd), chromium (Cr), copper (Cu), Ni, lead (Pb), and zinc (Zn) on the growth and mineral composition of this species were evaluated. The growth of A.pintodasilvae,measured by dry matter accumulation, was not influenced by the presence of Cr, Cu, Pb, Ni, or Zn in the soil, but Cd applications led to significant decreases in dry matter yield. The addition of heavy metals to the soil resulted in increased uptake and translocation byA. pintodasilvaebut only Ni was accumulated to high levels. In a second experiment, two cuts of A.pintodasilvae,grown on a Ni‐enriched soil, were compared. Nickel concentrations were higher in the second cut, suggesting the possibility of continued growth and harvest of this plant to detoxify Ni‐contaminated soils.

ISSN:0190-4167    

DOI:10.1080/01904169609365151

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Fine fescues(Festucaspp.) are generally considered acid tolerant compared to other cool‐season turfgrasses. However, there is little information on aluminum (Al) tolerance of fine fescues at both the species and cultivar levels. The objectives of this study were to identy cultivars of fine fescues with superior ability to tolerate Al, and compare the Al tolerance of endophyte infected and endophyte‐free cultivars in Al tolerance. A total of 58 cultrvars of fine fescues belonging to five species or subspecies [14 hard fescue (F.longifoliaThuill), 25 Chewings fescue (F.rubraL. ssp.commutataGaud), 15 strong creeping red fescue (F.rubraL. ssp.rubra),two slender creeping red fescue (F.rubraL. ssp. trichophylla), and two sheep fescue (F.ovinaL.)] were selected from the 1993 National Fineleaf Fescue Test and screened under greenhouse conditions using solution culture, sand culture, and acid Tatum soil (Clayey, mixed, thermic, typic, Hapludult). The acid Tatum soil had 69% exchangeable Al and a pH of 4.4. An Al concentration of 640 μM and a pH of 4.0 were used in solution culture and sand culture screening. The grasses were seeded and grown for three weeks before harvesting. Aluminum tolerance was assessed by measuring relative root length, shoot length, root weight, shoot weight, and total dry matter. Differences in Al tolerance were identified at both the species and cultivar level based on relative growth were as follows: i) hard fescue and Chewings fescue were more Al tolerant than strong creeping red fescue; ii) within species or subspecies, significant differences were found among cultvars of Chewings fescue, strong creeping red fescue, slender creeping red fescue, and sheep fescue; whereas no difference was observed among the hard fescue cultivars; and iii) the cultivars containing endophyte exhibited greater Al tolerance compared the eudophyte‐free cultivars. The results indicate that fine fescues vary in Al tolerance and there is potential to improve Al tolerance with breeding and to refine their management recommendations regarding soil pH.

ISSN:0190-4167    

DOI:10.1080/01904169609365152

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The Diagnosis and Recommendation Integrated System (DRIS) has been found reliable in diagnosing nutrient requirements, despite changes in the tissue sampling or the time sampling. Relatively few researchers use the results obtained by hydroponic culture to make a DRIS data bank. In this work, results obtained in this way have been utilized as DRIS reference values to evaluate the iron (Fe) supply influence on the nutrition of different citrus combinations under normal and deficient Fe conditions. The DRIS indices have been compared with standard methods to evaluate the effectiveness of this system of interpretation. TheCitrus macrophyllarootstock for lemons is more resistant to Fe chlorosis than Sour orange. Based on the diagnosis of visual symptoms, theCitrus volkamerianais more resistant to this nutritional deficiency for oranges than the Cleopatra mandarin.

ISSN:0190-4167    

DOI:10.1080/01904169609365153

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A sand culture experiment was conducted to study the effect of saline water on the growth and fruit quality of processing tomato(Lycopersicon esculentumMill.) Seedlings of five tomato cultivars were transplanted in quartz‐sand pots in a greenhouse at the Agricultural Experiment Station of Sultan Qaboos University. There were four saline nutrient solutions and a control consisting of half‐strength Hoagland solution. Salinity treatments were: 50 raM NaCl + 3 mM K2SO4(EC 6.75), 50 mM NaCl + 1.5 mM orthophosphoric acid (EC = 7.18), 50 mM NaCl + 1.5 mM orthophosphoric acid + 3 mM R2SO4(EC 7.29), and 50 mM NaCL (EC = 5.6). Treatments were applied daily commencing two weeks after transplanting. Data were collected on growth, and fruit yield and quality. Partitioning of mineral elements was determined in the vegetative tissue. The results obtained clearly show that concentrations of total soluble solids were increased in fruits treated with saline nutrients. Dry matter content of fruits exposed to salinity were higher than those from the control plants. Fruit acidity was increased with salinity, possibly due to a lower water content and increased organic acid accumulation. In the saline treatments, sodium (Na) content was decreased when potassium (K) was applied with NaCl but Na was higher in stems followed by root and leaf tissues. The partitioning of K followed a trend opposite to that for Na but with higher content in leaves. A similar situation was observed for calcium (Ca) and magnesium (Mg). Accumulation of phosphorus (P) was the lowest among all the ions. These results indicated that survival under saline conditions was accompanied by high ion accumulation. The study confirmed that saline nutrients are important for improving fruit quality of processing tomatoes.

ISSN:0190-4167    

DOI:10.1080/01904169609365154

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Osmotic and specific ion effects arc the most frequently mentioned mechanisms by which saline substrates reduce plant growth. However, the relative importance of osmotic and specific ion effect on plant growth seems to vary depending on the salt tolerance of the plant under study. Pea plants grew in Na2SO4and NaCl treatments up to the ‐1800 kPa level, but only in the Na2CO3treatments up to the ‐1200 kPa level. The higher toxicity of Na2CO3compared to that of Na2SO4and NaCl treatments was observed. This point was made clear by their effects on fresh dry matter and water content of the pea plants. The value of osmotic pressure was markedly increased with increasing NaCl concentration in the soil and under the moderate levels of the Na2SO4treatments, while it was significantly decreased with increasing Na2CO3concentration. This was also related to the accumulation of soluble saccharides, proteins, amino acids, and prolines in plants treated with NaCl and in plants grown under Na2SO4, with the accumulation of soluble saccharides and proteins observed. The chloride (Cl) and sulphate (SO4) contents accumulated to a greater degree for plants treated with NaCl and Na2SO4, respectively. Thus, these anion accumulations may contribute to the osmotic adjustment for the Cl‐ and SO4‐treated plants. Therefore, the degree of salt tolerance during pea plant growth in Na2CO3, Na2SO4, or NaCl may not be always the same.

ISSN:0190-4167    

DOI:10.1080/01904169609365155

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Two cultivars of corn(Zea maysL., ‘HS7777’ Al‐sensitive and ‘C525‐M’ Al‐tolerant) were grown in nutrient solution at low aluminum (Al) activity to investigate the Al toxicity effects on their growth and mineral nutrition. With increasing levels of Al in the nutrient solution, root growth and root dry weights decreased for both cultivars, while higher reductions were found for ‘HS7777’. The concentrations of nitrogen (N), calcium (Ca), magnesium (Mg), potassium (K), and manganese (Mn) in the shoot and roots and iron (Fe) and zinc (Zn) in the shoot only decreased with the increase of Al levels in solution for both cultivars. This increase of Al toxicity increased the concentrations of carbon (C), copper (Cu), and boron (B) in the shoot and C, P, Fe, and Cu in the roots for both cultivars. High average concentrations of Ca, Mg, Mn, and Cu were found in the shoot of ‘HS7777’. No differences in the concentrations of Al, Ca, Mg, P, and Mn were observed in the roots of the two cultivars. Aluminum concentrations were considerably higher in the roots than in the shoot, although lower Al concentrations in the shoot were found for ‘C525‐M’.

ISSN:0190-4167    

DOI:10.1080/01904169609365156

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Pre‐incubation of the tonoplast vesicles from corn roots with poly(L‐aspartate) (MW 14,000 Da) significantly inhibited the proton pumping associated with the ATP hydrolysis activity of the H+‐ATPase. However, this polyanion only slightly affected the hydrolytic activity. The potency of poly(L‐aspartate) to inhibit the proton pumping increased as the concentration of KCl or ionic strength decreased suggesting an electrostatic origin for the inhibition. When poly(L‐aspartate) was added after the initiation of the ATPase activities, no significant effect on proton pumping was noted. The results suggest that certain‐ NH3+groups on the cytoplasmic surface of the tonoplast membrane may electrostatically interact with poly(L‐aspartate) to produce observed inhibition. Furthermore, the accessibility of these ‐NH3+groups to poly(L‐aspartate), appears to be regulated by the functional state of the H+‐ATPase.

ISSN:0190-4167    

DOI:10.1080/01904169609365157

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The influence of nitrogen (N) on dry matter accumulation and yield in cotton is well documented, but its effects on carbon (C) assimilation and transpiration are less clear. The objectives of this study were to characterize leaf photosynthetic and stomatal responses of Pima cotton(Gossypium barbadenseL., cv. S‐6) plants, grown under different N nutritional regimes. Pima cotton was grown in pots under natural environmental conditions. Varying N regimes were imposed on 20‐day‐old plants by fertilizing with nutrient solutions containing 0, 0.5, 1.5, and 6 mM of nitrate (NO3) concentrations. Net carbon dioxide (CO2) assimilation rates, stomatal conductance, internal CO2partial pressures, transpiration rates, leaf carbohydrate status, ribulose 1,5‐bisphosphate carboxylase/oxygenase (Rubisco) activities, and leaf N concentrations were determined in the youngest fully expanded leaves. Net photosynthetic rates, stomatal conductance and transpiration were positively correlated with leaf N concentration. The maximum photosynthetic photon flux density‐saturated net assimilation rates were about 30 μmol m‐2s‐1when fed with 6 mM NO3and only about 15 μmol m‐2s‐1when fed with 1.5 mM NO3. Maximum net photosynthetic rates of high N‐treated plants were achieved at approximately 1,800 umol photons m‐2s‐1. Assimilation rates increased from 15 to 35 μmol CO2m‐2s‐1as leaf N increased from 16 to 45 g kg‐1leaf dry weight, respectively, at the rate of 0.6 μmol m‐2s‐1per unit increase in N. Stomatal conductance increased with increasing leaf N concentration, while the photosynthesis to water use efficiency (mg CO2/g H2O) was not affected by leaf‐N status. Rubisco activities were proportional to leaf N concentration. Leaf starch decreased with increasing leaf N while sucrose content increased. The ratios of starch/sucrose decreased from 5.3 to 1.2 as leaf N increased from 16.5 to 45 g kg‐1.

ISSN:0190-4167    

DOI:10.1080/01904169609365158

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The beneficial effect of titanium (Ti) on plant metabolism can result in more profitable use of fertilizer applied to a crop. A crop chamber experiment with paprika pepper(Capsicum annuumL., cv. Bunejo) seedlings under differential nitrogen (N) concentration levels in a nutrient solution (100% N, 75% N, 50% N, and 25% N) was performed. A third of the seedlings growing under each N support level remained Ti‐untreated and were used as the reference. Another third of the seedling received one and two 0.042 mM Ti(TV) ascorbate, pH 6.0, leaf spray treatments, respectively. The biomass production of the Ti‐untreated plants was only affected by the N supply of 50% or less. The Ti(IV) leaf spray treatments produced a biomass production greater than that of the corresponding reference plants, and both the 100% N+Ti and 75% N+Ti treatments had the highest biomass production. Seedlings receiving 50% N+Ti had a level of biomass production similar to that for the 100% N without Ti reference plants. In the same way, the 25% N+Ti treatment resulted in a plant fresh weight greater than that for the Ti‐untreated reference plants, although their biomass yields were not significantly lower than that for the corresponding 100% N and 75% N Ti‐untreated reference plants. Only the 50% N and 25% N Ti‐untreated plants had definite total‐N and nitrate‐nitrogen (NO3‐N) unbalances as compared to the other N rate‐Ti treatments.

ISSN:0190-4167    

DOI:10.1080/01904169609365159

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Four cultivare of triticale along with one check cultivar each of bread wheat and rye were field grown at Aligarh, India, to determine the effect of progressive application of combined nitrogen + phosphorus (N+P) fertilizer levels on nitrate reductase activity (NRA) in flag and penultimate leaf at three stages of crop development. Leaf NRA increased with increasing combined N+P levels up to 240 kg N+P/ha. Later, there was a general decrease in the activity of the enzyme despite increasing N and/or P in the fertilizer combinations. Leaf NRA was declined with the successive growth stages (tillering > heading > milky grain) as well as with the leaf age (unexpanded flag leaf > expanded flag leaf > penultimate leaf) at the corresponding stages. Moreover, the cultivare catagorically exhibited positive correlations between NRA levels and grain and protein yield at different growth stages, indicating towards the possibility of utilizing leaf NRA as a physiological parameter during the screening of improved cultivare of triticale.

ISSN:0190-4167    

DOI:10.1080/01904169609365160

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor