摘要:

A survey of precollege biology education materials revealed that fundamental plant mineral nutrition concepts typically received minimal coverage. The information provided was also often outdated and contained misconception's or errors,e.g.a description of plant hydrogen deficiency symptoms, a statement that plants absorb nitrogen only as nitrate, and a complete nutrient solution recipe with boron at a toxic 15 mg/liter. Despite these problems, plant mineral nutrition could and should become an essential part of precollege curricula because of its relevance to everyday life,e.g.fertilizer use in home gardening and commercial agriculture; the public fascination with hydroponics,e.g.Walt Disney World EPCOT Center's Land exhibit; the excellent hands‐on aspects of plant solution culture in the classroom; and the interdisciplinary nature of plant mineral nutrition, which links biology, chemistry, math, history and agriculture. Plant mineral nutritionists could play an important role in precollege education by assisting precollege teachers with classroom solution culture on a one‐to‐one basis, providing preservice and inservice workshops on solution culture and developing accurate plant mineral nutrition teaching materials, especially simple and inexpensive hands‐on classroom activities.

ISSN:0190-4167    

DOI:10.1080/01904169309364524

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Alfalfa (Medicago sativaL.) clones were selected by growing synthetic populations of AT‐4, B13‐AL4, AS‐4, and Williamsburg in Tatum soil (pH 4.5) and solution culture (pH 4.5, 111 μmol Al/L). Two‐month‐old clones were grown in a controlled growth room (28°C, 60% RH, 530 μmol/m2/s light for 14 h) at three levels of soil Al saturation (59%, 38%, and 0.3%) in a Porters soil (Umbrlc Dystrochrept) to evaluate differences in growth, nutrient uptake, and nutrient efficiency ratios (ER = shoot dry weight produced per unit of element in shoot). Shoot growth nutrient uptake and ER were significantly different with respect to soil Al saturation, clones, and their interactions. Overall shoot nutrient content showed significant (P<0.01) positive correlations with shoot weight and significant inverse relationships with shoot Al concentration and soil Al saturation. In general, ER values were inversely related to shoot Al concentration. Depending on the element involved, the correlations between ER and shoot dry weight and soil Al saturation were either positive or negative. The soil and solution culture methods used in this investigation to induce a range of soil acidity tolerance have helped to demonstrate interspecific diversity in alfalfa for growth and nutrient uptake parameters.

ISSN:0190-4167    

DOI:10.1080/01904169309364525

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Calcium (45Ca2+) absorption by roots of four sorghum [Sorghum bicolor(L.) Moench] cultivais decreased as aluminum (Al3+) concentration (0, 0.1, 1.0, and 10.0 mM) increased. The data fit a logarithmic curve. Cultivars were Funk GS22DR, GP‐10, SC574, and SC283. When plotted as percentages of the respective untreated test, the curves of the four cultivars were identical. Previously published ion carrier and ion channel inhibitor studies showed genetic differences in response to ion carrier and ion channel inhibitors. Uniformity of cultivar response to Al3+shows that the Al3+response was on the exterior side of the plasma membrane. Disruption of the Ca2+mediated second messenger and metabolic control system by Al3+would constitute a major Al3+toxicity sensitivity system.

ISSN:0190-4167    

DOI:10.1080/01904169309364526

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Erythrosine B (EB), a specific inhibitor of calcium (Ca2+)‐dependent Mg2+‐ATPase in plasma membranes, was evaluated for influence on45Ca2+uptake by 1 cm root tips from seedlings of four sorghum [Sorghum bicolor(L.) Moench cv Funk G522DR, GP‐1O, SC574, SC283] cultivars. Erythrosine B (0.01 μM) inhibited45Ca2+uptake 33% in SC574 and GP‐10; but higher concentrations (1 μM) were required to produce equivalent45Ca2+uptake inhibitions in SC283 and Funk G522DR.

ISSN:0190-4167    

DOI:10.1080/01904169309364527

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Increasing concentrations of calcium (Ca2+) channel blockers (i.e. ‐ nifedipine, verapamil, and diltiazem) in the presence of a sulfhydryl inactivator (1 mM PCMBS) were evaluated on root tips (1 cm) of sorghum [Sorghum bicolor(L.) Moench. cv GP‐10, SC574, SC283, Funk GS22DR]. Cultivar differences were found in response to all three Ca2+channel blockers. Ruthenium red inhibits Ca2+‐ATPase and in combination with verapamil causes major differences in response by all four cultivars to verapamil + PCMBS. None of the treatments induces complete inhibition of45Ca2+uptake, indicating multiple types of cation nutrient uptake channels.

ISSN:0190-4167    

DOI:10.1080/01904169309364528

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Root tips (1 cm) from sorghum [Sorghum bicolor(L.) Moench cv SC574, SC283, GP‐10, and Funk G522DR] cultivars were exposed concomitantly to45Ca2+and ruthenium red (0,0.001,0.01, 0.1, or 1 mM) at pH 5.5 in 0.01M sodium acetate buffer. Ruthenium red induced a decreased45Ca2+uptake that was 50% inhibited between 0.01 ‐ 0.1 mM ruthenium red. Ruthenium red is known to inhibit Ca2+‐ATPase but not H+‐ATPase. When the roots were exposed to 0.1 mM ruthenium red at pH 6.0, 5.5, 5.0, 4.5, or 4.0, deceased45Ca uptake occurred as H+concentration increased. Although there were differences between45Ca in total uptake when plotted as percentages of the uptake at 0 ruthenium red (pH 5.5) or at pH 6.0 (0.1 mM ruthenium red), inhibition of45Ca uptake by increased H+or ruthemum red concentrations was equivalent among the cultivars.

ISSN:0190-4167    

DOI:10.1080/01904169309364529

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The experimental material consisted of root segments excised from grape cuttings maintained in nutrient culture. In every experiment reported here washed roots absorbed Rb at substantially higher rates than unwashed root segments. The absorption of Rb per unit weight of root was generally in the same low range for unwashed roots with little regard to diameter, age, browning, or the presence of an intact root apex. On the other hand, after washing, uptake was much higher in large diameter roots than smaller ones, higher in white roots than in brown ones, and higher in younger tissues than older ones, The response to washing is markedly reduced by the presence of an intact attached root apex.

ISSN:0190-4167    

DOI:10.1080/01904169309364530

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Iron deficiency chlorosis (Fe‐DC) results in an extensive reduction in the fruit yield of strawberry(FragariaxananassaDuch.) grown on high pH calcareous soils. Three cultivars, differing in their response to Fe‐DC, were grown on a high pH (8.2) calcareous soil (15.4% calcium carbonate equivalent in surface 20 cm) in the field (Choueifat, coastal area of Lebanon) to determine what effect Fe‐DC had on fruit yield when the foliage was sprayed with Fe [FeEDDHA, Ferric ethylenediiminobis (2‐hydroxyphenyl) acetate], Unsprayed plants were used as the control. No significant interaction (p<0.05) between cultivar x Fe spray treatment was obtained, and no significant difference (p<0.05) between one and two Fe spray(s)/week treatments were noted for visual Fe‐DC rating, fruit numbers, and fruit yield. Cultivars sprayed once/week produced higher yields than unsprayed controls. Overall increases were 33% (13% for ‘Motto’, 30% for ‘Chandler’, and 56% for Douglas'). Even though only slight Fe‐DC was noted on the ‘Motto’ cultivar receiving no Fe spray, fruit yields were increased when plants were sprayed with Fe. However, significant increases in yield for the ‘Chandler’ and ‘Douglas’ cultivars with severe Fe‐DC ratings were obtained when they were sprayed with Fe.

ISSN:0190-4167    

DOI:10.1080/01904169309364531

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The effects of varying potassium (K) and sodium (Na) fertilization levels on ‘Shawnee’ blackberry (Rubus, subgenusEubatus, spp.) plant growth and leaf elemental content were studied in sand culture experiments. Increasing ? fertilizer levels linearly increased K, but decreased magnesium (Mg) and zinc (Zn) in the leaves. Concentrations of Na, calcium (Ca), copper (Cu), iron (Fe), and manganese (Mn) were not significantly influenced by ? fertilization. Plants contained six times more Na with high than with low Na fertilization. Sodium fertilization did not significantly affect leaf K, Ca, Mg, Fe, Cu, or Zn, but leaf Mn was linearly reduced by increasing Na fertilization. Leaf ? and Na were directly influenced by the amounts of supplied ? and Na. ‘Shawnee’ blackberries readily take up Na, but exhibit some salt tolerance at low to moderate Na fertilization levels. At high Na levels, they appear to lack a mechanism to reduce Na uptake which results in reduced plant growth.

ISSN:0190-4167    

DOI:10.1080/01904169309364532

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Aluminum‐tolerant soybean cultivars are needed for deeper rooting and increased drought tolerance in acid subsoils. A major limitation in the development of such cultivars is Al‐screening methodology. Shoot growth is often used to infer root growth, but the genotypic relationships between root and shoot growth of older soybean plants have not been evaluated. Our objectives were (i) to test the hypothesis that shoot growth is a reliable indicator of acid soil (Al) tolerance in soybean, and (ii) to determine the relative Al tolerances of selected soybean genotypes. Nine genotypes were evaluated for Al tolerance by growing them for 37 days in greenhouse pots of unlimed (pH 4.3) and limed (pH 5.3) Tatum subsoil. Aluminum tolerance was determined by root and shoot growth and plant symptoms. Aluminum tolerance was detected using both shoot and root growth, and agreement between these two selection criteria was good. Genotypic correlations between root and shoot growth for unlimed soil, for limed soil, and for growth on unlimed soil expressed as a percentage of that on limed soil were 0.89, 0.86 and 0.93, respectively. Results support the conclusion that shoot growth can be used effectively to screen for acid soil (Al) tolerance in soybean. PI 416937 and Perry cultivars were classified as most tolerant, but the former was more susceptible to petiole collapse than the latter, suggesting that their tolerance mechanisms may be different. Forrest, Bossier, and Chief were the least tolerant when grown in the Tatum subsoil at pH 4.3. When plants were grown on unlimed soil, the first trifoliolates of the Al‐tolerant, symptom‐free Perry contained significantly lower concentrations of Al and Fe than did those of PI 416937 which showed petiole collapse. First trifoliolates of Al‐tolerant Perry were also significantly lower in Al and Fe than those of Al‐sensitive Chief, which showed severe leaf distortion and stunting on the unlimed soil. We conclude that variation for Al tolerance exists in soybean and that this variability may be sufficient to warrant breeding attention.

ISSN:0190-4167    

DOI:10.1080/01904169309364533

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor