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Soybean [Glycine max(L.) Merr.] cultivars vary in plant growth response to Mn deficiency and toxicity. Cultivar selection for field studies to evaluate responses to Mn deficiency and toxicity is important. The objective of this study was to determine the differential sensitivity of cultivars to Mn deficiency and toxicity prior to regional field studies on the diagnosis and correction of Mn problems in the production of soybeans. For evaluating relative ranking of cultivars sensitive to Mn deficiency, seven soybean cultivars were grown in solution culture at severe (5 µg Mn/liter) and mild (50 µg Mn/liter) deficiency levels and compared with controls, (1,000 µg Mn/liter). For toxicity evaluations, seven cultivars were grown at severe (20 mg Mn/liter) and mild (10 mg Mn/liter) toxicity levels with controls at 0.5 mg Mn/liter. Cultivar sensitivity to Mn deficiency was partially dependent on the level of deficiency stress. ‘Davis’, ‘Lee 74’, ‘Bragg’, and ‘Pickett 71’ were the most sensitive under severe deficiency and Lee 74, Bragg and ‘Hutton’ were the most sensitive under mild deficiency. Davis, Lee 74, Pickett 71, Bragg, and ‘Ransom’ were the most sensitive to severe Mn toxicity at the severe Mn toxicity level. At mild toxicity, shoot weights as percent of control were similar for all cultivars. Visual symptom ratings and leaf blade Mn concentrations were significantly correlated with shoot dry weight as percent of control for Mn deficiency and toxicity stresses. The increased sensitivity to Mn toxicity by Lee 74 compared to that previously reported for the ‘Lee’ cultivar may be a result of genetic changes which occurred during the development of Lee 74.

Manganese (Mn) additions are required on certain southern Coastal Plain soils for maximum yield of soybeans (Glycine max(L.) Merr.). This study was conducted to determine the soil profile distribution of added Mn, the accumulation of Mn in soybean plant tops, and the production of plant dry matter in field plots having five rates of Mn and two soil‐pH levels. ‘Ransom’ soybeans were grown on an Olustee‐Leefield sand, an Ultic, Haplaquod‐Arenic, Plinthaquic Paleudult, adjusted to pH levels of 6.3 and 7.0 and supplied with Mn at 0, 5.6, 11, 22, and 56 kg/ha each year for three years. Near the end of the growing season in the first and third years, dry matter production and plant accumulation of Mn were determined on whole plants (R6 growth stage). At the end of the third year, extractable (DTPA and double‐acid) soil Mn was determined in 15‐cm increments to a depth of 90 cm. Considering all Mn rates and pH levels, < 0.5% of the added Mn could be accounted for in the plant tops. Soil depth samples showed that most of the added Mn remained in the upper 30 cm of soil, even though at the high Mn rate, a total of 168‐kg Mn/ha had been applied. Summation of the Mn contents of all soil depth increments revealed that double acid extracted 32 to 57% and DTPA 2.6 to 7.2% of the total amount of applied Mn. Total dry matter production was reduced at the 0‐ and 5.6‐kg Mn/ha rates at the high pH level compared to the 56‐kg Mn/ha rate. Maximum dry matter production was obtained on treatments producing plants containing as little as 59‐g Mn/ha. Correlations between plant top Mn content (g/ha) and extractable‐soil Mn (kg/ha) in various depth increments gave r‐values significant at the 1% level for both extractants. DTPA‐extractable Mn accounted for 72%, however, but double acid only 22% of the variation in plant top Mn, considering all Mn rates over both pH levels. Nearly all of the broadcast Mn applied to this very sandy soil remained in the rooting zone. Only a small fraction was accumulated into the tops of soybean plants, despite the fact that, in some treatments, the plants were under Mn‐deficiency stress. These results emphasize the inefficient utilization of broadcast Mn by soybean plants and suggest that other methods of application, such as foliar or band, should result in more efficient use of applied Mn.

Aluminum toxicity is frequently the limiting factor to crop production in acid soils. The diagnosis of Al toxicity for a specific wheat (Triticum aestivumL.) cultivar could be simplified by tissue analysis. Greenhouse studies were undertaken to determine the critical Al toxicity level for the cultivar ‘Stacy’ and tissue nutrients affected by Al status. Wheat plants were grown in 10 levels of Al (0, 1.9, 3.7, 9.3, 18.5, 37.1, 74.1, 148, 222, and 297 µMAl) in nutrient solution for 28 days. Aluminum toxicity reduced top dry weight, root dry weight, plant height, tiller numbers, and top/root dry weight ratio. Aluminum concentrations in the blade and stem tissues were low (maximum of 0.3 mmol kg−1in Blade 1, the most recently developed leaf with a developed ligule) and were linearly related to Al in nutrient solution. Aluminum is not readily accumulated in Stacy wheat. The critical Al toxicity levels, defined as the Al concentration in the tissue associated with a 10% decrease from maximum top dry weight due to toxicity, were 0.12 mmol kg−1in Blade 1 and 0.08 mmol kg−1in the whole plant. Knowing these tissue values, one may be able to detect Al toxicity from similar uncontaminated tissue from the Stacy cultivar sampled in the field. Using washed Blade 1 would be preferable to using the whole plant because soil contamination would be minimized. Aluminum toxicity decreased all elemental concentrations in Blade 1 and whole plants. With the exception of P and K in Blade 1, the decreases in elemental concentrations were related by either a linear or quadratic regression.

The authors propose a model for the arrangement of the phospholipid molecules in a lipid bilayer membrane, based upon both the structure of the fatty acyl chains packed in highly ordered hexagonal arrays below the main transition temperature and the ripple structures in which the ripple lines have a hexagonal symmetry. This assumption results in three kinds of the configurations, whose boundaries make the angle of 120° among them. According to this domain structure, the texture appearing on the freeze-fractured surface in the ripple phase can be explained consistently, and furthermore, the kinetics of the domain boundary motion can be understood satisfactorily.

The influence of Zn status on growth, photosynthesis, dark respiration, and carbonic anhydrase was determined to establish the relationship of these growth processes to the critical deficiency level (CDL) for growth of soybean (Glycine max(L.) Merr. cv ‘Bragg’). Soybean was grown in nutrient solution with Zn rates of 10, 20, 50, 100, 200, 500, and 1,000 µg Zn/liter for a period of 36 days after transplanting. Critical Zn deficiency level for top dry weight was determined as 12 µg/g dry weight in recently matured leaf tissue (blade 3 from the top). Maximum photosynthesis was associated with leaf blades containing also 12 µg/g. Zinc deficiency reduced photosynthesis and carbonic anhydrase activity. Minimum dark respiration was attained at the CDL for growth and severe Zn deficiency enhanced respiration.

Manganese deficiency is known to severely reduce growth and yield of soybean [Glycine max(L.) Merr.] plants, but little is known about the effects of Mn deficiency on soybean seed quality factors. Seed from field‐grown soybean plants containing leaf Mn concentrations ranging from 4 to 58 ppm were analyzed for oil and protein percentage. Seed oil and seed protein from selected treatments containing 4 to 44 ppm leaf Mn were analyzed for fatty acid and amino acid percentages, respectively. Severe Mn deficiency (less than 15 ppm Mn in the leaves) increased seed protein percentage and decreased seed oil percentage. Seed from plants with extremely low leaf Mn levels contained higher percentages of linoleic, palmitic, linolenic, and stearic acids and a lower percentage of oleic acid. The percentages of seed protein, seed oil, and fatty acids changed markedly at low leaf Mn levels but remained relatively constant above leaf Mn concentrations of 15 to 20 ppm. Percentages of amino acids in seed protein were relatively unaffected by Mn. The results show that several soybean seed quality factors can be markedly altered by deficient levels of Mn. These changes could have a significant influence on the quality of products derived from soybean seed.

Wheat (Triticum aestivumL.) production areas are expanding to soils low in available Mn in southern Georgia and to soils high in available Mn in northern Georgia. Useful data on Mn deficient and toxic levels in leaf tissue for top growth and physiological processes in wheat are needed to evaluate growth processes limiting wheat production. The objectives of this study were to correlate Mn deficiency and toxicity levels with top dry weight production, photosynthesis, chlorophyll concentration, and transpiration. Wheat plants were grown in 10 experimental concentrations ranging from 0.09 μMto 9.1 mMin nutrient solution. Photosynthesis and transpriration measurements were made on blade 1 of plants grown in the greanhouse. Total chlorophyll and Mn concentrations were determined on the experimental tissue after freeze‐drying. Foliar dry weights on a per pot (15 plants) basis were also determined. Severe Mn deficiency depressed top dry weight, photosynthesis, and total chlorophyll concentration, but transpiration was unaffected. Mild Mn toxicity reduced top dry weight but not photosynthesis, total chlorophyll concentration, or transpiration. Critical Mn deficiency levels for reducing top dry weight and apparent photosynthesis rates were similar, namely 0.23 and 0.30 mmol kg−1, repectively. Growth reduction from Mn deficiency is possibly due to reduced photosynthesis. Minimum Mn requirements for chlorophyll (0.14 mmol kg−1) is about one‐half of that for top production. The critical Mn deficiency level for transpiration could not be determined. The critical Mn toxicity level for top dry weight occurred at 7 mmol kg−1. Concentrations of 19, 19, and 24 mmol kg−1were required for the depression of photosynthesis, total chlorophyll concentration, and transpiration, respectively. Maximum growth and yield are expected when the range of Mn concentration in blade 1 is 0.23 to 7 mmol kg−1. The critical levels are prelimilinary values to be used in evaluating Mn status of field‐grown wheat for possible deficiency and toxicity.

Soybeans [Glycine max(L.) Merr.] have responded to supplemental Mn fertilizer on high water table soils when limed to soil pH levels near neutrality, but the effect of method and rate of Mn application under these conditions is not well understood. In a 3‐year study (1975–1977) on an Olustee‐Leefield sand (Ultic Haplaquod‐Arenic Plinthaquic Paleudult), four application methods (broadcast preplant, row at planting, sidedress, and broadcast preplant plus foliar spray), at four rates (0, 5.6, 11.2, and 22.4 kg/ha) of Mn were employed to evaluate their effects on yield, leaf blade concentrations, seed Mn levels, and extractable soil Mn levels. A 239% yield increase was obtained in 1977 with 11.2 kg Mn/ha compared to no applied Mn. Yield increases due to applied Mn were not obtained in 1975 and 1976, although visual deficiencies were evident early in the growing season every year. Yield increases were related to seed weight for the various Mn rates. Methods of Mn application did not influence yields in any given year. However, the row at planting application may have produced toxic effects since there were visual toxicity symptoms and trends of decreased yields each year. Leaf tissue sampled at the R‐2 growth stage indicated the Mn level should be greater than 15 ppm for maximum yields with broadcast application and the critical Mn level in the seed is 16 ppm. In this study, correlation and regression analyses indicated the seed Mn levels were better related to yield than leaf blade Mn levels. Double acid extractable soil Ma increased from 1975 through 1977 while DTPA extractable Mn showed a slight decrease. Both methods were well related to applied Mn rates. These data indicate that applied Mn rates influence soybean yields, soil Mn, tissue Mn, and seed Mn concentrations more than methods of Mn application.

Reference guideline values relating Mn concentration in plant tissue to growth is necessary for the assessment of the Mn nutritional status in cotton. Many of the presently available critical Mn levels were related to the presence or absence of deficiency symptoms. Refinement appeared necessary particularly in relation to the inter‐action of another nutrient. Therefore, a Mn ✕ B interaction study was conducted in nutrient solution under greenhouse conditions to determine the influence of low and adequate B levels on critical Mn levels of Upland cotton (Gossypium hirsutumL.) with 11 manganese rates from 0 to 4000 μg Mn/1 at two B levels of 35 and 500 μg B/1. The objectives were to determine 1) the most sensitive tissue relating Mn content to growth, 2) the critical Mn level in relation to growth and 3) the interaction of B on the critical Mn levels. Critical Mn levels of blade 1 through 5 ranged from 10 through 15 ppm Mn on a dry weight basis. Although Mn content in .blade 1 was the most sensitive in relating nutrient content to growth, the recently matured leaf (blade 3) was selected as the most practical tissue on the basis of sampling ease to use for evaluating the Mn status of cotton. The critical Mn level was 10 ppm Mn in blade 3. The critical Mn levels in blades 1 through 4 were independent of the B levels; however, low B increased the critical Mn level in the older blade (Blade 5). The stem and petiole tissue contained a small fraction of the Mn in blade tissue at high Mn levels. This reduced the desirability of selecting any of the vascular tissues for estimating the Mn nutrient status of cotton plants.

Interactions involving macro and micronutrients modify plant growth, as indicated by induced deficiencies or toxicities and growth reductions. The objective of this study was to determine the influence of Mn and B and their interactions on micronutrients in leaf tissues of upland cotton (Gossypium hirsutumL.). A 2 ✕ 11 factorial design included two B levels of 35 and 500 µg/liter and 11 Mn levels, varying from 0 to 4000 µg/liter in nutrient solution under greenhouse conditions. In blade 3, Mn tissue concentration less than the 10 µg/g critical level induced high Zn concentration of 127 µg/g in leaf tissue. As Mn concentration approached the critcial level, Zn concentrations decreased to 33 µg/g and remained constant with increasing Mn to 247 µg/g. Copper concentration was independent of Mn concentration. However, the reciprocal Mn‐Fe relationship was apparent where Mn concentrations of 4 and 247 µg/g were associated with Fe concentrations of 270 and 51 µg/g, respectively. Manganese nutrition had a small but significant influence on P concentrations where P concentrations of 2.37 and 1.84% were associated with Mn concentrations of 8 and 210 µg/g, respectively. The influence of B levels on micronutrient concentration in leaf tissue was not consistent. Low B induced lower Mn concentrations than did adequate B in young and recently matured tissue, whereas no effect of B levels on Mn concentration was evident in older leaf tissue. Low B induced a small but significantly lower Zn concentration in recently matured blades, while no effect of B nutrition on Cu was observed. However, low B induced higher Fe concentrations in old blades than did adequate B.

The modified‐diagnosis and recommendation integrated system (M‐DRIS) and sufficiency range method (SRM) have not been compared for accuracy of Zn and Mn diagnoses for soybean [Glycine max(L.) Merr.]. Consequently, M‐DRIS and SRM were evaluated for diagnosing Zn deficiencies for two site‐years in Alabama, and Mn deficiencies and sufficiencies for three site‐years in Georgia. The SRM was more accurate than M‐DRIS in detecting when Zn was deficient (P< 0.05) and when Mn was not deficient (P< 0.01). However, M‐DRIS and SRM did not differ (P> 0.10) where Mn was deficient. Partial regression analysis indicated that M‐DRIS also incorrectly diagnosed Ca as deficient in the Alabama studies. False M‐DRIS diagnoses of Mn and Ca deficiencies were attributed to their inflated concentration and ratio means in the M‐DRIS data base, which may also have contributed to false diagnoses of K, Mg, Cu, and Fe deficiencies in the Georgia study. Results demonstrate the danger of using inflated nutrient means in M‐DRIS diagnoses. Further work is needed to improve the diagnostic accuracy of M‐DRIS.

Soil extractants for Mn are often assigned critical deficiency levels based on indirect experimental evidence. This research was undertaken to calibrate four soil Mn extractants for critical deficiency levels using soybeans [Glycine max(L.) Merr. cv. ‘Ransom’]. Two adjacent field experiments were conducted on Olustee‐Leefield sand (Ultic Haplaquod‐Arenic Plinthaquic Paleudult) with soil pH, microelement, and Mn rate variables. Leaf samples taken at the R‐2 growth stage were analyzed for Mn and soil samples were analyzed for pH and extractable Mn by four separate procedures. Critical deficiency levels were determined using the Cate‐Nelson procedure as well as by comparing tissue Mn critical levels with soil Mn levels using a regression method. The latter method was unsatisfactory for determining critical levels except for two extractants for 1 year. Critical deficiency levels based on the Cate‐Nelson method averaged over the 3‐year experiment period were Double Acid—2.6 ppm, DTPA — 0.22 ppm, Mehlich (NH4Cl‐NH4F) — 1.8 ppm, and AB‐DTPA (NH4HCO3‐DTPA) — 0.4 ppm. Leaf Mn vs. extractable soil Mn correlation coefficients were best for the two DTPA‐based extractants, but all four coefficients were similar when soil pH was included in multiple regression equations.

The success of a plant tissue analysis program depends on the calibration relating growth and nutrient concentration in specified plant tissues for each essential element. The minimal nutrient concentrations in tissues associated with maximum growth have been determined from calibration curves that were drawn free‐hand to best fit the respective Xand Yvalues in graphical plotting. Statistical models to establish critical deficiency levels related to 90% maximum growth are desirable to reduce the arbitrariness of the graphical procedure. A modified Mitscherlich response equation was used to quantify critical deficiency levels by characterizing plant growth as a function of tissue nutrient concentration. The model presented is y = β(1 — γe‐ax) where yis the plant yield at tissue concentration x, and α, β, and γ are parameters to be estimated. Critical deficiency levels determined from the Mitscherlich model were significantly greater (P < 0.05) than the previously reported nutrient values of the same studies utilizing the graphical procedure.

There is little information concerning critical Mn deficiency and toxicity levels in forage plants, or how plant Mn concentration affects other plant constituents associated with forage quality. This study was undertaken to investigate possible interactions between plant Mn concentration and the growth and forage quality of wheat (Triticum aestivumL. cv. Stacy). Wheat plants were grown in nutrient solution containing 0.005, 0.02, 0.05, 0.25, 1, 5, 25, 100, 200, and 500 µg/g Mn. Plants were grown for 30 days after transplanting into nutrient solution and were harvested at the three‐leaf stage, lyophilized, and weighed. Manganese concentration, in vitro dry matter disappearance (IVDMD), neutral detergent fiber (NDF), in vitro cell wall disappearance (IVCWD), total nonstructural carbohydrates (TNC), and Ca and Mg concentrations were determined on wheat shoot. Critical Mn deficiency and toxicity levels affecting normal growth of wheat shoot were determined to be 35 and 475 µg/g dry wt, respectively. These values are useful in determining deficiency and toxicity in wheat production. Percentage NDF, IVDMD, TNC, and IVCWD were reduced in tissue from plants that were critically Mn‐deficient. In vitro dry matter disappearance and TNC were increased in tissue from critically Mn‐toxic plants. In vitro dry matter disappearance ranged from 71 to 89%, with the lowest values observed for Mn‐deficient and the highest for Mn‐toxic plants. The high IVDMD of the Mn‐toxic plants appeared to be related to an accumulation of TNC, while the relatively lower IVDMD of the Mn‐deficient plants was related to reduced cell wall digestibility. Both Ca and Mg concentrations decreased as Mn concentration in the plants increased above 475 µg/g. Results of this study indicate that Mn deficiency and toxicity in wheat have a significant effect on amount of growth and the concentration of plant constituents associated with forage quality. These constituents remain relatively constant over the adequate range of Mn nutrition and plant Mn concentration should be kept within the 35 and 475 µg/g range.

Critical and sufficiency concentrations of Mn in soybean [Glycine max(L.) Merr.] leaves are levels which are deficient and adequate, respectively. These levels have been determined with a single cultivar. However, since several cultivars are often grown in Mn deficient areas, it becomes important to know if cultivars have different Mn requirements. A 3‐year study was conducted on an Olustee‐Leefield sand (Ultic Haplaquads — Arenic Plinthaquic Paleudults) near Tifton, Georgia to evaluate Mn treatments on soil test values, on nutrient concentration in leaves and seed, and on seed yields of eight soybean cultivars. The addition of Mn increased the amount of Mn extracted from the soil each year by the double acid (0.05 NHCl + 0.025 NH2SO4) and DTPA (diethylenetriaminepentaacetic acid) solutions, but double acid extracted considerably more Mn than did DTPA. Significant differences in yield, concentration of Mn in tissue, and seed weight among cultivars from Mn application were obtained only in the third year (1977) when the soil pH was increased to 7.0. The addition of Mn to the soil increased leaf Mn in all cultivars and seed Mn and seed yields in five of eight cultivars. Concentrations of Mn in recently matured leaves (R2 stage) varied among cultivars in untreated plots from 10 to 17 ppm and in Mn treated plots from 20 to 28 ppm. Seed Mn varied from 8 to 14 ppm in untreated plots and 13 to 20 ppm in Mn treated plots. Average seed yield (across cultivars) in the third year was increased 5.3 quintals/ha or 27% by Mn over no Mn with more than one‐third of the yield increase attributed to increased seed weight. Nutrients, other than Mn, in plant tissue were not affected by Mn treatments; however, small differences occurred among cultivars in concentration of P, K, Ca, Mg, Cu, Fe, and Zn in leaves and seeds. A regression equation indicated that the average critical and sufficiency levels of leaf Mn for eight soybean cultivars were 18 and 29 ppm, respectively. Our data suggest that several cultivars should be used to establish critical or sufficiency values for leaf Mn in order to develop an adequate range in values for the number of cultivars usually grown in Mn deficient areas.

Wheat (Triticum aestivumL.) production areas have expanded to soils low in available Mn and to low pH soils with excess available Mn. The purpose of this study was to determine the effect of Mn deficiency and toxicity effects on ‘Stacy’ wheat growth components and to determine the Mn critical deficiency level (CDL) and critical toxicity level (CTL) in specific plant tissue in relation to top dry weight. The critical deficiency and toxicity values could be used as guidelines in tissue analysis to diagnose Mn deficiency and toxicity. Wheat plants were grown in nutrient solution containing 10 Mn rates from 0.09 μMto 9.1 mMin the greenhouse. Plants were harvested 26 days following treatment with Mn and tissue samples were analyzed for Mn and other elements in the wet ashed extract. Manganese deficiency and toxicity reduced top dry weight, root dry weight, plant height, and tiller number compared with plants supplied at adequate Mn levels. The CDL and CTL defined as the elemental concentration in the tissue associated with a 10% reduction in growth due to a deficiency or toxicity, respectively, were determined from the relationship of Mn concentrations in the tissue and top dry weight. The Mn CDL values for blades 1, 2, 3, and stem of Stacy wheat were 13,39,82, and 12 μg g‐1, respectively. Blade 1 is recommended for tissue sampling since the transition zone in the response curve is narrow and blade 1 is metabolically active and the most recently matured blade with a developed ligule. The Mn CTL values of the sampled tissues were 380, 900, 1100, and 200 μg g‐1for blades 1, 2, 3, and stem tissue, respectively. Maximum growth would be expected when tissue Mn concentrations are within the CDL and CTL of a specific plant tissue. The Mn concentration in tissues increased as Mn supply was increased. A reciprocal Fe/Mn and P/Mn concentrations existed in blade 1. Manganese deficiency and toxicity reduced K, Ca, and Mg concentrations.

Sorghum [Sorghum bicolor(L.) Moench] production has increased in the Southeastern United States as a second crop in many double‐cropping systems. Guidelines are needed for Zn concentration in leaf blade tissue for the diagnosis and correction of Zn deficiency and toxicity problems. The Zn critical deficiency level (CDL) and critical toxicity level (CTL) are the minimum and maximum concentrations, respectively, associated with a 10% yield reduction from maximum yield due to Zn deficiency and toxicity. Sorghum was grown in nutrient solutions containing Zn concentrations ranging from 0.0 to 91.78 nmol L−1in 14 increments in the greenhouse. Individual blades were sampled at 49 days growth and analyzed for Zn concentration by atomic absorption spectrometry. The Zn CDL values in blades were 10, 10, 9, 13, and 24 µg g−1for blades 1 (top), 2, 3, 4, and 5 (bottom), respectively, as calculated from the exponential relationship of Zn concentration in blades and top dry weight. The Zn CTL values in blades were 64, 68, 80, 100, and 195 µg g−1in blades 1, 2, 3, 4, and 5, respectively. For tissue sampling to diagnose Zn deficiency and toxicity, blade 1 is recommended. The Zn CDL and CTL are 10 and 64 µg g−1, respectively, sampled at growth stage 2 and near maximum vegetative growth harvested at this time is expected if the Zn concentrations are within the CDL and CTL.

The 2B/X2.8 flare on 1982 March 30 is investigated in optical, radio and X-ray regions. The X-ray burst seems to consist of an impulsive component and a thermal component. In the early phase, the core of the hard X-ray (20–40 keV) source is located at one end which seems to be a footpoint of a loop or arcade. Then the core shifts to the center of the source which would be the center of the loop or arcade, in the main and later phase. A rather good relation between the images of the soft X-ray (7–14 keV) source and the Hα flare and a synchronous motion of the hard X-ray core with the peak of the 35 GHz one-directional intensity distribution has been found.

In absorption studies with excised roots, the nutritional status of roots in relation to root growth has been difficult to assess prior to the absorption period. Since the antecedent nutrition greatly influences the subsequent K absorption, it is important to assess the nutritional status of roots undergoing ion absorption. Therefore, this study was initiated to determine the influence of antecedent nutrition of K, P, Ca, NO3‐N, and overall salt status of excised barley (Hordeum vulgare) roots on K absorption. Assessment of the nutritional status of the plants was made by comparing the analytical results of the excised roots to the corresponding critical nutrient value of 13.5 meq, 4.5 mmol, 2.9 meq, and 2.5 meq kg‐1fresh wt, for K, P, Ca, and NO3‐N, respectively. Under severe K deficiency, excised barley roots absorbed less K than comparable roots slightly deficient in K. Losses of K to the absorbing solution occurred from roots with high endogenous K. Excised roots from Pdeficient plants, low in endogenous K, absorbed less K than roots low in endogenous K with adequate P. Nitrogen deficiency alone did not increase the capacity for K absorption. Calcium deficiency suppressed K uptake primarily as a result of high endogenous K in Ca deficient roots. A combination of N deficiency and low endogenous K increased the capacity for K absorption. Low salt plants however, had the largest capacity to absorb K.

Aluminum is a major deterrent to crop production in acid soils. The specific effects of Al toxicity on photosynthesis, chlorophyll, and transpiration in Al stressed plants have received little attention. The objective of this study was to determine the influence of Al stress on photosynthesis, chlorophyll, and transpiration in wheat (Triticum aestivumL.) and sorghum [Sorghum bicolor(L.) Moench] under greenhouse conditions. Plants were grown in modified Steinberg solution containing 10 Al rates (0, 1.9, 3.7, 9.3, 18.5, 37.1, 74.1, 148, 222, and 297 μmol L−1) in the greenhouse for 28 days after transplanting. The initial pHs were 4.0 and 3.3 for wheat and sorghum, respectively. Photosynthesis and transpiration measurements were made on intact recently matured leaves. Chlorophyll concentrations were determined on the same tissue. In wheat, Al toxicity decreased photosynthesis, chlorophyll concentration, and transpiration. The critical Al toxicity levels in wheat blade associated with decreases in photosynthesis, chlorophyll concentration, and transpiration were 0.15, 0.13, and 0.14 mmol kg−1, respectively. In sorghum, photosynthesis and chlorophyll concentration were also decreased by Al stress, but transpiration was increased. The critical Al toxicity levels for these parameters in sorghum could not be determined due to low levels of Al concentration in the blade. Transpiration in nonstressed sorghum was approximately one‐third the rate of wheat. Thus, the growth reduction of wheat and sorghum under Al stress may be due in part to decreased photosynthesis.

Summary Intracellular location of cytochrome oxidase (cytoxidase) active in vivo was studied cytochemically with four strains of cyanophytes, using 3,3'-diaminobenzidine (DAB) oxidation. DAB was oxidized in the dark bySynechocystis sp. PCC6714 and two strains ofAnacystis nidulans (Tx20 and R2) grown under photoautotrophic, heterotrophic and salt-stressed conditions, respectively. Electron microscopic observations showed that DAB-oxidation in the dark occurred in the thylakoids, but was insignificant on or around the cytoplasmic membrane. However, deposition of DAB-oxidation product around the cytoplasmic membrane was observed with cells of the thylakoid-less cyanophyteGlaeobacter violaceus ATCC29082. All DAB oxidations observed with the four strains were inhibited completely by cyanide, the inhibitor of cyt-oxidase, but not by 3-amino-1,2,4-triazole, the inhibitor of peroxidase. The results show that (1) DAB was oxidized by the cyt-oxidase functioning in the respiratory system, and that (2) cyt-oxidase in thylakoids was active in vivo.

Foliar application of 2,3,5‐triiodobenzoic acid (TIBA) has been recently used on soybeans [Glycine max(L.) Merr.] to enhance yields. Root application appeared as an alternative naethod of applying TIBA to the plant. This study was initiated to provide information on effects of root‐absorbed TIBA on growth, nutrient absorption, and nutrient distribution. Plants were grown, in Hoagland solution with TIBA at eight levels from 0 to l0 ppmw. Nutrients absorbed were determined by their disappearance from samples taken periodically. Although young leaves and internodes showed no visible response at concentrations lower than 5 ppmw. typical symptoms were observed at 5 and 10 ppmw TIBA. The 10‐ppmw dosage reduced elongation of the stems. Roots were more sensitive than tops to TIBA, and morphological effects were observed as low as 0.1 ppmw. Shoot/root ratios showed that TIBA equally influenced the dry weights of these tissues. TIBA appeared to enhance the rate of P uptake from the nutrient solution. Within a 6‐day period 5 ppmw TIBA enhanced total P uptake about 25% above controls, while absorption of NO3‐N, K, Ca, Mg, Mn, and Fe was not influenced.

Variations in plant response to foliar application of 2,3,5‐triiodobenzoic acid (TIBA) on soybean [Glycine max(L.) Merr.] under field conditions appeared to be related to temperature and soil moisture conditions near application time. Greenhouse and growth chamber studies were conducted to provide information on the interacting effects of temperature and soil moisture. A 2 ✕ 2 ✕ 2 factorial experiment with soybeans in the greenhouse included two levels of premoisture, postmoisture and TIBA. Three temperature regimes simulating cool (21/16 C), warm(27/21 C), and hot (32/24 C) climates were additional variables to the greenhouse experiment for a 3 ✕ 2 ✕ 2 ✕ 2 factorial growth chamber experiment. Effects on plant height and reproductive development were studied. The TIBA response, as determined from plant height measurements under greenhouse conditions, was reduced by soil moisture stress following TIBA application. Under growth chamber conditions the TIBA effect on plant height generally increased as temperature increased from cool to hot. Floral and/or pod abortion was enhanced under high soil moisture and high temperatures. TIBA applied at floral initiation aided in the retention of greater numbers of pods under high temperature and high soil moisture.

A mm-wave thermal burst has been observed at 73 GHz. The simultaneous observation at 17 GHz revealed that this mm-wave burst was quite a different component from the non-thermal burst co-existing at a cm-wavelength range. Since the source of this burst seemed to be opaque or nearly opaque, the temperature became several tens of thousands degrees. Considering also the similarity between time profiles of the 73 GHz intensity and the Ha light curve, it is concluded that this mm-wave burst is situated very close to the Ha flare region.

Hot regions in solar flares produce X-radiation and microwaves by thermal processes. Recent X-ray data make it possible to specify the temperature and emission measure of the soft X-ray source, by using, for instance, a combination of the 1–8 Å (peak response at about 2 keV) and the 0.5–3 Å (peak response at about 5 keV) broad-band photometers. The temperatures and emission measures thus derived satisfactorily explain the radio fluxes, within systematic errors of about a factor of 3. Comparison of 15 events with differing parameters shows that a hot solar flare region has an approximately isothermal temperature distribution. The time evolution of the correlation in a single event shows that the hot material originates in the chromosphere, rather than the corona. The density must lie between 1010 and 2 × 1011 cm-3. For an Importance 1 flare, this implies a stored energy of roughly 2 x 1030-1029 ergs. A refinement of the data will enable us to choose between conductive and radiative cooling models.

Abstract: A combined water culture and pot culture technique was developed for the study of the K nutrition of potatoes. The water culture technique permitted control of the K nutrient supply while the pot culture technique provided support for plant growth and for tuber development in a low K medium. Both plant growth and tuber quality reflected the K supply of the culture solution.

Summary: The electrophoretic mobilities for the micelles of sodium dodecyl sulfate and sodium dodecyltrioxyethylene sulfate in the presence of various electrolytes were measured by paper electrophoresis and compared with the mobilities obtained from Tiselius- type electrophoresis. There is a good correlation between the mobility from paper electrophoresis (U P ) and that from Tiselius electrophores is (U T ), and a factor in conversion from U P to U T was found to be 0.60. The value is not affected by the type of electrolytes present and the ionic strength of solutions. In addition, the paper electrophoretic behavior of the micelles of sodium dodecyl sulfate in the aqueous solutions of a series of sodium polyphosphates was also investigated.

The location and size of a solar impulsive hard X-ray burst have been determined in one dimension to a considerable precision with a balloon-borne X-ray modulation collimator. The center of the X-ray source is on the line passing through the center of a big Ha flare region of 3 arc min. The size of the X-ray source is remarkably smaller and may be one arc min or less.

Even mild perioperative hypothermia is associated with several severe adverse effects. Resistive heating has possible advantages compared with other active warming systems because it can heat several fields independently. To assess this new warming system, we measured core temperature in patients during surgery who were warmed with circulating water mattresses, forced air covers or resistive heating covers.