bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dehydrogenase Levels in Cold‐Tolerant and Cold‐Sensitive Alfalfa1,2
Authors: Krasnuk M. , Jung G. A. , Witham F. H. 
Published: July 2010

AbstractCertain soluble proteins are believed to be closely associated with cold tolerance. The objectives of this work were to determine whether the proteins exhibited dehydrogenase activity and if there were qualitative and/or quantitative differences in dehydrogenases between hardened and nonhardened plants. Cold‐tolerant ‘Vernal’ and cold‐sensitive ‘Sonora’ alfalfa (Medicago sativa L.) plants were grown for 66 days under simulated summer (non‐hardening) and winter (hardening) conditions, using growth chambers, and were assayed for the levels of cold tolerance developed at three freezing temperatures (−6, −8, and −10 C). To determine differences in dehydrogenases, soluble proteins were separated from extracts of crown and root tissues by polyacrylamide disc gel electrophoresis. Localization of dehydrogenases on gels and densitometric scanning of zymograms indicated that activities of glutamate, lactate, isocitrate, glucose‐6‐phosphate, 6‐phosphogluconate, nicotinamide adenine dinucleotide (NAD) malate and nicotinamide adenine dinucleotide phosphate (NADP) malate dehydrogenases were high in both cultivars exposed to hardening and were generally highest in Vernal. Percent increases for winter over summer levels of glutamate, lactate, glucose‐6‐phosphate, and 6‐phosphogluconate dehydrogenases were large compared with those of isocitrate, NAD‐malate, and NADP‐malate dehydrogenases. Moreover, the magnitude of change in enzyme activity between summer and winter plants also was influenced by extractant (distilled water, pH 7 or 0.10 M tris‐HCl, pH 7) and varied quantitatively according to the solubility of the dehydrogenases in the two extractants. Enzyme solubility differences related to cultivar or environmental influences and cold tolerance were also observed, especially for isocitrate dehydrogenase. Large quantitative differences in glucose‐6‐phosphate and lactate dehydrogenase activities and substantial increases in isocitrate and 6‐phosphogluconate dehydrogenases localized within gel column regions 7 and 8 of zymograms developed from winter samples implied a close relationship of these enzymes to cold tolerance. Forms of lactate, glucose‐6‐phosphate, and isocitrate dehydrogenases were present in hardened tissues that were not present in un‐hardened tissues. It is concluded that the observed differences in dehydrogenasees between hardened and non‐hardened plants are major indicators of the cold tolerant state. Based on these and past studies, the reactions analyzed by representative hydrolytic and dehydrogenase enzymes may serve as a working hypothesis for future studies concerning the mechanics of induction and the suspected catenary nature of the hardening process.
Influence of Manure Application Rates and Continuous Corn on Soil‐N1
Authors: Magdoff F. R. 
Published: July 2010

AbstractManure application to continuous corn (Zea mays L.) should provide some or all of the crop N needs and help maintain or increase soil organic matter. This should be done without damaging the environment by adding excess nutrients to ground or surface waters. A range of factors may influence manure decomposition, and hence N availability to crops. However, application recommendations are usually not site specific. To attempt to deal with site specific considerations, a comparison was made of the effect of manure on soil‐N and crop response to inorganic‐N between similar continuous corn experiments at two different sites.The manure‐N experiments with continuous corn were conducted on both a somewhat poorly drained Panton clay (Typic Ochraqualf) and a well‐drained Calais loam (Typic Fragiorthod). Manure rates of 0, 22, 44, and 66 metric tons/ha/year were combined in factorial arrangement with ammonium nitrate rates of 0, 112, and 224 kg N/ha/year. Comparison of calculated theoretical soil‐N with experimentally determined levels after 5 years and the response of corn to fertializer‐N indicate that mineralization of manure organic‐N, when applied to the Panton clay, was less than when applied to the Calais loam. Thus, manure‐N was less available to the growing crop on the clay and accumulated in the soil at a greater rate than in the loam. The annual manure application rates required to maintain initial soil N levels in Panton clay and Calais loam under continuous corn production were calculated to be 40 to 52 tons/ha respectively. Two mineralization models were examined: Model 1 assumed only the first year manure mineralization rate above native soil organic matter decomposition rate; Model 2 assumed a 5‐year mineralization decay series. Both were effective in predicting final soil‐N levels.
Leaf Temperature and Internal Water Status of Wheat Grown at Different Root Temperatures1
Authors: Kirkham M. B. , Ahring R. M. 
Published: July 2010

AbstractBoth root temperature and plant water status are important in controlling plant growth. Yet few studies report the influence of root temperature on the water relations of plants. Therefore, to determine the effect of root temperature on leaf temperature and internal water status, a cultivar of winter wheat (Triticum aestivum L. em Thell. ‘Ponca’), considered to be drought sensitive, was grown for 82 days, under growth room conditions, at six different root temperatures (15.6, 19.9, 24.7, 28.5, 32.1 and 37.3 C). The air temperature remained constant at 25 C. Leaf temperature and stomatal resistance were measured daily starting on day 18. Leaf water, osmotic, and turgor potentials were determined every other day starting on day 44. No seeds germinated at 37.3 C. During the experiment, leaf temperatures were lower than air temperature by 1.46, 1.16, 1.12, 0.98, and 0.71 C for the 15.6, 19.9, 24.7, 28.5 and 32.1 C root temperatures, respectively. Stomatal resistances averaged 21.5, 19.9, 19.8, 22.1, and 27.4 sec/cm for the 15.6, 19.9, 24.7, 28.5, and 32.1 C root temperatures, respectively. Leaf water, osmotic, and turgor potentials were highest at the 24.7 C root temperature. Potentials were lowest at the highest root temperature (32.1 C). The experiment was repeated using a wheat cultivar considered to be drought resistant (‘KanKing’). KanKing seeds germinated at 37.3 C. For KanKing, leaf temperatures were cooler than air temperature by 1.75, 1.51, 1.36, 1.32, and 1.02 C for the 15.6, 19.9, 24.7, 28.5, and 32.1 C root temperatures, respectively. Stomatal resistances averaged 44.6, 41.9, 33.5, 37.0, and 37.4 sec/cm for the 15.6, 19.9, 24.7, 28.5, and 32.1 C root temperatures, respectively. Potentials were not determined for KanKing. The drought sensitive cultivar grew taller than the drought resistant cultivar. But the heights of both cultivars, decreased in the following order with root temperature: 24.7, 28.5, 19.9, 15.6, and 32.1 C. The results showed that the drought resistant cultivar maintained a larger difference between leaf and air temperature at the different root temperatures than did the drought sensitive cultivar. This suggested that leaf temperature measurements could be used to screen plants for drought resistance.
A Tractor‐Mounted Row Marker Using a Rotating Barrel1
Authors: Cobb D. L. , Doyle B. L. , Webster J. A. , Smith D. H. , Ries D. K. 
Published: July 2010

AbstractSmall, portable, row markers that can be transported easily to off‐station cereal nursery sites are needed. We designed a marker, consisting of a rotating barrel attached to a 3‐point hitch frame. Angle‐iron pieces, attached lengthwise to the barrel sides, mark the rows in the soil as the unit is pulled by a tractor. Chains attached around the barrel mark alleys perpendicularly to the rows. This method has been successfully used in large nurseries and in small, specialized nurseries that are used for plant resistance studies.
Effect of Fertilization on Penncross Creeping Bentgrass1
Authors: Waddington D. V. , Turner T. R. , Duich J. M. , Moberg E. L. 
Published: July 2010

AbstractAlthough turfgrass fertilization influences many factors that affect turfgrass quality, little information is presently available that encompasses the interrelationships between fertilization, soil fertility, and turfgrass response and quality. A field study was conducted on Hagerstown soil (fine, mixed, mesic Typic Hapludalf) to determine the effects of N sources (Agrinite, Milorganite, ureaform, and urea), P rates (0, 0.49, 0.98, and 1.95 kg/100 m2), and K rates (0, 0.76, and 1.52 kg/100 m2) on soil nutrient levels and the growth, quality, and chemical composition of ‘Penncross’ creeping bentgrass (Agrostis palustris Huds.) maintained as putting green turf. Wilting, disease, chlorosis, and annual bluegrass (Poa annua L.) infestation were used to assess quality.Fertilization with Milorganite increased available soil P and Mg. Available P and K in the soil ranged from 11 to 94 ppm and 0.06 to 0.28 meq/100 g, respectively. Elemental content of clippings was affected by all treatments, and treatment × date of sampling interactions that occurred could limit the usefulness of tissue analyses for diagnosing the nutritional status of turfgrasses.When K was applied at 0.76 kg/100 m2, both tissue and available soil K increased. When the K rate was increased to 1.52 kg/100 m2, the additional increment of K caused a greater increase in soil K and a smaller increase in tissue K than was obtained with the first increment of added K. The greatest change in tissue P occurred with the first incremental addition of P. Tissue P was not greatly affected by soil P above 24 ppm. Phosphorus fertilization had little effect on clipping yield; however, K fertilization tended to increase growth, as well as decrease chlorosis noted in early spring. Less severe summer wilting was observed with Agrinite, Milorganite, and K treatments. Less dollar spot (Sclerotinia homoecarpa F. T. Bennett) infection was noted with urea fertilization. Annual bluegrass invasion was favored by P and K fertilization and the effect of one was enhanced by the other. Milorganite, which increased soil P, also favored annual bluegrass. Results of this study indicated a need for more work in soil test calibration for turfgrasses.
Growth and Water Relations of Cereal Crops as Influenced by Salinity and Relative Humidity1
Authors: Hoffman G. J. , Jobes J. A. 
Published: July 2010

AbstractCrop salt tolerance is not absolute but depends on environmental factors such as relative humidity (RH), as well as management of irrigation and fertility. The objective of this study was to evaluate the influence of atmospheric relative humidity on plant growth and how it interacts with salinity to influence salt tolerance and water relations of barley (Hordeum vulgaris L. ‘CM‐67’), wheat (Triticum aestivum L. ‘Siete Cerros’), and sweet corn (Zea mays L. ‘Bonanza’). The studies were conducted in sunlit climate chambers with temperatures cycled daily between 10 and 27 C for barley and wheat and between 17 and 32 C for corn and with average daytime RH controlled near 45% for the low and near 90% for the high RH treatments. The root medium of each crop was maintained at four different osmotic potentials (s Ψo), the range depending on the crop's salt tolerance. With a nonsaline root medium, increasing the RH from 45 to 90%, increased the wheat yield by 24%, had no influence on corn yield, and reduced barley yield by 16%. High RH increased the salt tolerance of barley and corn but did not affect the tolerance of wheat. For all three crops at all sΨo levels, water‐use efficiency (yield per unit of water consumed) was higher at 90% than at 45% RH. Linear relationships were found between leaf total water (LΨt) and osmotic (LΨo) potentials and sΨo for barley and wheat. Leaf pressure potential (LΨp) was reduced by low RH and salinity. The relationship between crop yield and LΨt was linear. The difference between full yield and almost no yield was 2.0 megaPascals for both barley and wheat. RH must be considered when evaluating the salt tolerance of barley and corn but not for wheat.
Influence of Soil Moisture and Plant Cultivar on Cation Uptake by Wheat with Respect to Grass Tetany1
Authors: Karlen D. L. , Ellis R. , Whitney D. A. , Grunes D. L. 
Published: July 2010

AbstractSeveral researchers' report that the incidence of grass tetany is most severe when soils are nearly water‐saturated. This report prompted three growth‐chamber studies to determine the influence of soil moisture and wheat cultivar on K+, Ca++, and Mg++ ion uptake and the estimated tetany potential of wheat forage. Hard red winter wheat (Triticum aestivum L. ‘Centurk’, ‘Eagle’, and ‘Newton’) was grown in pots containing 2 kg of Eudora loam (Fluventic Hapludoll) soil. Two soil moisture levels (13 and 27 volume %) were maintained by weighing the pots and watering daily. Final pot weights were increased periodically to account for plant growth. In samplings where cation concentrations were significantly different, K concentrations in leaf, crown, and root tissue from plants grown at 27% moisture decreased 0.10%, increased 0.29%, and increased 0.58% respectively; Ca concentrations decreased 0.12%, 0.05%, and 0.35%, respectively; Mg concentrations decreased 0.01%, 0.02%, and 0.06%, respectively. The equivalent ratio K/(Ca + Mg) in the three plant parts increased 0.49, 0.53, and 0.92, respectively. The average Mg concentration in the root tissue (0.22%) was higher than in either the crown (0.16%) or leaf (0.18%) tissue, indicating that among other factors contributing to low forage Mg, there might be translocation mechanisms that limit the movement of Mg into leaf tissue. Analysis of non‐vernalized wheat tissue showed significant cultivar differences. Average K concentrations in Eagle wheat (6.29%) were greater than in either Newton or Centurk wheat (5.94 and 5.52%, respectively); Ca and Mg concentrations in Eagle wheat (0.823 and 0.193%) were lower than Ca and Mg concentrations in Newton and Centurk wheat (0.980 and 0.222%; 0.940 and 0.217%, respectively). These differences in cation composition resulted in an average equivalent ratio in Eagle wheat of 2.80 compared to 2.27 and 2.28 in Newton and Centurk wheat, respectively. Cation concentrations in the samplings of vernalized wheat showed no significant cultivar differences; however, average equivalent ratios for Newton, Centurk, and Eagle wheat (2.56, 3.00, and 3.47, respectively) were significantly different. This result indicated that Eagle wheat would be a more tetany‐prone forage than either Newton or Centurk wheat. These studies have shown that soil moisture content, cultivar, and possibly translocation mechanisms influence the cation concentrations of wheat forage. They also indicate that perhaps a breeding program could be developed to produce wheat cultivars that have a more balanced cation composition and a lower potential for inducing grass tetany in grazing cattle than those now grown.
Soybean Root Growth during the Reproductive Stages of Development1
Authors: Kaspar T. C. , Stanley C. D. , Taylor H. M. 
Published: July 2010

AbstractControversy exists concerning photosynthate sink relationships associated with seed development and their effects on soybean (Glycine max (L.) Merr.) root development. Seven cultivars were studied in the Ames rhizotron (root observation laboratory) to determine the rate which each cultivar increases its rooting depth during flowering and seed development. Depth of rooting and stage of development were measured three times a week from 16 June to 30 Aug. 1976. Rooting depth continued to increase until the maximum depth of each rhizotron compartment (217 cm) was reached. Some root growth occurred until physiological maturity (R 7). The maximum rate of downward root growth occurred during early flowering (R1 to R3) for all seven cultivars. Cultivars differed significantly in the rate of downward growth during the periods between planting and growth stage R1, R1 and R2, and R5 and R6. The cultivar ‘Hawkeye’ had the greatest rate of downward growth (8.1 cm/day) between the R1 and the R2 stages, and ‘Beeson’ had the greatest overall rate (2.8 cm/day).
Effect of Soil Temperature on Development of Perennial Forage Grasses1
Authors: Morrow L. A. , Power J. F. 
Published: July 2010

AbstractSoil temperature has a great influence on the development and establishment of all types of plants. The lack of soil temperature information on the development of perennial forage grasses led to the initiation of this study. Seedlings of crested wheatgrass [Agropyron desertorum Fisch. (Schult.)], western wheatgrass (A. smithii Rydb.). smooth brome (Bromus inermis Leyss.), Altai wildrye (Elymus angustus Trin.), Russian wildrye (E. junceus Fisch.). green neellegrass (Stipa viridula Trin.), sideoats grama [Bouteloua curtipendula (Michx.) Torr.], and blue grama [B. gracilis (H.B.K.) Lag. ex Steud.] were grown in a Temvik silt loam soil (typic Haploborolls, fine , silty, mixed) for 12 weeks in a growth room at soil temperatures ranging from 3.3 to 33.3 C in 5 C increments. Air temperature was held constant and a 16‐hour photo period was used. Plant height and water use were measured weekly and dry matter and nitrogen concentration were measured at the conclusion of the study. Crested wheatgrass, Altai wildrye, and green needlegrass reached maximum aboveground dry matter production at 23.3 C. Western wheatgrass, smooth brome, and Russian wildrye produced the most aboveground dry matter at 18.3 C. Crested wheatgrass was the most efficient in water use. Root dry matter production was greatest at 18.3 C for most grasses. Nitrogen concentration of aboveground tissue was usually greatest at soil temperatures of 18.3 or less but all grasses contained sufficient N for grazing livestock. Of the grasses studied, crested wheatgrass, western wheatgrass, and smooth brome appear to be best for dry matter forage production under northern Great Plains climatic conditions.
Foliar Application of P. I. Screening of Various Inorganic and Organic P Compounds1
Authors: Barel D. , Black C. A. 
Published: July 2010

AbstractThe suitability of 32 different P compounds for foliar application was tested by using a new technique in which predetermined quantities of P were applied to a fixed leaf area. This made it possible to obtain quantitative data on absorption of added P and on translocation of absorbed P out of the treated area. Presently foliar applications of P are used less than N, one reason being that no P compound is available which can be sprayed on plants in large enough quantities without damaging the leaves. Several representatives of the condensed phosphates and some compounds containing P‐N bonds or P‐N‐P linkages proved promising. Both group of compounds hydrolyze spontaneously to release orthophosphate, and all share the quality of delayed action. These P sources could be applied at 2.5 to 3 times the quantity of P that could be applied as orthophosphate in a greenhouse experiment without causing leaf damage. The most successful compound for corn (Zea mays L.) was ammonium tripolyphosphate, which could be applied at 370 µg of P/cm2 without causing leaf damage; 66% of the applied P was absorbed within 10 days, and 87% of the absorbed P was translocated out of the area of application in the same period. Other successful compounds for corn were ammonium tetrapolyphosphate and phosphoryl triamide. Soybeans (Glycine max L. Merr.) proved more sensitive than corn and could, in general, tolerate only two‐thirds to three‐fourths of the quantity of the various compounds that could be applied to corn, with the exception of phosphonitrilic hexaamide, which could be applied at 340 µg of P/cm2. Ammonium tri‐ and tetrapolyphosphate could be applied at 220 µg of P/cm2 to soybeans. Rapid intake is suspected to be an important reason for the damage observed with orthophosphate. Several organic P compounds were tested, but none of them was superior to the condensed P sources.
Alachlor and Trifluralin Effects on Nutrient Uptake in Oats and Soybeans1
Authors: Bucholtz D. L. , Lavy T. L. 
Published: July 2010

AbstractAlachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl)acetanilide] and trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) have been reported by several investigators to inhibit root growth in a variety ot plants. However, the biochemical significance of this inhibition is not known. The inhibition of root growth could interfere wth the uptake of plant nutrients. The greenhouse experiments of the present study were conducted to determine what effects the herbicides, alachlor and trifluralin have on the growth and on the uptake of H32PO2−4 and 35SO2−4 of oats (Avena sativa L. ‘Neal’) and soybeans [Glycine max (L.) Merr. ‘Clark 63’]. Oats is regarded as an alachlor and trifluralin‐sensitive species, and soybean is regarded as an alachlor and triflurafin‐tolerant species. Root weight of both species was reduced with increasing concentrations of both soil‐incorporated herbicides. The reduced root biomass of soybean was accompanied by a proportional reduction in shoot biomass, but in oats the shoot biomass was reduced more than the root biomass. Root biomass and the accumulation of H32PO2−4 and 35SO2−4 in oat and soybean shoots were directly correlated.Alachlor and trifluralin altered biochemical processes in oats and soybeans which control root and shoot growth. The herbicides selectively altered the plants' abilities to absorb H32PO2−4 and 35SO2−4.
Leaf Water Potential and Gaseous Exchange of Wheat and Tomato as Affected by NaCl and P Levels in the Root Medium1
Authors: Cerda Antonio , Bingham F. T. , Hoffman G. J. , Huszar C. K. 
Published: July 2010

AbstractThe phosphorus nutritional status of some plants has been shown to influence the plant's response to salinity. The objective of this study was to determine if this interaction influenced the plant's water relations, fixation of CO2, and yield. Tomato (Lycopersicon esculentum Mill.) and wheat (Triticum aestivum L.) were grown to maturity in nutrient solution cultures containing low to excessive concentrations of NaCl and P.Leaf total water potential (Lψt) and its components, osmotic (Lψo) and pressure (Lψp), decreased for both crops as salinity levels increased. Increases in the P concentration tended to increase Lψt and Lψo but decrease Lψp, although the changes were not always consistent. Interactions between salinity and P treatments caused significant differences in Lψt and Lψp for wheat. Statistically significant multiple regression equations were developed for Lψt, Lψo, and Lψp as a function of NaCl and P concentrations for both crops. Plant yields were well‐correlated with Lψt and Lψo, indicating that these measurements may provide a good characterization of salt stress.Measurements of leaf stomatal diffusion resistance to water vapor (rH2O) and carbon dioxide (rCO2) and calculated values of mesophyll resistance (rm) increased significantly as salinity increased for tomato. Although the resistance values for wheat also increased as salinity increased, only the rCO2 measurements rose significantly. The significant increases in rCO2 and rm for tomato with additions of salinity indicate a significant reduction in the rate of photosynthesis. Increasing P values consistently reduced the gaseous resistance levels although the reductions were not always statistically significant. There were no significant interactions between salinity and P treatments for any of these resistance measurements.