@article{villavicencio_blankenship_yencho_thomas_raper_2007, title={Temperature effect on skin adhesion, cell wall enzyme activity, lignin content, anthocyanins, growth parameters, and periderm histochemistry of sweetpotato}, volume={132}, number={5}, journal={Journal of the American Society for Horticultural Science}, author={Villavicencio, L. E. and Blankenship, S. M. and Yencho, G. C. and Thomas, J. F. and Raper, C. D.}, year={2007}, pages={729–738} }
 @article{rincon_raper_patterson_2003, title={Genotypic Differences in Root Anatomy Affecting Water Movement through Roots of Soybean}, volume={164}, DOI={10.1086/375377}, abstractNote={The ability of root systems to absorb water was determined as the root hydraulic conductance for five exotic genotypes (PI 416937, H2L16, N95‐SH‐259, PI 407859‐2, and PI 471938) and the commercial cultivar Young of soybean (Glycine max [L.] Merrill). The genotypes were grown for 28 d in flowing hydroponic culture to minimize possible variations in physical or chemical constraints on root development and functioning. Root hydraulic conductance was determined in response to applied hydrostatic pressure to the solution inside a pressure vessel to induce solution flow through the root system to the nonpressurized cut‐stem surface. Almost twofold differences in hydraulic conductance of from 0.43 to $$0.79\times 10^{-7}$$ m3 s−1 MPa−1 among the six genotypes were statistically significant. External root surface area and surface area of the stele were determined as estimates of the dimensions of exodermal and endodermal Casparian bands as barriers to radial movement of water. Volume of the cortex was considered to be proportional to the possible resistance of the symplastic pathway through the cortical cells themselves. Abundance of large metaxylem elements with radii 20 μm or greater was determined for comparison of relative axial conductance through root sections. Root hydraulic conductivity based on external surface area, which ranged from 2.20 to $$3.82\times 10^{-7}$$ m s−1 MPa−1, did not account for a statistically significant portion of the genotypic difference in water conductance. The relationship between root hydraulic conductance and surface area of the stele, however, accounted for 35% of the genotypic variation in conductance. The endodermis thus appears to be a limiting barrier to water conductance with dimensions relative to the exodermis that vary among the genotypes. Although statistically significant differences occurred among the genotypes for cortex volume and relative axial conductance, these differences were not correlated with differences in conductance. The diversity among the six genotypes for root anatomical traits that apparently influence water movement through the root system under well‐watered conditions is sufficiently large to justify exploration of the relationship between root hydraulic conductance and performance of soybean under water‐limiting conditions.}, number={4}, journal={International Journal of Plant Sciences}, author={Rincon, C. Amalia and Raper, C. David, Jr. and Patterson, Robert P.}, year={2003}, month={Jul}, pages={543–551} }
 @article{rowe_blazich_raper_2002, title={Nitrogen nutrition of hedged stock plants of Loblolly Pine. I. Tissue nitrogen concentrations and carbohydrate status}, DOI={10.1023/A:1020551029894}, number={1}, journal={New Forests}, author={Rowe, D. Bradley and Blazich, Frank A. and Raper, C. David}, year={2002}, month={Jul} }
 @article{chipman_raper_patterson_2001, title={ALLOCATION OF NITROGEN AND DRY MATTER FOR TWO SOYBEAN GENOTYPES IN RESPONSE TO WATER STRESS DURING REPRODUCTIVE GROWTH}, volume={24}, DOI={10.1081/PLN-100103779}, abstractNote={Drought stress significantly limits soybean [Glycine max (L.) Merr.] yield in the Southeastern United States. The Plant Introduction 416937 (PI), which has lower yields than adapted cultivars under favorable conditions but a relatively lesser yield reduction under water-stress conditions, has been identified as a potential source of drought avoidance germplasm. It is unclear whether the mechanism of drought avoidance is associated with shoot or root. Also unclear is the effect of the PI's restricted yield potential on the extent of its yield reduction in response to a water stress. To determine the differences in response between the PI and an adapted cultivar, Deltapine 105, to reproductive sink size and water stress, inoculated PI and Deltapine plants were grown in sand-filled pots in controlled-environment chambers. The fixed rooting volume of the pot culture restricts the influence that genotypic differences in rooting patterns may have in accessing soil water. During the 24-day period of pod development between R-3 and R-6 growth stages, plants were subjected to one of two water regimes, either well-watered or water-stressed to a leaf water potential of about −0.95 MPa. Within each water treatment, plants of both genotypes were depodded at the R3 stage to remove all pods (full depodding), one-half of the pods (partial depodding), or no pods (no depodding). Tissues of plants harvested at the R6 stage were separated, dried to a constant mass, weighed, and analyzed for nitrogen. Photosynthate production was calculated from dry matter and nitrogen content. Photosynthate production and nitrogen fixation by Deltapine plants were unaffected within a pod load by the mild water stress, but both photosynthate production and nitrogen fixation by the PI plants were diminished by the mild water stress except when a reproductive sink was absent. It thus appears that a sizeable component of the drought tolerance observed in field experiments for the PI plants may be attributed to root characteristics. Leaf nitrogen concentration decreased during water stress in Deltapine plants but not in the PI plants. Also, the decrease in nitrogen concentration in stems was greater in response to increased reproductive load for Deltapine plants than for the PI plants. These data suggest that the PI does not remobilize leaf nitrogen as readily as Deltapine.}, number={6}, journal={Journal of Plant Nutrition}, author={Chipman, R. B. and Raper, C. David and Patterson, Robert P.}, year={2001}, month={May}, pages={873–884} }
 @article{silva_smyth_raper_carter_rufty_2001, title={Differential aluminum tolerance in soybean: An evaluation of the role of organic acids}, DOI={10.1034/j.1399-3054.2001.1120208.x}, abstractNote={The role of organic acids in aluminum (Al) tolerance has been the object of intensive research. In the present work, we evaluated the roles of organic acid exudation and concentrations at the root tip on Al tolerance of soybean. Exposing soybean seedlings to Al 3+ activities up to 4.7 μ M in solution led to different degrees of restriction of primary root elongation. Al tolerance among genotypes was associated with citrate accumulation and excretion into the external media. Citrate and malate efflux increased in all genotypes during the first 6 h of Al exposure, but only citrate efflux in Al‐tolerant genotypes was sustained for an extended period. Tolerance to Al was correlated with the concentration of citrate in root tips of 8 genotypes with a range of Al sensitivities (r 2 =0.75). The fluorescent stain lumogallion indicated that more Al accumulated in root tips of the Al‐sensitive genotype Young than the Al‐tolerant genotype PI 416937, suggesting that the sustained release of citrate from roots of the tolerant genotype was involved in Al exclusion. The initial stimulation of citrate and malate excretion and accumulation in the tip of all genotypes suggested the involvement of additional tolerance mechanisms. The experiments included an examination of Al effects on lateral root elongation. Extension of lateral roots was more sensitive to Al than that of tap roots, and lateral root tips accumulated more Al and had lower levels of citrate.}, number={2}, journal={Physiologia Plantarum}, author={Silva, Ivo R. and Smyth, Thomas J. and Raper, C. David and Carter, Thomas E. and Rufty, Thomas W.}, year={2001}, month={Jun} }
 @article{silva_smyth_israel_raper_rufty_2001, title={Magnesium Ameliorates Aluminum Rhizotoxicity in Soybean by Increasing Citric Acid Production and Exudation by Roots}, DOI={10.1093/pcp/pce067}, abstractNote={Superior effectiveness of Mg over Ca in alleviating Al rhizotoxicity cannot be accounted for by predicted changes in plasma membrane Al3+ activity. The influence of Ca and Mg on the production and secretion of citrate and malate, and on Al accumulation by roots was investigated with soybean genotypes Young and PI 416937 which differ in Al tolerance. In the presence of a solution Al3+ activity of 4.6 microM, citrate and malate concentrations of tap root tips of both genotypes increased with additions of either Ca up to 3 mM or Mg up to 50 microM. Citrate efflux rate from roots exposed to Al was only enhanced with Mg additions and exceeded malate efflux rates by as much as 50-fold. Maximum citrate release occurred within 12 h after adding Mg to solution treatments. Adding 50 microM Mg to 0.8 mM CaSO4 solutions containing Al3+ activities up to 4.6 microM increased citrate concentration of tap root tips by 3- to 5-fold and root exudation of citrate by 6- to 9-fold. Plants treated with either 50 microM Mg or 3 mM Ca had similar reductions in Al accumulation at tap root tips, which coincided with the respective ability of these ions to relieve Al rhizotoxicity. Amelioration of Al inhibition of soybean root elongation by low concentrations of Mg in solution involved Mg-stimulated production and efflux of citrate by roots.}, number={5}, journal={Plant and Cell Physiology}, author={Silva, Ivo R. and Smyth, Thomas J. and Israel, Daniel W. and Raper, Charles D. and Rufty, Thomas W.}, year={2001}, month={May} }
 @article{silva_smyth_israel_raper_rufty_2001, title={Magnesium is More Efficient than Calcium in Alleviating Aluminum Rhizotoxicity in Soybean and its Ameliorative Effect is not Explained by the Gouy-Chapman-Stern Model}, DOI={10.1093/pcp/pce066}, abstractNote={The mechanistic basis for cation amelioration of Al rhizotoxicity in soybean was investigated through a series of studies comparing protective effects of Ca and Mg against Al inhibition of root elongation in a background 0.8 mM CaSO4 solution (pH 4.3). A modified Gouy-Chapman-Stern model was used to evaluate the effect of cations on electrical potential and Al3+ activity at root plasma membrane surfaces. Activities of Al3+ up to 4.6 microM in the background solution inhibited soybean tap root elongation by more than 80%. There was little or no response in root elongation when Ca and Mg were added to background solutions in the absence of AL: When added to Al-toxic solutions in the micromolar concentration range, Mg was 100-fold more effective than Ca in alleviating Al toxicity, whereas both cations were equally effective when added in the millimolar concentration range. The protective effect of micromolar additions of Mg on root elongation was specific for Al and it failed to alleviate La rhizotoxicity. In contrast to wheat, Mg amelioration of Al toxicity to soybean root elongation at low Mg concentration could not be explained by changes in potential and Al3+ activity at the root plasma membrane surfaces as predicted by a Gouy-Chapman-Stern model. These results suggest that Mg is not acting as an indifferent cation when present at low concentration and implies the involvement of a mechanism other than pure electrostatic effects at the root surface.}, number={5}, journal={Plant and Cell Physiology}, author={Silva, Ivo R. and Smyth, Thomas J. and Israel, Daniel W. and Raper, Charles D. and Rufty, Thomas W.}, year={2001}, month={May} }
 @article{rapp_shear_robison_2001, title={Soil, groundwater, and floristics of a southeastern United States blackwater swamp 8 years after clearcutting with helicopter and skidder extraction of the timber}, volume={149}, DOI={10.1016/s0378-1127(00)00558-2}, abstractNote={We compared the impacts of helicopter and rubber-tired skidder extraction of timber after harvesting on the structure and function of a blackwater forested wetland. This study was initiated in 1991, in a cypress-tupelo forest adjacent to the South Fork Edisto River in South Carolina, USA. Our objective, eight growing seasons after harvest, was to focus on the properties that showed effects of the harvest after three years: soil chemistry, organic matter decomposition, groundwater chemistry, and plant community composition. Concentrations of total nitrogen, phosphorous, and magnesium were lower in some of the harvest treatments than in the unharvested control. Cellulose decomposition at 5 and 10 cm below the soil surface was significantly greater in the harvested treatments than the unharvested, though there were no differences in soil temperature. There were no differences among treatments in the concentrations of NO3−, NH4+, and PO4 in groundwater sampled from depths of 0.2 and 1 m. Sedimentation was significantly greater in the harvested treatments than the unharvested treatment, and had apparently filled the ruts caused by the skidder. Ordination of the canopy vegetation plots using their importance values showed no separation of vegetation communities by treatment. In contrast, ordination of the midstory and understory vegetation plots cover showed a separation of communities between the harvested and unharvested treatments. There was no apparent environmental advantage to using helicopters rather than skidders to extract timber from this forest.}, number={1-3}, journal={Forest Ecology and Management}, publisher={Asheville, NC : U.S. Dept. of Agriculture, Forest Service, Southern Research Station}, author={Rapp, John and Shear, Theodore and Robison, Daniel}, year={2001}, month={Aug}, pages={241–252} }
 @article{wright_coble_raper_rufty_1999, title={Comparative responses of soybean (Glycine max), sicklepod (Senna obtusifolia), and Palmer amaranth (Amaranthus palmeri) to root zone and aerial temperatures}, volume={47}, number={2}, journal={Weed Science}, author={Wright, S. R. and Coble, H. D. and Raper, C. D. and Rufty, T. W.}, year={1999}, pages={167–174} }
 @article{saravitz_devienne-barret_raper_chaillou_lamaze_1998, title={Nitrate Uptake Rate by Soybean and Wheat Plants Determined by External Nitrate Concentration and Shoot-Mediated Demand}, DOI={10.1086/297551}, abstractNote={When NO3- is maintained at concentrations greater than those required to sustain maximum cumulative uptake by wheat (Triticum aestivum) and nonnodulated soybean (Glycine max [L.] Merrill), the net rate of uptake is not constant but oscillates between maxima and minima. The amplitudes of both the maxima and the minima increase with increases in NO3- concentration of the solution. To determine if the amplitudes of oscillations decline when NO3- in solution is maintained at suboptimal concentrations, net rates of NO3- uptake were monitored daily during 22 d of vegetative growth under controlled environmental conditions for wheat from solutions containing 0.1, 0.25, 0.4, 0.5, 0.8, 1.5, 3.0, and 5.0 mM NO3- and for soybean from solutions containing 0.05, 0.1, 0.5, and 1.0 mM NO3-. The amplitudes of variations in daily net rates of NO3- uptake increased with the increases in concentration of NO3- in the nutrient solutions. The differences in magnitude of the amplitudes in oscillation, expressed as coefficients of variability for daily uptake rates, were positively related to calculated rates of export of nitrogen from root to shoot. To explain these oscillations in the long-term patterns of net rates of NO3- uptake, acquisition of nitrogen by plants is viewed as the summation of two separate mechanisms. One mechanism, which is dependent on NO3- concentration in solution, regulates net movement of nitrogen from the external solution into the root symplasm. The second mechanism, which is contingent both on availability of nitrogen in the symplasm and on shoot activity via phloem transport of substrates such as amino acids and carbohydrates, regulates movement of nitrogen from the symplasm into the xylem for translocation to the shoot.}, number={2}, journal={International Journal of Plant Sciences}, author={Saravitz, C. H. and Devienne-Barret, F. and Raper, C. D. and Chaillou, S. and Lamaze, T.}, year={1998}, month={Mar} }
 @article{villagarcia_collins_raper_1998, title={Nitrate uptake and nitrogen use efficiency of two sweet potato genotypes during early stages of storage root formation}, volume={123}, number={5}, journal={Journal of the American Society for Horticultural Science}, author={Villagarcia, M. R. and Collins, W. W. and Raper, C. D.}, year={1998}, pages={814–820} }
 @article{raper_vessey_henry_chaillou_1991, title={Cyclic variations in nitrogen uptake rate of soybean plants: Effects of pH and mixed nitrogen sources}, volume={29}, number={3}, journal={Plant Physiology and Biochemistry}, author={Raper, C. D., Jr. and Vessey, J. K. and Henry, L. T. and Chaillou, S.}, year={1991}, pages={205} }
 @article{raper_patterson_parsons_kramer_1977, title={Relative growth and nutrient accumulation rates for tobacco}, DOI={10.1007/BF00010102}, number={2}, journal={Plant and Soil}, author={Raper, C. David and Patterson, David T. and Parsons, Lawrence R. and Kramer, Paul J.}, year={1977}, month={Feb} }
 @article{raper_smith_downs_1975, title={Factors affecting the development of flue-cured tobacco grown in artificial environments: Growth responses to light schedules}, volume={177}, number={5}, journal={Tobacco International}, author={Raper, C. D., Jr. and Smith, W. T. and Downs, R. J.}, year={1975}, pages={37} }
 @article{raper_smith_york_1974, title={Geometry of tobacco leaves: Effect on estimation of leaf area}, volume={176}, number={3}, journal={Tobacco International}, author={Raper, C. D., Jr. and Smith, W. T. and York, E. K.}, year={1974}, pages={31} }
 @article{raper_weeks_downs_johnson_1973, title={Chemical Properties of Tobacco Leaves as Affected by Carbon Dioxide Depletion and Light Intensity<sup>1</sup>}, DOI={10.2134/agronj1973.00021962006500060042x}, abstractNote={Abstract Plants growing in controlled‐environment rooms are frequently subjected to self‐depleted CO 2 levels that manufacturers' “make‐up air systems” do little to alleviate. Flue‐cured tobacco ( Nicotiana tabacum L. ‘Coker 319’) rapidly depletes CO 2 from a 400 ppm (μl/liter) ambient level of 200 ppm. When compared with plants grown to maturity in an atmosphere continually adjusted to the 400 ppm level by supplementary CO 2 , chemical assays of leaf constituents indicated lesser effects of the CO 2 depletion than anticipated. The contents of starch, soluble carbohydrates, and polyphenolics were meagerly depressed in a CO 2 ‐depleted atmosphere. A reduction in light intensity below 322 hectolux had a greater effect accumulation of these compounds than did CO 2 depletion, The CO 2 depletion did affect the composition of the soluble carbohydrate fraction in leaf tissue. The CO 2 and light treatments in this experiment were continued until au advanced stage of leaf senescence. Both CO 2 depletion and reduced light intensities prolonged the growth period of leaves before the onset of senescence. We conclude that the extended period of growth, as well as the chronological timing of other morphological eve:ats, explains many of our reported results.}, number={6}, journal={Agronomy Journal}, author={Raper, C. David and Weeks, W. W. and Downs, R. J. and Johnson, W. H.}, year={1973}, month={Nov} }
 @article{raper_downs_1973, title={Factors Affecting the Development of Flue‐Cured Tobacco Grown in Artificial Environments: IV. Effects of Carbon Dioxide Depletion and Light Intensity<sup>1</sup>}, DOI={10.2134/agronj1973.00021962006500020019x}, abstractNote={Abstract Plants grown in controlled‐environment rooms are usually under a CO 2 stress that the so‐called “make‐up air systems” do little or nothing to alleviate. Tobacco ( Nicotiana tabacum L.) rapidly depletes the CO 2 from 400 ppm (v/v) ambient level to 200 ppm. This report evaluates the effects of this CO 2 stress by comparison with plants grown in an atmosphere where CO 2 was maintained at the ambient 400 ppm level by supplemental CO 2 . Light intensities of 215, 322, and 450 hlx were superimposed on both CO 2 regimes. Plant development was evaluated by physical and chemical properties of mature leaves and has been compared not only among the imposed treatment conditions, but also with the development that occurs in a natural field environment. Several abnormalities of tobacco were noted under CO 2 stress. These include: a low concentration of reducing sugars in the cured leaves, presumably reflective of low soluble carbohydrate accumulation in mature leaves; reduced internode elongation; and epinasty of leaves during maturation. A reduced dry matter accumulation in aerial organs, concomitant with the reduced internode growth, was recorded under the CO 2 stress. Only small differences between CO 2 levels occurred for dry matter accumulation in leaf tissue. Decreased light intensity increased accumulation of nitrogen and potassium by the plants independent of CO 2 level. Most of this increase was attributed to actively expanding tissue, in this case to growth of secondary meristems.}, number={2}, journal={Agronomy Journal}, author={Raper, C. David and Downs, R. J.}, year={1973}, month={Mar} }
 @article{raper_1973, title={Temperatures in early post-transplant growth: Alteration of leaf shape in field environments}, volume={175}, number={2}, journal={Tobacco International}, author={Raper, C. D., Jr.}, year={1973}, pages={31} }
 @article{raper_johnson_downs_1971, title={Factors Affecting the Development of Flue‐Cured Tobacco Grown in Artificial Environments. I. Effects of Light Duration and Temperature on Physical Properties of Fresh Leaves<sup>1</sup>}, DOI={10.2134/agronj1971.00021962006300020026x}, abstractNote={Abstract Tobacco ( Nicotiana tabacum L. ‘Coker 319‘) plants were grown to maturity in the facilities of the North Carolina State University Phytotron (Southeastern Plant Environment Laboratory) to determine effects of temperature and light duration on the physical characteristics of fresh leaves. Leaf area, shape, and specific leaf weight (dry weight per unit leaf surface area) were determined at six stalk positions. The lower temperatures resulted in small, relatively wide leaves at the base of the plant and elongated leaves at the top. Higher temperatures tended to reverse the normal shape and size ordering sequence of leaves; at the highest temperature condition the largest, as well as the broadest, leaves were developed at the uppermost stalk positions. The specific leaf weight was increased by an increase in the duration of the high intensity light period and by decreases in temperature. The increased light duration also enhanced the relative width of leaves.}, number={2}, journal={Agronomy Journal}, author={Raper, C. D. and Johnson, W. H. and Downs, R. J.}, year={1971}, month={Mar} }
 @article{raper_1971, title={Factors Affecting the Development of Flue‐Cured Tobacco Grown in Artificial Environments. III. Morphological Behavior of Leaves in Simulated Temperature, Light‐Duration, and Nutrition Progressions During Growth<sup>1</sup>}, DOI={10.2134/agronj1971.00021962006300060008x}, abstractNote={Abstract The growth environment of a plant determines the ultimate expression of many characteristics of development. Among other environmental variables, a plant growing in the field encounters seasonal progressions of temperature, daylength, and nutrient supply. To determine if these natural, seasonal progressions are essential for reproducing “normal” field growth of flue‐cured tobacco ( Nicotiana tabacurn L. ‘Coker 319’) in controlled‐enviromnent facilities, simplified simulations of temperature, light‐duration, and nitrogen and potassium nutrition were established in controlled‐enviromnent rooms. Regression‐descriptors plots of regression equations with leaf‐stalk position as the independent variable) of size, shape, and specific weight of mature leaves from plants grown under combinations of these simulated progressions and constant temperature, light‐duration, and nutrition regimes were evaluated relative to characteristic regression‐descriptors derived from field grown plants. A seasonal progression of temperature and progressive reductions of nitrogen and potassimn supply are critically involved in determining the physical attributes of leaves characteristic of “normal”, field‐grown tobacco. Combined with a continuous daily light‐duration of 9 hours, the simulated progressions of temperature and nutrition most nearly facsimilated a “normal” leaf‐size ordering and resulted in the least disruption of “normal” variations of leaf shape and specific leaf weight due to stalk position.}, number={6}, journal={Agronomy Journal}, author={Raper, C. D.}, year={1971}, month={Nov} }
 @article{raper_johnson_1971, title={Factors affecting the development of flue-cured tobacco grown in artificial environments. 2. Residual effects of light duration, temperature and nutrition during growth on curing characteristics and leaf properties}, volume={173}, number={1}, journal={Tobacco International}, author={Raper, C. D., Jr. and Johnson, W. H.}, year={1971}, pages={31} }