bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Different Endomycorrhizal Fungi on Five Host Plants Grown on Calcined Montmorillonite Clay1
Authors: Plenchette Christian , Furlan Valentin , Fortin J. Andre
Published: August 2022

Series of greenhouse experiments were made to determine the effects of different endomycorrhizal fungi on the growth of oat (Avena sativa L., cv. Alma), strawberry (Fragaria × ananassa, cv. Redcoat), leek (Allium porrum L., cv. American Flag), apple (Malus domestica Borkh., cv. Beautiful Arcade), and asparagus (Asparagus officinalis L., cv. Mary Washington) plants which were grown in a calcined montomorillonite clay (Turface) medium and fertilized with a Long Ashton nutrient solution at 100 ml/week·pot (20 cm diameter). Plants were inoculated with 1 g of fresh ash (Fraxinus americana L.) roots harboring the different fungi. Out of 6 endomycorrhizal inocula used, 4 were well-identified: Gigaspora calospora (Nicol. & Gerd.) Gerd & Trappe, Glomus epigaeus Daniels & Trappe, Glomus macrocarpus Tul. & Tul., var. macrocarpus, and Glomus monosporus Gerd. & Trappe. The results indicate that Turface is a good growing medium for this type of study, as it permits good plant growth and abundant mycorrhiza formation with standard growing conditions. The fungi used produced different effects according to plant host. There was no correlation between the percentage of root infection and the stimulation of growth in the case of strawberry. Contrarily, there was a significant correlation (1% level) in the case of apple, asparagus, leek, and oats plants. No fungal specificity of the endophyte for the host plant was observed. The unknown endomycorrhizal species had effects on plant growth comparable to those of Glomus epigaeus with apple and strawberry plants.
Effects of Carbon Dioxide, Oxygen, and Ethylene Levels of Kentucky Bluegrass Sod1
Authors: King J. W. , Beard J. B. , Rieke P. E.
Published: August 2022

Sods of ‘Merton’ Kentucky bluegrass (Poa pratensis L.) were placed in atmospheres containing 0, 9, 18, or 27% CO2; 0, 2, 4, 8, or 16% O2; and 0, 2, 4, or 8 ppm C2H4. Neither CO2 nor C2H4 toxicity nor O2 deficiency caused sod injury in commercial sod toads. Ventilation tubes inserted in commercial sod toads failed to increase gas exchange and heat dissipation beyond a 3-cm distance.
Effects of Black Polyethylene Mulch on Strawberry Leaf Elongation and Diurnal Leaf Water Potential1
Authors: Renquist A. Richard , Breen Patrick J. , Martin Lloyd W.
Published: August 2022

‘Olympus’ strawberries (Fragaria × ananassa (Duch.) with and without black polyethylene mulch were compared in terms of leaflet elongation and diurnal water potential (ψ) of leaves at 2 levels of drip irrigation. Mulch increased leaflet elongation at both irrigation levels, but had no appreciable effect on soil water potential at 20 cm depth, nor on leaf ψ or leaf turgor. Leaflet elongation with black polyethylene may have been favored by the increased soil temperature throughout the upper 20 cm. At the 10-cm depth, mulched, high-moisture soil was an average of 3.0°C warmer during a diurnal cycle. Greatest warming was in late afternoon and late evening in low and high moisture soil, respectively.
Physiological and Compositional Changes Associated with Maturation of ‘Kerman’ Pistachio Nuts1,2
Authors: Labavitch John M. , Heintz Christi M. , Rae Henry L. , Kader Adel A.
Published: August 2022

As the pistachio (Pistacia vera L. cv. Kerman) nut matured, kernel moisture, respiration rate, and total protein content decreased, while kernel dry weight increased. At optimum maturity, ether-extractable fat and total sugar contents reached a peak. Either or both of these constituents may be useful as a maturity index, in addition to ease of hull separation, to determine optimum harvest date for pistachio nuts. Nut quality was acceptable for harvest during a 2- to 3-week period bracketing the time when the hull separates easily from the shell. Compositional analyses of hulls indicated some limitations on their potential use as animal feed.
Phenotypic and Cytologie Analyses of Spontaneous Mutations of the ‘Montmorency’ Cherry (Prunus cerasus L.)
Authors: Goldy R. G. , Andersen R. L. , Dennis F. G.
Published: August 2022

Eleven suspected somatic mutations, consisting of 7 trees and 4 individual branches of the ‘Montmorency’ cherry, were compared with standard ‘Montmorency’ for phenotypic traits including tree height, trunk circumference, leaf area, crotch angle, resistance of flowers to frost injury, pollen germination, fruit set, individual fruit weight, fruit removal force, and yield. Differences occurred between some variants and ‘Montmorency’ controls for all characters except fruit removal force. All variants were tetraploid (2n = 32), as is standard ‘Montmorency’, with no evidence of cytochimerism.
Influence of Leaching, Fertilizer Source and Rate, and Potting Media on Foliage Plant Growth, Quality, and Water Utilization1
Authors: Poole Richard T. , Conover Charles A.
Published: August 2022

Method of fertilization application and leaching had little effect on response of Dieffenbachia maculata (Lodd.) G. Don ‘Perfection’ (dumbcane) and Brassaia actinophylla Endl. (schefflera). The recommended fertilizer rate increased top but reduced root growth. Plants utilized 5 to 10% more water when leached. In a second experiment, plant grade and vegetative growth decreased with a decrease in the fertilizer rate but root grade and growth increased. Plants growing in the peat/sand (3:1) potting medium were rated superior to plants in the peat/bark/shavings (2:1:1) medium. Leaching with 10% excess water or fertilizer solution slightly improved plant response of schefflera, but overall data indicate leaching of pots is unnecessary for short term foliage crops fertilized properly. Increased fertilizer rates increased water utilization efficiency and vegetative growth, but reduced root growth.
Studies Related to the Description and Evaluation of Pistachio Nut Quality1
Authors: Kader Adel A. , Heintz Christi M. , Labavitch John M. , Rae Henry L.
Published: August 2022

The chemical composition and sensory attributes of pistachio nuts (Pistacia vera L.) were studied in relation to genotype, production area, maturity, moisture content, degree of shell staining, and storage conditions. ‘Kerman’ kernals were rated higher in firmness and sweetness, and lower in crispness, bitterness, and rancidity than those of the ‘Red Aleppo’, ‘Trabonella’, and ‘Bronte’ cultivars. Differences in composition and flavor of ‘Kerman’ pistachios harvested from 3 production areas were small. Nuts harvested at near optimum maturity were superior in quality to those harvested earlier or later. Drying nuts to 4–6% moisture levels resulted in the best quality. Shell staining did not influence eating quality of kernels but detrimentally affected shell appearance. Dried pistachio nuts can be kept for 12 months at 20°C. Moisture content influenced crispness and firmness while total sugars content was related to sweetness and overall flavor intensity.
Assimilation Patterns of [14C]-Photosynthate in Developing Sweet Potato Storage Roots1
Authors: Chua L. K. , Kays S. J.
Published: August 2022

Patterns of deposition of [14C]-photosynthate in the storage roots of Ipomoea batatas (L.) Lam. at 3 stages of development (44, 74, 105 days from planting) were distinct for each labeling period. [14C] initially accumulates in the vascular cambial region after labeling (24 hours); however, all areas of the storage root show discernable activity. Label in this region is lost with time probably through cell division with the majority of the label ending up in bundle parenchyma. Deposition of [14C]-photosynthate appears to occur for more than 24 hours reflecting either continued transport from aerial portions of the plant or redistribution within the root. Roots labeled early in their development do not have a uniform distribution of [14C] in the central stele, possibly due to later development of anomalous cambium. [14C] in the cortical region does not appear to be redistributed inward during subsequent growth of the root. [14C] deposited early in the development of the storage root was concentrated at the distal end with longitudinal bulking proceeding toward the proximal end. Invaginations along the surface of the root giving a furrowed appearance appear to be due to differential rates of activity of the vascular cambium in those regions.
Modeling Temperature Requirements for Rest Development in Cornus sericea1
Authors: Kobayashi Kent D. , Fuchigami Leslie H. , English Marshall J.
Published: August 2022

Temperature requirements for rest development were determined and used in developing an empirical model for predicting rest development in terminal vegetative buds of Cornus sericea L. Vegetatively mature plants were exposed to 5° to 20°C under a 12-hr photoperiod (SD) in growth chambers, and depth of rest was measured by days to terminal bud break at 20°/15° (day/night) under a 16-hour photoperiod (LD). Rest development proceeded only after vegetative maturity was attained. Time from vegetative maturity to maximum rest decreased with decreasing temperature. Rate of rest development at all temperatures varied and was dependent on growth stage. The annual growth cycle and rest development were described and quantified by a degree growth stage (°GS) model. Using temperature and accumulating °GS, the model predicted maximum rest within 2 days in both years.
A Sand Culture System for Simulating Plant Responses to Phosphorus in Soil1
Authors: Coltman Robert R. , Gerloff G. C. , Gabelman W. H.
Published: August 2022

A sand medium containing activated alumina was developed to provide a range of stable, reproducible P concentrations in plant cultures. The lowest P levels compare favorably to concentrations found in soils. Activated alumina was “loaded” by absorption of phosphate from 0.01 m NaCl solutions containing KH2PO4. Phosphorus concentrations in solutions expressed from sand-alumina mixtures were dependent upon the P concentrations used to absorb P onto the alumina. Increasing the density of a specifically loaded alumina did not affect the average solution P concentration in the cultures but did result in substantial increases in total dry weight yields of tomato (Lycopersicon esculentum Mill.) plants grown in the cultures. Thus, diffusion of P to root surfaces seems to be a prominent limiting factor in this system as in soils. The sand alumina culture technique shows promise for simulating plant responses to P at concentrations and under conditions comparable to those found in soils.
Ozone Sensitivity of Herbaceous Plants: Modification by Ethylenediurea1
Authors: Cathey H. M. , Heggestad H. E.
Published: August 2022

[N-[2-(2-oxo-l-imidazolidinyl)ethyl]-N’-phenylurea (EDU or ethylenediurea) was applied as a soil drench and as foliar sprays to evaluate protection from ozone injury in controlled fumigations on 44 species of herbaceous plants. At least 4 doses of EDU were compared on 5 plant species: Begonia cucullata var. Hookeri Willd., (fibrous rooted begonia), Tagetes erecta L. (marigold), Antirrhinum majus L. (snapdragon), Lycopersicon esculentum Mill, (tomato), and Chrysanthemum morifolium Ramat. (chrysanthemum). Protection from ozone injury was directly related to EDU dose up to about 500 ppm. The spray and drench treatments gave about the same protection from ozone. EDU had no measurable effect on plant growth. Genera showing relatively high sensitivity to ozone and good protection with EDU included Ageratum, Amaranthus, Browallia, Capsicum, Celosiay Dahlia, Lobelia, Lycopersicon, Nicotiana, Perilla, Salvia, and Zinnia. The EDU treatments used did not protect adequately Hedera Lactuca, Rosa, or Zea mays (sweet corn). Species of several genera showed little or no foliar injury even at the highest ozone dose (0.60 ppm/3 hr), including Brassaia, Catharanthus, Chlorophytum, Coffeay Cyclamen, Dizygotheca, Philodendron, Saintpaulia, and Torenia. ‘Fred Shoesmith’ chrysanthemum was insensitive to ozone.
Inheritance of Foliar α-Tomatine Content in Tomatoes1
Authors: Juvik J. A. , Stevens M. A.
Published: August 2022

Evaluation of progeny populations from crosses between tomato accessions (Lycopersicon spp.) with high and low alkaloid levels indicated that variation in α-tomatine content is controlled by the segregation of 2 co-dominant alleles at a single locus.
Nuclear Magnetic Resonance of Water in Deuterated Citrus Leaf Tissue1
Authors: Rouse R. E. , Wiltbank W. J. , Brey W. S.
Published: August 2022

Nuclear magnetic resonance (NMR) H resonance signals of water in deuterated disks from acclimated and nonacclimated satsuma (Citrus unshiu Marcovitch) leaves appear to be a measure of bound water. The D resonance signal was lost when initial freezing occurred along with a partial loss in H resonance, which was attributed to D2O and bound H2O forming ice. Acclimated tissues retained a larger percentage of unfrozen H2O at initial freezing and at several subfreezing temperatures, suggesting that changes in H2O binding occur during cold acclimation. Further, NMR line widths of nonacclimated leaf tissue increased abruptly during freezing and only gradually in acclimated leaf tissue, suggesting increased binding structure of H2O molecules of the bound fraction and cellular constituents in acclimated tissue. Portion of total H2O replaced with D2O was 69% in both, suggesting this portion was free water.
Potassium Nutrition during Tomato Plant Development1
Authors: Widders Irvin E. , Lorenz Oscar A.
Published: August 2022

K concentrations in xylem exudate and K concentrations and contents in stem, petiole, leaf lamina, and fruit tissues were determined at 10-day intervals during the development of field-grown tomato plants (Lycopersicon esculentum Mill.). Four determinate-type processing tomato cultivars were compared. Xylem exudate K+ concentrations of 9 to 12 meq/liter were measured prior to anthesis but declined to 7 to 8 meq/liter with the onset of fruiting. Vegetative growth rates were highest at 70 days after planting. Maximum rates of K accumulation in the plants occurred at 90 days, which coincided with the period of maximum K accumulation in the fruit. The rate of K accumulation in the plant relative to the shoot dry weight was correlated with the relative growth rate. About 70% of the K accumulated in the plant at harvest was taken up during fruiting. K redistribution from vegetative tissues contributed a maximum of only 12% of the total accumulated K by the fruit. K content in leaf lamina, petiole, and stem tissue decreased by about 20 to 40%, 20 to 30%, and 15%, respectively, during fruiting, depending on the cultivar.
Plum Root Growth in a Variable-strength Field Soil1
Authors: Grimes D. W. , Wiley P. L. , Carlton A. B.
Published: August 2022

Root growth is restricted in compact soil zones irrespective of whether the zones result from cultural equipment or are genetic in origin. Because yield may be reduced and production costs increased, proper diagnosis is important. To that end, penetrometer soil strength measurements were used in the field to characterize root-limiting soil-impedance characteristics for ‘Eldorado’ plums (Prunus salicina Lindl.). A penetrometer soil strength of 16 bars, measured at a volumetric water content of 16.9% (field capacity), was sufficient to lower root density to about 50% of that observed for low-strength soil. Tree growth (trunk circumference) was highly correlated with the averageprofile root density and the amount of silt present at a mid-profile depth. Low values of these parameters most probably were related to a water stress condition that reduced tree growth.
Cytogenetical and Fertility Studies of Selected Nontuberous Solanum Species and their Hybrid Derivatives1
Authors: Attavian B. N. , Jelenkovic G. , Pollack B. L.
Published: August 2022

Reciprocal crosses among the nontuberous Solanum species S. gilo Raddi, S. integrifolium Poir, and S. nodiflorum Jacq. were performed under controlled conditions. Meiotic chromosome pairing of the hybrids was regular, and no reductions in chiasma frequency at diakinesis were observed. Normal disjunction in first and second meiotic divisions of fertile hybrids indicates that there is no conspicuous genomic differentiation at the chromosomal level. The gametic chromosome number was found to be n = 12 for all species and interspecific hybrids. BC1 and F2 populations consisting of fully fertile, partially fertile, and completely sterile seedlings were obtained. The fertile hybrid derivatives in these progenies may be of practical value in genetic improvement of the cultivated eggplant. Data for 3 phenotypic traits in selected F2 and BC1 populations indicate normal allelic segregation, and also indicated homology among the genomes of these species. Only in 2 cases were small deviations from expected ratios observed.
The Effect of Temperature, Photoperiod, and Freeze Treatment on the Morphology of Chrysanthemum X morifolium Ramat. ‘Astrid’1
Authors: Fayyaz Mohammad M. , Struckmeyer B. Esther , Beck G. E.
Published: August 2022

More rhizomes were initiated by plants of ‘Astrid’ chrysanthemum grown in short day and cool air temperature than in long day and warm air. Rhizome development was greatest, shoot growth was enhanced, and root length and dry weight increased with warm compared to cool soil temperature. Rhizomes grown at a cool soil temperature either in long or short days had the least cellular injury after exposure to –8°C.
Effectiveness of Selected Herbicides and Discing on Volunteer Horseradish Control1
Authors: Burke Michael C. , Herbert J. Hopen
Published: August 2022

Methods were compared for controlling volunteer horseradish (Armoracia rusticana Gaertn, Mey. & Scherb.) resulting from commercial horseradish production. The most effective treatment was glyphosate [N-(phosphonomethyl) glycine] (4.5 kg/ha) applied in mid-September 6 to 8 weeks after discing. 2,4,5-T [2,4,5-trichloro-phenoxy acetic acid] was also effective, while dicamba [3,6,dichloro-o-anisic acid] and a dicamba plus glyphosate mixture provided less control. Horseradish roots can sprout from 90-cm deep and still be susceptible to a mid-September glyphosate application.
Flower Initiation and Development in Leucospermum cv. Red Sunset1
Authors: Jacobs Gerard
Published: August 2022

Plants of Leucospermum cv. Red Sunset, a natural hybrid between L. cordifolium (Salisb. ex Knight) Fourcade and L. lineare R. Br., are in the induced state for flower initiation between April 25 and June 20 in South Africa. A gradual loss of the induced state occurs after June and by Oct. 22, plants have returned to the noninduced vegetative state. Heavy shading during summer prevented flower initiation. Defoliation reduced flower dry weight and style number. Shade and late removal of primary inflorescences adversely affected quality of secondary inflorescences.
Transplant Quality, Yield, and Heavy-Metal Accumulation of Tomato, Muskmelon, and Cabbage Grown in Media Containing Sewage Sludge Compost1
Authors: Sterrett S. B. , Reynolds C. W. , Schales F. D. , Chaney R. L. , Douglass L. W.
Published: August 2022

Transplant quality, as measured by height and dry weight, of cabbage (Brassica oleracea L. Capitata group) and tomato (Lycopersicon esculentum Mill.) was lower for plants grown in media containing sewage sludge compost with a high heavy-metal concentration (HM) than for plants grown in peat-vermiculite (P-V) or low-metal (LM) sewage sludge compost media. Compost source had no significant effect on transplant quality of muskmelon (Cucumis melo L.) seedlings. Marketable yield of cabbage, tomato, or muskmelon was similar regardless of the media used to grow the transplants. The concentration of Zn, Cu, Mn, Ni, and Cd were significantly higher in transplants grown in HM media than in those grown in LM media. With the exception of Cd, metal levels in transplants grown in LM media were similar to those grown in P-V. Transplant media had little influence on the heavy-metal concentrations found in either foliar samples or the edible portions of the crops studied. Heavy-metal concentrations in foliar samples of all 3 crops were lower than those found in transplants. The lowest concentrations were found in tomato and muskmelon fruit, and in cabbage heads. The Cd concentrations in edible portions were very low regardless of the source of compost in the transplant media, indicating that sewage sludge composts, particularly those low in heavy metals, can be used safely in the growing media of vegetable transplants.
Differential Sensitivity of Seventeen Poinsettia Cultivars to Sulfur Dioxide in Relationship to Bract Color1,2
Authors: Krizek Donald T. , Semeniuk Peter
Published: August 2022

Comparative SO2 sensitivity was determined for red, pink, marble, and white cultivars of poinsettia, Euphorbia pulcherrima Willd. ex Klotzsch, belonging to 4 groups of sports: ‘Paul Mikkelsen’, ‘Annette Hegg’, ‘Eckespoint C-l’, and ‘Oakleaf’. Based on injury to the bracts, sports of the ‘Eckspoint C-l’ group were the most insensitive, whereas sports from the ‘Annette Hegg’ and ‘Paul Mikkelsen’ groups were the most sensitive. However, based on the number of leaves showing SO2 injury, sports from the ‘Oakleaf’ group were the most insensitive and those of the ‘Paul Mikkelsen’ group were the most sensitive. True leaves were generally much more sensitive to SO2 exposure than were corresponding bracts. There was no consistent relationship between bract color and extent of SO2 injury.
Stomatal and Nonstomatal Inhibition of Photosynthesis in Water-stressed Apple Seedlings1
Authors: Swietlik Dariusz , Korcak R. F. , Miklos Faust
Published: August 2022

The effect of polyethylene glycol (PEG)-induced water stress on stomatal and nonstomatal inhibition of photosynthesis of apple seedlings (Malus domestica Borkh.) grown in solution culture was investigated. Water stress was applied gradually by modifying the nutrient solution water potential daily to a minimum of -8.0 bar. Nutrient solution of less than or equal to water potentials -6 bar decreased net and gross photosynthesis rates. Stomatal and nonstomatal factors were responsible for photosynthetic inhibition. Nonstomatal inhibition of photosynthesis appears to be due to decreased capacity for CO2 fixation and not increased photorespiration. The ratio of gross to net photosynthesis was not affected. A higher level of water stress was required to affect mesophyll resistance than stomatal resistance and/or there was a lag time for mesophyll resistance to respond to stress.
Growth, Mineral Uptake, and Evapotranspiration of Air Layers from Blight-affected and Healthy Grapefruit Trees with Two Nutrient Regimes1,2
Authors: Wutscher Heinz K.
Published: August 2022

Air layers from 6 blight-affected and 6 healthy grapefruit, Citrus paradisi Macf., trees were grown in a greenhouse with low N, low S, and lime and high N, high S, and no lime regimes, one air layer from each tree in each treatment. Shoot fresh weight of air layers from healthy trees was 25%, and root fresh weight was 38% greater than that of air layers from blighted trees, after 8 months of treatment (shoot/root ratios of 1.59 and 1.90). Shoot weight was the same with both nutrient treatments; root weight was 40% smaller with high N, high S, and no lime than with low N, low S, and lime (shoot/root ratios of 2.12 and 1.37). Air layers from blighted trees had higher concentrations of N, P, and water-soluble phenolics, and lower Ca and Na in the wood; more S, Fe, Zn, Cu, and Mo in the bark; more N and K, and less Mg, Na, and Cl in the roots, and more P and less B and Cl in the leaves than air layers from healthy trees. Low N, low S, and lime induced higher K and Mo in the wood, higher K in the bark, and lower Na and Cl in the roots of air layers from blighted trees; high N, high S, and no lime increased Mg and Zn in the roots, Fe in the wood, and Zn in the leaves of air layers from blighted trees above the levels of healthy air layers. There were curvilinear relationships between evapotranspiration and root weight and the shoot/root ratio; air layers from blighted trees transpired more water than those from healthy trees on a per unit shoot and root weight basis.
Growth of Asparagus Transplants as Influenced by Nitrogen Form and Lime1
Authors: Precheur Robert J. , Maynard Donald N.
Published: August 2022

Transplants of asparagus (Asparagus officinalis L.) were grown in sand culture under varying ratios of NO3 and NH4. Maximum growth occurred in a nutrient solution with a N ratio of 75% NO3 – N and 25% NH4 – N. Growth was significantly reduced when the N composition was either 100 or 75% NH4 – N. CaCO3 reduced ammonium toxicity but also reduced seedling growth.
Conductivity Tests to Screen Fall-applied Growth Regulators to Induce Cold Hardiness in Young ‘Delicious’ Apple Trees1
Authors: Raese J. Thomas
Published: August 2022

Chemical growth regulators were applied in early fall to 1-year-old ‘Delicious’ apple trees (Malus domestica Borkh.) to evaluate cold hardiness and cold injury during late fall to late winter. Evaluations were made by the conductivity test and expressed as the percentage of electrolytes. Of the 18 chemicals tested, CGA-15281 (500 ppm) showed the most promise for increasing cold hardiness, especially in November. During freeze tests in November or February of 1976, AMO-1618 (1000 ppm), GA3 and GA3 + fluoridamid (500 and 6000 ppm, respectively), and Thidiazuron (100 ppm) induced significantly greater cold hardiness than the controls. When tested separately or in combination with other chemicals, ancymidol, CGA-15281, DEPEG, PP 528, and NIA-10637 produced slightly more cold hardiness relative to the controls in more than 50% of the tests. Daminozide, ethephon, GA3, glyphosine, and UBI-P293 were the least effective chemicals for inducing cold hardiness.
Reaction of Peach and Nectarine Cultivars and Selections to Infection by Botryosphaeria dothidea1
Authors: Okie W. R. , Reilly C. C.
Published: August 2022

Commercial and exotic cultivars and selections of peach and nectarine [Prunus persica (L.) Batsch] were evaluated for reaction to gummosis caused by Botryosphaeria dothidea (Moug. ex Fr.) Ces & de Not. (B. ribis Gross & Dugg.). Commercial germplasm was susceptible. Mature trees of several exotic lines showed very little natural infection. ‘Eagle Beak’, Plant Introduction (PI) 43289 from China, was the most resistant to gummosis. Artificially inoculated twigs of this line gummed only slightly, although the fungus could still be isolated from some wounds after 16 months.
Physical Properties of Container Media Composed of a Gasifier Residue in Combination with Sphagnum Peat, Bark, or Sand1
Authors: Regulski Francis J.
Published: August 2022

The physical and water-release characteristics of a gasifier residue in combination with bark, Canadian sphagnum peat, and sand were determined. Both gasifier residue and peat had characteristics more favorable for plant growth than bark or sand alone. The combination of gasifier residue and peat produced characteristics superior to gasifier residue or peat alone. Gasifier residue and combinations of gasifier residue and peat had almost twice the available water of a standard nursery medium. The addition of sand or bark decreased the performance of gasifier residue in a number of physical parameters. Unsieved gasifier residue had a particle size distribution suitable for container plant production.
Water Relations and Net Photosynthesis in Hybrid Geranium1
Authors: Armitage A. M. , Vines H. M. , Zeng-Ping Tu , Black C. C.
Published: August 2022

The relationships of net photosynthesis (Pn) to soil water potential, leaf diffusive resistance, leaf water potential, and relative water content were studied with hybrid geranium (Pelargonium × hortorum Bailey cv Sprinter Scarlet) grown under conditions of greenhouse pot culture. Net photosynthesis went through 4 stages according to the effects of water stress on the plants. As water stress increased, Pn went from a steady-state maxiumum rate to slow decline, to rapid decline, to total inhibition. During rapid Pn decline, soil water potential rapidly decreased from −4 bars to −14 bars, and leaf diffusive resistance increased from 4 s cm−1 to 80s cm−1. Leaf water potential was −7 bars, and relative leaf water content was 81–87%. Leaf water potential appeared to be the best indicator of imminent Pn decline. After rewatering water-stressed plants, 3 days were required to elevate Pn to a steady-state maximum which was only 90% of initial steady-state Pn.
Genotypic Variation for Rate of Respiration in Tomato Fruits1
Authors: Hewitt J. D. , Stevens M. A.
Published: August 2022

Measurement of respiration rate and ethylene production at the climacteric of fruits of 4 tomato (Lycopersicon esculentum Mill.) cultivars and breeding lines—LA 1563 (1563), ‘VF145B-7879’ (‘7879’), ‘UC 134’ (‘134’), and R982 (982)—showed that fruits of ‘7879’ have lower rates of respiration and ethylene evolution than those of the other 3 genotypes. Analysis of progeny from a cross between 1563 and ‘7879’ suggested that a small number of genes with mostly additive effects control the difference in respiration rate between these 2 lines. A joint scaling test indicated that an additive-dominance model was adequate for analysis of the genetic variation. The number of effective factors was estimated to be 1.28 and the calculated narrow sense heritability was 0.49.
Significance of Pollutant Concentration Distribution in the Response of ‘Red Kidney’ Beans to Ozone1
Authors: Musselman R. C. , Oshima R. J. , Gallavan R. E.
Published: August 2022

Bean plants (Phaseolus vulgaris L. cv. Red Kidney) exposed to ozone with a simulated ambient concentration distribution showed significantly more injury, less growth, and lower yield than those exposed to an equivalent dose of ozone with a uniform concentration distribution. The concentration distribution did not alter the type of biological response of ‘Red Kidney’ beans to ozone, an indication that uniform concentration distribution fumigations are appropriate for investigations of mode of action of pollutants on plants. However, this study suggests that research using a uniform concentration distribution of pollutants may underestimate the magnitude of growth and yield responses to ambient pollutants.
Temperature and Gibberellin-induced Respiratory Changes in Capsicum annuum during Germination at Varying Oxygen Concentrations
Authors: Watkins J.T. , Cantliffe D.J. , Sachs M.
Published: August 2022

Concentrations of O2 greater than 21% stimulated germination rate of Capsicum annuum L. (sweet pepper) at 25°C but inhibited germination rate at 15°. At a 10% O2 concentration, germination rates were reduced at both temperatures. Gibberellins A4A7 (GA4+7) increased germination rates at 15° and 25° in air. At 25° in 100% O2, germination rates of GA-treated and nontreated seeds were the same. At 15° and 100% O2, germination rates were increased slightly by GA4+7 application; however, the rates were slower than in air. Total respiratory activity at 25° was higher in 100% O2 than in air. High O2 concentrations did not affect the proportion of respiration which was in the cyanide-sensitive and -resistant pathways. Cyanide-resistant respiration comprised only a small percentage of total respiratory activity. At 15°, total respiration and the cyanide-sensitive and -resistant components were similar regardless of O2 treatment. The addition of GA increased respiratory activity only after radicle emergence occurred. Thus, germination rate of pepper seed can be increased by increasing temperature, higher O2 concentrations at the higher temperature, and GA4+7 at normal and low temperatures. GA appears to affect germination through metabolic events which occur before radicle emergence and which do not include alteration of respiratory activity.
Alternate Bearing in Citrus: Long-term Effects of a Single Girdling Treatment on Individual ‘Michal’ Tangerine Branches
Authors: Monselise S.P. , Goldschmidt E.E. , Golomb A. , Rolf R.
Published: August 2022

Scaffold branches of ‘Michal’ tangerine (a Citrus reticulata hybrid) trees were fall-girdled once. Individual branches were driven into opposite phases of alternate bearing which continued for at least 3 successive years, without an additional stimulus. Bearing and nonbearing branches behaved like whole on- and off-trees, with regard to macronutrient and starch concentration in leaves and twigs, respectively. Off/on ratios for individual factors, however, were closer to unity than those previously found for whole alternating ‘Wilking’ trees, possibly due to the moderating effect of the common root system.
Maturity Studies of Avocado Fruit Based on Picking Dates and Dry Weight
Authors: Lee S.K. , Young R.E. , Schiffman P.M. , Coggins C.W.
Published: August 2022

Avocado (Persea americana Mill.) fruit from various locations in California were analyzed for oil and subjected to taste tests every 2 weeks throughout the fruiting season over a period of 5 years. Oil content at acceptable taste differed among cultivars, and the 8% requirement was too low to serve as a good maturity standard for many cultivars. While the date of acceptable taste of fruit grown at the same location was not significantly different from year to year, it varied significantly among and within the widespread avocado production areas. Dry weight, which was highly correlated with increasing oil content, was evaluated as a maturity index. The dry-weight analysis with a microwave oven was much easier than determining oil content. The average dry weight at 8% oil (the existing legal standard in California) was 19.4% for ‘Bacon’, 19.1% for ‘Fuerte’, 19.8% for ‘Hass’, 18.9% for ‘Pinkerton’, and 18.4% for ‘Zutano’ fruit. Dry weight at acceptable taste was 20.0% for ‘Bacon’, 21.0% for ‘Fuerte’, 22.8% for ‘Hass’, 20.0% for ‘Pinkerton’, and 20.2% for ‘Zutano’.
Postharvest Decay of Blueberries as Influenced by Water Dips and Captafol
Authors: Ballinger W.E.
Published: August 2022

Blueberries can be handled in water if 10 mg/liter of captafol is added to the water and the berries are immersed for at least 30 minutes. Addition of 100 mg/liter and immersion for 3 or 10 minutes produced similar control of decay. Captafol controlled decay due to Colletotrichum gloeosporioides [the imperfect stage of Glomerella cingulata (Ston.) Spauld. & Shrenk] better than it did decay due to Alternaria and Botrytis spp.
Comparison of Controlled-release Nitrogen Fertilizers, Urea, and Ammonium Nitrate on Yield and Nitrogen Uptake by Fall-grown Head Lettuce
Authors: Pew W.D. , Gardner B.R. , Bessey P.M.
Published: August 2022

Urea, ammonium nitrate (NH4NO3), and several controlled-release N (CRN) fertilizers were compared as sources of N for head lettuce (Lactuca sativa L.). CRN fertilizers varied widely in their effectiveness. Materials with the fastest N-release characteristics gave the poorest results when applied preplant. Effectiveness of some slow-release materials depended on time of application. Neither NH4NO3 nor urea were good sources when applied preplant but were effective in 3 equal 56 kg N/ha applications throughout the season. Methylene urea (MU), F2950, was most effective when applied 30 days after planting. Sulfur-coated urea (SCU), F9999, produced the most vigorous seedlings and plants with the greatest uniformity and harvestable heads with earliest maturity, best head size, and color.
Citrus Blight Effects on Carbon Dioxide Assimilation
Authors: Sinclair T.R. , Allen L.H. , Cohen M.
Published: August 2022

Leaf chambers were placed on 6 leaves each of 3 trees of orange [Citrus sinensis (L.) Osbeck cv. Valencia] budded on rough lemon [Citrus limon (Lush) Burm. f.] rootstock, of which one tree was healthy and one in an early stage and one in an advanced stage of citrus blight, a decline disease of unknown etiology. Carbon dioxide exchange rates (CER) and leaf transpiration were measured every 7.5 minutes, continuously over a 2-week period. No difference in average leaf CER was observed among the 3 trees, but the decrease in leaf area associated with blight was confirmed. Leaf area index appeared not to have decreased sufficiently, even in the advanced-blight tree, to reduce light interception and thereby to reduce overall tree CER significantly.
Crop Productivity Efficiency of Petunias in the Greenhouse
Authors: Merritt Richard H. , Kohl Harry C.
Published: August 2022

Crop productivity efficiencies (CPE) of around 8% (the ratio of the dry weight gain of the crop to the potential to produce dry weight), were realized with petunias (Petunia hybrida Villm.), provided that the crop canopy was essentially closed at the beginning of the 9- to 12-day experimental periods and that there were many branches (sinks). This was found at either long or short photoperiods or at either a normal (15.6°C) or reduced (7.2°) temperature for the 16-hour night periods. Long photoperiods resulted in significantly increased CPE through increased size of the leaves before the crop canopy was closed. Elevated root temperature increased CPE after a sizeable number of lateral branches had formed.
The Growth and Development of Chrysanthemum X morifolium ‘Bright Golden Anne’ in Low-Oxygen Environments
Authors: Konjoian Peter S. , Staby George L. , Tayama Harry K.
Published: August 2022

Cuttings of Chrysanthemum X morifolium Ramat. cv. Bright Golden Anne were rooted for 2 weeks in chambers designed to maintain shoot environments of 4-5% O2 and 300-500 ppm CO2 with ambient root environments, after which fliey were grown on to flower using chambers containing either 2.0-5.1% or 20.5-21.5% O2 and 200-500 or 700-1500 ppm CO2, again maintaining ambient root environments. Plants grown in low O2 flowered 10-12 days later than plants grown in air, but had more inflorescences, more flowers/inflorescence, and greater dry-weight accumulation of vegetative tissues. Plants grown in 20.5-21.5% O2 and 700-1500 CO2 were generally of highest quality. Using similar treatments, stock plants grown in low O2 produced twice as many cuttings through 3 flushes of growth as plants grown in ambient O2. Cutting production was also accelerated as plants grown in any of the 3 modified atmospheres produced cuttings one week earlier at each flush than plants grown in air.
Pollen Tube Growth in Cross- and Self-pollinated ‘Nonpareil’ Almond
Authors: Pimienta E. , Polito V.S. , Kester D.E.
Published: August 2022

Investigation of pollen grain germination and retention on the stigma, and pollen tube frequency in the style following compatible (cross) and incompatible (self) pollinations in ‘Nonpareil’ almond [Prunus dulcis (Mill.) D.A. Webb Syn. Prunus amygdalus Batsch.J revealed that rejection of incompatible male gametophytes occurs on the stigma as well as in the style. Self-pollinations are characterized by lower pollen grain retention on the stigma, reduced and delayed pollen germination, and, where pollen germination had occurred, a low frequency of pollen tubes growing through the style. Pollen tube growth slowed greatly after the tubes entered the ovarian locule before they reached the ovule.
Factors Affecting the Recovery of Juice and Anthocyanin from Cranberries
Authors: Sapers G.M. , Jones S.B. , Maher G.T.
Published: August 2022

In the paper “Factors Affecting the Recovery of Juice and Anthocyanin from Cranberries” by G.M. Sapers, S.B. Jones, and G.T. Maher [J. Amer. Soc. Hort. Sci. 108(2):246–249, 1983], there is an error in the magnification in the Fig. 1 legend. The correct version of the legend is as follows:
Changes in Seed Structure and Composition during Development and Their Effects on Leakage in Two Endosperm Mutants of Sweet Corn
Authors: Styer Roger C. , Cantliffe Daniel J.
Published: August 2022

Field- and greenhouse-grown seeds of 2 sweet corn (Zea mays L.) endosperm mutants—shrunken-2 (sh2) and sugary (su)—were harvested 18 to 46 days postpollination (dpp). Mature sh2 seeds had a greater imbibition and leakage rate than did su. Leachate conductivity was greater from field-grown sh2 seeds than greenhouse-grown sh2 at maturity. No difference in carbohydrate leakage was observed between genotypes at maturity. Leakage generally decreased in all seed types with increasing maturity. Cracking of the pericarp was not noticeable in either sh2 or su during development. In mature seeds of both genotypes, the pericarp appeared to be thicker and adhered more tightly to the aleurone layer than in immature seeds. Dry seeds of sh2 contained considerably less total carbohydrates and starch than su 18 to 46 dpp. Field-grown su seeds accumulated more total carbohydrates during development than greenhouse-grown su or sh2. The lowest amounts of sugars in dry seeds occurred at maturity with no difference noted between field- and greenhouse-grown sh2 and field-grown su. Immature fresh kernels (freeze-dried) of su and sh2 contained 2 to 3 times, respectively, more sugars than immature dry kernels. At maturity, fresh and dry kernels of either genotype had equal amounts of sugars, but fresh kernels contained more starch.
Effects of Ambient Nitrate Concentration and Prior Exposure to Nitrate on Net Nitrate Uptake by Chrysanthemum
Authors: Elliott George G. , Nelson Paul V. , Jackson William A.
Published: August 2022

Rooted cuttings of chrysanthemum (Chrysanthemum X morifolium Ramat cv. Fiesta) were transplanted to flowing nutrient solutions with sustained NO-3 concentrations of 75, 125, and 210 µm. On days one and 8 following transplanting, plants were transferred to static, nonreplaced solutions at the same concentrations at 0900 hr and solutions were sampled at 30 minute intervals for 8 hours (drawdown series). On day 8, an additional experiment was conducted in which plants were transferred to static solutions sampled and replaced hourly (replacement series). At the end of each series, plants were harvested and roots and shoots were analyzed for total- and NO-3-N. In the drawdown series, on both days, uptake rates initially increased but then decreased. The concentration of NO-3 at which net NO-3 uptake ceased (C0) was unaffected by the initial concentration of NO-3 (Ci) but increased from day one to day 8. Maximum uptake rates decreased, but C0 increased, from day one to day 8. In the replacement series, uptake rates initially increased but did not subsequently decrease, and were significantly less when Ci was 210 µm than when Ci was 75 or 125 µm. Concentrations of total-N and NO-3-N in roots and shoots were significantly affected by Ci treatment, and prior exposure to NO-3. Results support the hypothesis that ambient NO-3 supply, plant NO-3 status, and metabolism interact in determining rates of net NO-3 uptake. These interactions may seriously complicate the interpretation of uptake-concentration relationships derived from drawdown experiments.
Sampling for Field Evaluation of Peach and Nectarine Flower Bud Survival
Authors: Scorza R. , Ashworth E.N. , Bell R.L. , Lightner G.W.
Published: August 2022

Sample sizes for detection of differences of flower bud survival in peach and nectarine [Prunus persica (L.) Batsch] were chosen on the basis of theoretical confidence intervals (Cl) and least detectable differences (LDD) for the binomial distribution. Theoretical Cl and LDD for 1000-bud samples were comparable to Cl and Duncan's multiple range test separation computed from an analysis of variance for 1000 buds, based upon 10 replicates of 100 buds. Variability in survival was a function of eultivar, height of bud in canopy, and bud type. Variability may be minimized by sampling a given bud type (single, double, distal) at >1.5 m above ground level.
Carbon Balance of Peperomia obtusifolia Plants during Acclimatization to Low PPFD
Authors: Mbah B.N. , McWilliams E.L. , McCree K.J.
Published: August 2022

The CO2 exchange rates of Peperomia obtusifolia A. Dietr. plants (tops and roots) were measured for 12-hour light and 12-hour dark cycles during 5 weeks of acclimatization at 30 µEs-1m-2. A carbon balance analysis of the data indicated that the growth conversion efficiency (Yg) remained constant (0.73 ± 0.1 and 0.77 ± 0.04 before and after acclimatization, respectively). The daily rate of substrate production from photosynthesis (ΔS/Δt) remained constant at 18 ± 2 mg C plant-1 24 hr-1, at the acclimatization photosynthetic photon flux density (PPFD), but the daily rate of synthesis of carbon into new material (ΔW/Δt) increased by 55% within the first week. The maintenance coefficient (m) decreased from 13.0 ± 0.9 to 7.4 ± 0.4 mg g-1 24 hr-1, and change in m may be a criterion for selection of plants that can be adapted for use at low PPFD. The light compensation point (LCP) was reduced during acclimatization, but its use underestimated the PPFD required for 24-hour plant maintenance because of failure to account for night-time respiratory losses. It is suggested that the PPFD at which ΔW/Δt is zero or slightly above is more reliable than the light compensation point for determining PPFD required for plant maintenance.
Dynamic Growth Characteristics in Seedling Asparagus
Authors: Dufault Robert J. , Greig James K.
Published: August 2022

Growth studies of field-seeded hybrid and open-pollinated asparagus (Asparagus officinalis L.) were conducted to determine the differences in shoot, bud, and crown growth during the first season after seeding and to determine growth relationships between shoot and crown variables that indicate critical periods of bud and crown production. F1 hybrid (UC 157) and UC800 open-pollinated (OP) asparagus seedlings emerged 4 to 6 weeks after seeding. A lag phase of shoot and root growth lasted 4 to 5 weeks after emergence in both cultivars. UC157 initiated more roots and accumulated more fern and crown fresh weight than UC800 early in the season, but by harvest crowns were not different in root and bud number, fresh weight, or fructose content (crown quality). Root/shoot ratios increased from a 2:1 ratio 6 weeks after emergence to 8:1 (UC157) and 6:1 (UC800) 23 weeks after emergence. Shoot/bud ratios stabilized from an approximate 2:1 ratio initially to an approximate 1:2 ratio 18 weeks after emergence. Bud production in the F1 and OP cultivars increased 6 and 10 weeks after emergence, respectively, and continued unabated up to crown harvest 23 weeks after emergence. Shoot number and fresh weight were not correlated highly with bud number. The number of roots vs. buds and the crown vs. fern fresh weights were correlated highly and were the best indicators of quality crown production. Vigorous fern development throughout the growing season increased the potential to produce higher-quality large crowns.
Preharvest AVG Treatment of ‘Bartlett’ Pear Fruits: Effects on Ripening, Color Change, and Volatiles
Authors: Romani Roger , Labavitch John , Yamashita Tom , Hess Betty , Rae Henry
Published: August 2022

Preharvest treatment with 400 ppm aminoethoxyvinylglycine (AVG) delayed the ripening of ‘Bartlett’ pears kept at 20°C. The effect was not uniform, with the delay in ripening ranging from a few to 112 days. Prolonged storage at 20° was accompanied by a relatively steady, low level of respiration, gradual degreening, and partial suppression of the eventual climacteric. The combined effect of AVG treatment and prolonged ‘nonripening’ storage at 20° led to a marked attentuation of the production of 4 readily measurable volatiles including methyl-, ethyl-, and hexylacetate as identified by cochromatography and combined gas chromatography–mass spectrometry. Surprisingly, prolonged storage resulted in a much increased production of 2 other volatile fractions when AVG inhibition was reversed by C2H4 treatment. The emanation of all measured volatiles was closely coincident with the climacteric peak. These observations confirm prior reports of disuniform effects of preharvest AVG treatment and reveal that metabolic transitions during prolonged, nonripening storage may have adverse effects on fruit quality.