bluuebunny/crossref_metadata_2025 huggingface dataset:
Rust Reaction and Pubescence in Alubia Beans
Authors: Zaiter Haytham Z. , Coyne Dermot P. , Steadman James R.
Published: October 2019

Sixteen Alubia lines (15 with long, straight hairs and one with short, hooked hairs on trifoliolate leaves) derived from single-plant selections made in an Alubia landrace (Argentine) were used to evaluate the relation of abaxial leaf pubescence to reaction to rust in a greenhouse experiment. The pinto cultivar UI-114 (short, hooked hairs) was used as a susceptible check. One plant per pot, replicated six times, in a randomized complete-block design was used. The primary leaves and the sixth trifoliolates of all plants from 12- and 50-day-old plants, respectively, were inoculated with a water suspension of urediniospores (105 cells/ml) of rust isolate US-NP85-10-1. Pustule size and rust intensity were assessed 14 days later. No rust pustules were observed on the sixth trifoliolate leaves of the pubescent (long, straight hairs) Alubia lines, but large pustules were observed on the primary leaves (short, hooked hairs) of all Alubia lines and pinto `UI-114'. as well as on the sixth trifoliolate leaf of A-07-2 and pinto `UI-144' (the latter two with short, hooked hairs).
Use of Geotextile Disks for Container Weed Control
Authors: Appleton Bonnie L. , Derr Jeffrey F.
Published: October 2019

Disks of several geotextiles, paper, fiberglass, and black polyethylene were compared with the herbicides oxyfluorfen plus pendimethalin, oxadiazon, and oryzalin plus benefin for suppression of weed growth around container-grown Southwestern white pine (Pinus strobiformis Engelm.), Chinese pistache (Pistacia chinensis Bunge.), and `Fashion' azalea [Rhododendron indicum (L.) Sweet × `Fashion']. The greatest weed control was obtained with a combination geotextile-preemergence herbicide (trifluralin) disk, indicating a possible new method of container weed control. Several of the barrier materials, including heavy wrapping and compressed peatmoss papers, black polyethylene, and one spunbonded geotextile, were inferior due to degradation or to weeds growing around the disk edges or center hole. No difference in crop growth was noted among the treatments. Chemical names used: 2-chloro-1- (3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene (oxyfluorfen); N-(1-ethylpropyl)-3,4 -dimethyl-2,6-dinitrobenzenamine (pendimethalin); 3-[2,4-dichloro-5 -(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one (oxadiazon); 4-(dipropylamino) -3,5 -dinitrobenzenesulfonamide (oryzalin); N-butyl-N-ethyl-2,6 -dinitro-4-(trifluoromethyl) benzenamine (benefin); 2,6-dinitro-N,N-dipropyl-4-(ttifluoromethyl)benzenamine (trifluralin).
Preconditioning Grapefruit Callus Tissue Reduces Methyl Bromide-induced K+ Leakage
Authors: Forney Charles F. , Peterson Sharon J. , Hartsell Preston
Published: October 2019

Callus tissue grown from `Marsh' grapefruit (Citrus paradisi Macf.) albedo tissue was grown at 30C for ≈ 40 days. Calli were preconditioned in normal air for 5 days at 10 or 30C before being fumigated for 2 hr with 0, 32, or 48 g of methyl bromide (MB)/m 3. Calli were then held at 10C and K+ leakage was measured after 1, 10, 20, and 30 days. The amount of K+ leaked from MB-fumigated calli was greater than that for nonfumigated calli and increased with higher MB dose. Leakage also increased with time following fumigation. Leakage of calli preconditioned at 30C and fumigated with 48 g MB/m3 was 140%, 196%, and 260% greater than leakage from nonfumigated calli 10, 20, and 30 days after fumigation, respectively. Leakage from calli preconditioned at 10C for 5 days before MB fumigation was less than that from calli held at 30C. MB doses of 32 and 48 g·m-3 increased leakage of calli preconditioned at 10C by 6% and 43% and for those preconditioned at 30C by 99% and 140%, respectively, 10 days after fumigation. In addition to K+ leakage, MB induced the development of a tan to orangish-brown discoloration.
Influence of Planting Depth and Interval to Initial Harvest on Yield and Plant Response of Asparagus
Authors: Lindgren Dale T.
Published: October 2019

Four planting depths and two time intervals (1 or 2 years) between transplanting and initial year of harvest of asparagus (Asparagus officinalis L.) yield were compared for 4 years. Spear emergence and initial spring harvest date were delayed and susceptibility to spring frost injury was decreased with increasing planting depth (from 5.0 to 20.0 cm). Over years, crown depth increased for the shallowest planting and decreased for the deepest planting. Harvesting after 1 year vs. 2 years from planting reduced yield. There were no significant interactions between year of initial harvest and depth of planting.
Leaf Blade Stomatal Characterizations and Evapotranspiration Rates of 12 Cool-season Perennial Grasses
Authors: Green R.L. , Beard J.B. , Casnoff D.M.
Published: October 2019

The objectives of this investigation were to determine the stomatal frequencies of 12 perennial cool-season turfgrasses, encompassing nine species, and their associated evapotranspiration (ET) rates under nonlimiting soil moisture and controlled environmental conditions. Significant differences in stomatal density were found among the 12 cool-season turfgrasses on both the abaxial (P > F = 0.0008) and adaxial (P > F = 0.0009) leaf surfaces. Significant differences (P > F = 0.0007) in ET rates also were found among the 12 cool-season turfgrasses. The Kentucky bluegrass (Pea pratensis L.) cultivars exhibited the highest ET rates, while the fine-leafed fescues (Festuca rubra and longifolia L.) exhibited the lowest rates, except for `Big Horn' sheep fescue (Festuca ovina L.), which exhibited an intermediate ET rate. No significant correlation was found between ET rate and either adaxial or abaxial stomatal density. It was concluded that, under nonlimiting soil moisture conditions, stomatal density was not reliably associated with ET rate.
pH Affects Seed Germination of Eight Bedding Plant Species
Authors: Shoemaker Candice A. , Carlson William H.
Published: October 2019

Seeds of eight commonly grown bedding plant species [Ageratum houstonianum Mill., Begonia × semperflorens Hort., Impatiens wallerana Hook., Lobularia maritima (L.) Desv., Petunia × hybrida Hort., Pelargonium hortorum L.H. Bailey, Salvia splendens F. Sellow, Tagetes patula] were germinated at pH values from 4.5 to 7.5 at 0.5 increments. Seeds were germinated in petri dishes on filter paper saturated with buffer solutions or in petri dishes containing a 50 sphagnum peat: 50 coarse vermiculite (peatlite) medium moistened with buffer solutions. Germination on filter paper was affected by pH for all species tested. Peatlite medium pH affected germination of all species tested, except Salvia splendens. Species response to similar pH values differed between the two germination procedures. Total percent germination of seeds germinated was less in peatlite medium than on filter paper.
Fertilizer Placement Effects on Soil Nitrogen and Use by Drip-irrigated and Plastic-mulched Tomatoes
Authors: Cook Wilton P. , Sanders Douglas C.
Published: October 2019

The effects of fertilizer placement and soil moisture level on soil N movement, uptake, and use by tomato plants (Lycopersicon esculentum Mill) grown with drip irrigation and plastic mulch were evaluated at two locations on two types of sandy soils. Broadcast or band fertilizer placement had no effect on fruit size, fruit number, or total yield. Fruit size was increased at one location, and the incidence of blossom-end rot was decreased by increased frequency of irrigation. Nitrate-N distribution within the bed was not affected by initial N placement. In the soil with a rapid infiltration rate, NO3-N levels in the center of the bed were always low, with highest concentration observed in the areas of the bed most distant from the drip tube. In the soil with the slower infiltration rate, NO3-N concentrations were more uniform throughout the bed, with highest concentrations in the bed center: Increasing soil moisture levels (–20 kPa vs. –30 kPa) resulted in increased leaching and reduced NO3-N concentration throughout the bed. Foliage N concentration was not affected by N placement, but decreased seasonally. Total N uptake by the above-ground portion of the plants was not affected by fertilizer placement or soil moisture level.
Loss of Firmness and Changes in Pectic Fractions during Ripening and Overripening of Sweet Cherry
Authors: Fils-Lycaon B. , Buret M.
Published: October 2019

Pectic fractions soluble in water, oxalate, or hydrochloric acid were prepared from an alcohol-insoluble residue of cherry (Prunus avium L., `Bigarreau Napoléon') tissue. Galacturonic acid and neutral sugar contents were measured during the ripening and overripening of fruit. Fruit firmness was also determined. The changes occurring during fruit development gave prominence to three physiological stages and suggested the progressive degradation of the middle lamella and primary cell wall. The firmness measurement was related to the equilibrium between the relative parts of these pectic fractions.
Ēxopolygalacturonase Elicits Ethylene Production in Tomato
Authors: Baldwin Elizabeth A. , Pressey Russell
Published: October 2019

Exopolygalacturonase (exo-PG) (EC 3.2.1.67) was investigated for ability to induce ethylene production in green cherry tomatoes (Lycopersicon esculentum Mill.). The fruit were vacuum-infiltrated with various levels of exo-PG from green tomato fruit, squash flower, or oak pollen and compared to boiled enzyme or salt controls for ethylene production. In all cases, fruit treated with active enzymes produced significantly higher levels of ethylene than did control fruit. The ethylene response was evident 2 hours after treatment and was transient in nature, returning to basal levels by 22 hours. The amount of ethylene produced did not appear to be influenced by the source of exo-PG.
Calcium Influences Growth and Leaf Mineral Concentration of Citrus under Saline Conditions
Authors: Zekri Mongi , Parsons Lawrence R.
Published: October 2019

We determined whether the ability of sour orange seedlings to withstand saline irrigation water could be improved by the addition of calcium to the water. Sour orange (Citrus aurantium L.) seedlings were treated for 4 months with a nutrient solution containing either no NaCl, 40 mm NaCI, or 40 mm NaCl plus various concentrations of CaSO4, CaCl2, or KCl. After 4 months, the NaCl alone reduced root and shoot dry weights by ≈ 30% with no leaf necrosis. Addition of 1, 5, or 7.5 mm CaSO4 to solutions containing 40 mm NaCl significantly inhibited the NaCl-induced reductions in shoot dry weight. Addition of 7.5 mm CaCl2 or 7 mm KCl to the NaCl solution reduced leaf Na, but increased Cl to the toxicity level; hence, growth was not improved. The beneficial effect of CaSO4 was mainly attributed to a reduction in the accumulation of Na and Cl below the toxicity level in the leaves (0.4% and 0.5%, respectively) without a major increase in total dissolved salts. This study demonstrated that the beneficial effect of adding Ca depended on the anion associated with the Ca salt. Calcium sulfate, but not CaCl2, was able to overcome the damaging effect of NaCl to sour orange seedlings.
Resistance in Eastern European Pyrus Germplasm to Pear Psylla Nymphal Feeding
Authors: Bell R.L. , Stuart L.C.
Published: October 2019

`Fifty-nine cultivars and wild seedlings of pear (Pyrus spp.) from Eastern Europe were evaluated for resistance to feeding by early instar pear psylla [Cacopsylla pyricola (Foerster)] in a 24-hour assay. `Bartlett' (P. communis L.) and NY 10352 (P. communis × P. ussuriensis Maxim. BC1 hybrid) were used as susceptible and resistant controls, respectively. A. high degree of resistance, measured as increased mortality and reduced frequency of feeding, was found in 11 plant introductions: `Erabasma' (PI 483370), `Krupan Burnusus' (PI 483387), `Topka' (PI 484489), `Zelinka' (PI 483393), `Mednik' (PI 483399), `Karamanlika' (PI 502165), `Katman' (PI 502172), `Smokvarka' (PI 502176), `Obican Vodenac' (PI 502177), a clone thought to be `Smiljerka' (PI 502178), and an unnamed seedling (PI 506382).
EVALUATIONS OF PRODIAMINE AND METHAZOLE FOR CONTAINER ORNAMENTAL WEED CONTROL
Authors: Wells D. W. , Constantin R. J. , Wells J. W.
Published: October 2019

Six prodiamine treatments, three applied alone and three applied in combination with methazole, were compared with oxyfluorfen/oryzalin, oxadiazon, and controls (weeded and non-weeded) on ornamental and weed species. Ornamentals included green liriope, Asiatic jasmine, serissa, gardenia, `Needlepoint' holly, Japanese yew, `Prostrata' juniper, and `Carror' azalea. Weeds grown in separate containers were goosegrass, crabgrass, pigweed, and prostrate spurge. At 13 days after treatment (DAT), oxadiazon and oxyfluorfen/oryzalin caused some contact burn on liriope, and the injury persisted until the 81 DAT rating. Methazole/prodiamine treatments caused chlorosis on gardenia leaf tips, with plants recovering by 61 DAT. These combinations also resulted in slight injury to azalea at the first rating, but the injury disappeared by the second rating. Control of goosegrass, crabgrass, and pigweed was good to excellent with all chemical treatments. Control of spurge using oxadiazon and oxyfluorfen/oryzalin decreased at 81 and 100 DAT.
CHESTNUT PRODUCTION IN CHINA: A MODEL FOR DEVELOPMENT OF A CHESTNUT INDUSTRY IN THE SOUTHEASTERN U. S.
Authors: Norton J. D.
Published: October 2019

The Chinese chestnut (Castanea mollissima) has been cultivated in China for more than 1000 years. During this period, indigenous cultivars and traditional cultivation practices have been used. China is the leading producer of Chinese chestnut (Castanea mollissima) with 37% of the world' s production. In the last 4 years, improved cultivars and improved cultural practices have resulted in marked increases in production.

The leading provinces in Chestnut production are Hopei, Hubei, and Shandong. Severe injury, crop losses and tree mortality have resulted from the chestnut gall wasp in China Yields have increased greatly in Hubei province through cooperative breeding and developmental research between the Department of Horticulture Auburn University and the Hubei Academy of Agricultural Sciences. Two resistant seedlings from Auburn University are being utilized to save the chestnut industry in China and possibly worldwide.
SENSORY ATTRIBUTES OF JUICE PROCESSED FROM APPLES TREATED WITH CALCIUM CHLORIDE PRIOR TO STORAGE.
Authors: Porting Robert J. , Sams Carl E. , Conway William S. , Collins Jimmie L. , Penfield Marjorie P.
Published: October 2019

`Golden Delicious' and `Red Rome' apples were pressure infiltrated (69 kPa for 2 or 4 min) at harvest with 0, 1, 2, 3 or 4%, and 0, 2, 4, 6 or 8% CaCl2 solutions (w/v), respectively, and placed in 0°C storage. Juice was extracted from the apples after 0, 2, 4 or 6 months in storage. Sensory evaluation of the juice was conducted to determine if CaCl2 concentration affected color, off-flavors, suspended particles or overall acceptability of the juice. Juice color was judged lighter with increased CaCl2 in both cultivars. Detection of off-flavors decreased as CaCl2 was increased in juice from `Red Rome'; whereas, off-flavors increased as CaCl2 was increased in `Golden Delicious' juice. CaCl2 treatments decreased suspended particles in both cultivars. As CaCl2 was increased overall acceptability of juice from `Red Rome' increased, while acceptability of juice from `Golden Delicious' decreased.
AN ECONOMIC EVALUATION OF TWO YEARS OF ON-FARM PLASTIC MULCH EXPERIMENTS FOR SELECTED VEGETABLE CROPS IN BUTLER COUNTY, ALABAMA
Authors: Baharanyi N. , Stevens C. , Khan V. , Siaway A.
Published: October 2019

This study evaluated the potential economic returns of two years of on-farm plastic mulch experiments for `Market Topper' cabbage and `Vates' collard greens conducted on a field with serious weed and nematode problems in Butler County, Alabama. Assuming 1987 and 1988 wholesale prices for vegetable crops in Alabama and other appropriate prices for various inputs used, and after adjusting the cost of plastics in the enterprise budgets for having used the same in the two years, the estimated return for cabbage harvested from plastic mulch experiments was 5 times greater in 1987 ($2,776.83 and $551.02) and more than 10 times in 1988 ($2,775.00 and $49.40) than from non-covered field. The estimated return for collard greens from plastic mulch experiments was also 5 times greater in 19.87 ($1,416.70 and $287.96) and more than 10 times in 1988 ($339.50 and -$444.20) than from non-covered field. Questions remain as to the perceived economic benefits for other farmers and the non-biodegradable nature of the plastic used.
COMPARATIVE ULTRASTRUCTURES OF VITREOUS AND NON-VITREOUS SWEET POTATO (IPOMOEA BATATAS L.)LAM. PLANTS GROWN IN VITRO
Authors: Desamero Nenita V. , Rhodes Billy B.
Published: October 2019

Vitrification, a physiological disorder characteristic of in vitro grown plants, was observed in single-node cultures of sweet potato in mannitol-enriched medium during their second year of storage. Vitrified or vitreous sweet potato plantlets were watersoaked, translucent or glassy in appearance, with thick, swollen, leaves and stems, stunted shoot growth and poor root growth. These plantlets were not able to regenerate normal plants when transferred into fresh regeneration medium nor were they able to survive outside culture conditions.

Electron microscopy revealed changes in the ultrastructures of vitrified sweet potato plantlets. Vitrified plants had defective stomatal complex, starch grain-filled chloroplasts, disrupted cell wall, big air spaces (lacunae), high frequency of cell membrane separation from the cell wall, nuclear disintegration, and cytoplasmic disorganization. These changes in the internal structures of vitrified plants were reflected in their abnormal morphology and physiology.
PERFORMANCE OF ASIAN HEAR SCIONS ON PYRUS CALLERYANA ROOTSTOCK
Authors: Aung Hla , Matta Frank B.
Published: October 2019

One year old Asian pear scion cultivars were grafted onto Pyrus calleryana rootstock utilizing two grafting methods (whip grafting and splice side grafting). Percentage survival of grafted scions was 78 and 96 via the splice side graft and the whip graft, respectfully. Shoot length and caliper 80 days after grafting did not vary between cultivars. `Yakumo' and 'Chojuro' produced a greater number of branches as compared to the remaining cultivars. `Yakumo', `Chojuro', `Seuri' and `Hosui' produced the least amount of shoot growth. Branching angle was greatest for `Seigyoku', `Chojuro' and `Yakumo' with 60, 70, and 55 degrees, respectfully. As indicated by leaf area, `Seuri' and `Hosui' produced large leaves and `Yakumo' and `Chojuro' produced small leaves.
DIFFERENTIAL TOLERANCE OF VELVETLEAF (ABUTILON THEOPHRASTI), JIMSONWEED (DATURA STRAMONIUM), AND MORNINGGLORY (IPOMEA HEDERACEA) TO CLOMAZONE
Authors: White Carla D. , Weston L.
Published: October 2019

The purpose of this experiment was to determine if differential tolerance levels of velvetleaf (Abutilon theophrasti), jimsonweed (Datura stramonium) and morningglory (Ipomea hederacea) to 14C clomazone, a preemergence herbicide, was due to uptake, translocation and metabolism of clomazone. The plant species were placed in a clomazone Hoagland solution for 48 and 96 hours. Afterwards, extraction of chlorophyll, oxidation of plant material, and liquid scintillation spectroscopy procedures were used to determine if the differences existed. Morningglory were found to have a higher rate of metabolism and was the most tolerant to clomazone. It is hypothesized that these results are due to Morningglory's larger size and tendency to retain clomazone in the roots.
MAACKIA AMURENSIS NODULATES AND FIXES DINITROGEN
Authors: Batzli Janet M. , Graves William R. , van Berkum Peter
Published: October 2019

Maackia amurensis Rupr. & Maxim. is a leguminous tree with potential for increased use in urban landscapes. Information on the nutrition of M. amurensis is limited. To our knowledge, modulation and N2 fixation have not been reported. Our objective was to examine M. amurensis for nodulation and N2 fixation. Soil samples were collected near legume trees at arboreta throughout the United States, with additional samples from Canada and China. Seedlings were grown for six weeks in a low-N, sterile medium and inoculated with soil samples. Upon harvest, small white nodules were found on the lateral and upper portions of the root systems. Bacteria were isolated from the larger nodules, subculture, and used to inoculate seedlings. Inoculated plants nodulated and fixed N2 as determined by the acetylene reduction assay. We conclude M. amurensis forms N2-fixing symbioses with Rhizobium.
POINSETTIA DEVELOPMENTAL AND POST-PRODUCTION RESPONSES TO GROWTH RETARDANTS AND IRRADIANCE
Authors: Bailey Douglas A. , Miller William B.
Published: October 2019

Plants of Euphorbia pulcherrima Wind. `Glory' were grown under 13.4, 8.5, or 4.0 mol·m-2·day-1 and sprayed with water (control); 2500 mg·liter-1 daminozide + 1500 mg·liter-1 chlormequat chloride (D+C); 62.5 mg·liter-1 paclobutrazol; or 4, 8, 12 or 16 mg·liter-1 uniconazole to ascertain plant developmental and pest-production responses to the treatment combinations. Days to anthesis increased as irradiance was decreased. Anthesis was delayed by the D+C treatment, while other growth retardant (GR) treatments had no effect on anthesis. Irradiance did not affect plant height at anthesis, but all GR treatments decreased height over control plants. Bract display and bract canopy display diameters declined as irradiance was decreased. Growth retardants did not affect individual bract display diameters, but all GR treatments except paclobutrazol reduced bract canopy display diameter. Plants grown under lower irradiance had fewer axillary buds develop, fewer bract displays per plant, and fewer cyathia per bract display. Cyathia abscission during a 30 day post-anthesis evaluation was not affected by treatment; however, plant leaf drop was linearly proportional to irradiance. All GR treatments increased leaf drop over controls, and the D+C treated plants had the highest leaf loss. Results indicate the irradiance and GR treatments during production can affect poinsettia crop timing, plant quality at maturity, and subsequent post-production performance.
THE EFFECT OF MAGNETIC FIELD ON WATER IMBIBITION AND RADICLE GROWTH OF SEEDS
Authors: Liang Benjamin , Brown John M.
Published: October 2019

Nuclear Magnetic Resonance Imaging is currently being investigated as a nondestructively and noninvasively observing plant-water relationships, Researchers have not considered the effects of magnetic fields on plant growth and development. This study was conducted to investigate the effects of magnetic fields on seed water imbibition and radicle growth. Corn (cv. pioneer 3379), pea (cv. little marvel), and soybean (cvs. forrest and D86-4669) seeds were embedded in petri dishes with water saturated Smither's oasis porus foam, and were oriented for the East, South, West, and North. Seeds were exposed to either 1.5 Tesla or 1×10-10 Tesla static magnetic field for 48 hours. Changes in seed weights and radicle lengths were measured. Results showed that the strong magnetic field and seed orientations had no effect on the water imbibition rate. However, growth of corn and pea radicles was affected by the magnetic field. The 1.5 Tesla magnetic field enhanced the growth of corn radicle length, whereas it retarded the growth of pea radicles.
INFLUENCE OF SPACING AND PRUNING ON ECONOMIC RETURNS OF STAKED TOMATOES
Authors: Davis Jeanine M. , Estes Edmund A.
Published: October 2019

Stable prices and increased competitive market pressures have caused many staked tomato producers to examine the costs and benefits of adopting intensive production practices such as drip irrigation and plastic mulch. Inclusion of these practices with traditional growing practices often results in a total production cost in excess of $10,000 per acre. In 1988 and 1989, field studies were conducted in western North Carolina to determine if changes in plant spacing and pruning could reduce production costs, increase yields of large fruit and improve grower net returns from staked tomatoes (c. Mountain Pride). Combined data indicated that the greatest early season yields were obtained using early pruning (when suckers were 2-4 inches long) and in-row spacings of 18 inches or less. Net returns per acre were greatest when: 1) plants were pruned early and spaced closely in-row, which increased high priced early season yields and 2) plants were spaced 30 inches apart and either pruned early or not pruned, which increased total season yields. Non-pruned plants had lower yields of Jumbo and Extra Large size fruit, but higher total yields than pruned plants.
DOES CHRYSANTHEMUM DISPLAY AN ENDOGENOUS CIRCADIAN RHYTHM OF STEM ELONGATION?
Authors: Tutty Jason , Hicklenton Peter
Published: October 2019

The rate of internodal extension of chrysanthemum (Dendranthema grandiflora Tzvelev. cv. Envy) under various temperature and photoperiod conditions was studied to determine whether reproducible diurnal patterns of growth existed and whether any such patterns conformed to an endogenous circadian rhythm. Stem growth was monitored continuously by means of linear displacement voltage transducers. At constant temperature and under 11 h light/13 h dark photoperiod, stem elongation followed a clearly defined pattern consisting of a peak in rate immediately after the dark to light transition and then a gradual decline until the start of the dark period. During darkness, elongation rate increased and reached a maximum approximately 8 hours after the light to dark transition. This pattern differed when light period temperature was either above or below dark period temperature, but these patterns were also highly reproducible. When plants were subjected to continuous light at constant temperature, the rhythm of stem elongation initially showed a periodicity of approximately 27 hours. After 2 or 3 diurnal cycles the rhythm was less distinct and the rate became essentially constant. Furthermore, the interruption of a long period of continuous light with a 13 h dark period did not restore the rhythm. These findings do not support the existence of an endogenous circadian rhythm of stem elongation. Diurnally-cued rhythms do, however, exist and can be modified by temperature.
VEGETABLE AND GRAIN AMARANTH SEED YIELD AND QUALITY AFFECTED BY APPLIED NITROGEN
Authors: Makus D. J.
Published: October 2019

Twenty-one day old seedlings of a vegetable amaranth (RCC 241, Amaranthus tricolor) and a grain amaranth (K343, A. hybridus × A. hvpocondriacus) were transplanted on July 28, 1989. Equal applications of NH4N O3 were made on July 28 and August 25 to give total N rates of 0, 60, 120 and 240 kg/ha. Accessions were harvested on Oct. 18 and 14, respectively. Increasing N, induced a quadratic response in plant dry wt, seed wt/plant and seed size fractions in both amaranth types. Seed size fractions as a percent of the total seed, plant height and seed to plant dry weight ratio were not affected by increased N. Seed protein increased linearly whereas seed nitrate increased quadratically with increasing N application. Higher N rates increased residual soil NO3, NR4 and electrolytes and decreased pH. Decreasing soil pH appeared to reduce soil K and Cu but increase Fe and Mn availability. The effect of N rate on seed germination was inconclusive, but the larger seed size was higher in germination. There were differences among species in most responses tested. These data suggest that N applications be tailored to the season growing length required by the respective species/cultivar.
MEFLUIDIDE IMPROVED THE DEVELOPMENT OF TERMINAL FLOWER BUDS OF CHILLED PEPPER PLANTS
Authors: Chen Jing-fen , Li Paul H. , Davis David W.
Published: October 2019

Exposure of young pepper plants to chilling temperatures delays the development of terminal flower buds to flowering during post-stress growth. Degree of adverse influence depends on chilling intensity, exposure duration and varietal sensitivity. `Ma Belle' pepper plants were grown in a greenhouse (GH) during winter months on the St. Paul campus, No supplemental lighting was provided. When plants were at the 2- to 3-leaf stage, they were foliar sprayed with mefluidide (Technical grade) at 0, 5, 10 and 15 ppm. One day after treatment, some plants were transferred from GH to a cold room (3° ∼4°C day/night) with 12-h photoperiod. Treatad plants remaining in the GH served as the control. Plants were chilled for 1, 2, 4 and 6 days and then brought back to the GH for post-stress growth and development observation. Treated and untreated plants grown in the GH showed no difference in days to flowering, and reached 50% flowering at about 62 days after treatment. When untreated plants were chilled for 1,2,4 and 6 days, they showed a delay of 8, 18, 30 and 34 days, respectively, to flowering, If not killed, as compared to the control The long delay to flowering was due to the injury of the terminal flower buds. After 4 and 6 days of chilling, most terminal flower buds were killed. However, when plants were treated with mefluidide and subsequently chilled days to flowering were significantly shortened. A difference of 10-12 days was observed between chilled untreated plants and chilled treated plants. Concentrations of 5 to 15 ppm were equally effective in protection against chilling.
EFFECTS OF IRRIGATION WATER SALINITY AND LIMING RATE ON CATION UPTAKE BY QUEEN PALMS
Authors: Broschat Timothy K.
Published: October 2019

Queen palms (Syagrus romanzoffiana) were grown in containers of sand to determine the effects of irrigation water salinity and liming rate on cation uptake by the plants. Dolomite was incorporated at rates of 0, 3, or 6 kg/m3. Within each lime rate palms were irrigated with a solution of NaCl and CaCl2 (molar ratio =5Na:1Ca) at conductivities of .25, 1, 2, 4, or 6 dS/m. Plant height and dry weight and leaf Mg were decreased with increasing irrigation water salinity, whereas leaf Ca was increased at higher salinities. Leaf Mn and Zn increased, then decreased as salinity was increased. Leaf Ca and Mg increased with increased lime, but leaf Mn and Cu were decreased by increasing the lime rate. Leaf K increased, then decreased as lime rate was increased.
IN VITRO EMBRYOGENESIS DERIVED FROM LEAF CALLUS OF `TIFFANY' ROSE
Authors: Arif Mahmoud B. , Khatamian Houchang
Published: October 2019

Friable callus from leaf disks of Rosa hybrida `Tiffany' was initiated within two weeks under dark conditions and 25°C on Murashige and Skoog (MS) medium supplemented with 4 mg.liter-1 2,4-D. Callus was then transferred into MS medium containing 3 mg.liter-1 2,4-D. Within four weeks, rhizogenesis occurred on the callus surface.

The rhizogenic calllus was subculture on MS medium plus 3 mg.liter-1 2,4-D every 4-6 weeks. Within six months from initial culture, somatic embryos were developed on the aging callus in darkness.

Transfer of the aging callus with somatic embryos into 1/2 MS medium containing 1 mg.liter-1 kinetin and maintaining it under 46 μE m-2s-1 light for 16 hrs. resulted in greening of the somatic embryos.
WHOLE PLANT MECHANISMS OF AMMONIUM INDUCED INCREASES IN WATER STRESS AND SENSITIVITY OF MUSKMELON TO NaCl
Authors: Adler Paul R. , Wilcox Gerald E.
Published: October 2019

Two mechanisms that reduce water and salt stress, respectively, are an increase in root hydraulic conductivity (LP) and reduction in Na and Cl absorption and transport to the leaf. NH4+-N decreased muskmelon LP 55-70% while under 100 mM NaCl stress and 40-50% in the absence of NaCl stress. A decrease in LP increases the rate of water stress development as the transpiration rate increases. Although dry weight decreased about 70%, with NO-3-N, muskmelon remained healthy green, while with NH+4-N they became chlorotic and necrotic with a 100% and 25% increase in leaf blade Na and Cl compared to NO-3-N, respectively. Further investigation indicated that NH+4-N increased muskmelon sensitivity to NaCl through both an increased rate of net Na influx and transport of Na to the leaf. Since Na influx partitioning is controlled by mechanisms K/Na selectivity and exchange across membranes, the NH+4-N inhibition of K absorption may impair K/Na exchange mechanisms. Reduced K/Na selectivity or Na efflux are implicated as the source of the increased net Na influx with NH+4-N. The importance of K in preventing Na partitioning to the leaf was confined through removal of K from the nutrient solution thereby simulating the NH+4-N-induced gradual K depletion in muskmelon. Our work indicates that at a given level of water or NaCl stress, NO-3-N reduces the level of stress experienced by muskmelon through increasing LP and reducing the net rate of Na influx and transport to the sensitive leaf blade. This avoidance mechanism should enable muskmelon plants fertilized with NO-3-N to tolerate greater levels of stress.
PHYSIOLOGICAL AND CELL WALL METABOLIC RESPONSES OF GRANNY SMITH APPLES TO LOW OXYGEN STORAGE.
Authors: Huysamer Marius , Labavitch John M. , Kader Adel A.
Published: October 2019

Commercially grown Granny Smith apples were stored at 0°C in air or 1% O2, and 2 sets of samples were taken every 4 weeks over a 28 week period. One set was immediately analysed for weight loss, firmness, color, soluble solids, pH and titratable acidity. Alcohol-insoluble substances were analysed for starch, water-soluble uronides, water-insoluble uronides, cellulose and neutral sugars. The second set of samples was kept in air at 20°C for an additional week, during which respiration and ethylene production rates were measured, prior to the above analyses. Storage in 1% O2 led to the improved maintenance of firmness, reduced respiration and ethylene production rates in ambient air, and a reduced content of water-soluble uronides, suggesting a reduced degree of hydrolysis. The correlation between firmness and water-soluble uronide content was not very strong. The predominant neutral sugars present in the wall were arabinose and galactose, and activities of putative hydrolyses that may be involved in the metabolism of polymers containing these sugars will be discussed.
CHANGES IN ENZYMES AND PROTEINS IN SALT-SHOCKED VS. GRADIENT INCREASES IN NACL IN `POINSETT' CUCUMBER ROOTS
Authors: Hurley Anne K. , Cobb B. Greg
Published: October 2019

Cucumis sativus, L., `Poinsett' seedlings were grown under artificial light in 40% modified Hoagland's solution until an average plant plastochron index of 4.73 was reached. Plants were then placed in solutions of (1) 0 mM NaCl, (2) 80 mM NaCl (salt-shock), or (3) placed in a dropwise gradient solution of NaCl and Hoagland's until the final concentration of 80 mM NaCl was reached at 41 hours. Leaves of the 80 mM shock treatment wilted immediately, but recovered turgor within 6 hours. Leaves of 80 mM gradient did not wilt at anytime. The control and gradient treatments had relative growth rates which were similar to each other, but RGR decreased in the shock treatment. Invertase activity was measured in the roots at 24, 41, and 48 hours after initial treatment. Invertase activity of shock treatment increased significantly over the controls at 24 hours. The 80mM gradient was not significantly different than either treatment. Four isozymes of α– galactosidase were detected. The relative intensities of the bands varied with time and treatment. One invertase band was resolved in roots on 8% native acrylamide gels. SDS gels indicated increases in proteins in the gradient treatment compared to the control and the 80 mM shock treatment.
THE EFFECTS OF BA + GA4+7 AND DIKEGULAC-SODIUM GA4+7 ON INITIATION AND DEVELOPMENT OF VEGETATIVE SHOOTS OF AZALEA.
Authors: Bell Michelle L. , Larson Roy A. , Bailey Douglas A.
Published: October 2019

Experiments were designed to determine if the combination of 6-benzyl adenine + gibberellic acid 4+7 can promote increased lateral shoots of desirable number and length on azaleas (Rhododendron simsii Planch.). The use of dikegulac-sodium with the addition of GA4+7 was also investigated to determine if GA4+7 could overcome decreased plant height and diameter caused by dikegulac application. Treatments were applied by spraying 204 ml·m-2 to pinched plants of mean diameter and mean height of 16 and 13 cm, respectively, potted in 1.3 liter plastic containers. Shoot number, plant height and plant diameter were measured 9 weeks after application for the commercially prominent cvs. `Gloria' and `Prize'. Preliminary results indicate that 2100 mg·l-1 ai BA + 2100 mg·l-1 ai GA4+7 increases number of lateral shoots. Initial results suggest the addition of 2100 mg·l-1 ai GA4+7 to 3900 mg·l-1 ai dikegulac overcomes inhibition of internodal elongation induced by dikegulac alone. Further studies will determine the effectiveness of Promalin (N-(phenylmethyl)-1H-purine-6-amine + GA4+7, 1:1) as a pinching agent on azaleas.
STAYMAN FRUIT CRACKING AS RELATED TO CW COMPOSITION
Authors: Weiser Russell L.
Published: October 2019

Stayman apples are predisposed to cracking. Trees whose trunks were scored and foliage sprayed with GA4+7, NAA 800, and Vapor Guard had significantly fewer apples crack than controls. The skin strength and stretch distance were the same for control and treated apples. However, slices of treated apple expanded significantly more than control apples when immersed in distilled water for 45 minutes. During this treatment the amount of water taken up was not significantly different, which may indicate the difference lies in the cell structure. Hypodermal cells of control apples appear to be more elongated and have thicker cell walls than treated apples. Cell wall sugar and amino acid components will be measured to see if this discrepancy can be attributed to cell wall structural properties. These results suggest that stayman cracking occurs when the expansion of the hypodermic cannot keep pace with expansion of the fruit. It is further hypothesized that this difference is due to a difference in cell wall composition and consequent effect on wall extensibility.
WATER RETENTION IN SOILLESS POTTING MEDIA
Authors: Elliott George C.
Published: October 2019

Water retention was measured in soilless potting media irrigated by capillary mat, flood and drain, drip or overhead sprinkler. Media were amended with wetting agent or hydrophilic polymeric gel. Pots 12 cm high with a volume of 465 cm3 were loose-filled to the top with media. Potted media were wetted overhead with 120 ml water, then pots were randomly assigned to irrigation treatments. Capillary mat irrigation was continuous; other irrigation treatments were applied daily. Water retention was measured by weighing. Irrigation was continued until no further retention was measured. Water retention was significantly affected by irrigation method and medium amendments. Irrigation method followed the order overhead >= drip > flood and drain >= mat. Hydrophilic gel increased water retention, but in contrast to previous results, wetting agent did not, nor was any interaction of gel and wetting agent observed. Retention of water at container capacity, measured in situ at the end of each experiment, was significantly larger than actual retention.
RELATIONSHIP BETWEEN TEMPERATURE AND COLOR DEVELOPMENT IN THREE RED DELICIOUS APPLE STRAINS.
Authors: Singha S. , Baugher T. A. , Townsend E. C.
Published: October 2019

The objective of this study was to determine the relationship between temperature and color development in 3 strains of Red Delicious apple (Malus domestica Borkh). The strains `Scarlett Spur', `Ultrastripe' and `Starkrimson' were chosen based on variation in coloration. Chromaticity values (L* a* b*) were measured with a Minolta CR-200b calorimeter on 5 tagged apples on each of 4 trees of each strain. Measurements were made at approximately the same location on each fruit 23 times from July 11 through September 25, 1989. Differences in a*/b* ratio among strains were observed as early as the first sampling date; with `Scarlet Spur' having the highest ratio and `Starkrimson' the lowest. These differences were maintained for most the growing season. Temperature below 21C tended to enhance color development, whereas temperature above 21C reduced coloration. Temperature affected all 3 strains similarly.
PHOTOSYNTHETIC POTENTIAL OF SPUR LEAVES WITHIN AN APPLE CANOPY
Authors: Campbell Richard J. , Marini Richard
Published: October 2019

Light saturation curves were developed for detached, non-fruiting `Stayman' and `Delicious' spur leaves from interior, middle, and peripheral canopy positions throughout the season in 1989 and 1990, respectively. Be inning at bloom, measurements were made every 2 weeks for the first 8 weeks, and monthly thereafter. SLW was calculated simultaneously with photosynthetic measurements. MacArthur-Wilson saturation equations were used with non-linear regression to fit the saturation curves and SLW data, and curves were compared using indicator variables. Even at bloom, saturation curves and SLW differed among positions. The peripheral position bad a greater saturation point and equilibrium rate throughout the season, and the interior and middle positions were equivalent by about 6 weeks after bloom.
ASEXUAL PROPAGATION OF `DESERT MUSEUM' HYBRID PALO VERDE AND MESQUITE SPECIES UNDER INTERMITTENT MIST
Authors: Hagen Randall H. , Palzkill David A.
Published: October 2019

The `Desert Museum' hybrid between the Blue, Foothills, and Mexican palo verdes has been well received by the public. However, it has remained unavailable due to difficulties in asexual propagation. Studies were conducted on effects of IBA cone. (0 to 10,000 ppm), cutting position along the stem, size of cutting, season, and temperature of the medium.

For `Desert Museum', basal cuttings of slightly hardened new stem growth rooted much better than apical cuttings. Best rooting for apical cuttings was 79% using IBA from 2,500-5,000 ppm. Basal cuttings averaged 95% rooting and showed no response to IBA. Rooting of cuttings taken in September declined to 10% for apical and 2170 for basal cuttings averaged over all IBA levels. Six other species or hybrids of Cercidium and Parkinsonia and five of Prosopis were also rooted.
TOLERANCE OF ORNAMENTAL GRASSES TO POSTEMERGENCE GRASS HERBICIDES
Authors: Hubbard Joanna , Whitwell Ted
Published: October 2019

Ornamental grasses are popular landscape plants and often encounter turf encroachment or other grass weed problems. Several postemergence grass herbicides are available for use in turf and ornamentals and herbicide tolerance information is needed for ornamental grass species. Fifteen ornamental grasses including species from the genera Calamagrostis, Cortaderia, Eragrostis, Erianthus, Miscanthus, Sorghastrum, Spartina, Panicum and Pennisetum were field planted in Clemson, SC in May 1989 and Festuca species in November, 1989. Herbicide treatments were fenoxaprop-ethyl, fluazifop-P and sethoxydim at 0.4 kg a.i.·ha-1 applied 4 weeks after planting and an untreated control. Height and injury evaluations were taken at weekly intervals and plants were harvested 10 weeks after treatment. Fenoxaprop-ethyl treated Calamagrostis and Festuca species treated with all herbicides were the only treatments that were the same as untreated controls in terms of % injury, height and dry weight. Three ornamental Calamagrostis species were evaluated in a greenhouse study to determine the level of tolerance to fenoxaprop-ethyl at 0.4, 0.8, 1.6 and 3.2 kg a.i.·ha-1. No visual injury symptoms were seen on any treatments as compared to untreated controls but growth rates of the youngest leaves did vary among species shortly after treatment.
RESPONSE OF APPLE SHOOT CULTURES TO COLD TREATMENT
Authors: O`Connor P.A. , Korban S.S.
Published: October 2019

Established shoot cultures of three apple genotypes, `Dayton', `McIntosh', and `Golden Delicious' were subcultured into culture tubes containing a modified MS medium and maintained in a dark chamber at 1.0±0.5°C for periods of 3, 6, 9, and 12 months. Following each cold storage period, culture tubes of each of the three genotypes were transferred to a growth room and maintained under 16 h of light (60 uEs-1m-2) and 21°C. The overall morphological condition of each shoot was then recorded. After 4 weeks of growth, both number and length (in cm) of proliferating shoots were recorded. In general, shoots subjected to 3 or 6 months of cold storage remained green however most cultures did not initiate any new shoots. Cultures subjected to 9 or 12 months of cold treatment were etiolated however new axillary shoots were observed. The proliferation rate after 4 weeks of growth under standard growth conditions were variable among the different genotypes. The implications of using long term cold storage of apple shoot cultures will be discussed.
MUTATION, A MICROCOMPUTER MODULE DESIGNED FOR PLANT BREEDING AND GENETICS
Authors: Staub Jack E. , Braunschweig Karl
Published: October 2019

A teaching module was developed for computer-aided instruction of mutation theory. The Hypercard-driven, Macintosh compatible module illustrates the concepts of: 1) Changes in allele frequency with mutation pressure; 2) Number of alleles maintained in populations, and; 3) The Neutrality Hypothesis. The concepts are integrated in an application by using a game format.

Mutation is the ultimate source of genetic variation. Mutation pressure results in changes in allele frequency. Concept 1 illustrates the theoretical changes in allele frequency under pressure of reversible mutation. Mutation equilibrium is depicted as P=V/u+v; where v=mutation rates of allele A and u of allele a. The Infinite-Alleles Model of mutation is illustrated in Concept 2 and specifies characteristics of new mutations by F=1/4Nu+1, where F=fixation index and N=number in population. Concept 3 demonstrates the hypothesis that polymorphisms result from selectively neutral alleles maintained in a balance between mutation and random genetic drift.
TIMING OF CYTOKININ MEDIATED SHOOT INITIATION
Authors: Frett John J. , McCardell Richard
Published: October 2019

Several cytokinins at various concentrations were tested to determine which would stimulate the most synchronous shoot initiation. Kinetin was effective only at concentrations of 50 mg/L, while 2iP and zeatin where effective from 5 to 50 mg/L. BA at 10 mg/L produced the most synchronous and the greatest number of shoots. This treatment was used to determine at what point in development cytokinins stimulate shoots. Tissue was grown in the presence and absence of BA for various lengths of time. Application of BA for at least 10 days was required to initiate shoots. Explants were not effected by BA during the first 5 days of culture. Starving tissue for various periods caused a proportional lag in shoot production. Short pulses of BA at different developmental stages did not alter the cytokinin response. Vacuum infiltration of cytokinins prior to culture did not increase the BA response.
APPLE ROOTSTOCK INFLUENCE ON YIELD, YIELD EFFICIENCY, AND TRUNK GROWTH AFTER TWENTY-FIVE YEARS
Authors: Larsen Fenton E , Higgins Stewart S.
Published: October 2019

The influence of 9 rootstock on growth and production of `Goldspur' (GS) and `Wellspur Delicious' (WS), and of 3 rootstock on growth and production of `Red King Delicious' (RK) and `Golden Delicious' (GD) apple was evaluated. The spur-type `Delicious' (WS) produced more fruit per tree than the non-spur (RK) strain with Mailing (M) 7 and Malling-Merton (MM) 106 but not with M 26. GD produced more fruit per tree than GS on M 7 and M 26 but not MM 106. Yield efficiencies were usually superior with spurred strains. Efficiency of RK was markedly inferior to GD and WS. Comparing cumulative yields among 9 stocks within spurred strains showed that highest yields were with MM 106 roots. Clonal stocks were more efficient than seedling. The least size-controlling stocks (seedling, MM 104, MM 109, and M 25) tended to be less efficient than M 2, M 7, M 26, MM 106, or MM 111, but the trends throughout the experiment were not consistent. Seedling, MM 104 and MM 109 had the largest trees with spurred tops, and M 26 the smallest.