bluuebunny/crossref_metadata_2025 huggingface dataset:
CONVERSION OF BOUND TO FREE WATER IN ENDODORMANT APPLE BUDS
Authors: FAUST M. , LIU D. , LINE M.J. , STUTTE G.W.
Published: April 2024

Proton Density and T2 maps were created throughout the dormant season in `Anna' and Northern Spy′ apple cultlvars. The percentige of oixels with 15-25 ms T2 time increased from 30% in both cultlvars at the beginning of dormancy to 80 and 72% respectively, by the end of dormancy. The conversion in `Anna' was rapid and in `Northern spy was slow. Growth occured only when conversion of bound to free water reached 70% of the total number of pixels. Buds entered into a transitional phase when conversion of water reached 50%. Buds in the transitional phase are willing to respond to treatments aimed to end dormancy. Thus dormancy can be divided into two major part based on the boundness of freeness of water in the bud.
DROUGHT, LEAF GAS-EXCHANGE, AND WATER RELATIONS OF PAPAYA
Authors: Marler Thomas E. , Mickelbart Michael V.
Published: April 2024

A series of container studies was conducted from Sept. 1991 through July 1992 in which papaya plants were subjected to drying and re-wetting cycles to determine short term leaf gas-exchange and water relations responses to drought. The first response of papaya plants to a decline in substrate matric potential was a rapid reduction in stomatal conductance and net photosynthesis. Apparent quantum yield was reduced and light compensation point was increased shortly thereafter as stress continued to develop. However, leaf gas-exchange rapidly returned to the level of control plants after re-wetting. There was minimal or no effect of drought stress on relative leaf water content, pre-dawn xylem potential, dark respiration, the ratio of variable to maximum chlorophyll fluorescence, osmotic potential of leaf or root tissue, or root hydraulic conductivity of papaya plants. Chlorosis and shedding of the oldest leaves occurred following rewatering. These results indicate that papaya plants respond to short term drought by dehydration postponement via maintenance of water uptake and reduction of water loss.
NITROGEN AND CARBON TRANSLOCATION DURING EPISODIC GROWTH OF LIGUSTRUM JAPONICUM AND EFFECTS OF NITROGEN AND/OR LIGHT DURING DIFFERENT GROWTH EPISODES
Authors: Kuehny Jeff S. , Decoteau Dennis R. , Halbrooks Mary C.
Published: April 2024

Pulse-labels of 15N and 14C were used to determine nitrogen and carbon translocation during episodic root and shoot growth. Stored nitrogen (l5N) was translocated to both the first and second episode of shoot growth. Autoradiographs of 14C labeled plants indicated that fixed carbon was predominately translocated to roots during an episode of root growth and to shoots during an episode of shoot growth. Exclusion of nitrogen and/or light during different growth episodes decreased shoot length, leaf area, and fresh weight, thus affecting the rcot:shoot ratio for each episode. Translocation of newly fixed carbon and stored nitrogen between the shoots and roots of Ligustrum, and the supply of nitrogen and/or light are important factors that help maintain the functional balance of each episode of growth.
ROOT AND SHOOT GROWTH PERIODICITY OF GREEN ASH, SCARLET OAK, TURKISH HAZELNUT, AND TREE LILAC IN NEW YORK STATE
Authors: Harris J. Roger , Bassuk Nina L. , Whitlow Thomas H.
Published: April 2024

Four each of landscape-sized Fraxinus Pennsylvania Marsh. (green ash), Quercus coccinea Muenchh. (scarlet oak), Corylus colurna L. (Turkish hazelnut) and Syringa reticulata Hara `Ivory Silk' (tree lilac) were established on a rhizotron in Ithaca, New York, and root and shoot growth characteristics were observed throughout 1992. Root growth did not begin on any species before bud break. Green ash, scarlet oak and Turkish hazelnut exhibited recurrent shoot growth. Most root growth occurred during periods of bud rest, although no marked antagonism between shoot and root growth was evident. Green ash root growth was synchronous with shoot growth. The root harvest zone of green ash and tree lilac contained higher root length densities, and roots contained within appeared less suberized than that of Turkish hazelnut or scarlet oak. Root spread: crown spread ratio was greatest for Turkish hazelnut. Little root growth occurred on any species after fall leaf drop or when soil temperatures were below 5C. Implications for transplanting are discussed.
EFFECTS OF TESTA REMOVAL ON BROCCOLI SEED GERMINATION
Authors: Jett Lewis W. , Welbaum Gregory E.
Published: April 2024

The testae of seeds from the genus Brassica are not considered to constitute a significant barrier to radicle growth. It is hypothesized that in these seeds the testa splits during imbibition prior to the onset of radicle emergence. To test this hypothesis, the structural anatomy, the rate of hydration, the base water potential(Ψb), and the rate of germination of broccoli (Brassica oleracea L.) seeds were examined for both intact and decoated, primed and nonprimed seeds. Both primed and nonprimed seeds exhibited a marked increase in the rate of imbibition. The germination rates of primed and nonprimed decoated seeds were greater at all Ψ's compared to intact seeds. Priming did not lower the Ψb, of intact seeds. Removing the testa reduced the Ψb of both primed and nonprimed seeds. Observation of germinating seeds indicated that the testa was ruptured during the initial stages of radicle growth and not during the plateau phase of imbibition as previously believed. Priming did not appear to cause premature cracking or weakening of the testa. Priming did cause an irreversible change in volume due to free space that developed between the testa, radicle, and cotyledons. Thus, the testa of broccoli seeds does provide a barrier to radicle emergence that must be overcome by the expanding radicle during germination.
SOIL TEMPERATURE AND EMERGENCE OF WARM-SEASON VEGETABLES
Authors: Logan Joanne , Mueller Marcella A. , Coffey Thomas B.
Published: April 2024

In Tennessee, the 10% freeze probability dates occur during early April in most of the state. However, due to cool soils, most warm season vegetables are not planted until after May 1. The objective of this study was to quantify and map the soil temperature (2.5-5 cm depth) requirements for emergence of okra, sweet corn, cucumber, summer squash, snap bean and southern pea using different methods of temperature calculations. Field studies were conducted in Knoxville and Crossville, Tennessee in 1991 and 1992. Results show that the range of minimal average soil temperature for acceptable seedling emergence is 14 to 18°C, which is reached by mid-April in most of the state. Average soil temperature appears to be a better indicator of time to 50% emergence than other temperature-based calculations. It can be estimated from daily readings of present soil temperature in the early morning and mid-afternoon, or from air temperature, if necessary. Soil temperature maps, created in a geographic information system, can be very useful in selecting appropriate planting times for warm season vegetables.
TEMPERATURE EFFECT ON VEGETATIVE GROWTH OF CANTALOUPE
Authors: López J. , alvarez A. , Valenzuela P.
Published: April 2024

The objetive of this study was to determine plant growth characteristics of Cantaloupe (Cucumis melo) crop with different temperature regimes. The treatments consisted in four sowing dates.

Comparing the values of temperature, it was established the most suitable Growing Degree Days (GDD) and Threshold Temperature values of the plant.

This crop produces the firts harvest at 1152 and 1209 GDD with a 10 and 8oC of Threshold Temperature for cvs. `Primo' and `Cruiser', respectively.

Comparing these values with the temperatures recorded in other areas it could be easily determined the probability of vegetative growth stages.
ROOT ZONE CUPRIC HYDROXIDE TREATMENT ENHANCES SUBSEQUENT GROWTH OF TOMATO, BUT NOT PEPPER, TRANSPLANTS
Authors: Latimer Joyce G.
Published: April 2024

`Sunny' tomato (Lycopersicon esculentum Mill.) and `Jupiter' pepper (Capsicum annuum L), seeds were sown in TODD 100A flats (Speedling, Inc.) treated with 100 g/liter cupric hydroxide applied to the root cell surfaces in a latex based carrier (Spin Out, Griffin Corp., Valdosta GA). Total root numbers were not affected by cupric hydroxide but initial root dry weight of 33-day-old tomato plants was reduced 30% by the treatment. Two-weeks after transplanting to sand-culture in the greenhouse, total root dry weight of treated transplants was 4% greater than that of untreated tomato transplants. The rate of shoot dry weight gain of treated transplants over 12 days of sand culture was slightly greater than that of untreated transplants. However, roots of 45-day-old pepper transplants were slower to recover from the copper damage. Initial root dry weight of treated plants was reduced 32% relative to controls. After two weeks of sand culture, root dry weight of treated plants was still 22% less than controls. Shoot growth of pepper transplants was unaffected. Root development inside the plug was particularly lacking indicating reductions in lateral root branching.
CORN YIELD VARIABILITY AND UPTAKE OF VARIOUS NUTRIENTS IN RESPONSE TO PHOSPHORUS FERTILIZATION IN LOW-P SOILS
Authors: Roberts B. Warren , Smith Michael W.
Published: April 2024

Phosphorus was either banded, broadcast, or incorporated into raised beds at 33, 66, 99, or 132 kg·ha-1. Sweet corn was planted in two rows 30 cm apart on the beds. Substantial differences in plant growth were observed between the two rows on each bed. Yield response to P treatments was masked by this variability. Plant tissue samples were collected at mid-season and at harvest time, and were analyzed for P, K, Ca, Mg, Zn, and Fe. Strong positive correlations were found between corn yield and plant Fe content, and strong negative correlations were found between corn yield and plant Zn content. Phosphorus content of tissue was positively correlated with plant Fe and negatively correlated with plant Zn content. Differences in plant height measured at mid-season could not be explained by nutrient concentrations in the tissue at that time. Corn ear yield was best explained by Fe concentration of the shuck (positive correlation), and by zinc concentration of the foliage (negative correlation) at harvest time. The range in ear weight was greater with the banded P treatments than with broadcast or incorporated P.
INFLUENCE OF MYCORRHIZAL FUNGI AND DROUGHT ACCLIMATION ON GROWTH AND DROUGHT RESISTANCE OF ROSA HYBRIDA cv. MELNEBLE
Authors: Bo Sein Hla , Davies Fred T.
Published: April 2024

During water stress, non-drought acclimated (NDA) rose plants had a lower leaf water potential, stomatal conductance (g), and net photosynthesis than drought acclimated (DA) plants. DA plants conserved water (lower g prior to water stress) which allowed for better maintenance of gas exchange and water relations than NDA plants during stress. Osmotic adjustment (lower Ψπ) occurred in DA plants which allowed for greater turgor than NDA plants during stress. DA leaves had decreased leaf sucrose and total soluble carbohydrates. Mycorrhizal (VAM) plants colonized with Glomus intraradices had higher relative growth rates, net assimilation rates and water use efficiency than noncolonized (NVAM) plants, regardless of stress. Root growth was greater in VAM plants, but there were no differences in shoot mass, leaf area and macro-elements (P, N, K, Ca, Mg) with NVAM plants. DA-VAM plants had higher sucrose and total soluble carbohydrates than DA-NVAM plants. DA enhanced mycorrhizal colonization. Any mycorrhizal enhancement of plant water relations was not attributable to higher leaf P or confounded by differences in plant transpirational surface.
WATER CONSERVATION POTENTIAL OF NON-TURF GROUND COVERS VERSUS KENTUCKY BLUEGRASS UNDER INCREASING LEVELS OF DROUGHT STRESS.
Authors: Staats David , Klett James E.
Published: April 2024

In June 1991, a two yield field study was initiated to determine if three non-turf ground covers actually use less water than Kentucky Bluegrass (KBG). Irrigation treatments were based on percentages of ET (100%, 75%, 50%, 25%, 0%) and calculated by the modified Penman equation. Establishment rates, visual quality, soil moisture and canopy temperature were measured over two seasons. KBG sustained good appearance at irrigation rates as low as 50% ET. Potentilla tabemaemontani required irrigation rates between 50% and 75% of ET. It can be considered a low water user, but not a water conserving alternative to KBG. Cerastium tomentosum sustained good appearance at irrigation rates as low as 25% of ET. It can be considered a water conserving alternative to KBG but visual quality declined during seed formation. Sedum acre maintained good visual quality at irrigation rates as low as 25% of ET and is a water saving alternative to KBG.
EFFECTS OF WATER DEFICIT ON CIRCADIAN PATTERNS OF ROOT WATER FLUX IN HONEY LOCUST
Authors: Taylor Patricia A. , Premachandra G.S. , Joly Robert J.
Published: April 2024

The volume flux of water (Jv) through roots of 2-month-old honey locust seedlings (Gleditsia triacanthos var. inermis) was estimated by using applied hydrostatic pressure. Shoots were severed 8 cm above the root collar, and root systems were mounted in the lid of a pressure chamber with the cut stump protruding through a gasket. The chamber, filled with Hoagland solution, was pressurized to 0.34 MPa, and exudate was delivered from each root system to an electronic balance via an automated system. Jv was expressed on a fibrous-root dry weight basis and plotted over time for water-stressed seedlings and well-watered controls. A highly defined endogenous circadian rhythm in Jv was observed, regardless of treatment, with maximal and minimal fluxes occurring at mid-day and midnight, respectively; the rhythm continued for up to 90 h. Seedlings subjected to water stress exhibited an approximately 4-fold reduction in Jv at comparable points in the cycle. The severity of stress influenced both the amplitude and trajectory of the rhythm. Daily peaks of Jv decreased gradually over a 3-day period in both moderately-stressed and well-watered plants. In contrast, peak Jv from roots of severely-stressed plants increased by approximately 28% per day over the same time course. The electrical conductivity of the efflux also exhibited a highly defined rhythm which was phase-shifted from that of the Jv rhythm by approximately 12 h.
HYDRAULIC CONDUCTIVITY & EMBOLISMS IN SWEET CHERRY
Authors: Hubbard Mark A. , Flore James A. , Ewers Frank W.
Published: April 2024

Percent loss of conductivity of sweet cherry (Prunus avium `Emperor Frances') under dry conditions was determined by measuring hydraulic conductivity before and after high pressure perfusion removal of xylem embolisms. Cut stems were allowed to dry for 0 to 8 hours, recut underwater and the rate of flow of solution through the stems measured under positive pressure (∼8.0 kPa). Hydraulic conductivity (Kh)was then calculated, and typical values for well hydrated stems were 6 × 10-9 m4MPa-1s-1. Embolisms were then dissolved by high pressure perfusion (125kPa) and the subsequent flow rate measured. A second Kh was then calculated and the difference in Kh values before and after the high pressure treatment used as a measure of % loss of conductivity (or % xylem embolism). A curve of the `vulnerability' to xylem embolism was generated by plotting % loss of conductivity against initial stem water potential. The curve shows the stems undergo xylem embolism as soon as stem water potential reaches -1.5MPa, and at stem water potentials of -3 MPa, the stems are over 80% embolized. This cultivar appears to be vulnerable to embolism relative to other studied woody species, and xylem dysfunction likely is a problem early in a drying period. However, a particular rootstocks ability to supply water during a dry period and a cultivar's ability to limit water loss by stomatal closure will dictate the exact water potentials in the stem and thus its level of embolism.
INCREASED ADH1 ACTIVITY IN GUAYULE CULTIVARS WITH ANAEROBIC STRESS TOLERANCE
Authors: Oishi Karen K. , Chen Fu-Tai , Ray Dennis T.
Published: April 2024

In flood-intolerant species increased ADH1 activity is required to survive anaerobic stress. Guayule is a perennial shrub that grows well only in sandy well aerated soil. This study was conducted to determine the relative tolerance of three guayule cultivars, N565, N576 and 11605 to anaerobic stress, in comparison to the levels of induction of ADH1 activity. All three guayule cultivars had the same three ADH1 isoenzymes. Seedlings were anaerobically stressed for a maximum of 108 hr. N576 was the most tolerant to anaerobic stress and had the highest, 1860 IU/mg, and temporally the longest induction of ADH activity. N565 was the least tolerant to anaerobic stress and had the lowest, 400 IU/mg, and temporally the shortest induction ADH activity. N565 and 11605 had the same maximal induction of ADH activity and had many Adh1 DNA fragments in common. N576 had the least number of common Adh1 restriction fragments.
USE OF MICROWAVE-POWERED LAMPS AS A NEW HIGH INTENSITY LIGHTING SOURCE IN PLANT GROWTH CHAMBERS: SPECTRAL CHARACTERISTICS
Authors: Krizek Donald T. , Mirecki Roman M. , Britz Steven J. , Harris William G. , Thimijan Richard W.
Published: April 2024

The broad-band characteristics of microwave-powered E lamps (Fusion Systems Corp.) were determined in an EGC growth chamber with a water-cooled light cap and a plexiglass barrier. Radiation measurements were made from 0.29 to 3) μm with an Eppley PSP pyranometer and from 3 to 50 μm with an Eppley PIR pyrgeometer. Photosynthetic photon flux (PPF) was measured with a LI-COR quantum sensor. At full power, the lamps provided over 1700 μmol m-2 s-1 of PPF, 47.8 kW m-2 from 0.29 to 3 μm, and 678 W m-2 from 3 to 50 μm, and at half power, 650 μmol m-2 s-1 of PPF, 17.1 kW m-2 from 0.29 to 3 μm, and 404 W m-2 from 3 to 50 μm at a distance of 1.2 m. Spectral measurements were made every 2 nm from 250 to 792 nm with an Optronics Lab Model 752 spectroradiometer under a single bare lamp. Based on total irradiance between 250 and 792 nm, the distribution of irradiance from 250-280, 280-320, 320-400, 400-700, and 700-792 nm was 0, 0, 1.5, 88.1, and 10.5% for the E lamp and 0, 0.6, 7.8, 73.6, and 18.2% for a mid-day June sun at Beltsville, MD respectively. The phytochrome photoequilibrium for E lamps was calculated at 0.76 as compared to 0.72 for sunlight.
ASSIMILATE ACCUMULATION AND PARTITIONING IN PEPPER CULTIVARS DIFFERING IN SUSCEPTIBILITY TO STRESS-INDUCED ABSCISSION.
Authors: Turner A.D. , Wien H.C.
Published: April 2024

Pepper cultivars differ in susceptibility to stress-induced bud abscission. The stress susceptible cultivar `Shamrock' undergoes a larger reduction in net assimilation rate (NAR) under low light stress, and partitions less dry matter (DM) to reproductive structures than the more tolerant cultivar `Ace'. To determine if photosynthetic rates under low light stress could explain NAR differences, photosynthesis was measured on `Ace' and `Shamrock'. Assimilate partitioning was compared through measurement of leaf and bud respiration rates and analysis of bud sugar concentrations. Cultivar photosynthetic rates of exposed leaves did not differ under low light. Bud respiration rates fell to a lower level in `Shamrock' than `Ace' in low light-stressed plants, while expanded leaves respired at higher rates in `Shamrock' than `Ace' under both full and low light. Bud sugar concentrations were significantly lower in `Shamrock' than `Ace' after 3 days of low light stress. Susceptibility to low light stress-induced bud abscission in `Shamrock' appears to be associated with reduced assimilate partitioning to buds, perhaps caused by high assimilate consumption in maintenance of expanded leaves.
615 (PS 3) COMPETITIVENESS OF SIXTEEN WILDFLOWERS WITH BUFFALOGRASS AND BLUE GRAMA TURF
Authors: Lindgren Dale T.
Published: April 2024

Sixteen species of herbaceous perennial flowering plants were planted with five different treatments (three buffalograss lines, one blue grama line, and no turf) to determine the growth and flowering characteristics of these herbaceous plants with the turf treatments. Plants were measured for survival, time of emergence, percent of plants flowering, initial flowering, number of flower stalks, plant height, and pod number/plant one-year after planting. There were highly significant differences for all traits for plots, species, and plot × species interaction. Individual plant vigor was highest where there was no grass competition. Species that performed well in all turf treatments included Echinacea pallida, Linum perenne, Salvia azurea, Solidago rigida, and Ratibida pinnata.
616 (PS 3) DELAYING BUDBREAK OF BARE-ROOT CHINESE CHESTNUT SEEDLINGS WITH FOLIAR APPLICATIONS OF PACLOBUTRAZOL
Authors: Arnold Michael A. , Davis W. Edgar
Published: April 2024

Foliar applications of paclobutrazol (PAC) at rates of 0, 400, 800, and 1200 mg/liter were applied to one-year-old liners of Castanea mollissima Blume in the field on August 27 and September 27, 1991. In January, 1992, the seedlings were lifted from the field and placed in 4 C storage. At transplanting to the field (May, 1992) an additional set of seedlings received the same PAC treatments. The objective was to determine if PAC treatments could be used to delay budbreak (BB, green visible between bud scales) and/or 1st leaf expansion (LE, 1 cm length) until significant amounts of new roots were regenerated to enhance initial transplant establishment. PAC applications prior to fall lifting delayed BB by 1 to 3 days and LE by 1 to 3 days compared to controls. Numbers of new small (< 1mm diameter) roots present at BB and new large (≥ 1 mm diameter) roots at LE were greater on PAC treated seedlings, but were insufficient to improve 1st year growth or survival. PAC at 800 and 1200 mg/liter applied at transplanting reduced internode length by approximately 20 percent. End of season new shoot dry weights, total leaf area per plant and average area per leaf were not affected by PAC level or time of application.
617 (PS 3) FACTORS AFFECTING PROPAGATION OF MAACKIA AMURENSIS FROM SOFTWOOD CUTTINGS
Authors: McNamara Steven T. , Pellett Harold , Graves William R.
Published: April 2024

Little is known about asexual propagation of Maackia amurensis Rupr. & Maxim. (Amur maackia), a N2-fixing tree species with potential for increased use in the landscape. Terminal cuttings were collected from 20 trees (10 at the Minnesota Landscape Arboretum and 10 in the Washington, D.C., area) at two times in 1992. Cuttings were treated with either 0 or 2500 mg·kg-1 IBA and held in a humidified greenhouse for 12 weeks. Primary and secondary roots were counted, and a subjective rooting score was assigned at harvest. The rooting percentage of the genotypes ranged from 19 to 92, and the number of roots and the rooting scores of the genotypes also varied significantly. Collection date and IBA had relatively minor effects on rooting. We conclude that M. amurensis can be propagated from softwood cuttings, but the usefulness of this method varies with genotype.
622 (PS 3) STUDY ON THE PRODUCTION OF TREES GROWN IN CONTAINERS
Authors: Duchesne I. , Rioux J.A.
Published: April 2024

The growth potential was observed for young trees of Tilia cordata `Glenleven', of Malus floribunda `Red Splendor' and of Fraxinus pensylvanica `Patmore' when produced in field or in containers. The three species were submitted to five treatments: field planting, above or sunk below ground containers with or without a copper coated fabric container. The 15 “species-treatments” combinations were randomly distributed in a block and repeated 4 times. Results demonstrate that the mean trunk diameter is greater by 18% for apple trees and by 6% for ash trees grown in containers compared to the other trees grown in field. Moreover, the trunk diameter of linden is 9% greater for trees in sunk below ground containers; the root dry mass is also more important in above ground containers. It is our opinion that the superior yields obtained with containers are due mainly to the better care given to the trees in terms of fertilization and irrigation. The greater quantity of due mass obtained with trees produced in fabric containers could on the one hand be dye to root ramification caused by copper and on the other hand to an increased to apical tissus volume also caused by copper. Visual observations have permitted to detect the effect of temperature on root development in the zone adgacent to the side of the container, it may have a regulator effect on the development of the root system and seems to be combined to the effect of copper.
627 (PS 3) Determination of the Photo-Perceptor Site for Overcoming the Early Stage of Endodormancy
Authors: Guak S. H. , Shirazi A. M. , Fuchigami L. H.
Published: April 2024

Buds, leaves, or stems of red-osier dogwood (Cornus sericea L). plants were covered with aluminum foil and placed in a warm greenhouse under long day condition to determine the perceptor site for overcoming the early stage of endodormancy. The following categories with treatments were studied; Category A, foliated plants: A1) not covered, A2) buds covered, A3) stem covered, A4) stem and bud covered. Category B, foliated-covered plants: B1) leaves covered, B2) leaves and buds covered, B3) leaves and stem covered, B4) leaves, stem and buds covered. Category C, defoliated plants: C1) not covered, C2) buds covered, C3) stem covered, C4) stem and buds covered. These studies indicate the bud as the long day (LD) perceptor site for overcoming the early stage of endodormancy. However, the presence of leaves (Category A) stimulated terminal budbreak only in bud covered (A2) and stem and bud covered (A4) treatments. In addition, etiolation treatments (Stem covered, A3, A4 and C3) resulted in significant root initiation on stem internodes within 2 weeks. The rate of presence of roots in stem-covered treatment promoted shoot growth.
ADVENTITIOUS SHOOT REGENERATION FROM IN VITRO-CULTURED LEAVES OF RUBUS GENOTYPES
Authors: Turk Barbara , Swartz Harry J. , Zimmerman Richard H.
Published: April 2024

Regeneration of adventitious shoots from in vitro-derived leaves of several Rubus genotypes was tested with various concentrations of cytokinins and auxins, different basal media, duration of dark incubation periods, temperatures and photosynthetic photon fluxes (PPF). Thidiazuron (TDZ) was significantly more effective than benzyladenine (BA), and indolebutyric acid (IBA) more effective than naphthaleneacetic acid (NAA). Leaves of `Summit' and `Sentry' raspberries and MD-ETCE-1 blackberry were most responsive (percentage of leaves responding, number of shoots formed) to 1 μM or 10 μM TDZ plus 0.5 μM or 1 μM IBA; MD-ETCE-1 leaves did not respond to BA or TDZ with either 2.7 or 5.4 μM NAA. More organogenesis occurred on MS than on half-strength MS, Anderson modified, WPM or N6 media. For the five cultivars tested (`Autumn Bliss', `Canby', `Sentry', `Summit', MD-ETCE-1), the most shoots formed when leaves were incubated at 20°C (vs. 25°C) for 1 week in the dark before they were exposed for 16 h per day to a PPF of 40 μmol·m-2·s-1. Significant differences in regeneration frequency were observed among four cultivars with the highest 71% for `Autumn Bliss' and the lowest 29% for `Summit'.
FIELD PERFORMANCE OF MUSCADINE GRAPE MICROPROPAGATED FROM SHOOT TIPS
Authors: Robacker Carol D. , Lane R.P.
Published: April 2024

Phenotypic stability and yield of muscadine grape (Vitis rotundifolia) plants produced via micropropagation from shoot tips must be demonstrated to overcome reluctance to use micropropagated plants in vineyards. `Golden Isles' plants produced from culture of fragmented shoot tips were planted in the vineyard, and yield data were collected three, four and five years after planting. Yield of four-year old vines was comparable to that collected in earlier years at this location from `Golden Isle' plants from stem cuttings. Yield in the fifth year, however, declined significantly, perhaps due to late cold spring weather or heavy fruiting the previous year on these young vines. After five years in the vineyard, trunk diameter, shoot length, leaf area, berry size and soluble solids of the micropropagated plants were compared to those from stem cuttings. The only difference detected was for soluble solids, a trait highly influenced by environmental conditions. All micropropagated plants appeared similar to each other and to the `Golden Isles' cultivar.
LIQUID MEDIUM OVERLAYS ENHANCE GROWTH AND MULTIPLICATION OF IN VITRO APPLES AND GRAPES
Authors: Ahmad Masooma Ali , Safadi Farida , Hughes Harrison
Published: April 2024

Previous studies have shown that liquid medium additions on established cultures enhance shoot growth and proliferation. In the present report, the growth and multiplication of apples and grapes were evaluated after the addition of liquid media to established cultures. Grapes and apples were micropropagated on agar solidified nutrient medium with 5μM BAP, and 4.4μM BAP, 1.4μM GA, 4.9μM IBA, respectively. A liquid overlay of similar medium was added after 4 to 6 weeks in both cultures. Improved growth, number of shoots, and a reduction in callus growth were observed in both species as compared to shoots transferred to fresh solid media. The number of micropropagated apple shoots and their height increased significantly by 35% and 69% respectively. Proliferation of grape shoots increased by 198% while callus growth decreased by 64% when compared to cultures transferred to fresh solid media.
653 (PS 4) VASCULAR CONNECTION IN STEM-ROOT TRANSITION REGION OF IN VITRO GRAPES (Vitis sp.'Valiant')
Authors: Ali-Ahmad Masooma , Hughes Harrison
Published: April 2024

Incomplete vascular connection between roots and shoots of various in vitro plantlets has been implicated in the poor survival of acclimatized plants. In this study, the anatomy of the stem-root transition region of in vitro and acclimatized grape (Vitis sp.`Valiant') were studied by light microscopy. Grape plantlets were micropropagated on MS medium supplemented with 5μM BAP for multiplication and 0.4 μM NAA for rooting. Roots developed directly from stem tissues after two weeks in rooting media. Subsequently in vitro rooted plantlets were acclimatized in the greenhouse for 6 weeks. Continuation of xylem vessels were observed in the stem-root transition region of the in vitro plantlets. No anatomical differences were observed in stem-root transition regions between direct rooting in vitro and those acclimatized ex-vitro for 6 weeks. Therefore, poor survival of in vitro propagated grapes are not due to incomplete vascular connection between roots and shoots.
MICROPROPAGATION OF GAS PLANT (DICTAMNUS ALBUS)
Authors: Jones Rodney , Geneve Robert
Published: April 2024

Gas plant is an elegant ornamental which blooms in early summer. It is commonly propagated by seed which is limited by a complex dormancy. Micropropagation was investigated as an alternative method for efficiently propagating gas plant. Rapidly growing two node stem pieces were taken from mature greenhouse grown plants, surface sterilized and placed in MS medium with 1 μM benzyladenine (BA). Shoot multiplication was studied using in vitro derived four node explants cultured on MS media containing BA at 0, 1, 5, or 10 μM. Explants cultured on BA at 1 and 5 μM averaged 3.9 and 5.6 shoots per explant respectively and a mean yield of 2.7 and 2.5 shoots greater than 2 cm in length. Explants cultured at 10 μM produced 5.7 shoots per explant with only 0.8 shoots greater than 2 cm in length. Microcuttings failed to root in vitro even in the presence of indolebutyric acid (IBA). Microcuttings directly stuck ex-vitro in a peat-lite medium root at 90% with 1.9 roots per cutting.
THE DEVELOPMENT OF TRICHOME-LIKE STRUCTURES IN CALLUS CULTURES OF SPRING BEAUTY (CLAYTONIA VIRGINICA)
Authors: Kester Sharon T. , Geneve Robert L. , Jones Rodney O.
Published: April 2024

Tissue cultures were initiated in spring beauty from petal or sepal tissue on a MS medium. Using a factorial combination of naphthaleneacetic acid and kinetin, only sepal tissue responded to form callus. Callus proliferating on the 5.4 μM NAA + 9.3 μM KN would periodically form shoots at a low frequency. After six months in culture on this medium, trichome-like structures developed along the surface of the proliferating callus. Two types of trichome-like structures were observed in these cultures. One type was a multibranched structure and the second type was linear with a glandular tip. The trichome-like structures were assimilated as the callus mass increased in size. In addition, the cells in the callus just below the surface were pigmented. The pink pigment was visually similar to the natural petal coloration. Leaf, sepal and petal tissue did not produce obvious trichomes on greenhouse grown plants.
671 (PS 5) RESPONSE OF `PRIZE' AZALEA TO UNICONAZOLE APPLIED AT FOUR STAGES OF SHOOT APEX DEVELOPMENT
Authors: Keever G.J. , Olive J.W.
Published: April 2024

Forcing azalea cultivar `Prize' was treated with 15 or 30 mg a.i. uniconazole/liter at four stages of shoot apex development (SOD 0 = vegetative; 1 = change in shape of terminal; 2-3 = first row of floral parts originated or petals differentiated; 4 = anthers differentiated). Plant height and growth index increments increased when uniconazole was applied at a later SOD but decreased with increasing concentration. Bypass shoot number decreased quadratically with increasing concentration, but was not affected by SOD. Time to flower and flower number varied with SOD and concentration. Plants treated at SOD 0 or 1 flowered earlier and with more blooms than control plants; plants treated with 15 mg a.i. uniconazole/liter at SOD 2-3 flowered at the same time as control plants with a similar number of blooms. Plants treated with 30 mg a.i. uniconazole/liter at SOD 2-3 or at SOD 4 with either concentration flowered after control plants with fewer blooms.
679 (PS 5) Evaluation of Hand Held, Flat Electrode pH, Electrical Conductivity, Potassium, and Nitrate Meters
Authors: Yelanich Mark V. , Biernbaum John A.
Published: April 2024

Cardy flat electrode pH, electrical conductivity, potassium and nitrate meters were evaluated for their application to greenhouse solution and media testing. The pH, EC, K, and NO3-N levels in 7 recirculated nutrient solution reservoirs were monitored weekly for 8 weeks using Cardy meters and standard methods. Regression analysis of the results of the Cardy meters against those of standard methods resulted in slopes of 0.64, 0.94, 1.05 and 1.03 for pH, EC, NO3-N and K respectively. Saturated media extract (SME) samples of a peat-based medium were diluted to provide concentrations of 10 to 200 mg·liter-1 NO3-N. The regression equation describing the relationship between the colorimetric and Cardy determinations was: ppm NO3-N = 0.86 * Cardy ppm NO3-N + 11.1 (R2=0.98). In a separate experiment, KNO3 and Ca(NO3)2 were added to a commercial peat-based medium to provide 27 to 490 mg·liter-1 NO3-N using the SME method. The regression equation describing the relationship between the colorimetric and Cardy determinations was: ppm NO3-N = 1.05 * Cardy ppm NO3-N -2.05 (R2=0.98). Chloride in the range of 0 to 1400 mg·liter-1 resulted in a 0.02 mg·liter-1 increase in NO3-N with every 1 mg·liter-1 increase in chloride.
GENETIC DIVERSITY IN POPULATIONS OF NATTVE GRASSES AND FORBS IN MINNESOTA
Authors: Concibido Kerstin , Strefeler Mark S.
Published: April 2024

The Legislative Commission on Minnesota Resources initiated a program to develop a viable seed industry for the production of native grasses and forb. A part of this program is to measure the amount of genetic diversity among and between populations in Minnesota. This information will be used to develop strategies for the distribution of seed in land reclamation and for management of seed production to maintain the genetic diversity of commercial seed lots. Two grasses, Andropogon geradii and Schizachyrium scoparium, and two forbs, Monarda fistulosa and Liatris sp., were used in this study. Genetic diversity of populations was measured using morphological traits and isozyme analysis of 30 to 50 individuals from each of the 13 to 49 populations. Thirteen enzymes systems were examined to detect polymorphisms. Isozyme polymorphisms have been detected in Liatris populations for PGM, MDH and ACP. No isozyme polymorphisms have been detected in grass populations. Morphological characteristics were measured in a common nursery to remove genotype × environment interactions. Variation in height, number of stems and number of inflorescences were observed within and among grass populations. Liatris populations varied in leaf number, width and length and shoot dry weights.
696 (PS 5) PUSSY WILLOW BRANCHES - A NEW CROP FOR SUSTAINABLE AGRICULTURE
Authors: Yoder Kent S. , Moser Bruno C.
Published: April 2024

Field experiments were conducted to investigate the potential of using pussy willow (Salix discolor) as part of filter strip plantings to control soil erosion and chemical runoff from agronomic crops into nearby waterways. Of special interest was the possibility of obtaining economic return from the filter strip planting in the off-season for agronomic farmers.

Pussy willow cuttings were planted six feet apart in three rows between agronomic cropland and a waterway with ten feet between the rows in spring 1990. Branches were first harvested in February 1992 and again in February 1993. Harvest techniques included removal of all branches at 10 inches or 24 inches above ground level.

The 1992 harvest yielded 72 salable branches per plant which were graded into four sizes. The total weight and number of branches decreased with increasing row distance from the cropland. The 1993 harvest yielded larger, more uniform branches. Comparisons of yields from multiple year harvesting techniques will be presented and economic possibilities discussed.
711 (PS 6) EFFECT OF NITROGEN FERTILIZATION ON GROWTH AND YIELD OF AMARANTH
Authors: Whitehead Wayne F. , Singh Bharat P.
Published: April 2024

This study was conducted to establish the optimum level of N fertilization for the production of vegetable amaranth, Amaranthus tricolor, in middle Georgia. The soil fertilization treatments consisted of 0, 45, 90 and 135 kg N ha-1, applied in two equal doses, first at 18 days after planting and again when plants were 5 weeks old. Accession RRC 241 was planted on 19 June in randomized complete block design with four replications. The crop was harvested 48 days after planting and data on leaf number, leaf fresh weight, stem fresh weight, and green yield were collected. Green yield for treatments 0, 45, 90 and 135 kg N ha-1 were 5.3, 10.7, 13.2 and 13.5 Mg ha-1, respectively. Regression of N fertilization on all vegetative components were significant. A linear response was seen for stem fresh weight, a quadratic response for green yield and cubic responses for leaf number and leaf fresh weight. The R2 values for leaf number, leaf fresh weight, stem fresh weight, and green yield were 0.61, 0.63, 0.29 and 0.85, respectively. The results indicate that 90 kg N ha-1 of fertilization should provide optimal vegetative growth in amaranth.
RESPONSES OF MULCHED TOMATOES TO UNDER-BED TRENCHING AND PROCESSED MUNICIPAL WASTE APPLIED TO CALCAREOUS SOILS
Authors: Bryan H. H. , Lance C. J.
Published: April 2024

Trenches 0, 25 and SO cm deep (d) and 15, 30 and 45 cm wide (w) were dug, refilled, and bedded-over in 1985. Tomatoes were planted in 1985, `86 and `88. Daorganite processed sludge was initially applied broadcast; in 50 cm deep × 45 cm wide trenches; and in 45 cm wide strips on beds, and rototilled 10 cm deep at rates of 0, 6.7, 13.4, and 26.8 t/ha. Three subsequent annual applications were strip rototilled at 0.5x the above rates to determine effects of initial and residual rates on tomato yields. In 1989, 0 and 9 t/ha of Daorganite or Bedminster Bioconversions compost were applied in trenches 0, 12.5, 25 or 50 cm deep and 45 cm wide; and 0, 6.7, or 13.4 t/ha of each were strip rototilled. Inorganic fert. was applied at approx. 0.5x recommended rate. Yields of large and marketable fruit increased with increasing depth and width of trenches. Tomatoes responded best to 6.7 and 13.4 t/ha annual sludge applications, and to rototilled strips or trench placements of sludge. Yields of large and marketable fruit increased with increasing depth of trenches. Yields were higher with 9 t/ha sludge in trenches plus 6.7 or 13.4 t/ha sludge strip rototilled, and with 13.4 t/ha of either sludge or compost strip rototilled in the bed.
TOLERANCE OF PEACH ROOTSTOCKS TO IRON CHLOROSIS
Authors: Sperry Wade J. , Walker David R.
Published: April 2024

Bailey, Lovell and Halford peach rootstocks were evaluated to determine their tolerance to iron chlorosis. Two year old trees budded with Redhaven scions were used. Experiments were carried out in a greenhouse with trees grown in nutrient solutions and soil. Soil was obtained from an orchard with a history of severe iron chlorosis problems. Nutrient solutions were treated with bicarbonate, and pH was maintained at approximately 8.3 to induce iron chlorosis symptoms. Mean chlorophyll content of leaves from Redhaven on Halford was 42 mg/m2 which was significantly higher than Redhaven on Bailey (30.3 mg/m2) and Redhaven on Lovell (28.4 mg/m2). Photosynthetic rates of leaves from Redhaven on Halford were significantly higher (16.6 μm/m2/sec) than those on Bailey (7.3 μm/m2/sec) and on Lovell (2.1 μm/m2/sec). Shoot growth was measured weekly. Redhaven shoots on Halford had significantly more shoot growth (80 cm) from the beginning of the experiments than on Bailey (23 cm) and on Lovell (19 cm). Results from these experiments show that Halford rootstock with a Redhaven scion is more tolerant to iron chlorosis than Bailey and Lovell rootstocks with Redhaven scions.
YIELD COMPONENTS IN SPUR VS. NON-SPUR STRAINS OF `DELICIOUS' APPLE ON TWO ROOTSTOCKS
Authors: Dennis F.G. , Masabni J. , Ketchie D.O.
Published: April 2024

Yield components of spur and non-spur strains of `Delicious' apple, on 2 rootstocks were compared over 4 years (5th through 8th leaf). Yield per unit trunk cross-sectional area was higher in spurs than in non-spurs with but few exceptions. Differences in fruit set, rather than in flower density or fruit size, were largely responsible for this difference in yield. Yields were higher on EMLA 7 than EMLA 111 rootstock, partially because of earlier bearing. When cropload was factored out, fruit size was slightly greater on EMLA 7 than on EMLA 111.
732 (PS 7) EFFECT OF LIGHT ON ENDOGENOUS IAA AND IBA CONCENTRATIONS DURING THE INDUCTIVE PHASE OF ROOTING IN MALUS PUMILA M.9 JORK
Authors: Sutter Ellen G. , Caboni Emilia
Published: April 2024

Shoots of M.9 Jork, grown in vitro, were treated with IBA and then incubated in the dark or light for 5 days to determine the effect of light on endogenous IAA and IBA concentrations during root initiation. Incubation in the dark resulted in significantly greater percentages of rooting and more roots per plant than when the shoots were placed in the light during the inductive period. Uptake of IBA continued throughout the 5 days with both IAA and IBA concentrations in the basal portion of the stems increasing during this period. The increase of both free and total IBA was significantly greater than that of IAA. Relatively little IBA was converted to IAA. An increase of peroxidase activity was noted in the dark, resulting in less free IAA being present in the dark than in the light. Considering the greater amount of IBA relative to that of IAA, however, we concluded that IBA itself, and not its conversion to IAA, is the active agent during root initiation.
733 (PS 7) TEMPERATURE OPTIMUMS FOR ANTHOCYANIN SYNTHESIS IN `BRAEBURN', `DELICIOUS', `FUJI', AND `GALA' APPLE TISSUE
Authors: Curry Eric A.
Published: April 2024

Color in apple skin is a composite of varying concentrations of chlorophyll, carotenoids, and anthocyanins/flavanols. Anthocyanin biosynthesis is influenced by a number of factors including rootstock, nitrogen status, wounding, certain plant growth regulators, light, and temperature. This study investigated changes in the optimum temperature for anthocyanin accumulation of `Braeburn', `Delicious', `Fuji', and `Gala' apple tissue disks. Preclimacteric (core ethylene < 1.0 ul·liter-1) apples with little color development were harvested in September, 1992 and immediately brought to the laboratory. Six 15mm disks about 3mm thick were removed from the shaded side of each fruit and transferred to moistened filter paper on temperature-controlled blocks preset at temperatures ranging from 15C to 40C at intervals of 5C and covered with plastic (CO2 permeable) film. The disks were illuminated for up to 48 hours with a high pressure sodium lamp at a distance of about 1m. Following the illumination period individual peel disks were extracted with acidic methanol for anthocyanins. The temperature optimum for maximum anthocyanin biosynthesis for each cultivar will be reported.
737 (PS 7) POLLINATION OF ANJOU PEAR
Authors: Ketchie D. O. , Fairchild E. D.
Published: April 2024

A two-year study was conducted on 12 possible varieties as pollen sources for Anjou pear. Bloom dates of the varieties were compared with bloom date of Anjou. Viability of pollen was determined including germination and tube growth. The Anjou trees were hand-pollinated using the various sources of pollen, then later we determined fruit set. The fruit was harvested and size of fruit, number of seeds, firmness, soluble solids, titratable acidity and physiological disorders were determined. Bloom dates corresponding most closely to Anjou were Bartlett, Pyrus calleryana and the Asian pear Nijisecki. Pollen from El Dorado, OHxF 33 and OHxF69 had the highest percent germination and the best pollen tube growth. Bartlett, Pyrus calleryana, Nijisecki, OHxF333 and OHxF69 showed the highest percent fruit set. The largest fruit was from flowers pollinated with Nijisecki, Dawn, Bose and self-pollinated. Fruit with highest numbers of seeds was fruit with pollen from Nijisecki, Usserienses, Dawn, Comice and Bosc. There was no difference in firmness, soluble solids or tritratable acidity, and there was no physiological disorders. The study indicated Bartlett pear is the best all-round pollinizer for Anjou pear.
MECHANCIAL PEACH THINNING
Authors: Glenn D. Michael , Peterson Donald L. , Giovannini Daniela , Faust Miklos
Published: April 2024

The purpose of these studies was to compare two mechanical means of thinning with hand thinning peaches 40-60 days after full bloom. A spiked-drum canopy shaker and a trunk impacter shaker were used to thin `Loring' peach trained to `Y' shape. Initial studies demonstrated that the spiked-drum shaker removed more fruit from horizontal than vertical branches. The spiked-drum shaker did not preferentially remove larger or smaller fruit. The yield of large fruit was not significantly different for hand or mechanically thinned trees when fruit was thinned 40-60 days after full bloom.
HORTICULTURAL SOLUTION TO PROTECTING YOUNG CITRUS TREES FROM SUBTERRANEAN TERMITE DAMAGE
Authors: Rouse Robert E. , Stansly Philip A.
Published: April 2024

The eastern subterranean termite, (Reticulitermes flavipes (Roller) has caused extensive losses in localized areas of young citrus in southwest Florida by girdling trees between the crown roots and planted soil line. Applications of insecticides provided only short term deterrence lasting only a few months, and granular formulations in general have been most effective. Since termites will not venture far from the protection of moist soil and their primary area of attack has been found to be the trunk cambium below the soil line and not the roots, shallow planting and/or removal of soil have been found to be effective controls. Removing the soil around the affected trees to expose the tops of the crown roots has almost always resulted in arresting termite attack and allowing the tree to recover. Planting trees shallow does not slow tree growth.