bluuebunny/crossref_metadata_2025 huggingface dataset:
POSSIBLE ROLE OF MANNITOL 1-OXIDOREDUCTASE IN CELERY SINK TISSUE
Authors: Stoop Johan M. H. , Pharr D. Mason
Published: April 2024

Mannitol represents a major carbon storage compound in celery petioles. Recently, a novel mannitol dehydrogenase was isolated from celeriac (Apium graveoiens L. var. rapaceum) root tips and partially purified to a specific activity of 210 μmol/h/mg protein. This NAD-dependent enzyme catalyzes the oxidation of mannitol to mannose. not fructose, and this is uniquely different from the mannitol oxidation in lower organisms. Data are presented that show that the enzyme is also present in celery (Apium graveoiens L. var. dulce) sink tissue. The product of the mannitol oxidation in celery was determined to be mannose. Previous studies suggested that differences in fertilizer concentration in the root zone of celery could alter carbon partitioning between mannitol and hexose sugars and change enzyme activities. In this study, plants were grown hydroponically at two different salt concentrations, E.C.=2.7 mS/cm and E.C.=6.0 mS/cm. A high mannitol to hexose ratio was observed in celery petioles of plants grown at high salt concentration, supporting the hypothesis that the salt environment might alter both mannitol and hexose pools in a coordinate way. Plants grown at both salt concentrations did not differ in root or shoot fresh weight. These data support the hypothesis that mannitol might be involved in osmoprotection by acting as a compatible solute. Mannitol accumulation in celery petioles might be, in part, regulated through a mannitol catabolizing pathway involving mannitol oxidation to mannose by the NAD-dependent 1-oxidoreductase, mannose phosphorylation by mannose kinase, mannose-6-P conversion to fructose-6-P by phosphomannose isomerase and further conversion to hexoses through a sucrose intermediate. The novel mannitol 1-oxidoreductase might therefore be a key enzyme in controlling mannitol levels in sink tissues.
SOIL-ROOT INTERFACE WATER POTENTIAL IN Prunus × cistena GROWN IN DIFFERENT SOIL MIXES
Authors: Xu Hui-lian , Caron J. , Bernier P. Y. , Gosselin A.
Published: April 2024

Water potential at soil-root interface (WPs-r) appears to be a good indicator of soil water availability to the plants. However, it is not easy to measure it routinely. Plant water status is more convenient to manage from bulk soil water potential (WPsoil) determination if a good relationship between WPsoil and WPs-r can be established. In order to elucidate this relationship in different substrates, three soil mixes: Mix-1) composted bark, peat, sand; Mix-2) peat, bark, sand, compost; and Mix-3) peat, sawdust, sand, were used with Prunus × cistena. Two-year-old field grown plants were placed in a greenhouse. After soil water was depleted to different levels, WPsoi1, xylem water potential (WPxylem). transpir-ation as well as stomatal conductance were measured using a portable gas exchange system. WPs-r was calculated from these measured data. Plants grown in Mix-2 kept higher WPs-r until WPsoil decreased to -24 KPa, while WPs-r in the plants grown in Mix-1 began to decrease at -5 KPa of WPsoil. Mix-3 showed a medium critical WPsoil for WPs-r to decrease. Since there was a better availab-ilty of soil water to the plants, plants in Mix-2 also showed higher WPxylem. Dynamic analysis showed that plants in Mix-2 kept better plant water status mainly by avoiding water stress. Plants in Mix-3 also avoided water stress, but it was, at least in part, attributed to less leaf area
EFFECT OF POTASSIUM AND DROUGHT STRESS ON GAS EXCHANGE, WATER RELATIONS AND WATER USE EFFICIENCY OF HIBISCUS ROSA SINENSIS L. cv. LEPRECHAUN
Authors: Egilla Jonathan N. , Davies F. T. , Boutton T. W.
Published: April 2024

Rooted cuttings of Hibiscus rosa sinensis L. cv. Leprechaun were irrigated with full strength Hoaglands solution containing 0, 2.5, or 10 mM K+. Half of the plants at each K+ level were subjected to a 21-day slowly developing drought stress cycle (DS) followed by a recovery period (day 22), while the other half were non-drought stressed (NDS). Midday leaf water potential (Ψleaf) at day 21 were -1.5 to -1.6 MPa for DS and -0.5 MPa for NDS plants. Photosynthesis (A) was lowest during early stress and recovery of 0 mM K+ plants. Transpiration (E), stomatal conductance (g), and instantaneous water use efficiency (A/E), were generally lowest in 0 mM K+ plants. During peak stress, A was highest in the 2.5 mM K+ plants, whereas E was lowest and A/E highest in 10 mM K+ plants. Ψleaf did not differ among K+ treatments during peak stress and recovery, but osmotic potential was highest (least negative) and turgor potential lowest in 0 mM K+ plants. DS plants had lower carbon isotope discrimination (Δ) compared to NDS plants at all K+ levels, suggesting higher A/E for DS plants. Although there was no significant K+ effect, there was a trend at peak drought stress of Δ lower A and higher A at the 2.5 mM K+ level.
INFLUENCE OF POTASSIUM ON PLANT GROWTH AND 86Rb+-LABELED LIVE ROOTS OF DROUGHT-STRESSED HIBISCUS ROSA SINENSIS L. cv. LEPRECHAUN
Authors: Egilla Jonathan N. , Davies F. T. , Drew M. C.
Published: April 2024

Rooted cuttings of Hibiscus rosa sinensis L. cv. Leprechaun were grown in fine sand and irrigated with full strength Hoaglands solution containing 0, 2.5, or 10 mM K+. Half of the plants at each K+ level were subjected to a 21-day slowly developing drought stress cycle (DS) and the other half were non-drought stressed (NDS), which yielded a midday leaf water potential (Ψleaf) at day 21 of -1.5 to -1.6 MPa and -0.5 MPa, respectively. Drought stress reduced leaf area (LA), leaf area ratio (LAR), shoot, root, leaf and total dry weights of 2.5 and 10 mM plants and increased the root:shoot ratio of all K+ treatments. Increasing K+, increased all growth parameters measured in both DS and NDS plants, except for LAR, which was greatest at 0 mM K+. At 0 mM K+, drought stress did not affect LA, LAR, shoot, root and total dry weights. Neither drought nor K+ treatments affected specific leaf area (SLA). In NDS plants, K+ had no effect on percent live root ratio (PLR) as indicated by translocation of 86Rb+ from leaves into living roots, determined by autoradiography. Although drought stress reduced PLR at all K+ levels, PLR was greatest at the higher K+ levels.
EVALUATION OF WATER USE BY TWELVE SPECIES OF ORNAMENTAL GRASS IN A CONTROLLED ENVIRONMENT
Authors: Wolfe June , Zajicek Jayne M. , Hussey Mark A.
Published: April 2024

Twelve species of native and introduced ornamental grasses were subjected to a drought treatment in a greenhouse. The objective of this study was to determine which species had the lowest water use and which were most aesthetically pleasing under water stress. Visual observations of progressive water stress were compared to instrumental measurements of water consumption, leaf water potential, stomatal resistance, and transpiration. Differences in water use were found between species when compared on a leaf area basis. The relationship between visual observations and plant water status was not consistent across species.
CUTICULAR STRUCTURE IN MEXICAN REDBUD
Authors: Tipton Jimmy L.
Published: April 2024

Mexican redbud (Cercis canadensis var. mexicana) plants exhibit leaf phenotypes with either a thin, dull cuticle or a thick, glossy cuticle. We compared leaf and cuticular structure of greenhouse-grown Eastern redbud (Cercis canadensis) (ER), Dull Mexican redbud (DMR), and Glossy Mexican redbud (GMR) seedlings via scanning electron microscopy. Mexican redbud leaves were almost twice as thick as ER and had a multilayered palisade parenchyma common among arid land plants. Both the lower (adaxial) and upper (abaxial) cuticles of MR were significantly thicker than those of ER. The surface of the upper cuticle in ER and DMR was covered with blocky crystalline structures. The surface of the upper cuticle in GMR was smooth. There was no difference in lower cuticle thickness or leaf thickness between DMR and GMR. The upper cuticle of GMR was significantly thicker than that of DMR. Mature DMR and GMR growing in a landscape in El Paso, Texas, had similar characteristics. Detached leaves of ER lost water at a significantly greater rate than did either DMR or GMR. There was no significant difference in water loss rates by detached leaves of DMR and GMR.
EFFECT OF SALINITY ON THE GROWTH AND COMPOSITION OF CUCUMBER FRUIT
Authors: Tazuke Akio
Published: April 2024

Salinization of the nutrient solution with 60 mM NaCl in spring caused severe growth inhibition of cucumber cv. `Asomidori 5 Go' fruit which resulted in the formation of carrot-like shaped fruit. Growth activity of fruit was initially enhanced, then rapidly inhibited after 3 DAA. Growth inhibition of the fruit accompanied concomitant inhibition of the growth of ovules. In such fruits, marked changes in composition were observed including depletion of glucose and fructose, Na and Cl accumulation and Ca deficiency. Fruit firmness was markedly increased. Acid invertase activity of the fruit was enhanced by salinity. Sucrose synthase activity of the fruit was slightly reduced. These results seemed to suggest how translocation of assimilates, growth and sugar metabolism of fruit are altered by salinity.
SOYBEAN GROWTH UNDER MICROWAVE-POWERED LAMPS, HIGH IRRADIANCE DISCHARGE LAMPS, OR SOLAR RADIATION, AT AMBIENT OR ELEVATED CO2
Authors: Britz Steven J. , Krizek Donald T. , Lee David R. , Harris William G. , Hungerford Wayne E. , Bailey William A.
Published: April 2024

Soybeans (Glycine max [L.] Merr. cv. Williams) were grown to a standard developmental stage (6th trifoliate leaf c. 50% fully expanded) in a sunlit, temperature-controlled greenhouse (27±3°C) or in growth chambers (27±1°C) under microwave-powered (MP) E lamps (Fusion Systems, Rockville, MD) or a 50-50 mixture of high pressure sodium and metal halide (HID) lamps. Daily PAR in growth chambers was 44 mol m-2, provided either as a square-wave (HID; 875 μmol m-2s-1) or in steps (MP; peak irradiance c. 1650 μmol m-2s-1). Growth chamber experiments were conducted at 400 μl l-1 or 700 μl l-1 CO2“ambient” or “elevated”, respectively). Total dry matter was similar for all treatments at ambient CO2 but MP-grown plants were more like greenhouse plants with respect to Leaf Area Ratio, Specific Leaf Weight, and length of stem and petiole. Axillary growth, however, was much less under greenhouse conditions. Elevated CO2 resulted in a significant stimulation of plant growth under both HID and MP, but gains were greater under MP illumination. Enhanced growth of MP plants was marked by increased partitioning into roots. It is possible that morphological modifications in MP plants rendered them more efficient at conversion of PAR into dry matter.
618 (PS 3) FACTORS INFLUENCING AXILLARY BUD BREAK AND SHOOT PROLIFERATION OF ROSA HYBRIDA L.
Authors: Hsia Chi-ni , Korban Schuvler S.
Published: April 2024

The effect of node position of axillary buds of greenhouse-grown Hybrid tea rose cultivars `Carefree' and `Adelaide Hoodless' on shoot induction and proliferation was investigated. Explants were cultured on a Murashige and Skoog (MS) medium containing 2 mg/l 6-benzyladenine (BA) and 0.1 mg/l α-napthaleneacetic acid (NAA). Axillary buds collected closest to the shoot apex gave rise to the highest shoot proliferation; whereas, those collected from the second, third, and fourth nodes yielded longer shoots and higher leaf number/explant. The influence of varying levels of BA concentrations in the culture medium was also investigated. It was observed that high BA concentrations, 1-3 mg/l, stimulated shoot proliferation. The effect of carbohydrate source, fructose versus surcose, on shoot induction was also investigated. A high shoot number/explant was observed on media containing fructose; however, longer shoots (>1 cm) were observed on media containing surcose as a source of carbon.
624 (PS 3) SOIL AMENDMENT INCREASES GROWTH OF SALVIA SPLENDENS AND CATHARANTHUS ROSEUS
Authors: Smalley Timothy J. , Wade Gary L. , Corley Will L. , Thomas Paul A.
Published: April 2024

Commonly used soil amendments for ornamental annual plantings were compared to determine their effect on growth of Salvia splendens `Hotline Red' (Salvia) and Catharanthus roseus `Peppermint Cooler' (Vinca). Transplants of the annuals were planted in amended outdoor beds on June 12 1992. Treatments were 1) an unamended, rototilled control and 2) aged pine bark, 3) granite sand or 4) a regionally commercially available product Mr. Natural™. Mr. Natural™ consists of granite sand, expanded shale, and composted poultry litter. A 9-cm-deep surface layer of the amendments was rototilled into 20 cm of clay soil. One-half of the plants were fertilized with the recommended rate of 0.15 kg/m2 of 14-14-14 Osmocote, and one-half were not fertilized. On July 14 and August 10, shoot dry weight was determined, and a growth index was calculated from the width and height of growth. Fertilizing increased the growth index and dry weight in all treatments. Plants in the aged pine bark and no fertilizer treatment were consistently the smallest plants and exhibited nitrogen deficiency symptoms. For both dates, the Mr. Natural™ vinca plants had the greatest dry weight and growth index. On the first date, Mr. Natural™ salvia plants did not differ from the sand treatment but had 50% greater dry weight than the unamended control. Mr. Natural™ salvia plants were the largest plants on the second harvest date.
631 (PS 3) WOUND CLOSURE RESPONSE TO TRUNK INJECTION OF THE GROWTH RETARDANT FLURPRIMIDOL
Authors: McGillivary Larry D. , Wiest Steven C. , Hensley David L.
Published: April 2024

Over $1 billion per year is spent nationally for pruning trees to restrict growth. Plant growth regulators offer a means to extend pruning cycles, reducing future pruning costs. In this study, the influence of flurprimidol (flur) on wound closure rate was investigated. Acer saccharinum, Celtis occidentalis, Fraxinus pennsylvanica, Gleditsia triacanthos, and Populus deltoides were injected using an Arborchem pressure injection system, followed by trunk wounding. Injections of flurprimidol (at both 1X and 3X rates) and wounding were conducted in spring, early summer, and late summer. Without flur, wound closure rate was slowest in maple and most rapid in cottonwood. Flur suppressed wound closure rate most greatly in hackberry, and had the least influence on cottonwood. In addition, wound closure rates in the presence of flur were influenced by the timing of the treatments. These results will be of particular use to utility companies that prune trees under power lines.
IMPROVING SEED GERMINATION OF AQUILEGIA CHRYSANTHA BY TEMPERATURE MANIPULATION
Authors: Davis Tim D. , Sankhla D. , Sankhla N. , Upadhyaya A. , Parsons J.M. , George S.W.
Published: April 2024

Seeds of Aquilegia chrysantha Gray were germinated under a variety of temperature regimes. Germination was nearly 90% under a day/night temperature regime of 25/20C but was reduced to 40% or less under constant 25C or a 25/10C day/night temperature regime. At day temperatures between 25 and 29C (night temperature = 20C), germination percentage dropped gradually to about 60% with increasing temperature. Above a day temperature of 29C, germination declined dramatically such that no germination occurred at 31C. Neither kinetin (1-10 mg/liter) nor ethephon (1-30 mg/liter) were able to reverse the inhibitory effects of a 33C day temperature. Our results indicate that seed germination of A. chrysantha is quite sensitive to temperature and that germination percentages of 75% or greater can be obtained under a 25-27C day/20C night temperature regime.
645 (PS 4) VITRIFIED VS. GLAUCUS ONION (ALLIUM CEPA L.) LEAVES: A MICROSCOPIC COMPARISON
Authors: Schloupt Renee M. , Splittstoesser Walter E. , Skirvin Robert M.
Published: April 2024

The purpose of this study was to observe the difference in leaf surface characteristics between in vitro (vitrified and glaucus) and greenhouse grown onion leaves. Scanning electron microscopy (SEM) was used. Vitrified (hyperhydrated) leaves had little epicuticular wax and the leaf surface appeared twisted and wavy. Stomata were raised above the epidermis, appeared round instead of oblong and openings were malformed and clogged with waxy deposits. Both glaucus in vitro and greenhouse leaves had thick layers of epicuticular wax, the wax appearing to be heavier on greenhouse leaves. Stomata were oblong and sunken beneath layers of epicuticular wax. Vitrified plants died when transferred to the greenhouse under mist, while glaucus in vitro plants survived transplanting. Vitrified plantlets have a translucent, glass-like appearance and do not survive transfer to ex vitro conditions. Factors affecting vitrification will be addressed in later publications.
PARTICLE BOMBARDMENT OF APPLE LEAF EXPLANTS INFLUENCES REGENERETION OF APPLE INFLUNCES
Authors: Gercheva Petya , Zimmerman R.H. , Owens L.D. , Berry Christine , Hammerschlag F.A.
Published: April 2024

Particle bombardment has been shown to be useful for genetic manipulation of many plants; however, a critical component for successful transformation is the ability of transformed cells to regenerate plants. This study describes factors that affect the regeneration efficiency of apple leaf explants following particle bombardment. Basal leaf segments of micropropagated `Royal Gala' apple were treated with 1μm gold particles (0.5 μg/10μl), accelerated at either 4.5, 6.2, 7.6, 9.3 or 13.8 MPa, and cultured on N6 salts + l0μM TDZ regeneration medium for 5, 10 or 20 days in the dark. Both microprojectile-treated and control explants exhibited 85-100% regeneration. However, only 30-60% of the explants bombarded at 7.6, 9.3 and 13.8 MPa had more than 10 regenerants and 6-10% had more than 20 regenerants, whereas for control explants and those bombarded at 4.5 and 6.2 MPa, 70-90% had more than 10 regenerants and 30-50% had more than 20.
654 (PS 4) TISSUE AND PROTOPLAST CULTURE OF SOLANUM OCHRANTHUM
Authors: Kobayashi Ruth S. , Sinden Stephen L. , Stommel John R.
Published: April 2024

Solanum ochranthum, a woody non-tuber bearing species, may possess genes for insect and disease resistance which could be useful in solanaceous crop improvement. Methods for tissue and protoplast culture of S. ochranthum were developed as part of an ongoing project to improve tomato and potato using wild relatives and in vitro techniques such as somatic hybridization. For protoplast experiments, axenic shoot tip cuttings were propagated on medium containing MS salts, Staba vitamins, 100 mg·l-1 casein, 3% sucrose and 0.6% activated charcoal (OM) or medium containing MS salts and vitamins, 100 mg·l-1 casein and 2% sucrose (TPM). Plants grown on OM were significantly taller, had higher root dry weight and gave protoplasts with higher average plating efficiency than plants grown on TPM. Leaf protoplasts from 5 week old plants cultured in medium with high Ca2+ and myoinositol generally had higher percent viability and plating efficiency than protoplasts grown in a modified Kao and Michayluk 8p medium.
659 (PS 4) CYTOKININS AND DONOR PLANTS AFFECT REGENERATIVE CAPACITY OF AMERICAN ELM LEAVES
Authors: George Mary W. , Tripepi Robert R.
Published: April 2024

Adventitious shoots can be regenerated from leaf explants of American elm (Ulmus americana L.), but the effects of cytokinins and donor plants were unknown. The goal of this study was to examine factors that influence regenerative capacity of American elm leaves. Excised leaves from 2-year-old seedlings were surface sterilized, and 1 cm2 sections were taken from the midrib portion of the leaves. Three to six seedlings were used as donor plants in various experiments. Zero, 7.5, 15, or 22.5 μM of benzyladenine (BA), thidiazuron (TDZ), kinetin, zeatin, or 2iP were added to Driver Kuniyuki Walnut (DKW) medium. Basal medium (DKW and Murashige and Skoog [MS]) effects on shoot regeneration were also examined. Leaves placed on media with BA or TDZ formed adventitious shoots, with TDZ inducing the highest percentage of regeneration. The donor plant also affected the efficiency of shoot regeneration, with certain seedlings having 1.5 to 7 times more explants forming shoots compared to others. Leaf explants from donor plants with the highest regenerative capacity had a higher percentage of regeneration on DKW than MS medium. Explants from productive donor plants should be placed on DKW medium supplemented with TDZ to improve shoot regeneration efficiency from American elm leaves.
THE PRODUCTION OF HAPLOID CALLUS FROM ANTHER CULTURE IN SWEET CHERRY (PRUNUS AVIUM L.)
Authors: Long Christopher M. , Iezzoni Amy F. , Mulinix Colleen A.
Published: April 2024

Map development in Angiosperm tree crops is hampered by the lack of suitable mapping populations and the time and space required to grow large progeny populations. An alternate strategy for developing a linkage map for sweet cherry using haploids derived from anther culture as the progeny populations is being developed. The genetic markers will be RAPDs which segregate 1:1 among the progeny. Our initial objective is to obtain haploid microspore-derived callus cultures from sweet cherry. Two sweet cherry cultivars, Bing and Emperor Francis, were chosen which are heterozygous for Pgi, and Pgi and 6Pgd-1, respectively. Branches were forced in the laboratory. When the microspores reached the uninucleate stage the anthers were plated on medium containing 4.4 μM BA and 4.5 μM 2,4-D. After 50 days, callus which burst from the anther was placed on Woody Plant Medium supplemented with 1 μM 2,4-D and 3 μM 2iP and routinely transferred. To date, 64 callus cultures from Emperor Francis exhibited only one allele each from Pgi and 6–Pgd–1 and are therefore putative haploids. Four callus cultures of Bing exhibited only one allele for Pgi.
EFFECT OF UNICONAZOLE RATE AND TIME OF APPLICATION ON MORPHOLOGICAL QUALITY CHARACTERISTICS OF MINIATURE POT ROSES
Authors: Kyalo T. M. , Pemberton H. B. , Zajicek J. M. , McDonald G. V.
Published: April 2024

Uniconazole was sprayed at 25, 50, 75 or 100 mg·liter-1 on plants of Rosa L. `Meirutral', `Meijikatar' and `Meilarco' in experiments at Overton and College Station. A short cycle production schedule was used consisting of liner establishment in 11.4 cm pots, severe cut back and a final forcing period. In late summer experiments, the 25 mg·liter-1 treatment reduced plant height, peduncle length and increased days to harvest by 3 days, but either increased or had little effect on the number of flowers. All cultivars were affected similarly. Higher concentrations severely reduced plant height, number of flowers, peduncle length and caused a slightly longer delay in days to harvest. Application of uniconazole to new shoots that had grown 5-7 cm long after the cut back was as effective in reducing plant height as a split application (half the full rate at each time) made when new shoots were 5-7 cm and when new shoots exhibited pea size buds. A single application at pea-bud stage was not effective in controlling height. When experiments were repeated in early spring, uniconazole had a stronger effect on plants than in the summer. Further research is needed concerning the interaction of environmental variables and uniconazole rate for optimum control of pot rose growth.
680 (PS 5) SORPTION ISOTHERMS INDICATE THAT CALCINED CLAY AND ALUMINUM AMENDMENTS INCREASE PHOSPHATE RETENTION OF SOILLESS SUBSTRATES
Authors: Williams Kimberly A. , Nelson Paul V.
Published: April 2024

Soilless container substrate components such as sphagnum peat moss and pine bark have very little PO4 adsorption capacity; thus, one way to reduce PO4 leaching during container production is to increase the PO4 retention of container substrates. Laboratory experiments have been conducted to create sorption isotherms at 26 C for arcillite, a calcined product of the 2:1 clays montmorillonite and illite, and a medium of 70 peat moss: 30 perlite. Thirty ml of Ca(H2PO4)2 solutions at rates of 0, 100, 300, and 500 μg P/ml were added to 5 cm3 samples of the test materials. Both materials were amended with aluminum at rates of 6.4 and 19.2 mg Al/cm3 test material from Al2(SO4)3 solutions. Adsorption isotherms confirmed that unamended medium does not retain PO4 and indicated that arcillite is effective at adsorbing PO4 as it retained 1900 μg P/cm3 test material at the 500 μg P/ml rate. The isotherms also showed that Al amendments increase PO4 retention in both arcillite and the medium. Desorption isotherms suggested that the unamended arcillite and Al-amended medium and arcillite will continue to release low levels of PO4 for an extended period of time.
693 (PS 5) KARYOTYPIC ANALYSES IN ALSTROEMERIA PELEGRINA L.
Authors: Lu Chunsheng , Bridgen Mark
Published: April 2024

Karyotypic analyses on two color forms of Alstroemeria pelegrina (white and pink) and their intraspecific hybrid A. pelegrina (white) × A.pelegrina (pink) showed that all genotypes have 2n-16 chromosomes. They also have the same basic karyotypic formula of three metacentric (r-1.0-1.7), one subcentric (r-1.7-3.0), and four telocentric (r»7.0) chromosomes. All of the three karyotypes are highly asymmetric, with a chromosome ratio of the largest:smallest being greater than 3. Satellites were observed on four pairs of chromosomes in A.pelegrina (white), but were not clearly identified in the studied plants of A.pelegrina (pink) and the hybrid. Meiotic studies of the hybrid indicated that the chromosome pairing was normal. Pollen viability of the hybrid was 97%; this is higher than both parents, A.pelegrina (white) and A.pelegrina (pink), which had a viability of 58% and 95%, respectively. The role and function of the satellites need further investigation.
694 (PS 5) IRON AVAILABILITY IN LEAFY GREENS
Authors: Wauters Michael A. , Rangarajan Anusuya
Published: April 2024

An experiment to determine iron availability in six different leafy greens was conducted. The experiment determined both total iron within the specific greens as well as the digestible iron available from the total iron. Data were compared, and percent iron available was determined.
EFFECT OF PLANTING DATE AND CULTIVAR ON PROCESSING SWEET CORN PRODUCTION IN TENNESSEE
Authors: Mullins Charles A. , Straw R. Allen , Shamiyeh N. Bill
Published: April 2024

Six processing type sweet corn cultivars were evaluated for productivity and production problems at eight planting dates at the Plateau Experiment Station at Crossville, TN. Plant size and yields declined rapidly after the fourth planting date. During this period soil moisture was adequate and temperatures were relatively cool, therefore, plant growth responses may have been attributed to day length or light interception. Insect populations and insect damage increased as the harvest season progressed. `Reveille' had poor ear fill throughout the season, while percentage ear fill of all of the other cultivars, with the exception of `More', decreased rapidly after the fourth planting date. `More' plants were the most vigorous throughout the trial. `More' was one of the most productive cultivars throughout the season and especially at the later planting dates.
EFFECTS OF PHOTOPERIODS ON GREENHOUSE TOMATO AND PEPPER PRODUCTION
Authors: Demers Dominique-André , Dorais Martine , Yelle Serge , Gosselin André
Published: April 2024

Most works on artificial lighting of winter greenhouse vegetable crops studied the effects of photosynthetic photon flux but rarely photoperiod. Over the last three years, we conducted experiments to find out the best photoperiods for production of greenhouse tomato and pepper. We found that extending photoperiod up to 20 hrs increased productivity of pepper plants while continuous light (24 hrs) decreased yields. For tomato plants, productivity reached a maximum under a 14-hr photoperiod while longer photoperiods (16 to 24 hrs) did not increase yields. For both pepper and tomato plants, optimal growth (shoot fresh and dry weights) was obtained under the same photoperiods that gave the best productivities. We also observed leaf chloroses on tomato plants after 6 weeks under photoperiods of 20 and 24 hrs and leaf deformations (wrinkles) on pepper plants exposed to continuous lighting. We also observed that plants under continuous light grew better and flowered earlier during the first 5 to 7 weeks of treatments. So, tomato and pepper plants can use advantageously continuous supplemental lighting for a short period of time but are negatively affected on a long term basis. Future works should look at varying photoperiods to optimize yields.
705 (PS 6) EFFECTS OF ORGANIC AND CONVENTIONAL PRODUCTION SYSTEMS ON YIELD AND ACTIVE INGREDIENT CONCENTRATION OF MEDICINAL PLANTS
Authors: LaFlamme Lucette , Charbonneau Josée , Gosselin André , Rochat Etienne , Martel Claudine
Published: April 2024

The major objective of medicinal plant production is to optimize dry matter yield as well as active ingredient concentration. This research examined the influence of three organic production systems and one conventional production system on dry matter yield and active ingredient concentration. Plants of thyme, horehound and camomile (Thymus vulgaris L., Marrubium vulgare L., Matricaria recutita [L.] Rauschter, respectivly) were sown in greenhouse and then transplanted to the field. Preliminary results showed that dry matter yield was higher with the conventional production system for all species and active ingredient concentration was higher in the organic systems for thyme and horehound. Higher active ingredient concentration in these two species was obtained in the organic-biodynamic system. For camomile, highest active ingredient concentration was found with the conventional production system. These results indicate that both dry matter yield and active ingredient concentration are affected differently by organic and conventional production systems.
709 (PS 6) THREE-YEAR EFFECT OF INITIAL SOIL ORGANIC MATTER AMENDMENT ON VEGETABLE CROP PRODUCTIVITY
Authors: Dann Michael S. , Steffen Kenneth L. , Fager Ken
Published: April 2024

We evaluated the effects of soil organic matter amendments on crop growth and yield over a three-year period. In Spring, 1990, we added 3.8 cm of spent mushroom compost and 1.3 cm of well-rotted horse manure to the top 0.2 m of selected plots in a 0.4 ha field. Other plots received recommended amounts of synthetic NPK. Total yield and yield of No. 1 grade tomatoes were 25% and 67% greater, respectively, in the amended plots than in the conventional plots the first year. In 1991, we no-till planted three varieties of sweet corn into this field. The conventional plots received either 75% or 100% of recommended N. Previously amended plots received no further N. Sweet corn production was 46-200% greater in amended plots, depending on variety. In 1992 following moldboard plowing, we planted snap beans followed by broccoli or cabbage. Conventional plots received the recommended amount of N (in 100% N plots from 1991) or no N (in 75% N plots from 1991) while plots amended in 1990 received no further N. Yields of snap beans were comparable in all three treatments. Broccoli heads had greater diameters in plots that had been amended. Cabbage from the amended plots were more mature based on growth stage. The beneficial effect of this initial amendment has continued for three growing seasons. This observation suggests that while the initial cost of organic soil amendments may be higher than synthetic fertilizer for the first year, comparable or greater yields may be expected allowing this approach to be cost-effective over a three-year period.
MATHEMATICAL MODELLING OF TREE CROP ORCHARD DESIGN: INTERTREE SHADING DURING CRITICAL SEASONAL GROWTH AND DEVELOPMENTAL WINDOWS AND ITS IMPLICATIONS ON OPTIMAL SPACING
Authors: Burcaw Jeffrey W. , Wood Bruce W. , Poole Michael W. , Burnette Mark T.
Published: April 2024

The authors have developed a computer model designed for shade-intolerant tree crops which describes the amount of intertree shading in an orchard. These data are used to formulate an optimal orchard design based on shading reduction in orchards for any tree crop during any developmental window at any global location.

Tree shape is modelled as an ellipsoid bisected about the semi-minor axis, with ellipsoid dimensions and eccentricity altered to reflect growth stages of the trees. Intertree shading is measured as the surface area of the projected shadow on the ellipsoid. Variables include crop, light extinction, ellipsoid dimensions, intertree spacing, orchard geometry, time and day of the year, and geographical coordinates. Simulations compared the sunlight-related attributes of a variety of orchard geometries for different growth phases of the trees during different parts of the year for several global locations. Results indicate extensive variability of intertree shading to be a function of latitude, regardless of other variables.
734 (PS 7) FRUIT GROWTH RESPONSES IN `HEDELFINGEN' SWEET CHERRY WITH FIVE ROOTSTOCK CULTIVARS, BLOSSOM THINNING, AND IRRIGATION
Authors: Choi Cheol , Andersen R. L. , Robinson T. L.
Published: April 2024

Small fruit size reduces fresh-market value and potential net income in sweet cherry. Several new rootstock cultivars for sweet cherry induce greater precocity, heavier blossom density, and a range of dwarfing but also may reduce fruit size. A field study was undertaken with sixth leaf `Hedelfingen' scions grown on Prunus avium L. `Mazzard' seedling rootstock or on one of 4 new rootstock cultivars: `Damil,' `Gi 148/1,' `Gi 172/9,' and `Gi 196/4.' Factorial treatments included (+/-) trickle irrigation when soil tensiometer readings reached 20 k Pa and (+/-) hand thinning to single fruits/cluster aat 7 days after full bloom. High natural precipitation reduced irrigation effect but fruit size was increased significantly by thinning. Yield differences were also seen between rootstock cultivars.
736 (PS 7) CHANGES IN OIL CONTENT, FATTY ACID, AND VITAMIN E COMPOSITION IN DEVELOPING HAZELNUT KERNELS
Authors: Ebrahem Kais S. , Richardson D. G. , Tetley R. M.
Published: April 2024

Kernel oil content increased while moisture content decreased during development. Oil concentration of varieties was between 59.6% and 67%, at harvest and the major lipid class was triglycerides. Oleic acid increased from 10% to become the most abundant fatty acid at harvest (74%). Linoleic increased from about 4% to around 30% early in the season but then decreased although it finally represented a high proportion of total fatty acids (19-22%). Total vitamin E increased as oil content increased. α-tocopherol was the major form of vitamin E and its concentration increased to around 400μg/g oil throughout the season and was almost 90% of total vitamin E. β-tocopherol was only a minor constituent and decreased from the beginning to around 10-20 μg/gm of oil at the end. Γ-tocopherol increased during the first stage of growth and then decreased during the second and third stages.
SCION/ROOTSTOCK EFFECTS ON TREE SIZE, CUMULATIVE YIELD AND YIELD EFFICIENCY OF 'GRANNY SMITH' APPLE AND ITS SPORTS, `GRANSPUR' AND `GREENSPUR'
Authors: Larsen Fenton E , Higgins Stewart S.
Published: April 2024

Cumulative yield, tree size (trunk cross-sectional area) and cumulative yield efficiency were evaluated after 6 years of production on trees of `Granny Smith', `Granspur', or `Greenspur' on seedling (sdlg), MM 111, MM 106, M 26 or M 7a rootstocks. There were no interactions between scion and rootstock for any of the measured response variables. After 6 years, `Granny Smith' produced more fruit than either `Granspur' or `Greenspur'. Trees on MM 106 produced the highest cumulative yield per tree while trees on M 26 produced the least. Trees on M 7a, MM 111 and sdlg roots were intermediate in production. Trunk cross-sectional area of `Granny Smith' was larger than either `Granspur' or `Greenspur'. Trees on sdlg roots were larger than all others, and trees on M 26 were smaller. `Granny Smith' and `Greenspur' had higher yield efficiencies than `Granspur'. Trees on MM 106 and M 26 had higher yield efficiencies than on other roots, and trees on sdlg had lower yield efficiencies.
SCION AFFECTS INCIDENCE OF PEACH TREE SHORT LIFE
Authors: Beckman Thomas G. , Okie William R. , Nyczepir Andrew P.
Published: April 2024

Preliminary results of a field trial of 49 different scion varieties grafted onto Nemaguard plus `Redhaven'/Lovell suggest that scion influence on incidence of peach tree short life (PTSL) may be comparable to that of rootstock. After 6 growing seasons survival of the various scion treatments ranged from 5 to 85%. Correlation analyses indicated that those scion varieties exhibiting either early bloom or late defoliation survived better and that those varieties exhibiting both characteristics survived the best. Results indicate that final testing of rootstock candidates for PTSL tolerance must be done with grafted materials and that it may be possible to recommend the planting of certain scion varieties on PTSL sites as well as particular rootstocks for maximum longevity.
CHANGES IN MONO-, DI-,AND POLYAMINE LEVELS IN CITRUS FRUIT TISSUES DURING FRUIT ENLARGEMENT
Authors: El-Otmani Mohamed , Coggins Charles W. , Lovatt Carol J.
Published: April 2024

Mono-, di- and polyamines are known to influence growth and development processes in plant organs. Because of the complexity of citrus fruit, we investigated the relative distribution and changes occurring in endogenous levels of the free form of these compounds in the three major fruit tissues (i.e., flavedo, albedo, and juice vesicles) of the `Washington' navel orange (Citrus sinensis L. Osbeck) during the period of exponential growth (i.e., from 2 to 8 cm in diameter). In young fruit (2 to 4 cm), putrescine levels were highest in juice vesicles > flavedo > albedo, decreasing during growth to a minimum when fruit were 4 to 5 cm in diameter. Fully grown fruit undergoing maturation exhibited a significant increase in putrescine with albedo > flavedo > juice vesicles. Spermidine followed similar trends in albedo and flavedo, but decreased in the endocarp. Spermine levels steadily declined in all tissues with fruit growth to barely detectable amounts when fruit reached full size. Phenylethylamine was absent in the flavedo, whereas tyramine and dopamine were present in significant amounts, especially during early fruit growth. The significance of these changes to fruit growth and development will be discussed.
WATER CONSERVATION PROGRAM
Authors: Horst Garald L. , Steinegger Donald H.
Published: April 2024

Lincoln, Nebraska is probably ahead of other major municipalities in the Mid-west to initiate water awareness and conservation programs. The average commercial, industrial, or residential water user has a poor concept as to the amount of water their irrigation system applies or water application uniformity. The average Christiansen Uniformity Coefficients (UCC) was 67, with 83% of the UCC values below 80. Almost 80% of the scheduling coefficients were two or greater, meaning that a large portion of landscape water waste from irrigation is hidden from the consumer. An estimate of the potential reduction in water use if the prescribed water conservation program was followed indicated a reduction in water use of 50%. This estimate is drawn from weather station ETp estimates, lysimeter, and soil water estimates. Crop coefficient (Kc) values which take into consideration the plant type were initially at 0.9. Accuracy of this estimate will be noted. Data from the above sources will be presented as well as irrigation uniformity. The impact of “Horace's Water O' Meter” an outgrowth of these findings on landscape water use in Lincoln is discussed.
ANALYZING PERCENTAGE DATA
Authors: Marini Richard P. , Marini Michele Choma
Published: April 2024

Data generated from horticulture experiments often are expressed as percentages. Since these data may not approximate normality, we often automatically transform the data before analysis. Is this automatic transformation always correct? Non-transformed data may already approximate a normal distribution. Should these data be transformed? What does transforming a normal data set do to it? To address these questions, a real data set was used to check the assumption of normality and examine regression models before and after transformation of normal and non-normal percentage data. Transformations include both standard arcsin of the square root of the proportion and a log (log) transformation. We will show that transforming normal data can make it non-normal and alter conclusions. Testing assumptions before and after transformation will be emphasized. The SAS procedures GLM and UNIVARIATE will be used to generate output and demonstrate results of normality tests and different conclusions resulting from unnecessary transformations.
BRINGING EXPERIENTIAL LEARNING TO THE CLASSROOM
Authors: Steams Dan T. , Morgan Perry M. , Lehman Julie R.
Published: April 2024

Experiential learning has proven to be a valuable component of the Landscape Contracting curriculum in Penn State's Department of Horticulture. Implemented in four classes, two with design orientation and two with construction orientation, experiential learning has been utilized to stimulate and encourage critical thinking among students, both individually and in group situations. This teaching method serves to ignite student interest in further exploration of both concepts and process. Students involved in experiential projects have taken initiative to go beyond problem statement requirements to expand project scopes and elevate the quality of finished products. Indications of exceptional student motivation include requests by course enrollees for additional work to further develop design concepts, and organization of work sessions outside of class time to accommodate expanded work objectives. Successful integration of experiential learning into course outlines requires instructor skills that differ substantially from those employed in traditional lecture or studio formats.
“LIVING DISPLAY”: A NEW APPROACH TO DISSEMINATING CONSUMER-HORTICULTURE INFORMATION
Authors: Morrone Vicki L. , Nuss J. Robert
Published: April 2024

The Agriculture Cooperative Extension is increasingly involved in programs that reach out to new audiences to provide information on horticulture and environmentally aware practices. Numerous types of educational displays and demonstrations are used to provide information and create enthusiasm for the topic. Most approaches use static, visual displays. A key factor toward creating a successful display for a lay audience is its entertainment value. A “living display” is a new approach, which entertains and catches the eye of the passing observer and provides information on the featured topic. The “living display” features three-dimensional information and actors that mime the “how-to's” and the benefits of the educational material. We will demonstrate the use of a living display by The Master Gardeners of Pennsylvania entitled “The Splendors of Composting”- a display oriented toward persons of all ages. It introduces how to create a backyard compost and presents the benefits derived from composting. Data on audience response to this display will be presented.
ADAPTATION OF FAST PLANTS® AS MODEL ORGANISMS FOR HANDS-ON INSTRUCTION OF FUNDAMENTAL CONCEPTS IN HORTICULTURE
Authors: Treaster Sharon , Knee Michael , Jourdan Pablo
Published: April 2024

The Wisconsin Fast Plants® (rapid cycling forms of Brassica rapa) have become a major educational tool in basic botany, plant physiology and plant genetics courses because of their versatility, ease of manipulation, and short life cycle (40-day generation). Various educational activities already developed by the Fast Plants Network can be incorporated effectively into established horticulture courses. We have been utilizing these plants in some of our introductory courses and have developed additional protocols and materials. Some of the new educational activities utilize the rapid cycling form of B. oleracea, Examples of these materials will be presented, including: new genetic stocks and use of isoenzyme markers; use of growth regulators (e.g., uniconazole) to modify plant growth and development; post-harvest physiology (e.g., growth, chlorophyll and starch content); hydroponics and plant nutrition; cell and tissue culture (micropropagation, anther culture, protoplast culture, transformation); and biochemical studies (e.g., enzyme isolation and characterization, extraction and characterization of DNA, etc).
A LABORATORY EXERCISE TO ILLUSTRATE ASPECTS OF BIOLOGICAL N2 FIXATION TO PLANT SCIENCE STUDENTS
Authors: Graves William R. , Wilkins Lorna C.
Published: April 2024

A laboratory exercise on biological N2 fixation (BNF) using two diverse legume species was developed. Students plant surface-sterilized seeds of Robinia pseudoacacia L. and Glycine max (L.) Merill together in plastic pots with a sterile medium. Pots are assigned to one of six treatments. Pots in treatments A, B, and C are irrigated with a solution lacking nitrogen, whereas those in D, E, and F receive a compete solution. Seedlings in treatments A and D are inoculated with a strain of Bradyrhizobium, and seedlings in B and E are inoculated with a strain of Rhizobium. Development of plants is monitored before a destructive harvest 7 weeks after inoculation. Results illustrate host plant-rhizobial specificity, the inhibition of nodulation by nitrate, and that dependency on BNF reduces growth compared with plants receiving nitrate.
FRUIT AGE, PERIOD OF FRUIT AND SEED STORAGE, AND FERMINATION AFFECT EMERGENCE OF PUMPKIN
Authors: Lepe Leonel , Wessel-Beaver Linda
Published: April 2024

The effect of fruit age (30 to 50 days after anthesis), fruit storage (seed extracted 0 to 20 days after harvest), and seed storage (0 to 12 months) on seed weight, emergence and vigor were studied in two tropical populations of pumpkin (Cucurbita moschata). In separate experiments fermentation of extracted seed was studied using several tropical and temperate genotypes. Emergence reached nearly 100% in seeds from fruit harvested 45 days after flowering, no matter how many days these fruits were stored. Seed weight and emergence markedly increased for seed extracted from less mature fruit (harvested 30 to 45 days after anthesis) when those fruits were stored for 15 to 20 days after harvest. Emergence improved during the first 3 months of seed storage, then leveled off during the remainder of the study. Fermentation of the seed and placental material for 48 hrs followering extraction does not damage seed. The seed extraction process is simplified and the emergence rate appears to increase possibly due to faster imbibition in fermented seed.
GENOTYPIC VARIATION IN BROCCOLI FOR TOLERANCE TO THE HERBICIDE OXYFLUORFEN APPLIED AT POST-TRANSPLANT AND PREEMERGENCE STAGES
Authors: Farnham Mark W. , Harrison Howard F.
Published: April 2024

Oxyfluorfen has been recently labeled for use as a pre-transplant herbicide for use in cole crops. Potential susceptibility to oxyfluorfen injury limits the situations in which this herbicide can be utilized. In a preliminary screen of broccoli cultivars, we observed variable responses to oxyfluorfen applied post-transplant. Two susceptible cultivars, Early Dawn and Green Goliath, were further tested with two tolerant cultivars, Emerald City and Pinnacle, to characterize differences in tolerance. Oxyfluorfen was applied to 3-leaf stage transplants at rates of 100, 200, 400, 800, and 1600 kg/ha in greenhouse and field trials. In addition, preemergent treatment with oxyfluorfen was tested by applying the herbicide immediately following the seeding of pots. The effect of the herbicide was assessed by rating foliar damage (0-9) and by fresh weight measurement taken 2-3 weeks after treatment. At all rates of application with both transplant and preemergent treatments Pinnacle exhibited the greatest level of tolerance exhibiting the least foliar damage and reduction in fresh weight. Green Goliath was very susceptible to oxyfluorfen injury while Early Dawn and Emerald City had intermediate responses.