bluuebunny/crossref_metadata_2025 huggingface dataset:
Particle Bombardment of Apple Leaf Explants Influences Adventitious Shoot Formation
Authors: Gercheva P. , Zimmerman R.H. , Owens L.D. , Berry C. , Hammerschlag F.A.
Published: February 2019

Shoot regeneration from apple (Malus domestica Borkh.) leaf explants following particle bombardment at various acceleration pressures was studied. Basal leaf segments of micropropagated `Royal Gala' apple were bombarded with 1 μm gold particles, accelerated using helium pressures of 4.5, 6.2, 7.6, 9.3, or 13.8 MPa (650–2000 psi), and cultured on shoot regeneration medium consisting of N6 salts supplemented with 10 μM TDZ for 5, 10, or 20 days in darkness. Bombarded and control explants exhibited 63% to 100% shoot regeneration. With a 5-day dark period, average shoot production per explant ranged from 6.1 to 14; bombardments of 4.5 and 6.2 MPa significantly increased shoot production over the controls. With a 10-day dark period, average shoot production per explant ranged from 9.1 to 22 following bombardment at 9.3 and 6.2 MPa, respectively. Following bombardment at 6.2 MPa, 75% of the explants produced more than 20 regenerants per explant. With a 20-day dark period, average shoot production per explant ranged from 8.9 to 19 following bombardment at 13.8 MPa and following no bombardment, respectively. Shoot production per explant was significantly less than the controls following bombardments ranging from 6.2 to 13.8 MPa. Shoot production was highest per explant with particle bombardment at 6.2 MPa followed by incubation in darkness for 10 days. Chemical name used: thidiazuron (TDZ).
Inheritance of Resistance to Watermelon Mosaic Virus in Cucumis melo L.
Authors: Gilbert Raphael Z. , Kyle Molly M. , Munger Henry M. , Gray Stewart M.
Published: February 2019

Resistance to watermelon mosaic virus (WMV) was transferred by successive backcrossing with selection from Cucumis melo PI 414723 to three melon varieties. Levels of resistance to virus accumulation in leaf tissue were evaluated using enzyme-linked immunosorbent assay, and procedures are described to select resistant individuals efficiently and accurately in segregating populations. Resistance is controlled by a single dominant. gene designated Wmr. Plants that carry this gene initially develop mosaic symptoms on inoculated leaves, but eventually recover from symptoms, and low or no virus can be detected in the youngest leaves. In contrast, susceptible plants show similar symptoms initially, but remain stunted and symptomatic with reduced fruit yield and fruit quality. Co-infection with other cucurbit viruses, specifically cucumber mosaic virus, papaya ringspot virus, and zucchini yellow mosaic virus, did not overcome resistance to WMV conferred by Wmr.
Greenhouse Screening of Citrus Rootstock for Tolerance to Bicarbonate-induced Iron Chlorosis
Authors: Sudahono  , Byrne D.H. , Rouse R.E.
Published: February 2019

Eighteen citrus rootstock seedling lines were tested for their tolerance to Fe chlorosis using sand culture. Potassium carbonate was used to induce Fe-deficiency chlorosis. Chlorosis was quantified by 1) visual ratings, 2) SPAD-502 chlorophyll meter readings, 3) leaf chlorophyll concentration, 4) leaf active Fe, and 5) leaf total Fe. The first four criteria were well correlated among each other but not with leaf total Fe. Although any of the first four measurements could be used to quantify chlorosis, visual ratings and SPAD-502 readings were more convenient. The rootstock that have been reported to be tolerant or very susceptible to Fe chlorosis in calcareous soils were rated similarly for tolerance to bicarbonate-induced Fe chlorosis. Nontrifoliate types such as Texas sour orange (C. aurantium L.), Cleopatra mandarin (C. reticulata Blanco), Vangasay lemon (C. limon Burro.), and Ridge pineapple x Milam 1578-201 (C. sinensis L. Osbeck x C. jambhiri) were tolerant to moderately tolerant. Although most of the trifoliate hybrids tested were moderately susceptible to very susceptible, Smooth Seville x Argentine trifoliate {[C. grands (L.) Osbeck x C. aurantium] x Poncirus trifoliata (L.) Raf.} and F-81-12 citrange (C. sinensis x P. trifoliata) exhibited relatively high tolerance to lime-induced Fe chlorosis.
Effect of Colonization of Pear Stigmas by Pseudomonas syringae pv. syringae on Fruit Set
Authors: Mansvelt E. Lucienne , Calitz F.J.
Published: February 2019

`Packham's Triumph' (Pyrus communis L.) pear blossoms were inoculated with Pseudomonas syringae pv. syringae van Hall upon emasculation and then hand-pollinated at different times to assess the effects of bacterial colonization on fruit set. The pathogen significantly reduced fruit set by 24%. No lesions developed on pear flowers at any stage of the trials.
Ozone Air Pollution Increases Petroleum Spray Oil Phytotoxicity
Authors: Retzlaff W.A. , Barnett W.W. , Williams L.E. , DeJong T.M.
Published: February 2019

Japanese plum (Prunus salicina Lindel. `Casselman') trees exposed to three atmospheric ozone partial pressure treatments were sprayed with a summer application of Volck Supreme oil (1% aqueous solution) to control an outbreak of spider mites (Tetranychus spp.). Phytotoxic effects were observed on the foliage of trees in the plots exposed to ambient or higher atmospheric ozone partial pressures 5 days following spray application. Foliage on trees exposed to 0.044 and 0.081 μPa·Pa-1 ozone [12-h mean (8 Apr. to 12 June 1992)] partial pressures developed water spotting and more foliage abscission than trees exposed to charcoal-filtered air (0.024 μPa·Pa-1 ozone). Thus, ozone air-pollution stress may predispose plants to increased phytotoxicity from summer oils.
Gibberellin- and Cytokinin-induced Growth and Flowering Responses in Rudbeckia hirta L.
Authors: Harkess Richard L. , Lyons Robert E.
Published: February 2019

BA and GA4+7, were applied to vegetative, mature Rudbeckia hirta plants at the beginning of long days (LD). There were no synergistic effects, but BA inconsistently affected branching and had no effect on flowering. Floral initiation of the terminal inflorescence was promoted by GA4+7, although axillary inflorescences were not. Increasing GA4+7 levels decreased the time to terminal inflorescence anthesis. However, the interval between the terminal and second axillary inflorescence anthesis was increased. The net result was no significant effect on the time to second axillary inflorescence anthesis. Gibberellins may enhance the LD effect on the apical meristem of Rudbeckia, but axillary meristems, which initiate later, remained unaffected. Chemical names used: benzyladenine (BA), gibberellin4+7, (GA4+7).
Interaction of Bulb Vernalization and Shoot Photoperiod on `Nellie White' Easter Lily
Authors: Dole John M. , Wilkins Harold F.
Published: February 2019

Easter lily (Lilium longiflorum Thunb. `Nellie White') bulbs were exposed to 1, 2, 3, 4, 5, or 6 weeks of cold before shoot emergence; 0, 1, 2, 3, 4, 5, or 6 weeks of long days (LD) upon shoot emergence; or a combination of cold followed by LD: 1/5 (weeks cold/weeks LD), 2/4,3/3,4/2, or 5/1. Experiments were repeated for three consecutive years. LD did not substitute equally for cold; at least 3 weeks of cold were required before LD treatments resulted in anthesis. Depending on the year, 100% of the plants flowered when treated with 3 to 6 weeks of cold alone or in combination with LD. Days to first flower anthesis from planting increased with decreasing weeks of cold in years 1 and 3, but was similar for all treatments in year 2. Decreasing weeks of cold in combination with LD, however, decreased days to anthesis in years 1 and 2, but had no effect in year 3. Regardless of LD, days from emergence to visible bud increased with decreasing weeks of cold in all years, and days to emergence from placement in the greenhouse increased with decreasing cold in years 1 and 3, but not in year 2. Increasing weeks of cold, regardless of LD, decreased leaf count, but had no effect on plant height. Flower count was unaffected by cold when combined with LD, but was significantly reduced by increasing weeks of cold.
Influence of Blossom and Fruit Thinning on Peach Flower Bud Tolerance to an Early Spring Freeze
Authors: Byers Ross E. , Marini R.P.
Published: February 2019

Peach trees [Prunus persica (L.) BatSch.] blossom-thinned by hand were overthinned due to poor fruit set of the remaining flowers; however, their yield was equivalent to trees hand-thinned 38 or 68 days after full bloom (AFB). Blossom-thinned trees had three times the number of flower buds per unit length of shoot and had more than two times the percentage of live buds after a March freeze that had occurred at early bud swell the following spring. Blossom-thinned trees were more vigorous; their pruning weight increased 45%. For blossom-thinned trees, the number of flowers per square centimeter limb cross-sectional area (CSA) was two times that of hand-thinned trees and four times that of the control trees for the next season. Fruit set of blossom-thinned trees was increased four times. Flower buds on the bottom half of shoots on blossom-thinned trees were more cold tolerant than when hand-thinned 68 days AFB. Fruit set per square centimeter limb CSA was 400% greater the following year on blossom-thinned trees compared to controls. Removing strong upright shoots on scaffold limbs and at renewal points early in their development decreased dormant pruning time and weight and increased red pigmentation of fruit at the second picking. The number of flower buds per unit shoot length and percent live buds after the spring freeze were negatively related to crop density the previous season for trees that had been hand-thinned to varying crop densities at 48 days AFB. According to these results, blossom thinning and fruit thinning to moderate crop densities can influence the cold tolerance of peach flower buds in late winter.
Nondestructive Dry-matter Estimation of Rose Shoot Leaves, Stems, and Flower Buds Using Regression Models
Authors: Pasian Claudio C. , Lieth J. Heinrich
Published: February 2019

Nondestructive dry-weight (DW) estimates of plant parts are important for analyzing production and partitioning patterns of horticultural crops, particularly when repeated measurements of the same plant must be made without affecting growth. Equations were developed for estimating leaf, stem, and flower bud DW (LDW, SDW, and FDW, respectively) from linear measurements of the flowering shoot parts of Rosa hybrida L. `Cara Mia'. We used a stepwise forward polynomial regression to develop a set of equations that represented the data well; from these, we chose equations to make data collection as simple as possible. LDW was computed from leaf length. LDW of the whole shoot was calculated by adding the computed LDW of each leaf on a shoot. Each stem was divided into 30-mm segments and the DW of each segment was correlated with its diameter. SDW was calculated by adding all of the stem segments' DWs. FDW was directly correlated with flower bud diameter. The selected models can be used for rose shoot DW prediction; although in some cases, errors were encountered. Despite these errors, this approach may represent the only feasible method for DW estimation when destructive methods cannot be used.
Formation of Somatic Embryos from Protoplasts of Coffea arabica L.
Authors: Tahara Mari , Yasuda Takeshi , Uchida Naotsugu , Yamaguchi Tadashi
Published: February 2019

Somatic embryos were regenerated from protoplasts isolated from embryogenic callus on young leaf explants from mature coffee trees. Embryos were regenerated on modified Murashige and Skoog medium supplemented with 5 μm BA. Somatic embryos developed into intact plants. Mannitol at 0.5 m was adequate as an osmoticum for isolating protoplasts, but subsequent culture required 0.3 m mannitol. A culture system in which osmolality was decreased gradually accelerated formation of colonies and somatic embryogenesis. Chemical name used: N-(phenylmethyl)-1H-purine-6-amine (BA).
Potato Genotypes Differ in Petiole Nitrate-nitrogen Concentrations Over Time
Authors: Lewis Randy J. , Love Stephen L.
Published: February 2019

Petiole NO3-N concentrations (PNCs) of seven potato (Solanum tuberosum L.) genotypes grown under four N treatments were studied. In 1986-88, the cultigens were planted in plots with a gradient of available N created by adding 0,140,280, or 420 kg N/ha ammonium nitrate split between preplant and periodic seasonal applications. PNCs were significantly (P ≤ 0.05) affected by year, sampling time (four times per season), N rate, and cultigen. All first- and second-order interactions were also significant (P <0.05). The relative PNC ranking among cultigens remained nearly constant across years when averaged across sampling dates and N rates. Regression-equation distinctiveness for each cultigen relating PNC to sampling time demonstrated a genotypic influence on seasonal PNC and allowed separation into four response classes. Using a data subset consisting of the 1988 trial, an optimal N rate was determined and regression equations were computed relating PNC to sampling date for each cultigen at the applied N rate nearest to the optimum. Tests for distinction separated the equations of the seven cultigens into six unique classes; `Frontier Russet' and `Ranger Russet' equations were coincident.
Chemical Regulators Affect Growth, Postproduction Performance, and Propagation of Golden Pothos
Authors: Wang Yin-Tung , Gregg Lori L.
Published: February 2019

Drench paclobutrazol or uniconazole applications (0.1-1.0 mg/0.5-liter pot or 0.05-0.2 mg/pot, respectively) were effective in suppressing stem elongation of golden pothos [Epipremnum aureum (Linden & Andrè) Bunt.]. Although the leaf production rate was reduced by both retardants, treated plants produced larger leaves than the controls, resulting in greater total leaf areas. Response to foliar paclobutrazol or uniconazole applications (0-200 and 0-100 mg·liter-1, respectively) was similar to the soil drench patterns, except that the leaf production rate was unaffected. Following 10 weeks in an interior environment, plants previously treated with either retardant produced shorter stems, fewer but larger leaves, and lower fresh weights than the nontreated plants. Cuttings collected from stock plants previously treated with a paclobutrazol or uniconazole soil drench (0.1 or 0.05 mg/0.5-liter pot, respectively) produced longer stemmed shoots, more and larger leaves, and heavier shoot fresh weights than cuttings from the nontreated plants. Foliar paclobutrazol application (0-200 mg·liter-1) to stock plants resulted in cuttings producing larger leaves and heavier shoot fresh weights than controls. Chemical names used: (2RS,3RS)-1-(4-chlorophenyl)-4,-4-dlmethyl-2-(l,2,4-trizol-l-yl)pentin-3-ol (paclobutrazol);(E)-1-(4-chlorophenyl)-4,-4-timethyl-2-(1,2,4-trizol-l-yl)l-penten-3-ol (uniconazole).
Postharvest Water Loss and Storage Quality of Nine Pepper (Capsicum) Cultivars
Authors: Lownds N.K. , Banaras M. , Bosland P.W.
Published: February 2019

Nine pepper cultivars (Capsicum annuum L.) representing five pepper types were studied to determine water-loss rates, flaccidity, color, and disease development when stored at 8,14, or 20C for 14 days. Water-loss rate was markedly higher at 14C than at 8C, and was somewhat lower at 20C than at 14C. There were significant differences in water-loss rates between pepper cultivar with `NuMex R Naky', `NuMex Conquistador', and `New Mexico 6-4' (New Mexican-type peppers) having the highest water-loss rates. Flaccidity followed a pattern similar to water loss at each storage temperature, suggesting a direct relationship. Color development was cultivar- and package-dependent, and ratings increased with temperature. Placing pepper fruit in perforated polyethylene packages reduced water-loss rates 20 times or more, so that water loss no longer limited postharvest storage. Packaging also eliminated flaccidity and reduced color development across cultivars at 14 and 20C. Packaged fruit, however, developed diseases that limited postharvest longevity.
Restriction Fragment Length Polymorphism Analysis of Anther-culture-derived Solanum chacoense
Authors: Birhman Ram K. , Rivard Sylvain R. , Cappadocia Mario
Published: February 2019

Using restriction fragment length polymorphism (RFLP) analysis, the genetic architecture of some anther-culture-derived S. chacoense Bitt. plants was studied, and their origins were elucidated. Our RFLP analyses showed that 1) several plants, even of different ploidy but otherwise genetically identical (clones), can be regenerated from callus originating from a single microspore and, conversely, that 2) some plants regenerated from single callus can have different genetic constitutions and, therefore, must have originated from two different microspore. These findings imply that previous anther culture efficiency estimates might have to be reconsidered.
Propagation of Atlantic White Cedar by Stem Cuttings
Authors: Hinesley L. Eric , Blazich Frank A. , Snelling Layne K.
Published: February 2019

Hardwood and softwood stem cuttings of 5-year-old Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] were cut to 12-cm (short) or 24-cm (long) lengths, treated with 0 to 15 g IBA/liter in 50% isopropyl alcohol, and rooted in a raised greenhouse bench under intermittent mist. When hardwood cuttings were collected in February, short cuttings survived and rooted better than long cuttings. Survival and percent rooting for softwood cuttings collected in late August was virtually 10070 regardless of cutting length. Long cuttings produced more roots and longer roots with hardwood and softwood material. IBA was unnecessary for rooting, but it markedly increased the number of roots. Chemical name used: 1H-indole-3-butyric acid (IBA).
GAMETOPHYTIC SELECTION OF THE FUSED VEIN TRAIT IN SQUASH
Authors: Carle R. Bruce , Loy J. Brent
Published: February 2019

Three experiments were conducted to delineate gametophytic selection of the fused vein trait in Cucurbita pepo L. Gametophytic subvitality was verified by comparing fused vein and normal pollen tube growth. Microscopic examination of partitioned, co-pollinated flowers revealed fewer and slower growing fused vein tubes than normal. The effects of gametophytic subvitality on seed yield and inheritance were shown by manipulating the severity of reproductive competition. Fused vein, normal, and F1 lines were pollinated with fused vein, normal, 50:50 mix, and F1 pollen at three different pollen loads. Analysis showed that fused vein pollen generated significantly fewer seed per fruit in all lines. In ensuing F2 and testcross populations, a reduction in load and thus competition significantly increased the number of fused vein individuals. Leaf number and area for normal, fused vein, F1, F2, and testcross plants were assessed to test pleiotropic effects on growth common to gametophytic subvitals. Although normal and fused vein lines differed in leaf number and size, their total leaf areas were not significantly different. F2 and testcross plants showed no difference between normal and fused vein individuals; leaf size and number were independent of leaf morphology.
DIAMMONIUM PHOSPHATE INCREASES YIELD OF LOWBUSH BLUEBERRIES
Authors: Smagula John M. , Dunham Scott
Published: February 2019

Eight commercial lowbush blueberry fields received preemergent application of diammonium phosphate at 0, 44.8, or 89.6 kg P/ha. Leaf samples taken in July of the application year showed a linear increase in P concentration with increasing DAP application. However, P concentrations in soil samples were not raised by DAP. Stem length, branching, and the number of flower buds per stem increased with DAP application. Yield, obtained by hand raking the 3 × 9-m treatment plots, increased with increasing rate of DAP. The average yield increase in response to 44.8 and 89.6 kg P/ha from DAP was 824 and 1679 kg/ha, respectively.
EFFECTS OF WARMING DURING STORAGE ON ACCUMULATION AND OXIDATION OF ∞-FARNESENE, AND ON SCALD DEVELOPMENT ON APPLES
Authors: Du Zhanyuan , Bramlage William J.
Published: February 2019

When Cortland apples were stored at 0 and 20C, 0C reduced ethylene production and increased accumulations of ∞-farnesene and conjugated trienes (CTs) in fruit peel, but it resulted in a lower CT258: CT281 ratio than did 20C. At 20C no fruit developed scald, but at 0C, 84% of the fruit scalded. When fruit were stored at 0C but transferred to 20C for 5 days after 0 to 8 weeks at 0C, only transfer after 2 or 4 weeks reduced scald. During warming, ethylene production and accumulations of ∞-farnesene and CTs increased, but after 20 weeks of storage, when scald developed, warming at 2 and 4 weeks reduced CT281 and increased the CT258: CT281 ratio. Warming at other intervals had no effect.
KENAF AS A COMPONENT OF GROWTH MEDIA
Authors: Pill Wallace G.
Published: February 2019

Kenaf core (xylem) particles (2 to 4 mm in diameter) were submersed in ammonium nitrate solutions (0 to 5000 mg N/liter) for 5 days. The kenaf was incorporated into complementary components as 30% kenaf: 70%. sphagnum moss or 10% kenaf: 10% vermiculite: 10% calcined clay: 70% sphagnum moss. These media received standard preplant fertilizer additions. Tomato and impatiens bedding plant shoot dry weights increased with up to 5000 mg N/liter in media containing 10% kenaf and with up to 3000 mg N/liter in media containing 30% kenaf. By selecting the N concentration of the kenaf soak solution, shoot growth could be matched to that achieved with commercial peat-lites after any post-transplanting period (2 to 9 weeks). A further study revealed that kenaf was an effective carrier for Bonzi and Sumagic growth regulators. By combining N-soaked kenaf with growth-regulator-soaked kenaf in the growth medium, bedding plant shoot growth was healthy but restricted.
USE OF PAPER SLUDGES AS SOIL AMENDMENTS IN LANDSCAPE HORTICULTURE
Authors: Norrie Jeffrey , Beauchamp Chantal J. , Gosselin André
Published: February 2019

Residues and by-products resulting from papermaking and recycling are receiving increased attention as beneficial soil amendments. Our research examines de-inked and primary paper sludge as a principal constituent of several substrate mixtures used as soil amendments in landscape horticulture. Three factors will be examined in a strip-split-plot design with four replications: substrate mixture (with organic soil and sand), fertilizer level, and plant species. Several paper sludge–organic soil–sand mixtures (maximum 50% sludge) were compared to an organic soil–sand control. A 15-cm layer of each mixture was incorporated into existing soil to a depth of 30 cm. Species of Spiraea, Physpcarpus, and Thuja were grown in addition to Kentucky bluegrass (seed and sod) and ryegrass (seed). Growth, rooting, and plant nutrition (foliar analysis) were examined. Preliminary results indicate poor ground cover and N deficiency in plants grown in all unfertilized plots. For sod and seeded grasses, control plots were slightly more healthy than sludge-amended plots, which was likely due to a greater concentration of available N from the organic soil. The bush species exibited similar responses. We conclude that a base fertilization is needed to decrease the C: N ratio of these substrates to ≈20 to 30 for sustained plant growth regardless of sludge amendments. Toxicity effects were due to the presence of organic contaminants, heavy metals, or both.
IMPACT OF GROWTH CONDITIONS ON POSTHARVEST QUALITY OF CUT ROSES
Authors: Ménard Claudine , Dansereau Blanche
Published: February 2019

The general objective of this project was to study the impact of preharvest growth conditions [supplementary lighting as high-pressure sodium (HPS) or metal halide (MH) lights, and fertilization] on the postharvest quality of greenhouse roses. On 25 Jan. 1991, 288 plants (Rosa × hybrida `Royalty', `After-Glow', and `Obsession') of 3× caliber were planted in pots. A split-split plot experimental design made up of four blocks was used. Light treatments (three) were main plots while fertilization (two) and cultivars (three cultivars; four plants per cultivar) were subplots and sub-sub-plots, respectively. The two fertilization regimes used had respective N: K (in ppm) ratios of 150 N: 300 K (F1) and 300 N: 300 K (F2). Three light treatments [ambient light conditions (control) and ambient light conditions + PPF of 100 μmol·m-2·s-1 supplied by 400-W HPS or MH lamps] were compared. Yields were significantly affected by supplemental light treatments, fertilization, or both regardless of cultivars. Results indicate that stems harvested from HPS and MH light treatments combined with fertilization F1 had a longer vase life than those grown with F2. HPS lamps significantly increased vase life compared to MH. The level of abscisic acid (ABA) was higher under MH than under HPS lamps at time zero (T0), and this was similar for all cultivars. Furthermore, when supplemental light was combined with the F1 fertilization, a lower ABA level was obtained. Low ABA levels were correlated to longer vase life expectancy.
CALIBRATING TREE GROWTH WITH DIFFERENT STREET-TREE PLANTING SPECIFICATIONS: A STUDY OF WASHINGTON, D.C., AREA WILLOW OAKS
Authors: Neal Barbara A. , Whitlow Thomas
Published: February 2019

There is broad consensus that we need a greater understanding of the interaction between trees and urban planting sites. This study was conducted to correlate annual increment growth with different street-tree planting specifications, with a primary emphasis on effective rooting volume of soil. The primary site of analysis was Pennsylvania Avenue in Washington, D. C., with four outlying sites chosen for comparison. From a cohort of 450, a randomly generated sample of 60 Pennsylvania Avenue willow oaks was chosen and increment cores taken at diameter breast height. A total of 60 cores was taken from willow oaks at the comparison sites. The annual incremental growth was measured using a microscope equipped with a computerized stage micrometer. The incremental growth per year in the nursery ranged between 6 and 8 mm and transplant shock generally lasted for 2 to 3 years, until growth regained or exceeded pretransplant levels.
PHOTOSYNTHESIS DURING INUNDATION FOR ACER RUBRUM L. POPULATIONS FROM CONTRASTING HABITATS
Authors: Anella Louis , Whitlow Thomas H.
Published: February 2019

Changes in photosynthesis and root morphology during flooding were studied in container-grown 2- to 3-year-old Acer rubrum L. saplings. The seed was collected from opposite ends of a hydrologic gradient: two upland xeric sites [the George Washington National Forest in Page County, Va. (38°25'N, 78°35'W), and the Robinson Forest in Perry County, Ky. (37 °9'N, 83°7'W)] and a floodplain hydric site [the Presquile National Wildlife Refuge along the James River in Chesterfield County, Va. (37°21'N, 77°16'W)]. Each xeric site, containing various half-sib families (maternal parent known, paternal parent from one or more sources), was compared to a different hydric site half-sib family. After 1 week of flooding, the xeric-site trees had lower net photosynthesis than the hydric-site trees and remained significantly lower for the duration of the study. After an initial drop, hydric-site plants showed a recovery in net photosynthesis, indicating a greater ability to acclimate to a flooding stress. Seventy-one percent of the hydric-site plants developed adventitious roots and all retained their leaves. Xeric-site plants did-not develop adventitious roots and 61% were defoliated after 60 days of continuous flooding. The results indicate ecotypic differentiation in physiological response between Acer rubrum populations collected from opposite ends of a hydrologic gradient.
TRANSPLANTATION OF POTATO SPROUT CUTTINGS ON WET PAPER TO IMPROVE AND INCREASE ROOTING AND SPEED UP MULTIPLICATION BY STEM CUTTING
Authors: Frève Andrew , Auger M.
Published: February 2019

Rooting sprout cuttings (spc) is sometimes less successful than stem cuttings (stc). A rooting technique was developed between 1988 and 1991 at La Pocatière. The spc were taken after standing 72 hours in the dark followed by 1 day with 16 hours of light. The spc can be very small (2 mm): a node can be split in half if there are two axillary buds face to face. The spc were soaked in IBA and sandwiched between two paper towels. As many as 300 to 400 spc can be placed in a 28 × 53-cm flat. The papers were placed in flats between two transparent covers; the bottom cover contains water. The paper was moistened with water. The cuttings were maintained at 100% relative humidity for 7 days, then planted in soil in flats. After 5 days on paper, the unrooted cuttings were treated again with IBA on a larger surface and put back in the sandwich. There was less damping-off because the cut part was not placed immediately into the soil. One week after plantation, the plantlets' shape was better and more uniform than those planted directly into soil. The plants rooted on paper produce more stc/spc and more stc/stc than those rooted in soil.
GROWTH, CARBON ACQUISITION, AND SOURCE-SINK RELATIONSHIPS IN `TITAN' RED RASPBERRY
Authors: Fernandez G. , Pritts M.
Published: February 2019

Seasonal changes in growth, photosynthetic rates, temperature, and light response curves of `Titan' red raspberry (Rubus idaeus L.) were obtained from potted plants grown under field conditions. Primocane dry weight accumulation underwent two phases of linear growth at the beginning and the end of the season, but growth slowed during fruiting. This slower rate of dry weight accumulation also coincided with an increase in root dry weight. Primocane NAR and SLA were highest early in the season. Light response curves differed depending on cane type and time of year. Floricane photosynthetic rates (A) were high during the fruiting period, while primocane A rates remained steady throughout the season. Both primocane and floricane leaflets displayed a midday drop in A rate, with a partial recovery in late afternoon. Photosynthetic rates of both primocane and floricane leaves were very sensitive to high temperatures. Temporal convergence of sink demand from fruit, primocanes, and roots occurs when plants experience high temperatures. This may account for low realized yields in raspberry and the high level of yield component compensation typical of source-limited plants.
EFFECT OF SPECTRAL QUALITIES OF PLASTIC MULCH ON WEED DEVELOPMENT AND GROWTH
Authors: Aziz Fahrurrozi , Stewart Katrine A.
Published: February 2019

The types of plastic mulch used in horticultural production often fulfill only a few of the grower's needs. Black plastic mulch controls weeds, but can burn young plants. Clear mulch, while warming the soil and enhancing early crop growth, allows prolific weed growth and development. Accordingly, an experiment using a randomized complete-block design with-four replications was set up to compare the effects of black, microperforated black, silver, and wavelength-selective (IRT-76) green mulches, and bare soil on weed growth and development, and on soil temperature and moisture. Each mulch was evaluated for its optical properties. All mulches significantly reduced final stands of seeded weeds compared with bare soil. IRT-76 green had the warmest mean soil temperatures, followed by silver, black, and microperforated black mulches, and bare soil. Soil moisture content was generally higher under plastic mulches than bare soil.
THE EFFECTS OF TUFTED APPLE BUDMOTH INJURY OR REDUCED FUNGICIDE PROGRAMS ON THE STORABILITY OF APPLES
Authors: Barden C.L. , Greene G.M. , Hull L.A. , Hickey K.D.
Published: February 2019

Tufted apple bud moth (TABM) damage had little or no effect onthe soluble solids, starch, or firmness of stored apples. Decay increasedfrom 0% to 18% in `Golden Delicious' and from 2% to 6% in `Delicious' between control fruit and those with the most TABMdamage (> 10 mm aggregate diameter, significant linear relationships R2 = 0.41 and 0.12, respectively). Weight loss increased 2- to 3-fold in apples in the highest damage category. These results show that the post-storage quality of apples with slight TABM damage (<5 mm aggregate diameter) does not decline more rapidly than undamaged fruit. The best controlled atmospheres for storing undamaged fruit were also the best for storing damaged fruit. Widely varying fungicide spray programs did not influence the quality or decay levels of apples following storage. However, even those fruit from blocks with few or no sprays had very little decay due either to low inoculum or unfavorable environmental conditions.
TRANSLATABLE mRNA IN THE PERICARP OF TOMATO CULTIVARS DIFFERING IN CHILLING TOLERANCE
Authors: Yu Han-Ling , Willemot Claude , Yelle Serge , Castonguay Yves , Nadeau Paul
Published: February 2019

Translatable mRNAs from two tomato (Lycopersicon esculentum Mill.) cultivars differing in chilling tolerance were compared after 16 days of chilling at 4C and after return to 20C for 1 and 5 days. Before chilling, the translation products, resolved by 2D NEPHGE, showed significant differences between more tolerant `New York 280' (NY) and less tolerant `Early Cherry' (EC). In NY, chilling reduced the level of five to 10 mRNAs and enhanced or induced that of several other mRNAs. After transfer to 20C, the trend was progressively reversed. Changes in the levels of two low-molecular-weight basic peptides were most noticeable. One, absent in NY before chilling, was strongly expressed after chilling and 24 h after transfer to 20C, but disappeared 5 days after transfer. The level of this peptide increased slightly in EC at low temperature and was maintained after transfer to 20C. The level of the other, high in NY before chilling, was sharply reduced after chilling. In contrast, the level of this polypeptide was low in EC under all treatments.
EFFECTS OF FERTIGATION MANAGEMENT ON WATER RELATIONS OF TOMATO PLANTS GROWN IN PEAT, ROCKWOOL, AND NFT
Authors: Xu Hui-lian , Gauthier Laurent , Gosselin André
Published: February 2019

Tomato plants (Lycopersicon esculentum Mill. cv. Capello) were grown in peat bags, rockwool slabs, and NFT in a greenhouse to examine the effects of nutrient solution electrical conductivity (EC) and potential evapotranspiration (PET)-dependent EC variation on plant water relations. Peat bags were irrigated by a PET-dependent irrigation system. EC was varied from 1 to 4 mS·cm-1 according to PET under –5 and –9 kPa of substrate water potential setpoints (SWPS). The plants in rockwool and NFT were treated with ECs of 2.5, 4, and 5.5 mS·cm-1. Peat bags and rockwool slabs were overwatered once a week to wash out the accumulated salts. Leaf water potential (ψ1) and relative water content (θ) were measured before and after plants were overwatered. Turgor (P) and osmotic π potentials were estimated from the pressure-volume method. Before plants were overwatered, ψ1 was significantly lower in the plants with high EC and low SWPS treatments and also lower in variable EC-treated plants, but P maintained close to the control value. After plants were overwatered, ψ1 recovered close to the control level and P became higher because of the lower π in the treatments of high EC, variable EC, and/or low SWPS. At a given ψ1 the plants with high EC, variable EC, and/or low SWPS maintained higher θ. The analysis of the pressure-volume curve showed that the leaves treated with high EC, variable EC, and/or low SWPS had higher turgid water content, higher symplasmic (osmotically active) water content, lower apoplasmic (osmotically inactive) water content, and lower θ point of zero turgor (incipient plasmolysis). Maintenance of P after overwatering was directly proportional to photosynthetic capacity. We suggest that osmotic adjustment occurs in response to high EC, low SWPS, or both and that overwatering substrates and varying EC can not only avoid salinity stress, but also improve turgor maintenance.
THE USE OF PROPANE BURNERS FOR CONTROL OF ANNUAL BLUEGRASS (POA ANNUA L.) IN SOD PRODUCTION
Authors: Laganière Marc , Desjardins Yves
Published: February 2019

At present, there is no herbicide registered for use in Canada to control annual bluegrass in sod production. Under serious infestations, aesthetic qualities are reduced and sod harvest becomes more complicated. The efficiency of propane burners to control annual bluegrass was tested in a trial initiated in Spring 1993. Specific objectives were to determine the appropriate period for treatment application and the heat intensity required for optimal control. Twenty-one plots (13 × 3 m) were treated with a conventional burner; a similar group was treated with a pipe burner. In addition to an untreated check, the combination of two tractor-burner speeds (3.6 and 5 km·h-1) and three gas pressures (20, 30, and 40 psi) made up the seven treatments. Randomized complete blocks were used and each treatment was replicated three times. The sod recovered well from all heat treatments. After 3 weeks, the best heat treatment reduced the annual bluegrass population by 70%. Unfortunately, this reduction lasted for about 1 month, after which the annual bluegrass population recovered. At best, weed population was reduced by 40% when evaluated in mid-September. Another trial is planned to identify environmental and edaphic factors that may reduce the effectiveness of heat treatments in controlling annual bluegrass in sod production.
MOLECULAR CHARACTERIZATION AND TRANSIENT EXPRESSION OF MAIZE SUS1 PROMOTER
Authors: Huang Xiao-Fang , Nguyen-Quoc Binh , Yelle Serge
Published: February 2019

Sucrose synthase (SS) is one of the key enzymes in plant carbohydrate metabolism. In maize, this enzyme is encoded by two genes, Sh1 and Sus1. We have isolated and determined the 5'-upstream sequence of maize Sus1 gene and compared it with the corresponding sequence in Sh1 gene. Sequence analysis revealed that there was a weak homology between the two promoters and no common sequence elements were found. To understand the differential regulation of the expression of the two genes, we constructed chimeric GUS fusions using the two promoters of SS genes. By using the biolistic system, we delivered these constructs into various plant tissues, and their transient expression was studied. Our results showed that the two promoters of SS genes directed tissue-specific expression in the same way that the two genes are expressed in vivo. The effectiveness of the expression of the constructs was recorded by counting the total blue expression units (blue spots) per shot and by fluorometric assays. High levels of GUS activity were detected in the immature embryos, young coleoptiles, and heterotrophic young leaves bombarded with the Sus–GUS construct. More than 100 expression units were observed in these tissues. Compared with the transient expression of the 35S promoter in the same tissue, Sus promoter activity was twice as high. Strong Sus–GUS expression was also detected in the aleurone cells of developing kernels. In contrast, the Sh-GUS construct was expressed only in the endosperm with an activity twice as high as that of Sus–GUS and 35S–GUS in the same tissue. The results will be discussed in terms of the physiological roles of the two SS isozymes in plant tissues.
ENHANCED RESISTANCE OF TOMATO PLANTS TO FUSARIUM OXYSPORUM F.SP. RADICIS-LYCOPERSICI UPON TREATMENT WITH CHITOSAN: CYTOCHEMICAL ASPECTS OF INDUCED RESISTANCE
Authors: Benhamou Nicole
Published: February 2019

Chitosan, a polymer of β-1,4-d-glucosamine derived from crabshell chitin, was applied to tomato plants before inoculation with the root pathogen Fusarium oxysporum f.sp. radicis-lycopersici. Whether chitosan was applied by leaf spraying, root coating, or seed coating, it reduced the number of root lesions caused by the fungus and increased the formation of physical barriers in infected root tissues. Formation of wall appositions such as papillae and occlusion of xylem vessels with coating substances were among the most typical features of host reactions. Another type of response was the accumulation of globular structures and electron-opaque masses in host cells neighboring colonized areas. Gold cytochemistry revealed that callose and lignin-like material were the main structural compounds induced in response to chitosan treatment and infection. Biochemical investigations showed that PR proteins as well as enzymes of the secondary metabolism were also significantly induced. The potential of chitosan as a biocontrol compound is discussed in relation to its ability to enhance plant protection against root pathogens.
UTILIZATION OF BIOSOLIDS IN HORTICULTURE
Authors: Beauchamp Chantal J. , Desjardins Yves , Yelle Serge , Gosselin André
Published: February 2019

Canadian environmental policies are aimed at reducing by 50%. the quantities of refuses intended for landfill by year 2000. In this perspective, landspreading and composting biosolids have been investigated as solutions. Paper sludges, wood wastes, and municipal solid wastes (MSW) are important components of landfill biosolids, but they are attractive by-products for agricultural use. Research projects were initiated to characterize the paper sludges produced by Daishowa Co. in Quebec City, wood wastes produced by Hydro-Quebec, and MSW composts produced from waste treatment at RITDM (Chertsey) and Conporec (Sorel). De-inked paper sludge and wood wastes have been landspreaded for growing potato and landscaping, whereas composted paper sludges have been evaluated as part of potting media for growing greenhouse plants and landspreaded for turfgrass production. The chemical and biological characteristics of these biosolids were investigated for their fertilization potential and their effect on plant growth.
Staminate and Pistillate Flower Production of Summer Squash in Response to Planting Date
Authors: NeSmith D.S. , Hoogenboom G. , Groff D.W.
Published: February 2019

Staminate and pistillate flower production in summer squash (Cucurbita pepo L.) fluctuates readily in response to the various crop production environments throughout the southeastern United States. `Dixie', `Senator `, `Lemondrop', `Meigs', and `Elite' squash were planted at various times over 2 years in Griffin, Ga., to determine the effect of planting date on staminate and pistillate flower counts for the first 2 weeks of flowering. Staminate and pistillate flower counts varied considerably depending on cultivar and time of planting, but no consistent pattern emerged. The production of staminate flowers was generally more variable than that of pistillate flowers. The distillate: staminate flower ratio was generally stable for `Senator' and `Elite', but not for the other cultivars, particularly `Dixie'. `Dixie' produced more distillate than staminate flowers 50% of the time, whereas `Senator' always produced more staminate flowers. Pistillate flower production for `Senator' and `Elite' was restricted during hot weather. These data indicate that staminate and pistillate flower counts of squash fluctuate under varying environmental conditions and that maintaining production over a range of planting dates will depend on careful cultivar selection.
Flowering Response of Bougainvillea Cultivars to Dikegulac
Authors: Norcini J.G. , Aldrich J.H. , McDowell J.M.
Published: February 2019

Foliar spray application of dikegulac at 1600 mg·liter-1 during production of Bougainvillea glabra Choicy `Mauna Kea White', and Bougainvillea `Raspberry Ice', `Royal Purple', `Summer Snow', and `Temple Fire' in 4.5-liter hanging baskets (25.4 cm in diameter) was investigated in relation to flowering. The effect of foliar-applied dikegulac at 0, 400, 800, 1200, and 1600 mg·liter-1 on bracteole size of `Mauna Kea White' was also determined. Liners of `Temple Fire' pruned at transplanting (0 weeks) and sprayed with dikegulac at, 0 and 4 weeks had increased flowering and a slightly more compact, pendulous growth habit than plants that had only been pruned at 0 and 4 weeks. Dikegulac had little to no effect on flowering of the other cultivars. Under late-spring to early summer conditions (generally increasing temperatures), bracteole size of `Mauna Kea White' was reduced ≈25 % by 400 mg dikegulac/liter compared to nontreated plants; 800 to 1600 mg dikegulac/liter reduced bracteole size ≈37%. Under late-summer to mid-fall conditions when the weather was cooler and wetter, dikegulac had little to no effect on bracteole size; however, bracteoles of nontreated plants were ≈25% smaller than those of plants grown under the warmer and drier conditions of late spring to early summer. Chemical name used: sodium salt of 2,3:4,6-bis -O- (1-methylethylidene) -α-l-xylo- 2-hexulofuranosonic acid (dikegulac).
Flowering and Growth of Phalaenopsis Orchids following Growth Retardant Applications
Authors: Wang Yin-Tung , Hsu Tsung-Yao
Published: February 2019

Bare-root, mature, hybrid Phalaenopsis seedlings were dipped in one of three growth retardant solutions for 5 seconds or sprayed with a growth retardant 4 weeks following planting during inflorescence elongation. Dipping the entire plant in daminozide (2500, 5000, or 7500 mg·liter-1) before planting delayed flowering by 5-13 days, whereas foliar applications had no effect. Paclobutrazol (50, 100, 200, or 400 mg·liter-1) or uniconazole (25, 50, 100, or 200 mg·liter-1) dips did not affect the bloom date but effectively restricted inflorescence growth below the first flower (stalk). Increasing concentrations produced progressively less growth. Foliarly applied retardant treatments were less effective than dipping. Flower size, flower count, and stalk thickness were unaffected by treatments. Dipping in high concentrations of paclobutrazol (200 or 400 mg·liter-1) or uniconazole (100 or 200 mg·liter-1) caused plants to produce small, thick leaves. During the second bloom season, inflorescence emergence and bloom date were progressively delayed by increasing concentrations of paclobutrazol and uniconazole. Neither retardant affected flower count or size. Foliarly applied daminozide increased stalk length. In another experiment, foliar paclobutrazol treatment restricted stalk growth more effectively when sprayed before inflorescence emergence. Its effect progressively decreased when treatment was delayed. Paclobutrazol concentrations from 125 to 500 mg·liter-1 were equally effective in limiting stalk elongation when applied to the foliage. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); (E)-1- (p -chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol(uniconazole); (2 RS, 3 RS) -1-(4-chlorophenyl)-4,4-dimethyl-2-(1 H- 1,2,4-triazol-1-yl) pentan-3-ol (paclobutrazol).
Wrapping in Polyvinyl Chloride Film Slows Quality Loss of Yellow Passion Fruit
Authors: Arjona Harvey E. , Matta Frank B. , Garner James O.
Published: February 2019

Vine-ripened yellow passion fruit (Passiflora edulis f. flavicarpa Deg.) were placed in styrofoam trays and wrapped with VF-60 plastic film and stored for 15 and 30 days. Wrapping prevented fruit weight loss while maintaining external appearance. Storage time contributed to quality loss of external appearance. Wrapping maintained fruit glucose and fructose content at 43 and 40 mg·ml-1 up to 15 days, respectively, and did not influence juice pH. Initial sucrose content of wrapped fruit declined 62% after 15 days in storage. Plastic film did not effectively modify O2 or CO2.
Decline of Oxamyl Residues in Tomatoes in Cool, Modified-atmosphere Storage
Authors: McGarvey Brian D. , Reyes Andres A. , Chiba Mikio
Published: February 2019

Residues of the insecticide-nematicide oxamyl in tomatoes (Lycopersicon esculentum Mill.) declined more quickly during storage at 15C in modified atmospheres consisting of 1.5% O2 + 98.5% N2 or 1.5% O2 + 4.0% CO2 + 94.5% N2 than in air. (21.0% O2 + 79.0% N2). Fruit ripened more quickly in air than in either modified atmosphere. Chemical name used: S-methyl N′,N′-dimethyl -N- (methylcarbamoyloxy)-1-thio-oxamimidate (oxamyl).