bluuebunny/crossref_metadata_2025 huggingface dataset:
876 PB 238 MICROPROPAGATION OF UNIOLA PANICULATA L. (SEA OATS) FROM TILLER EXPLANTS
Authors: Phiman Nancy , Kane Michael E.
Published: February 2019

Beach stabilization by replanting dune species such as Uniola paniculata L. (Sea Oats), is an accepted practice to control erosion in the southeastern United States. Increased restrictions on collection of sea oat seed and plant material for propagation is of increasing concern. Development of micropropagation protocols for establishment and production of sea oats from donor plants of known phenotype would be useful for selecting and producing plants with commercially valuable characteristics. Terminal and lateral shoot tips (3 mm wide and 4 mm high) from containerized plants were surface sterilized and established on Linsmaier & Skoog mineral salts and organics supplemented with 87.6 mM sucrose, 2.2 μM benzyladenine solidified with 0.8% TC® Agar. Terminal tiller shoot tips were more responsive than lateral shoot tips. Four monthly subcultures were. required for stabilized shoot multiplication from culture lines established from terminal tiller shoot tips. Shoot organogenesis frequently occurred from the cut leaf surfaces of subcultured shoot clusters. Microcuttings were established ex vitro in plug cells containing sand or vermiculite.
877 PB 261 MICROPROPAGATION PROCEDURES FOR LEONTO CHIROVALLEI
Authors: Lu Chunsheng , Ruan Yiqin , Bridgen Mark
Published: February 2019

Micropropagation has been used to rescue Leontochir ovallei, an endangered Chilean species in the Alstroemericeae. Cultures were initiated by aseptically germinating seeds of Leontochir on a medium containing 1/10 MS salts and vitamins and 0.3% sucrose. Three types of cytokinins (BAP, 2-iP and kinetin) at four concentrations (0, 2, 4, and 8 uM) were studied for shoot proliferation. In the 4 uM BAP treatment, new shoots were produced at an average of six per culture after four weeks of culture. Overall, there was an average of four shoots/culture/4 weeks for all BAP treatments. This was significantly higher than the 2-iP and kinetin treatments. Moreover, the increase of culture fresh weight over time was significantly greater in BAP treatments than those in other treatments. A rooting study compared the effect of NAA and IBA on root initiation. Over 85% of the cultures in 10 and 20 uM NAA treatments produced healthy and large roots. This was significantly higher than the 10 and 20 uM IBA treatments. In summary, a concentration of 4 uM BAP combined with 1 uM IBA in MS salts and vitamins supplemented with 146 mg glutamine/l is the best for shoot proliferation of leontochir; an MS basal medium containing 10 uM NAA is the best for root initiation. Micropropagated plantlets have been successfully transplanted into the greenhouse for further genetic and breeding studies.
878 PB 264 Micropropagation of pitaya (Hylocereus undatus Britt. et Rose)
Authors: Mohamed-Yasseen Yasseen
Published: February 2019

Pltaya is a member of the family Caztacaae and the genus Hylocerus which has several species producing edible fruits. A procedure for micropropagation of pitaya using thidiazuron is described. Explants were excised from young joints of mature plants, and cultured on Murashige and Skoog medium (MS) containing 0.5 uM Thidiazuron (TDZ), and 3.5 uM naphthaleneacetic acid (NAA) Produced shoots were cut longitudinally into three explants or decapitated and cultured on MS supplemented with 0.01, 0.09, 0.5, or 0.9 uM TDZ with 0.5 uM NAA. Decapitated expiants produced shoots with higher frequency and number of shoots was higher than 1/3 explants. Shoots produced from decapitated explants were longer, thicker and vigorous, compared to shoots developed from 1/3 explants. Most shoots developed from, the distal part in both explants and produced several lateral shoots from axillary buds. Shoots were rooted in MS then transferred to soil and produced normal plants.
883 PB 279 REGENERATING ADVENTITIOUS PLANTS FROM IN VITRO CULTURE OF LIATRIS SPICATA (L.) WILLD. COTYLEDONS
Authors: Stimart Dennis P. , Mather John C.
Published: February 2019

Cotyledons from developing embryos 6 to 8 weeks old of Liatris spicata (blazing star) were cultured on Murashige-Skoog (MS) medium containing 0, 0.4, 4.4, and 44.4 μ M benzyladenine (BA) or 0, 0.2, 2.2, and 22.2 μ M thidiazuron (TDZ) to induce adventitious shoot formation. The highest percent of cotyledons forming shoots with highest shoot counts was on medium containing 2.2 μ M TDZ. Vitreous shoots formed on medium with 22.2 μ M TDZ. Callus derived from cotyledons and cultured on medium containing 4.44 μ M BA or 2.2 μ M TDZ formed adventitious shoots with highest shoot counts on 4.44 μ M BA. Adventitious shoots derived from cotyledons and callus were rooted on MS medium with 5.0 μ Mindole-3-butyric acid, acclimatized and grown ex vitro. All micropropagated plants appeared similar to each other.
885 PB 305 SOMATIC EMBRYOGENESIS FROM CALLUS OF THE THERMOTOLERANT `GERMAN RED' CARNATION
Authors: Sankhla Daksha , Davis Tim D. , Sankhla N.
Published: February 2019

`German Red' is a thermotolerant cultivar of carnation (Dianthus caryophyllus) that blooms almost year-round in Texas. This study was initiated to evaluate the feasibility of inducing somatic embryos for use in gene transfer Studies and rapid mass propagation. Internodal explants, obtained from microshoots of plantlets cultured on MS medium containing 5 μM benzyladenine (BA) and 0.5 μM naphthaleneacetic acid (NAA), were used to initiate callus. Callus formation was induced on MS medium containing 3% sucrose, 0.1% casein hydrolysate and 2,4-D (1-5 μM) alone or in combination with BA (2 or 4 μM) or kinetin (2 or 4 μM). After about 5 weeks, the callus was transferred to either semisolid or liquid MS basal medium with or without kinetin and BA. Within 20-30 days, pro-embryogenic callus masses were observed. The embryos developed from white embryonic tissue and exhibited typical stages of embryogenesis. After 5 weeks, up to 70% of the cultures grown in the liquid medium with or without BA exhibited a profusion of embryo-like structures. Because only a small percentage of these developed into plantlets, more work is needed to enhance conversion frequency.
887 PB 463 SOMATIC EMBRYOGENESIS FROM ROSE LEAF EXPLANTS
Authors: George Mary W. , Tripepi Robert R.
Published: February 2019

Previous reports of somatic embryogenesis on rose tissues involved an embryogenic callus stage with either a complicated multi-step process or low numbers of embryos being produced. We have produced somatic embryos without a callus stage from leaf explants of the cut rose cultivar `Golden Emblem' by using a two step process. Explants were obtained from microshoots of `Golden Emblem' that had been in culture for three years. All experiments were repeated twice. When explants were maintained on Murashige and Skoog (MS) with 0.4 μM NAA and 0.4 μM kinetin for 10 weeks, 10% or less of the explants produced somatic embryos. Keeping the explants on the NAA/kinetin medium for two weeks, then switching to medium with 0, 0.5, 1.0, or 10.0 μM kinetin for the remaining 8 weeks failed to increase embryo production. Decreasing the time the explants were on the NAA/kinetin medium to 8 or 12 days, and then placing explants on MS medium with 1.0 μM kinetin increased somatic embryo production to a maximum of 25%. By limiting the length of time the rose leaf explants were exposed to auxin, direct somatic embryo production was increased.
TOWARDS GENETIC TRANSFORMATION OF QUINCE AND PEAR
Authors: Bunnag Sumontip , Martin Ruth C. , Mok David W.S. , Mok Machteld C.
Published: February 2019

Quince (Cydonia oblonga) is widely used as a dwarfing rootstock for pear (Pyrus communis). We have devised procedures for Agrobacterium-mediated gene transfer using leaf discs of quince. The following factors were particularly important for recovery of shoots after incubation of leaf discs with Agrobacterium: an efficient regeneration system, the use of an effective antibiotic to eliminate Agrobacterium while maintaining a high regeneration frequency, and the choice of selectable markers. The regeneration frequency of control leaf discs on a medium containing 30 μM thidiazuron and 0.3 μM naphthaleneacetic acid was 100%. The frequency decreased linearly with increasing concentrations of antibiotics. Timentin. which consists of ticarcillin and a 6-lactamase inhibitor, was more effective in eliminating Agrobacterium than cefotaxime and carbenicillin. Vectors with the bar gene (bialaphos resistance) were better than those with the npt 11 gene (kanamycin resistance), since kanamycin bleached the leaf discs, resulting in poor regeneration. Bialaphos-resistant quince shoots which were positive in Southern hybridization have been obtained. The same procedures are being applied for transformation of pear.
892 PB 496 RESPONSE OF THREE JUGLANS SPP. TO KANAMYCIN AND BIALAPHOS
Authors: Long Lynn M. , Preece John E. , Gaffney Gerald R. , Van Sambeek J.W. , Lightfoot David A.
Published: February 2019

Genetic transformation studies are aided by use of selection agents, such as antibiotics or herbicides. To determine the level of kanamycin to be used as a selection agent, cotyledonary stage somatic embryos from J. nigra lines J26 and J28, J. nigra × J. hindsii line S11, and J. regia line SU2 were placed on gelrite solidified WPM with 1 g/liter casein hydrolysate and 250 mg/liter cefotaxime and 3% (w/v) sucrose. Dosages for inhibiting secondary embryogenesis were 40 mg/liter kanamycin for J. nigra and J. nigra × J. hindsii and 100 mg/liter for J. regia. For the bialaphos experiments, somatic embryos of J. nigra lines J26 and J28 and J. nigra × J. hindsii line S11 were cultured on gelrite solidified LP medium with 0.5 g/liter casein hydrolysate and 3% (w/v) sucrose. Between 0.1 and 1.0 mg/liter bialaphos, inhibited secondary embryogenesis.
893 PB 499 HIGH FREQUENCY REGENERATION FROM THE LEAF OF CAPSICUM ANNUUM L. CV. CHUNGHONG
Authors: Shon Young Goel , Park Joong Choon , Jeong Byoung Ryong
Published: February 2019

Effect of combination and concentration of growth regulators on the regeneration of pepper plant from different explant tissues was studied. Seedlings were grown aseptically in 400 ml glass bottles containing MS agar medium at 26±2C under a 16 h·d-1 photoperiod (2000 lux, florescent lamps). Explants taken from 4 week-old seedlings were cultured under these conditions on 40 ml of MS agar (8 g·liter-1) medium containing 3 g·liter-1 sucrose in a 400 ml glass bottle. Primary and subsequent leaves attached to petiole regenerated better than cotyledon and hypocotyl. Among the combinations of different concentrations of cytokinin and auxin added in the medium, a combination of 5 μM IAA with either 10 μM zeatin or 10 μM BA gave the best regeneration. With these combinations, regeneration frequency of multiple shoots from the primary and subsequent leaves was greater than 70%. Regenerated shoots rooted readily in MS agar medium containing 3 g·liter-1 sucrose and 0.5 μM NAA.
894 PB 502 COMPARISON OF TWO CULTURE VESSEL ENCLOSURES ON THE GROWTH OF POTATO IN VITRO
Authors: Yorio N.C. , Mackowiak C.L. , Peterson B.V. , Wheeler R.M.
Published: February 2019

In vitro growth of white potato (Solanum tuberosum L.) cv. Norland was investigated comparing two types of culture vessel enclosures. Nodal cuttings were aseptically transferred to 25 × 150 mm glass culture vessels containing a solidified medium consisting of Murashige and Skoog salts, 1% sucrose, and pH adjusted to 5.8. The vessels were capped with loose-fitted (1 cm gap between the top of the vessel and the top of the cap) Magenta 2-way caps or Bellco Kap-uts with calculated air changes hr-1 of 2.25 and 1.43, respectively. Instantaneous PPF attenuations of 15% for Magenta caps and 23% for Bellco caps were also measured. The cultures were maintained for 28 d in an environmental growth chamber under Daylight fluorescent lamps with a 16 hr light/8 hr dark photoperiod, 200 μmol m-2s-1 PPF maintained for each cap type, constant 23 C, 65% relative humidity, and CO2 enrichment of 1000 μmol mol-1 external to the culture vessels. Results showed that increased plantlet height, fresh weight, and dry weight was obtained for plantlets cultured with Magenta caps. The differences in growth and internal CO2 concentration of the vessels correlated well with the difference in air exchange rates, suggesting that increased air exchange of culture vessels resulted in increased mixotrophic plantlet growth.
895 PB 505 STRATIFICATION OF AMERICAN GINSENG SEED
Authors: Proctor John T. A.
Published: February 2019

American ginseng is propagated by seed. In commercial practice ginseng seed is harvested in August or September, placed in a stratification box for about 12 months, and then direct seeded into raised beds. Germination takes place the following spring, some 18 to 22 months after seed harvest. Little is known about the dormancy-controlling mechanisms of ginseng seed. The objective of this study was to investigate seed development and temperature in the stratification box until it was removed 12 months later and seeded in the field. During stratification 3 embryo growth stages were identified. In Stage I of 250 days (September to mid-May) embryo length increased from about 0.5 to 1.0 mm, in Stage II of 100 days (mid-May to late August) length increased to 2.0 mm and in Stage III (late August to late November) length increased to 5.3 mm. Exocarp split width could also be placed in 3 stages. Changes in embryo length correlated with values for embryo: endosperm length ratio. The stratification box temperatures at all depths never exceeded -2°C even when the air temperatures dropped to -13°C and, therefore, were not damaging to the seeds.
896 PB508 A NOVEL METHOD OF AUXIN APPLICATION STIMULATES ADVENTITIOUS ROOT FORMATION IN WALNUT
Authors: McKenna James R. , Sutter Ellen G.
Published: February 2019

The use of auxin-impregnated toothpicks stimulated adventitious root formation in genotypes of Juglans `Paradox' that had been backcrossed to J. regia. These genotypes were selected as potential rootstocks because of improved tolerance to cherry leaf roll virus and Phytophthora spp. Other auxin applications including quick dips and talc formulations had little or no effect. The use of toothpicks lowered the concentration of IBA necessary for root initiation compared to previously reported results using quick dips. Toothpicks were inserted transversely into holes drilled 1 to 2 cm above the base of cuttings. Callus and roots always formed at the location of the toothpicks rather than at the base of the cutting. Roots were formed using this method in simple layering, hardwood, and semi-hardwood cuttings. Of all the cuttings that rooted, 90% rooted with toothpicks whereas only 10% rooted using a quick dip. This method may have potential for increasing the efficiency of rooting other difficult-to-root plants.
898 PB 532 LIGHT COMPENSATION POINT AND LOW TEMPERATURE AS STORAGE ENVIRONMENTS OF TRANSPLANTS
Authors: Kubota Chieri , Kozai Toyoki
Published: February 2019

A storage method of transplants in vitro was developed using light compensation points in conjunction with low temperatures. Broccoli (cv. Ryokurei) plantlets, aseptically germinated and cultured for three weeks in vitro, were used as model transplants. Culture conditions were: 23C air temperature, 160 μmol m-2s-1 PPF, and 3.6 air exchanges per hour of the vessel. Prior to storage, light compensation points were determined at 3, 5, 10, and 15C for the plantlets cultured with or without 20 g liter-1 sugar in the medium. Plantlets were stored for six weeks at 5, 10, and 15C under either 0 or 2 μmol m-2s-1 continuous PPF. The light compensation points varied with air temperature and with medium sugar level. Plantlet dry weight during storage was best maintained by keeping CO2 exchange rate of the plantlets close to zero throughout the storage period. High transplant qualities were successfully preserved at light compensation points: 2 μmol m-2s-1 PPF at 5-10C without sugar, and at 5C with sugar in the medium. This method may be applicable for storage of other crop transplants, plug seedlings and cuttings as well.
901 PB 538 STUDIES ON PROPAGATION OF GLOBE ARTICHOKE THROUGH TISSUE CULTURE TECHNIQUE
Authors: Okasha Kh. A. , Ragab M. E.
Published: February 2019

The aim of this study was to establish an effective method of micropropagation of globe artichoke from shoot-hp. This study involved establishment of an aseptic culture. multiplication of proliferated shook, rooting of these shook in vitro and adaptation of plantlets for free living

Highest survival percentage with no contamination was achieved after sterilizing the explants with 70% ethanol (5 Sec.) + 1.5 % sodium hypochlorite for 20 min.

The bast results of preventing browning of explants were obtained with 100 mg/1 ascorbic acid.

The highest proliferated shook were obtained when shoot tip with 4 mm length (taken in mid March) were cultured on MS medium with 10mg/1 Kin. + 0.5 mg/l IAA.

The highest multiplication rate was obtained when recultured on MS medium supplemented with 5 mg/1 Kin. + 0.5 mg/1 IAA.

Multiplication rate gradually increased with increasing number of subculturing till Me third subculture but subsequent subculture (4th subculture) had a low rate.
905 PB 526 DIFFERENTIAL EXPRESSION OF DEHYDRIN (47 KD) “BOILING STABLE” PROTEIN WITHIN POPULATIONS OF TWO DIPLOID POTATO SPECIES SEGREGATING FOR COLD TOLERANCE AND ACCLIMATION CAPACITY
Authors: Karlsson Bjorn H. , Palta Jiwan P. , Weiss Laurie S. , Harbage James F. , Bamber John B.
Published: February 2019

Cold-induced changes in gene expression have been demonstrated in a number of species that vary in freezing tolerance and acclimation capacity. Relative freezing tolerance was measured based on ion leakage for both nonacclimated and acclimated S. commersonii and S. cardiophyllum parents, F1 and backcross progeny segregating for cold tolerance and acclimation capacity. Western blot analyses showed increase in a dehydrin band (47 kD)(antisera courtesy of T. Close) following cold acclimation of cold tolerant S. commersonii, and a slight increase in cold sensitive S. cardiophyllum. Expression of 47 kD cosegregated with non acclimated freezing tolerance but not with acclimated freezing tolerance. Our results show that (i) expression of dehydrins is a heritable trait in the Solanum diploid population, (ii) there is no direct relationship between relative freezing tolerance and the presence or absence of dehydrm protein following cold acclimation and (iii) based on assays measuring the residual activity of the lactate dehydrogenase (LDH) enzyme following freezing, the cryoprotective influence of `boiling stable' proteins was species dependent and is related to the freezing tolerance of the species. Supported by USDA/NRI grant 91-3700-6636 to J.P.P. and J.B.B..
910 PB 150 PLANT GROWTH, YIELD, AND WEED CONTROL IN FOUR STRAWBERRY PRODUCTION SYSTEMS
Authors: Tedesco Angela K. , Nonnecke Gail R. , Obrycki John J. , Christians Nick E. , Gleason Mark L.
Published: February 2019

Field plots of four production systems of `Tristar' dayneutral and `Earliglow' Junebearing strawberry (Fragaria xananassa Duch.) were established in 1993. Productions systems included conventional practices (CONV), best-management practices including integrated crop management (ICM), organic practices using corn gluten meal, a natural weed control product, (ORG-CGM), and organic practices using a natural turkey manure product (ORG-TM). `Earliglow' plants grown with ORG-CGM showed the highest number of runners and total vegetative biomass. Plots with CONV and ICM systems using standard herbicide treatments had lower total weed numbers (11 and 18, respectively) than ORG-CGM (63) and ORG-TM (58). `Tristar' plant growth, yield and berry number were reduced when plants were grown under straw mulch in ORG-CGM and ORG-TM compared to CONV and ICM plots with polyethylene mulch.
915 PB 185 ROOT DISTRIBUTION AND YIELD OF BLUEBERRY
Authors: Nonnecke Gail R.
Published: February 2019

Soil probe samples were taken in the upper 1 m of the soil profile 0.5 and 1 m from the base of five blueberry cultivars (Vaccinium spp.) grown in a modified-pH soil. The samples were divided into 12 sections by depth: mulch, 0-5, 5-10, 10-20, 20-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, and 90-100 cm. Weights of the organic fraction of blueberry roots were determined by subtracting ashed weights from dry weights for each sample section. Duplicate soil probe samples were taken and soil pH determined at the 12 depths and two distances. Root weights were highest in the upper 20 cm of the soil profile at the 0.5 m distance for all cultivars. Soil pH was 5 and below in the upper 20 cm of the soil. Yield of 11 cultivars was obtained for five years (1988-1992). Total yield averaged over 5 years showed `Blueray' as the highest yielding cultivar with 4.43 kg/plant per year. `Patriot', `Elliott', and `Colville' were lower than `Blueray' but similar to each other, with yields of 3.42, 3.11, and 3.03 kg/plant per year, respectively.
916 PB 188 WEED THRESHOLDS BY MECHANICAL AND CHEMICAL CONTROLS IN WILD BLUEBERRIES
Authors: Yarborough David E. , Hess Timothy M.
Published: February 2019

Three hundred, 1 m2 plots with either 0%, 25%, 50%, 75% or 100% dogbane or bracken fern weed cover were used in the study. The experimental design was completely randomized with two species, three treatments (mow, wipe and untreated), five densities and 10 replications. One half of each plot had weed cover and one half was kept weed free in order to compare the effect of weed density on yield. Plots were treated with either 10% v/v glyphosate in a hand held weed-wiper, mowed with a string trimmer or left untreated. Wiping was more effective than mowing for reducing weed numbers in the following year. However, wiping reduced yields compared to mowing at higher weed densities. Mowing proved more effective at increasing yields up to 50% weed cover compared to wiping or not treating. Averages from 1991 and 1992 study indicate mowing increases yields compared to wiping up to 50% then tend to decline, but yields remain greater than not treating.
929 PB 506 A TECHNIQUE FOR INOCULATING PEPPER FRUITS WITH THE SOFT ROT PATHOGEN, ERWNIA CAROTOVORA
Authors: Stommel John R. , Goth Robert W. , Haynes Kathleen G.
Published: February 2019

Bacterial soft rot of bell pepper (Capsicum annuum L.), caused by Erwinia spp., is a destructive postharvest market disease of this crop. Control is presently limited to chemical treatments. Methods of inoculating pepper fruit were evaluated to develop a reliable technique for soft rot resistance screening. Erwinia carotovora subsp. atroseptica (Eca) was isolated from partially decayed field grown pepper fruit at Beltsville, MD. Fruit were inoculated with suspensions of Eca via: (a) abrasion with Carborundum, (b) hypodermic puncture, or (c) non-wounded tissue. Inoculated fruit were held under high humidity at 21-23C for two to three days prior to scoring. Degree of soft rot decay was determined via fruit weight loss from two replicates of the experiment over the course of the growing season. Significant differences were not evident among varieties or experiment dates for weight loss due to tissue decay. Hypodermic puncture inoculation was superior to other methods for inducing fruit rot.
932 PB 530 PAL INDUCTION AND FRESH-CUT LETTUCE QUALITY
Authors: Lopez-Galvez Gloria , Saltveit Mikal , Cantwel Marita
Published: February 2019

Phenylalanine ammonia-lyase (PAL) activity in iceberg lettuce (Lactuca sativa L.) is increased in response to several kinds of stress, including wounding, exposure to ethylene, and fungal infection. Ethylene-induced PAL activity is correlated with the discoloration and shelf-life of fresh cut lettuce (Couture et al. 1993. HortScience 28:723). The objective of this research was to further characterize the kinetics of wound-induced PAL in fresh cut lettuce. Leaves of different cvs were cut into salad pieces (1.5 × 3 cm), rinsed in chlorinated water, centrifuged manually, and placed into containers at 5 or 15C through which humidified air flowed. Samples were evaluated for overall visual quality and specific types of discoloration. Midrib tissue was also finely cut (1 × 0.5 cm) for enhanced wound-induction of PAL, which was assayed spectrophotometrically. The kinetics of PAL in midrib tissue of fine cut and salad cut lettuce were similar, with maximum activities obtained within 12-16 h at 15C and within 40-60 h at 5C. Maximum PAL levels in the fine cut lettuce were 1.5-2.0 times those observed in the salad cut pieces, and similar to those induced by ethylene. The usefulness of PAL as a predictor of the storage life of fresh cut lettuce depends on simplifying and expediting the PAL assay.
933 PB 528 CONTROL OF LIPID OXIDATION IN ASPARAGUS BY VACUUM INFUSION OF ASCORBIC ACID
Authors: Smith Durward , Cuppett Susan
Published: February 2019

Both fresh and frozen asparagus rapidly deteriorate in quality due, in part, to the formation of oxidative off-flavors. Anti-oxidants and chelating agents prevent lipid oxidation in vegetables, but increasing the levels of such compounds in whole vegetables is difficult. Vacuum infusion was optimized to saturate asparagus spears with ascorbic acid without damaging tissues. The combination of vacuum infusion of ascorbic acid and thermal blanching effectively prevented the formation of oxidative off-flavors and hexanal during frozen storage. Sensory evaluations correlated with hexanal levels following frozen storage.
934 PB 524 HEAT TREATMENTS EXTEND THE SHELF-LIFE OF FRESH BROCCOLI
Authors: Forney Charles F.
Published: February 2019

Freshly harvested heads of `Cruiser' or `Paragon' broccoli (Brassica oleracea L. Italica group) were heat treated by holding in water for 1 to 40 min at 42, 45, 48, 50, or 52C. Control heads were held in air at 20C or in 25C water for 40 min. Controls turned yellow in about 3 days at 20C. Treatments at 42C delayed yellowing by 1 or 2 days, while treatments of 45, 48, 50, and 52C prevented yellowing up to 7 days at 20C. Hot water treatments had no effect on water loss of broccoli during storage. Incidence of decay was greater in treated broccoli stored wet compared to the dry control. However, when free water was removed by spinning following treatment, no difference in decay was observed. Treatment of broccoli at 52C for 3 or more min sometimes induced a distinct off-odor. When broccoli was held at 0C for 3 weeks following treatment no differences were observed between control and treated broccoli. However, when broccoli was warmed to 20C following storage at 0C, yellowing of treated broccoli was inhibited. Hot water treatments also delayed senescence at 20C when broccoli was treated following 3 weeks of storage at 0C.
935 PB 521 MAIN SUGAR ANALYSIS OF FRUITS AND VEGETABLES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY
Authors: Siller-Cepeda Jorge , Sánchez Alfonso , Vázquez Francisco , Báez Manuel , Palacios René , Bringas Elsa , Araiza Evelia , Báez Reginaldo
Published: February 2019

A rapid and sensitive high performance liquid chromatography method for quantifying simultaneously sucrose, fructose and glucose in fruits and vegetables is reported. Samples were extracted in 95% ethanol, homogenized and treated at 95C for 20 min. The supernatant was stored at -20C overnight and filtered through a G-25 Sephadex column. Aliquots were evaporated, redissolved in water, filtered, and injected. A Sorbex NH2 column operated at room temperature was used for separations. The sugars were detected at 192 nm. The retention times were 4.8, 5.9 and 10.3 min for fructose, glucose and sucrose, respectively. The method was applied to twenty-one fruit and vegetable species with different maturity stages. In addition, quality characteristics such as firmness, pH, acidity, soluble solids and color were evaluated. Main sugars for the different samples varied among species. In temperate fruits, fructose and glucose were the predominant sugars, while in tropical and subtropical fruits, the main sugar was sucrose. On the sampled vegetables, fructose was the primary sugar, although at very low levels. Quality characteristics coincided with sugar levels found among the different species.
941 AQUARIUM PLANT MICROPROPAGATION: CRYPTOCORYNE BECKETII
Authors: Gargiulo Jennifer A. , Kane Michael E.
Published: February 2019

The genus Cryptocoryne (Araceae) contains some of the most commercially important amphibious species used in the aquarium plant trade. However, seed production is rare and vegetative propagation by rhizome division is extremely slow. Procedures for in vitro establishment, axillary shoot proliferation and plantlet acclimatization of Cryptocoryne Becketti Thwaites ex Trimen were determined. Surface sterilized rhizomatous shoot tips were established on a medium consisting of Linsmaier & Skoog mineral salts and organics supplemented with 87.6 mM sucrose, 2.2 μM benzyladenine (BA) and 0.57 μM indole-3-acetic acid (IAA) solidified with 0.8% TC® Agar. Effects of medium supplementation with factorial combinations of BA (0 - 25 μM) and IAA (0 - 10 μM) on axillary shoot proliferation from single node explants were determined after 28 days. Maximum axillary shoot proliferation (`l-fold increase) occurred on medium supplemented with 25 μM BA and 1.0 μM IAA. Excellent microcutting rooting (100%) was achieved by direct sticking in Vergro Klay Mix A. Greenhouse acclimatization of rooted microcuttings was 100%.
944 COLD-STORAGE TREATMENTS AFFECT WATER RELATIONS OF BARE-ROOT TREES
Authors: Bates Rick M. , Niemiera Alexander X.
Published: February 2019

Shoot and root water potentials were determined for bare-root Norway maple (Acer platanoides L.) and washington hawthorn (Crataegus phaenopyrum Med.) seedlings subjected to shoot and root exposure treatments for six cold storage durations. Shoot and root water potentials for all exposure treatments and both species decreased with increased time in storage, and the greatest degree of water stress occurred during the first six weeks of storage. Maple shoot and root water potentials for the exposed shoot treatment were the same as the whole plant covered treatment. In contrast, hawthorn shoot and root water potentials for the exposed shoot treatment were the same as values for the roots exposed treatment. Based on these data, we conclude that desiccation sensitive species such as washington hawthorn require root and shoot protection to minimize water loss.
949 EFFECT OF IRON AND LIGHT IN TENSITY ON GROWTH AND CHLOROPLAST DEVELOPMENT IN C3 AND C4 TURFGRASSES
Authors: Johnson Damon C. , Duysen Murray E , Lee Chiwon W.
Published: February 2019

The influences of elevated iron concentrations in the nutrient solution and light intensity on growth and the chlorophyll and chloroplast development in Kentucky bluegrass (Poa pratensis) `Touchdown' (C3), creeping bentgrass (Agrostis palustris) `Penncross' (C3), and buffalograss (Buchloe dactyloides) (C4) were investigated. Plants established in peatlite medium in 11-cm pots were fertilized with a Hoagland solution containing various iron concentrations (0, 0.01, 0.1, 1, 2, 4, 6, 8, 10 mM Fe+2) under two different light regimes. Preliminary results indicated that no biomass reduction or toxic symptoms developed in buffalograss when grown with iron levels up to 8 mM under high light conditions. As Fe+' levels were raised, plants became progressively greener with both the chlorophyll-a and chlorophyll-b contents increased. In Kentucky bluegrass, the sizes of chloroplasts and grana stacks in the cell were larger when grown with 2 mM than 0.05 mM Fe+2 in the fertilizer solution. The interactions of iron concentration and light intensity on pigmentation and photosynthesis of the three species are currently being determined.
950 PB 443 DOES WOUNDING BEFORE POLLINATION INCREASE SEED PRODUCTION IN SOLANACEOIJS PLANTS?
Authors: Muchmor Ellen K. , Taylor Loverine P.
Published: February 2019

Seed set is affected by many factors. One of the most important is the number of pollen grains that germinate on the stigma. Our research has shown that kaempferol (a plant natural product) is required for pollen germination. Pollen lacking kaempferol does not germinate, but this defect can be reversed by adding powdered kaempferol to the stigma at pollination. Within 24 hours of wounding the corolla or stamens of V26, a Petunia inbred, high levels of kaempferol accumulate in the stigma. The requirement for kaempferol in pollen germination, and the high levels that can accumulate in the stigma, suggested that seed set might be enhanced by wounding 24 hours before pollination. We tested this hypothesis in two inbred lines of Petunia, a Petunia outcross, and another solanaceous plant Nicotiana tobacum cv. Samsum. The number of seeds per capsule were correlated with the levels of kaempferol in the stigma in wounded and non-wounded flowers.
952 PB 449 HYDROGEN CYANAMIDE ENHANCEMENT OF FRUIT SET
Authors: Powell Jason C. , Lyons Calvin G.
Published: February 2019

The state of Texas suffers from a lack of chilling one out of every five years. Reduced yield in temperature fruit crops such as peach (Prunus persica) is one detrimental effect associated withinadequate chilling. Field trials with hydrogen cyanamide (Dormex) have demonstrated that a one to two percent solution applied six weeks prior to bloom will substitute for inadequate chilling of up to 150 hours. Field trials with this chemical have provided further insight into some other possible benefits associated with its use such as: increased marketable yields of fruit crops, enhanced fruit size, and an earlier more concentrated harvest. Advantages noted by the use of this product include a possible earlier crop and reduced labor costs.
956A PB 495 ASSAY FOR DETERMINING GLYPHOSATE TOLERANCE IN LACTUCA SATIVA
Authors: Gargiulo Jennifer A. , Nagata Russell T. , Bewick Thomas A.
Published: February 2019

An-assay was developed to determine the level of resistance to the herbicide glyphosate in trangenic seedlings of lettuce. Results of the seedling assay were correlated to results of a similar assay using callus lines of the identical transgenic plants. Transgenic plants were found to be a 32-fold increase in tolerance to glyphosate when compared to wild type plants. This was similar to the response of these transgenic lines in the callus line assay.
991 REGULATION OF PLANT GROWTH RESPONSES TO LOW SOIL WATER POTENTIALS
Authors: Shar Robert E.
Published: February 2019

Plant water deficits usually result in severe inhibition of shoot growth, while root growth is less inhibited or even promoted. Recent advances in understanding the physiology of the differential responses of root and shoot growth to low water potentials will be reviewed.

While it might be readily accepted that hormones arc important in transducing environmental conditions into growth responses, there is surprisingly little definitive evidence for the role of any hormone in regulating plant growth in soils of low water potential. Using maize seedlings as a model system, the increase in ABA that accompanies plant water deficits has been shown to be required for root growth maintenance, and also to play a role in shoot growth inhibition. The action of ABA in root growth maintenance appears to involve regulation of ethylene synthesis and/or sensitivity, while the mechanism of shoot growth inhibition is not known. Evidence that ABA acts as a root `signal controlling shoot growth in drying soil will also be considered.

The importance of osmotic adjustment as a mechanism of growth maintenance at low water potentials has been questioned by suggestions that solute accumulation may be merely a consequence of stress-induced growth inhibition. Recent studies will be discussed which do not support this idea, and suggest that the response may be useful for crop improvement.
992 STRESS TOLERANCE INDUCTION: THE ROLE OF ABA AND HEAT STABLE PROTEINS
Authors: Gusta L. V.
Published: February 2019

Plants acclimate to abiotic stresses, e.g. heat, freezing drought and salinity, in response to environmental cues such as temperature, daylength and water. Plants can respond within minutes to the cue e.g. heat tolerance or within hours or days, e.g. drought and freezing tolerance. Heat shock proteins are measurable within 20 to 30 minutes of a heat stress and the plants aclimate almost immediately. In contrast, proteins related to freezing tolerance are measurable within hours but days are required before a measurable increase in freezing tolerance can be detected. In almost all stresses it appears that the environmental cue effects the water status of the plant which in turn affects the level of endogenous abscisic acid (ABA). ABA has been implicated to ameliorate the stress by inducing genes to produce stress proteins. There is a certain degree of commodity between stresses in ragards to stress proteins, however each stress has their own unique set of stress proteins. For example heat shock proteins did not confer stress tolerance. Proteins involved in water and osmotic stress tolerance share a high degree of commonality. I” all stresses a unique class of proteins are synthesized which are classified as heat or boiling stable (do not coagulate at 100°). These proteins are suggested to be involved in the stress response. Many of these heat stable proteins are induced by ABA alone or in combination with jasmonic acid (JA). Analogs of ABA which are either slowly converted to ABA or are degraded slowly or taken up at a faster rate than ABA have been tested for the efficacy in inducing the stress responses. Analogs have also been identified which inhibit the ABA induced response. How these analogs may have practical significance will be discussed.
994 CALCIUM AND ITS ROLE IN PLANT STRESS RESPONSE
Authors: Palta Jiwan P.
Published: February 2019

In recent years evidence has been presented that implicates the role of free (cytosolic) Ca2+ as a major metabolic and developmental controller in plants. Calcium concentrations in the cytoplasm are kept very low under normal conditions (10-6 to 10-8 M). Small changes in the absolute amount of calcium can create a 10- to 100-fold change in the Ca2+ concentration without upsetting the ionic balance of the ceil. This feature makes Ca2+ an excellent candidate as a second messenger. Thus, a stress induced change in the cytosolic Ca2+ could bring a cellular/plant response to stress. This response is thought to be mediated through activation of Ca2+ and/or Ca2+-calmodulin-dependent protein kinases which in turn mediate the activity of various enzymes via phosphorylation. Recent evidences from the impact of salinity, low temperature, high temperature, and biotic stresses support such a role of calcium. Data on the association between stress-induced injury and perturbation of membrane/cytosolic calcium are available. In addition, evidences for the role of calcium in acclimation to stress have been reported. These studies suggest that manipulation of cellular Ca2+ may be one of the approaches we have on hand to bridge the gap between science and technology.
995 GENETIC ENGINEERING FOR CROP VIRUS RESISTANCE
Authors: Grumet Rebecca
Published: February 2019

One of the first major successes in the genetic engineering of useful traits into plants has been the engineering of virus resistance. The first example of genetically-engineered virus resistance was published in 1986, since then there have been more than 50 reports of genetically engineered plant virus resistance. These examples span a range of virus types, a variety of plant species, and have utilized several different types of genes. A unique feature of the genetically-engineered virus resistance is that the resistance genes came from the virus itself, rather than the host plant. Most examples have utilized coat protein genes, but more recently, replicase-derived genes have proved highly effective. Other strategies include the use of antisense or sense-defective sequences, and satellite or defective interfering RNAs. This talk will provide an overview of the different approaches, possible mechanisms, the crops and viruses to which they have been applied, and progress toward commercial applications.
996 NOVEL APPROACHES TO GENETIC RESISTANCE TO BACTERIAL PATHOGENS IN FLOWER CROPS
Authors: Kuehnle Adelheid R. , Chen Fure-Chyi , Sugi Nellie
Published: February 2019

Bacterial diseases continue to plague ornamental crops, Genetic resistance offers one way to manage disease; combined with use of indexed propagules and sanitation, it can be a powerful control. Classical breeding offers some genetic solutions. Introgression, by genetic engineering, of antibacterial genes derived from the Cecropiamoth is a second breeding approach which appears promising in other horticultural crops. A case study for control of Xanthomonas, species of which severely limit geranium, anthurium, and other ornamental production, is given for anthurium. Transgenic anthurium plants expressing or containing antibacterial genes coding for the antibacterial peptides Attacin, P13 and T4 lysozymes, and the modified cecropins Shiva and SB37 were produced and challenged with bacteria. Juvenile and adult plants showed various degrees of tolerance to bacterial blight. The implications of this approach to bacterial disease control in various ornamental cropping systems will be discussed.
998 CLASSICAL AND MOLECULAR APPROACHES TO BREEDING FRUIT AND NUT CROPS FOR DISEASE RESISTANCE
Authors: Mehlenbacher Shawn A.
Published: February 2019

Disease resistance is an objective of most breeding programs for small fruits, tree fruits, and nuts. Often a moderate level of resistance is adequate, and must be combined with many other desirable horticultural characteristics. Classical methods (a segregating population of the host plant is inoculated with a virulent isolate of the pathogen under environmental conditions appropriate for disease development) have been used with great success and have incorporated both horizontal and vertical resistance. Molecular approaches offer new opportunities and are likely to be appropriate and cost-effective in a few situations. Transformation is not yet routine in fruit and nut crops, and there is a shortage of useful genes. Genetic maps are being constructed using RFLP and RAPD markers in several species, allowing determination of number and location of important genes as well as indirect selection based on linked markers. This presentation will include examples of both classical and molecular approaches as they are used in the genetic improvement of fruit and nut crops with an emphasis on fungal and bacterial diseases.
1001 ANOXIA TOLERANCE OF MAIZE SEEDLING ROOTS
Authors: Cobb B. G. , Andrews D. L. , MacAlpine D. M. , Johnson J. R. , Drew M. C.
Published: February 2019

We have been examining the response of maize seedling roots to oxygen stress. Previously, we have shown that maize seedlings with primary root lengths of 10cm or greater require a pretreatment with low oxygen (hypoxia) for survival of greater than 12 hours of anoxia. During the pretreatment there is induction of mRNA and increase in enzymatic activity of alcohol dehydrogenase (ADH) and other enzymes that are necessary for alcoholic fermentation. However, we have found that younger seedlings do not need a pretreatment to survive anoxia. They appear to have high levels of ADH and other enzymes that are needed for anaerobic survival at levels equivalent to those that are induced in older seedlings. These results suggest that, at the time of seedling emergence, seedlings may be more adapted to oxygen stress than during later stages of growth.
1005 GENETIC AND MORPHOLOGICAL BASES FOR ROOT-BASED SEEDLING STRESS RESISTANCE
Authors: Zobel Richard W.
Published: February 2019

Different root types have different temporal and morphological patterns of development, functionality and adaptation. Root based adaptation to stresses can not be assessed on a root system basis, but must be employed on an individual root type basis. Three different types of root are developed by most seedlings: tap root, basal roots, and lateral roots. These have been demonstrated to have temporally and spatially different developmental and functional patterns. If a stress occurs prior to the onset of an especially sensitive type of root or after that type has shut down functionally, the seedling will demonstrate resistance, when it is not correctly resistant. Timing of screening treatments and scoring of the results is, therefore, extremely critical. Different genotypes within a species demonstrate strong differences in numbers and timing of root initiation and functional maturity for each of the root typos. In addition, different types of root demonstrate sensitivity/tolerance to different chemicals, suggesting that functionality and, therefore, resistance/tolerance mechanisms may differ. All root types present on a seedling must be scored for resistance/sensitivity to the stress, even if morphological/physiological symptoms are not readily apparent. The technology (knowledge, software and equipment) necessary to detect tolerance/resistance and to establish genetic selection schemes is available. Root type differences and the potential for genetic selection will be discussed.
1007 SYSTEMIC ACQUIRED RESISTANCE
Authors: Uknes S , Delaney T. , Vernooij B. , Friedrich L. , Williams S. , Chandler D. , Weymann K. , Kessmann H. , Alexander D. , Ward E. , Ciba Ryals J.
Published: February 2019

Systemic acquired resistance is a broad spectrum inducible defense response that is associated with the expression of a set of genes (SAR genes). Expression of one of these genes (PR-1a from tobacco) in transgenic tobacco confers increased tolerance to two oomycete pathogens.

A direct role for salicylic acid (SA) in signaling SAR has been established in tobacco by analysis of transgenic tobacco expressing salicylate hydroxylase (SAH, an enzyme that inactivates SA by conversion to catechol). Tobacco plants that express SAH are blocked in the accumulation of SA and the development of SAR when responding lo TMV. Furthermore, both Arabidopsis and tobacco expressing SAH have altered pathogen induced lesion morphology, exemplified by larger spreading lesions.

Putative mutants in SAR gene expression were isolated by screening M2 Arabidopsis plants for altered expression of PR-1 and PR-2 or for sensitivity to pathogen infection following INA treatment. The putative mutants all into two major classes,constitutive (cim, constitutive immunity) and non-inducible (nim, non-inducible immunity). Several cim mutants exhibits a disease lesion phenotype in the absence of pathogen.
1026 BEST MANAGEMENT PRACTICE FOR NITROGEN FERTILIZATION OF FLORIDA CITRUS IN DEEP SAND
Authors: Alva A.K.
Published: February 2019

Nitrate pollution of surfacial aquifer is fairly widespread in deep sandy soil areas of Central Florida. Since citrus is a predominant crop in this area, despite lack of conclusive evidence suggesting citrus fertilization as the source of nitrate pollution, investigations are in progress to develop Best Management Practice (BMP) recommendations for N fertilization of citrus in an effort to improve N use by the trees and to minimize potential nitrate leaching. Our ongoing studies on both young and mature trees have demonstrated that the use of improved fertilizer formulations and programmed application schedules have facilitated to decrease the rate of N application considerably without any adverse impact on tree growth and/or fruit production while minimizing nitrate leaching below the rootzone. Our approach involves developing BMP recommendations on the basis of iudicious irrigation management and generating database on N removal by the fruits, annual N contribution to the trees by mineralization of organic N, and N losses including leaching, denitrification, etc.