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Several cinnamic acids have been identified as principal toxic components of asparagus (Asparagus officinalis L.) root autotoxin and have been shown to synergize Fusarium infection of asparagus. The basis for this synergism was studied by exposing asparagus seeds and radicles from pregerminated seeds to ferulic (FA), caffeic (CA), or methylenedioxycinnamic (MDA) acids alone and in combinations of two or three of these acids. After treatment, seeds were placed in pots of peat-lite mix, and, depending on the experiment, all or half were inoculated with F. oxysporum (Schlecht) f. sp. asparagi (Cohen). Seedling emergence from each pot was used as a measure of toxicity. All cinnamic acids at 1% suppressed emergence compared with the control. Solutions combining FA and CA (0.5%/0.5%, v/v) were substantially more toxic than 1% solutions of either alone. Exposure of radicles (early postgermination) for 10 minutes to combined FA/CA before planting decreased emergence from pots, whereas emergence following a 10-minute exposure to 1% CA or FA alone did not differ from the controls. The 2-hour exposure to FA or to FA/CA and the 24-hour exposure to CA, FA, or FA/CA decreased emergence, with toxicity progressing as follows: CA < FA < FA/CA. Root tip squashes showed fewer mitotic figures in treated than in untreated radicles, and scanning electron microscopic (SEM) examination of the radicle epidermis revealed damage to the surface of epidermal cells and precocious root hair development, the extent of which paralleled treatment toxicity.

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Asparagus (Asparagus officinalis L.) seedlings inoculated with the sicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum (Thaxt. sensu Gerd.) Gerd. & Trappe (GF) d Fusarium oxysporum (Schlect.) Snyd. & Hans. (FO) were grown under field and greenhouse conditions. In the fi, shoot volumes of GF-inoculated plants were greater than nonGF plants from the 3rd through the 13th month of growth. By the 14th month, GF-inoculated plants grown in high-P soils had significantly lower disease ratings than nonGF plants grown in low-P soils, and rhizosphere populations of FO were lowest in high-P soils, regardless of VAM status. In greenhouse studies, FO inoculation of VAM-infected asparagus plants reduced GF root colonization levels under well-watered (0 MPa), but not under water stress, conditions (- 1.5 MPa). Well-watered plants inoculated with both FO and GF were less diseased and sustained lower rhizosphere populations of FO than plants inoculated with FO alone. The differences in FO populations and disease ratings in these studies were apparently unrelated to final plant tissue P levels.

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Freshly harvested asparagus (Asparagus officinalis L.) spears were exposed to an anaerobic N2 atmosphere for 0, 2, 4, or 6 hours at 2.5 or 20C and then returned to 2.5C. Carbon dioxide production was measured each day, starting 3 days before and ending 11 days after the treatment. Significant increases in CO2 production relative to 0-hour controls were found within 1 day of treatment at 20C and were directly proportional to the duration of the anaerobic exposure. At 2.5C, CO2 production relative to the 0-hour control was stimulated by the 2- and 4-hour treatments and depressed by the 6-hour treatment, with the relative rate of production inversely proportional to the duration of the anaerobic treatment. A decrease in CO2 production occurred 7 days after N2 treatment, regardless of temperature. A sensory panel evaluated effects of treatments on appearance quality 7 and 15 days after treatment and on taste quality 4 days after treatment. Judges could not detect any significant differences between anaerobic treatments and control. No significant difference was found in the percent of decayed asparagus among treatments as detected by visual evaluation 6 days after treatment. It appears that exposure to an anaerobic N2 atmosphere for up to 6 hours was not detrimental to the storability or quality of harvested asparagus spears. These results indicate that cooling with vaporized liquid N2, during which an anaerobic atmosphere could be produced before the spears were significantly cooled, would not reduce subsequent quality or storability.

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The influence of two drying regimes and two storage temperatures of primed asparagus (Asparagus officinalis L.) and tomato (Lycopersicon esculentum Mill.) seeds on germination after storage up to 3 months was examined. Seeds of `Mary Washington' asparagus and `Ace 55' tomato primed in synthetic seawater (-1.0 MPa, 20C, 1 week, dark) were surface-dried at 20C and 50% relative humidity (RH) for 2 h (42% to 49% moisture) or dried-back at 20C and 32.5% RH for 48 h (moisture = 13% tomato and 22% asparagus). These and nonprimed seeds were stored in tight-lidded metal cans and heat-sealed plastic pouches at 4 or 20C for up to 3 months before germination at 20C. After 3-month storage, primed surface-dried asparagus seeds stored at 4C had greater germination percentage and rate than nonprimed seeds, surface-dried seeds stored at 20C, or primed dried-back seeds. Dried-back primed tomato seeds had higher germination percentage than surface-dried primed seeds after 2 or 3 months of storage, with storage temperature having no effect on germination perecentage or rate. In a further study, primed surface-dried and primed dried-back seeds stored at 4 or 20C for 1.5 months in sealed containers were germinated at 15, 25, or 35C under low (-0.05 MPa) or high osmotic stress (-0.4 MPa). Primed surface-dried asparagus seeds stored at 4C, compared to nonprimed seeds, surface-dried seed stored at 20C, or primed dried-back seeds, had greater germination percentage at 15 and 35C and low osmotic stress, and higher germination rate at 15 or 25C. Primed tomato seeds had greater germination percentage than nonprimed seeds only at 35C and low osmotic stress, and higher germination rate at 15 or 25C. Storage of primed tomato seeds at 4C rather than 20C increased germination rate at 15 or 25C, and increased germination percentage at 35C and low osmotic stress. For maximal seed viability and germination rate after 1.5 to 3 months of storage, primed asparagus and tomato seeds should be stored at 4C rather than 20C; however, asparagus seeds should be surface-dried, and tomato seeds should be dried-back.

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Abstract

In propagating Asparagus officinalis L. through the method of shoot apex culture, apices of terminal buds of spears produced in vitro were found to be equally satisfactory as explants as those of lateral buds of spears obtained from the field. A maximum number of plants was obtained when the cultures were illuminated 4-20 hr daily with white fluorescent or Gro-Lux lamps at an intensity of 1000 lux. A constant 27°C temp was also optimum for plant formation in vitro. Histological examination revealed that roots arose adventitiously from callus which formed at the base of the explant, whereas spears originated from axillary buds.

Successful transfer of plants from laboratory to soil required a prior reculture in a medium lacking NAA and with the light intensity increased to 3000 or 10,000 lux. Examination of the chromosome numbers of plants propagated through shoot apex culture showed that the original diploid status had been retained in every plant.

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( Dransfield et al., 2008 ), Asparagus officinalis ( Park et al., 2003 ), Swietenia macrophylla ( Gouvêa et al., 2008 ), Rumex acetosa ( Ainsworth et al., 2005 ), and Vitis vinifera ssp. silvestris ( Caporali et al., 2003 ) belong to model I. However

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Asparagus (Asparagus officinalis L.) transplants and in vitro-cultured clones were grown and acclimatized under two photosynthetic photon flux (PPF) conditions (ambient and ambient + 80 μmol·s-1·m-2) and three atmospheric CO2 concentrations (330, 900, and 1500 ppm). Short- and long-term effects were measured in the greenhouse and after two seasons of growth in the field, respectively. In the greenhouse, CO2 enrichment (CE) and supplemental lighting (SL) increased root and fern dry weight by 196% and 336%, respectively, for transplants and by 335% and 229%, respectively, for clones. For these characteristics, a significant interaction was observed between SL and CE with tissue-cultured plantlets. In the absence of SL, CE did not significantly increase root or shoot dry weight. No interaction was observed between CE and SL for transplants, although these factors significantly improved growth. It was possible to reduce the nursery period by as much as 3 weeks with CE and SL and still obtain a plant size comparable to that of the control at the end of the experiment. Long-term effects of SL were observed after two seasons of growth in the field. Supplemental lighting improved survival of transplants and was particularly beneficial to in vitro plants. Clones grown under SL were of similar size as transplants after 2 years in the field.

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Abstract

Asparagus (Asparagus officinalis L. Cv. Cal. 711) grown both from seed and 1-year old crowns was maintained in a zero-tillage cultural system for 4 years and compared with that grown in a conventional tillage system. In the first 3 harvest seasons, yields of asparagus produced from crowns were increased 27% in the zero-tillage system. Asparagus from seed yielded as much as that from crowns after the third year, but spear size was appreciably smaller. Paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) in combination with either simazine (2-chloro-4,6-bis(ethylamino)-s-triazine), monuron (3-(P-chlorophenyl)-1,1-dimethylurea), or terbacil (3-tert-butyl-5-chloro-6-methyluracil) provided excellent weed control during each growing season without injuring asparagus. Rotary chopping was a satisfactory method for returning mature brush to the soil. Additional advantages of zero-tillage were a reduction in volunteer asparagus seedlings, improved late season weed control, and less mechanical injury to crowns and buds. This cultural system provided excellent weed control in fields produced by direct seeding where crown depth was shallow and tillage impractical.

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Abstract

A nutrient medium which enabled rapid formation of new spears and roots in shoot apices excised from buds as well as lateral branches of Asparagus officinalis L. spears was developed. This medium was composed of the following, in mg/1 : Murashige and Skoog’s inorganic salts; NAA, 0.3; kinetin, 0.1; thiamin·HC1, 1.0; pyridoxin·HCl, 5.0; nicotinic acid, 5.0; myo-inositol, 100; adenine sulfate·dihydrate, 40; sucrose, 25,000; Difco Bacto malt extract, 500; NaH2PO4·H2O, 170; and Difco Bacto agar, 6000. The shoot apices were cultured under 1000 lux Gro Lux or Plant Gro light and at constant 27°C. The explants were 0.15 mm in height and composed of the apical meristem plus a few visible subjacent primordial leaves. Within 6 weeks an avg of 80-90% of the cultures developed into miniature plants with several spears and roots. These plants, however, could not be transferred to soil with much success. The transfer necessitated further culture under another set of conditions, details of which are currently under investigation. The nutrient medium was inapplicable to shoot apex cultures of A. densiflora (Kunth) Jessop cv. Meyers, A. densiflora (Kunth) Jessop cv. Sprengeri, and, A. sarmentosus (Hort.).

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roles in carbohydrate metabolism and in the modulation of plant development ( Anne et al., 2011 ; Jain et al., 2008 ; Koch, 1996 ). For example, increased activity of acid invertase might be correlated with the senescence of asparagus ( Asparagus

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