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Despite its value as a crop and potential utility as an experimental system, relatively little is known about the molecular-genetic aspects of inheritance or physiology in the cultivated strawberry (Fragaria xananassa). This lack of information exists at a time when biotechnology may offer important remedies to address traditional and contemporary challenges that growers face. An improved understanding of genome structure will hasten the development of molecular markers and unveil clues to the composition of this unique, octoploid genome. Definition of gene function will guide the generation of transgenic resources for research use and possibly toward cultivar development. This review seeks to compile and present the current knowledge state of the molecular-genetic basis of cultivated strawberry genomic form and function. Ongoing studies promise to expand the use of genomic tools and appropriate model systems to rapidly discern the structural and functional basis for traits of interest to agriculture, such as those associated with disease, ripening, and volatile production. Together these studies bring new molecular tools to dissect complex traits, implement marker-assisted selection and address important physiological questions in the cultivated strawberry, the Fragaria genus, and the Rosaceae family. 相似文献
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The possible involvement of polyamines during strawberry ( Fragaria × ananassa Duch.) fruit development was investigated. Putrescine, spermidine, and spermine were identified in strawberry receptacles and achenes at all stages of development. Total (free) polyamine levels decreased from a maximum of 485 nmol g−1 fresh weight at pollination to a minimum of 55 nmol g−1 fresh weight in ripe receptacles. Total polyamine concentrations during corresponding stages of development were consistently higher in achenes than in receptacles, and ranged from 891 to 203 nmol g−1 fresh weight. Removal of achenes from the surface of developing receptacles 10 days after pollination reduced receptacle growth, and re-initiation of growth by application of 1 m M α-naphtaleneacetic acid (α-NAA) was accompanied by a rapid increase in polyamine concentrations 24 h after treatment. Polyamine content per receptacle increased >3-fold in normally developing receptacles and in de-achened, auxin-treated receptacles 10 days after removal of achenes, but did not increase during this period in de-achened receptacles not treated with exogenous auxin. α-NAA increased growth and polyamine levels to a greater extent than the structurally related, but less effective auxin, β-NAA. Polyamine concentrations in receptacles with intact achenes remained similar to those of auxin depleted (de-achened) receptacles, implying that the concentration of these compounds may not be limiting following achene removal. 相似文献
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Ethanol at 50% (v/v) and sodium bicarbonate at 1% (wt/v), either alone or in combination, were applied to organically grown strawberries 1 h before harvest to control the natural incidence of postharvest diseases. Botrytis cinerea was the major cause of decay in all of the experiments. In three experiments, ethanol significantly reduced the decay incidence after storage for 3 days at 1°C followed by 2 days at 24°C, while the efficacy of sodium bicarbonate was inconsistent. The combination of ethanol and sodium bicarbonate did not increase their efficacy. Postharvest hot water dips at 55 and 60°C for 30 s significantly reduced the decay incidence to 3.4 and 2.7%, respectively, while decay incidence in the control was 28.5% (the first experiment). The efficacy of the hot water treatments at 55 and 60°C for 30 s was consistent in three experiments. In the third experiment, the efficacy of hot water treatment at 60°C was significantly higher than that of hot water treatment at 55°C. All pre‐ and postharvest treatments significantly reduced natural fungal populations on the surfaces of fruits. None of the pre‐ and postharvest treatments caused surface injuries to the fruit or adversely affected weight loss and taste parameters. 相似文献
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Three-millimeter-long shoot tips of strawberry 'Senga Sengana' and raspberry 'Norna' encapsulated in calcium alginate were stored in vitro at 4 °C in the dark. The cultures which were donors for the shoot tips were grown before encapsulation on shoot multiplication media (Boxus medium with 2.2 µM BAP and 2.46 µM IBA for strawberry, and MS medium with NH4NO3 and KNO3 reduced by 50%, and with 3.55 µM BAP and 0.49 µM IBA for raspberry) as well as on these media supplemented with 10 g l–1 mannitol or paclobutrazol (1.7 µM for strawberry and 3.4 µM for raspberry). Sodium alginate was dissolved in water, water with sugar or in a culture medium without growth regulators. Regrowth ability of the stored explants and in vitro multiplication in three successive subcultures were evaluated. The encapsulated shoot tips could be stored for 9 months in beads containing sugar or a culture medium. The pre-conditioning of the donor cultures on a mannitol containing medium was beneficial for regrowth ability. The multiplication rate of strawberry and raspberry shoots in the first subculture after storage was lower than that of non-stored cultures. Particularly low multiplication was obtained for strawberry which had been stored for 9 months and for raspberry stored for 3 and 6 months, in combinations where the beads were prepared by dissolving sodium alginate in water. Multiplication of strawberry in the second subculture was generally higher than in non-stored cultures, but multiplication of raspberry was lower also in the second subculture, with the exception of the combination stored for 9 months and pre-cultured on mannitol. In the third subculture, shoot multiplication in both species was similar to that in non-stored cultures. 相似文献
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Transpiration, xylem water potential and water channel activity were studied in developing stolons and leaves of strawberry (Fragaria × ananassa Duch.) subjected to drought or flooding, together with morphological studies of their stomata and other surface structures. Stolons had 0.12 stomata mm–2 and a transpiration rate of 0.6 mmol H2O m–2 s–1, while the leaves had 300 stomata mm–2 and a transpiration rate of 5.6 mmol H2O m–2 s–1. Midday water potentials of stolons were always less negative than in leaves enabling nutrient ion and water transport via or to the strawberry stolons. Drought stress, but not flooding, decreased stolon and leaf water potential from –0.7 to –1 MPa and from –1 to –2 MPa, respectively, with a concomitant reduction in stomatal conductance from 75 to 30 mmol H2O m–2 s–1. However, leaf water potentials remained unchanged after flooding. Similarly, membrane vesicles derived from stolons of flooded strawberry plants showed no change in water channel activity. In these stolons, turgor may be preserved by maintaining root pressure, an electrochemical and ion gradient and xylem differentiation, assuming water channels remain open. By contrast, water channel activity was reduced in stolons of drought stressed strawberry plants. In every case, the effect of flooding on water relations of strawberry stolons and leaves was less pronounced than that of drought which cannot be explained by increased ABA. Stomatal closure under drought could be attributed to increased delivery of ABA from roots to the leaves. However, stomata closed more rapidly in leaves of flooded strawberry despite ABA delivery from the roots in the xylem to the leaves being strongly depressed. This stomatal closure under flooding may be due to release of stress ethylene. In the relative absence of stomata from the stolons, cellular (apoplastic) water transport in strawberry stolons was primarily driven by water channel activity with a gradient from the tip of the stolon to the base, concomitant with xylem differentiation and decreased water transport potential from the stolon tip to its base. Reduced water potential in the stolons under drought are discussed with respect to reduced putative water channel activity. 相似文献
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