Influence of UV-B radiation on developmental changes, ethylene, CO2 flux and polyamines in cv. Doyenne d'Hiver pear shoots grown in vitro |
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Authors: | Stefano Predieri Donald T Krizek Chien Y Wang Roman M Mirecki Richard H Zimmerman |
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Institution: | Consiglio Nazionale delle Ricerche, Centro Studi di Tecnica Frutticola, v. F. Re 6, 1–40126 Bologna, Italy;Climate Stress Laboratory;Horticultural Crops Quality Laboratory;Climate Stress Laboratory;Fruit Laboratory, USDA, Beltsville, MD 20705, USA. |
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Abstract: | In vitro shoots of cv. Doyenne ďHiver pear ( Pyrus communis L.) were irradiated under controlled environments for 6 h per day at 5 different levels of biologically effective UV-B radiation (UV-BBE). UV-B exposure caused a progressive increase in apical necrosis above background levels and stimulated leaf abscission. Shoots grown for 2 weeks at 7. 8 mol m−2 day −1 of photosynthetic photon flux (PPF) and treated with 8. 4 or 12. 0 kJ m−2 day −1 UV-BBE produced up to 4 times more ethylene than those given 2. 2 or 5. 1 kJ m−2 day−1 UV-BBE or untreated controls. Exposure of shoots to 12 kJ m−2 day −1 of UV-BBE caused an increase in free putreseine content after 4 to 14 days of irradiation. Shoots showed a decrease in CO2 uptake after 3 days of UV-B: thereafter, they appeared to recover their photosynthetic capacity. Under typical PPF conditions used in micropropagation (90 μmol m−2 S−1). 8. 4 kJ m−2 day −1 of UV-B radiation was injurious to realatively tender tissues of in vitro pear shoots: increasing the level of UV-BBE to 12 kJ m−2 day−1 produced even more adverse effects. |
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Keywords: | Carbon dioxide ethylene in vitro culture pear polyamine Pyrus communis UV-B radiation |
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