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Title: UV irradiance as an influence on growth, development and secondary products of lettuce and strawberries grown under polyethylene films
Author: Tsormpatsidis, Evangelos
ISNI:       0000 0001 3537 3008
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2008
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The current approach taken in horticulture is to use films that block UV radiation as studies have shown that blocking UV reduces insect pest population as well as the spread of diseases. However, blocking UV radiation can have a negative impact on aspects of quality since a number of studies have shown that increasing UV radiation can increase secondary compounds in plants such as health beneficial phenolics. Therefore a key aim of the study was to investigate the effect of increasing UV transmission on aspects of quality of two contrasting crops (lettuce and strawberries) in relation to growth and development. UV radiation had an inhibitory effect on lettuce growth whereas it promoted the synthesis of phenolic compounds. UVB (280-320 nm) accounted for the greatest increase in secondary products and the greatest reduction in yield suggesting that there could be a direct benefit to commercial production associated with the use of highly UV transmissive films. However, this study showed that the beneficial effects of UV transparent and UV blocking films can effectively be combined in a production system. The reduction in yield in response to UV radiation equId be primarily due to high metabolic cost of phenolic compounds as well as to internal shading to some extent due to the high anthocyanin accumulation. An increase in UV transmission increased early fruit production, hastened fruit colour development, increased firmness and increased the secondary compounds in strawberry fruit. This study showed that the increase in secondary compounds of commercial strawberry cultivars grown under highly transmitting films was not as profound as in the case of lettuce. However, wild strawber'ry species not only showed greater response to UV radiation compared to commercial cultivars but also had a significantly higher phenolic content. No inhibitory effects of natural levels UV radiation was observed on net photosynthesis and photosystem II suggesting that phenolic compounds may have effectively protected the photosynthetic apparatus.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available