Library Dissertation Showcase

Brassica rapa: responses to UV-B radiation and nitrogen addition

  • Year of Publication:
  • 2020

The rising level of climate change is resulting in detrimental damage to many plant species. The concern of increasing UV-B radiation has led to several studies reporting of the effects of UV-B radiation, however few studies consider interacting environmental factors. It is known that nitrogen deposition is rising as a result of increasing air pollution, this study therefore looks at the interaction of UV-B and nitrogen addition on the plant species Brassica rapa. The crop species, rapid cycling Brassica rapa was grown under 2 conditions of differing UV-B exposure in plant growth chambers, that controlled for temperature and humidity. Along with this, plants were grown in 3 differing levels of nitrogen addition (N0, N1, N2). The study was conducted over 24 days, to which parameters for growth including height, fresh and dry mass were measured along with petal size and UV absorbing compounds. It was found that UV-B exposure alone caused significant differences in height, and caused differences in floral phenology. Furthermore, the addition of nitrogen resulted in substantial differences in height, decreases in leaf size and also caused an increase in UV absorbing compounds. More interestingly, the interaction of UV-B and nitrogen caused B. rapa to have an increased sensitivity to UV-B, which caused delayed germination, decreases in dry mass but saw an overall increase in petal size. The results of this study suggest that enhanced UV-B radiation caused detrimental damage to B. rapa, by damaging the photosynthetic capacity, whilst the addition of nitrogen enhanced plant growth, until plants reached nitrogen saturation. The interaction however, had a negative effect, as nitrogen was seen to mediate plant responses and sensitivity to UV-B, suggesting an interplay of these two factors. Further research is therefore needed into this interaction and other factors, to predict the future of plants in our changing climate.

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