102(3)_str39

 

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 102, No. 3 (2015), p. 305–312
DOI 10.13080/z-a.2015.102.039

Chlorophyll a fluorescence of perennial ryegrass (Lolium perenne L.) varieties under long term exposure to shade

Piotr DĄBROWSKI, Bogumiła PAWLUŚKIEWICZ, Aneta Helena BACZEWSKA, Paweł OGLĘCKI, Hazem KALAJI

Abstract

The perennial ryegrass is the species widely used in Europe as forage as well as for creating lawns in urban areas. Unfavourable light conditions in cities are the principal reason of improper growth and functioning of grass communities. The aim of our work was to answer the following questions: what is the adaptive ability of photosynthetic apparatus of perennial ryegrass varieties to long-term reduction of solar radiation and which of the tested varieties has the best properties to be used for grassland establishment under reduced light conditions. A two-factor experiment was conducted with three varieties and three shading variants. Measurements of chlorophyll a fluorescence were provided, and the basic assessed parameters were: minimal fluorescence (F0), maximal fluorescence (Fm), variable fluorescence (Fv) and maximal photosynthetic efficiency of photosystem II (Fv/Fm). Gas exchange was also measured. We explored the differences between the selected varieties in terms of their photosynthetic apparatus adaptation to light conditions. During May, all varieties were characterized by increase in minimal and maximal fluorescence levels under reduced light. The most significant changes were noticed for variety ‘Taya’. During following months, a trend of decline in photosynthetic efficiency was observed for this variety. For this variety the most significant changes of CO2 were also noted. The stomatal conductance was not affected by shading. On the basis of our results, we have assumed that each variety is unique in terms of threshold values and demand for light.

Key words: chlorophyll a, grasses, green infrastructure, lawns, light, Lolium perenne, photosynthesis, unfavourable light conditions.

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