The effect of light and temperature on the growth of two subtropical and two temperate grass species

The effect of light intensity and temperature on the growth of young plants of two temperate (Lolium perenne, Festuca arundinacea) and two subtropical (Lolium rigidum, Bromus unioloides) grass species was studied in the northern part of the GDR under open-air conditions. It was found that the subtropical species reacted highly sensitive to changes in the two environmental factors and showed absolutely higher growth performance during the summer as compared with the temperate species. The multiple regression analysis showed positive correlations between the relative growth rate (RGR) and the net assimilation rate (NAR) on the one hand and temperature and light intensity on the other hand. For most regression functions the range of variation was found to be between 63.5 and 91.3 per cent. No clear proof could be found of the dependence of the leaf area ratio (LAR) on light and temperature. The results are discussed and compared with similar investigations.