| Summary: | The growth of <I>Lolium perenne </I>S23 was studied under different conditions of temperature and shade in laboratory and in garden plots. Data on plant and leaf dry weight were used to establish simple growth models. In the laboratory three light intensities (330, 165 and 85 μmol m<SUP>-2</SUP>s<SUP>-1</SUP>) were combined with temperature regimes of 10/10, 15/10, 15/15, 20/10, 20/15 and 20/20 <SUP>o</SUP>C in a 16h-photoperiod. Harvests were made when each of the first three leaves were fully expanded. In garden plots light quantity, light quality, R:FR ratio, temperature and total rainfall were monitored with seedlings grown in natural light (control), two artificial shade conditions (50 and 25% from total light) or two natural shade conditions effected by use of young poplar trees. Harvests were made at 5 day intervals per experiments conducted in June, July 1992 and August, September and October 1991. As expected significant effects of both light and temperature were found on total plant dry weight and on leaf dry weight. Increasing shade decreased plant weight at the same developmental stage, but tended to increase leaf length. These effects became progressively larger at successive harvests. Light also affected leaf cell number. Variation was largest in leaf three at 20/20 <SUP>0</SUP>C in high light and decreased with shade and temperature. In field experiments the influence of temperature was greater than that of shade on plant and leaf dry weight, leaf length and number of leaves coinciding in the main with laboratory findings. In contrast, cell number was more variable with no clear effect of shade on final cell number per leaf.
|
|---|
