Leaf colour patterns, vegetative and sexual reproduction of Episcia ...

40000
50
Incoming light (Lux)
35000
30000
25000
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15000
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10
5
Temperature (°C)
0
0
8:00
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Figure 18: Measurement of incoming light (black) and temperature (grey) reveal the
conditions the plants had to deal with; the maximum amount of sunlight was 34000 Lux; the
highest temperature 43,4 °C.
Results: After a month a definite change in colour of red leaf areas could be observed in
those plants that were planted in sunny locations. They became brighter while in the already
bright areas the changes were not so obvious, though it seemed the green had intensified. Due to
the fact, that the photos were not taken under controlled lightning conditions it cannot be
ascertained that the differences in colour are not caused by the photo camera. With those plants
that were kept in dark places in the main building no change in colour could be observed. Even
the small amount of light was sufficient for the plants.
Furthermore no difference in leaf colouration was detected in newly developed leaves. Plants
with dark leaves developed further dark ones as well as plants with patterned leaves developed
further patterned ones et cetera.
Discussion: The fact that the sun exposed plants had to be protected from dying off using a
fine net as cover shows that the heightened amount of light irradiation posed a stress factor for
the leaves. It is obvious that Episcia lilacina is a shade plant, perfectly capable of dealing with low
light situations but unable to cope with large amounts of sun irradiation. They cannot
compensate the loss of water caused by the increased evaporation and start to wither.
Disturbances in photosynthesis via destruction of the chloroplast structure and in further
consequence changes of photosynthetic pigments in leaves caused by UV-B radiation are known
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