Original air date: 18 January 1995
Above is a graphical presentation of the timeline of the episode, below is a more detailed text version
Selected material
Life in the shadows in the undergrowth can be very difficult when you have hardly any light to use for your photosynthesis. Yet there are plants that manage with these conditions. One kind of such plants is the begonia.
Attenborough showing how a plant that is seemingly starved of any sunlight manages to use its meagre sunlight to its maximum by reflecting what the sun rays that get through the leaf (left) back upwards using reflection on top of the underlying leaves underneath it (right).
Another species of a begonia uses a different trick
The feeble light that does fall on the leaf is, through the tiny lenses on the light brown parts of the leaf, concentrated on the chlorophylls inside the leaf (where it is used for photosynthesis)
Late in the programme Attenborough shows how to use growth rings to check the age of the tree
On the left Attenborough’s finger points at a dark ring (winter growth) for the tree. In between two such lines there is obviously the growth in the intermittent summer. Counting those lines gives the age of the tree.