“As interesting as watching grass grow” is a cliché. It is
also indicative of the ignorance that most people have of the fascinating world
of plants.
Granted, it is not very interesting to watch plants grow in
real time. But if their growth is compressed into the time span of human
perception, as in the superlative films of Sir David Attenborough, or if you
measure their growth over time, you can discover some very interesting things
about them. While plants do not have intelligence, they adjust their growth to
their environments in ways that look intelligent to us. Plants have to make a
living, like everyone else, and their growth patterns allow them to do this. As
a seedling grows, its stem may actually do a little circular dance (circumnutation)
in search of light. As its leaves expand, their anatomical structure adjusts to
the amount of light: thinner leaves with more chlorophyll in shade, thicker
leaves with less chlorophyll in bright sun. Meanwhile the roots penetrate the
soil and proliferate their growth in patches that are rich in nutrients. Plants
have a limited amount of food stored in their cells, and they invest this food
in growth that is appropriate to their conditions: they invest more in roots if
the soil is dry, and more in leaves if the soil is moist. Plants also prepare
for the future, producing next spring’s buds the previous autumn. When the
leaves burst open from buds in the spring, you are seeing merely the expansion
of tissues that were built the previous year.
Perhaps watching grass grow in real time is not very
interesting, but to envision its growth over the course of days and weeks in
the real and complex world can be astonishing.
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