93

“9x6” b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity

93

5. The Plant Self.................................................................

Chapter 5

I believe a leaf of grass is no less than the journey-work of the stars.

— Walt Whitman

Overview: Plants have a strong sense of self though less obvious to us. Their
roots can distinguish kin from strangers. They “talk” to one another with vol-
atile chemicals and root exudates. They alert their neighbors when attacked
by herbivores. They fight against pathogens and even have an innate immune
system. Whereas animals roam around in search of friendly habitats, plants
readily switch their metabolic strategies to cope with local, unexpected environ-
mental changes. Their way of dealing with animals is subtle and clever. They
recruit animals to spread their genes by wrapping their seeds in tasty coatings.
They prevent being overeaten by making chemicals that are toxic to animals but
harmless to themselves.

Plants are sessile and spend their life in one place. When kicked, they do
not hit back or run away. We humans seldom accord a sense of self to these
fellow living things. Nevertheless, plants do have a self that they carefully
maintain and protect, silently. In this chapter I shall bring out some exam-
ples of how plants express their selves, mainly in three contexts: self-defense,
communication, and competition. The three are closely related, as commu-
nication is the key mechanism for defense and competition.

5.1 Plant Protection of Self

All animals directly or indirectly derive their energy from plants, which
in turn obtain their energy from the sun. Thus, plants are under pressure