The Green Plant as an Intelligent Organism - Communication in Plants: Neuronal Aspects of Plant Life - page 11

Future changes in resource availability are also predicted. Reflected far-
red light from vegetation is used by many plants to predict likely future
(not present) light competition and to initiate a variety of leaf and stem
phenotypic alterations to avoid or ameliorate this situation (Aphalo and
Ballare 1995; Ballare 1994; 1999; Novoplansky et al. 1990). Tendrils adjust
their circumnutation pattern to position themselves to appropriate sup-
ports and can unwind if the decision turns out later to be poor (Baillaud
1962; Darwin 1882; Von Sachs 1879) The stilt palm moves out of shade by
differential growth of prop roots (Trewavas 2003; 2004). When provided
withwateronlyonceayearyoungtreeseventuallypredictthewatersupply
and synchronize their growth and development accordingly (Hellmeier et
al. 1997).
1.4.3
Internal Assessment of Present State Before Phenotypic Change
A statement by Seeley and Levin (1987) discussing intelligent hive be-
haviour can be paraphrased for plants. “It is not too much to say that
a plant is capable of cognition in much the same way that a human being
is. The plant gathers and continually updates diverse information about
its surroundings, combines this with information about its internal state
and makes decisions that reconcile its well being with its environment.”
Examples of internal assessment are common. Thus, excessive cadmium,
salt, osmotic stress, high or low temperatures or mechanical stress which
normally kill can be subsequently resisted by pretreatments under milder
conditions (Amzallag et al. 1990; Baker et al. 1985; Brown and Martin 1981;
Henslow 1895; Laroche et al. 1992; Zhong and Dvorak 1995). Other exam-
ples include the degree of leaf abscission, senescence (Addicott 1982) or
guard cell behaviour in water stress but determined by previous N status
(Taiz and Zeiger 1998), interactions between N and light on shoot growth
(Trewavas 1986), the degree to which root growth is enhanced under water
deprivation dependent on light status (Bloom et al. 1985), or the different
effectsonbranchgrowthaccordingtowhetheronebranchisshadedorthe
whole tree (Henrikkson 2001; Honkanen and Hanioja 1994).
1.5
Conclusions and Future Prospects
Plants exhibit the properties of intelligent behaviour described by biologists
for other organisms and should consequently be regarded as intelligent too.
Many plant biologists have a passive view of plant growth and development