PARENT SESSION
Oral Session #19: Plant Competition. Presiding: N. Slade.
Monday, August 6, 2001. 1:00 PM to 5:15 PM. Hall of Ideas J.
Self/non-self responses in roots.
Novoplansky, Ariel1, Falik, Omer2, 1 2
ABSTRACT- The size and architecture of root systems is often influenced by competition for limiting resources. Adaptive considerations predict that plants should minimize allocation in competition with self and maximize allocation in competition with non-self roots. We developed an experimental system in which pea plants (Pisum sativum L. var Dunn) were grown with two symmetrical shoots and roots ("split plants"). The split plants were grown in individual pots having the same spatial arrangement and in one of the following configurations: (a) INTACT plants, (b) SEVERED plants: the two sectors of the plant were severed from each other, and (c) COMBINATION plants: each pot was shared by two sectors that originated from two different split plants. After 18 days SEVERED plants produced more and longer side roots than INTACT plants and COMBINATION plants produced more and longer side roots than SEVERED plants. The results suggest that (a) Peas avoid competition with self and allocate more resources in competition with non-self roots, (b) The self/non-self discrimination is based on physiological correlation between organs that develop on the same plant rather than genetic recognition.
KEY WORDS: self/non-self, roots, competition, plasticity