PARENT SESSION
Poster Session #32: Plant Ecology I.
Wednesday, August 8, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Directional Self/Non-self Responses in Roots.

Falik, Omer¹, Reides, Perla¹, Gersani, Mordechai¹, Novoplansky, Ariel¹, ¹

ABSTRACT- Spatial distribution of roots is expected to affect competitive interaction between plants. In the current study we hypothesized that root development is influenced by the identity of neighboring roots. More specifically, we predicted that plants avoid competition with self and allocate more resources in competition with non-self roots. An experimental system was developed in which the growth of individual pea roots (Pisum sativum L. Dunn) could be followed in transparent pots while confronted by self roots on one side and similarly sized and distant non-self roots on their other side. After 18 days, the target roots developed 75% more and 66% longer side roots towards their non-self compared to their self neighbors. Additional experiments revealed that the ability of plants to differentiate between self and non-self neighbors was eradicated if their shoot was severed. It is suggested that pea plants are capable of minimizing competition with self roots and that this capability is based on whole-plant correlative controls that are not necessarily based on genetic recognition. The results demonstrate the implications of responses of individual organs and plants to interactions at higher population and community-levels.

KEY WORDS: self/non-self, roots, phenotypic plasticity, plant competition