Phosphoinositides as central mediators of plant growth responses: As sessile organisms, plants must adapt to changes in their environment in order to to survive. Plant adaptation to a changing environment usually involves a change in growth, for example bending towards light (phototropism), reorienting to a vertical position after being blown horizontally by the wind (gravitropism), and altering the pattern of growth under hyperosmotic conditions. It is of much greater importance to a plant than to an animal to be able to distinguish between a short-term and a long-term stimulus prior to making a commitment to irreversibly alter their pattern of growth. While there are many reports of transient changes in Ins(1,4,5)P₃ in response to stimulation, only recently was it shown that a sustained increase in Ins(1,4,5)P₃ may be a requisite for plant cell elongation. Our studies of the gravitropic signal transduction cascade in maize pulvini indicate that a sustained increase in Ins(1,4,5)P₃ is essential for cell elongation in gravistimulated maize and oat pulvini (Perera et al., 1999, 2001).

Cellular functions of Phosphoinositides

The inositol headgroup

Cellular localization of phosphoinositides

Phosphoinositides as central mediators of plant growth responses

Unique properties of plant phosphoinositide metabolism

Inositol 1,4,5-trisphosphate regulates intracellular Ca²⁺ levels