Foraging for light: photosensory ecology and agricultural implications


Dr Carlos L. Ballaré, IFEVA, Departamento de Ecología, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, (1417) Buenos Aires, Argentina.


This mini-review is concerned with one of the facets of the sensory physiology of plants that, in the last decade, has been intensively studied using genetically altered plants and eco-physiological techniques – the perception of the proximity of neighbouring plants through specific informational photoreceptors. We focus on the signalling mechanisms that allow individual shoots to ‘forage’ for light in patchy and highly dynamic canopy environments. We present evidence from recent experiments suggesting that the fitness of each individual plant in the population, the growth of the population as a whole, and the degree of growth inequality among neighbours are all strongly dependent on the timing and precision of foraging mechanisms controlled, at least partially, by phytochrome-B-like phytochromes. This evidence is discussed in the context of potential impacts on yield of agricultural crops resulting from the artificial alteration of plant sensitivity to proximity photo-signals. Directed overexpression of phytochrome genes appears to be an interesting avenue to explore in order to alter the photomorphogenesis of specific organs (or developmental stages) without affecting the overall ability of the plants to forage for light.