Maize leaves turn away from neighbors

MADDONNI, G.A.; OTEGUI, M.E.; ANDRIEU, B.; CHELLE, M.; CASAL, J. J

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Año: 2002 vol. 130 p. 1181 - 1189

0032-0889

In commercial crops, maize (Zea mays) plants are typically grown at a larger distance between rows (70 cm) than within the same row (16-23cm). This rectangular arrangement creates an heterogeneous environment in which the plants receive higher red light (R) to far-red light (FR) ratios from the inter-row spaces. In field crops, the hybrid DK696 showed an increased proportion of leaves toward inter-row spaces, whereas the hybrid Exp980 retained random leaf orientation. Mirrors reflecting FR were placed close to isolated plants to simulate the presence of neighbors in the field. In addition, localized FR was applied to target leaves in a growth chamber. During their expansion, the leaves of DK696  turned away from the low R/FR ratio signals, whereas Exp980 leaves remained unaffected. On the contrary, tillering was reduced and plant height was increased by low R/FR ratios in Exp980 but not in DK696. Isolated plants pre-conditioned with low R/FR simulating neighbors in a north-south row showed reduced mutual shading among leaves when the plants were actually grouped in north-south rows. These observations contradict the current view that phytochrome-mediated responses to low R/FR are a relic from wild conditions, detrimental for crop yield.