IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Physiological responses of spring rapeseed (Brassica napus L.) to red/far-red ratios and light irradiance on pre and post flowering stages
Autor/es:
RONDANINI, D; VILARIÑO, MP; ROBERTS, ME; POLOSA, M; BOTTO JF
Revista:
PHYSIOLOGIA PLANTARUM
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2014 vol. 152 p. 784 - 794
ISSN:
0031-9317
Resumen:
Early shade signals promote the shade avoidance syndrome (SAS) which causes  petiole and shoot elongation and upward leaf position among others. In spite of the importance of light signals for plant performance, these photomorphogenic responses have not been deeply studied in rapeseed (Brassica napus L.). In opposition to other crops like maize and wheat, rapeseed has a complex developmental phenotypic pattern as it evolves from  an initial rosette, to the main stem elongation and an indeterminate growth of floral raceme. In this work, we analyzed i) morphological and physiological responses at individual plant level due to changes in red/far-red (R/FR) ratios during the vegetative and reproductive phases of development, and ii) changes in biomass allocation, grain yield and grain composition at crop level in response to light quality and quantity in two modern spring rapeseed genotypes. We carried out pot and field experiments modifying R/FR ratios and irradiance at vegetative or reproductive stages. In pot experiments, low R/FR ratio increased thepetiole and lamina length ,caused an upward leaf position, and also accelerated leaf senescence. Furthermore, irradiance and secondarily R/FR signals reduced main floral raceme and increased floral branching with higher remobilization of soluble carbohydrates from the stems. In field experiments, low irradiance during post flowering reduced grain yield, harvest index and grain oil content, and high R/FR ratio reaching the crop partially alleviated such effects. Our results suggest that photomorphogenic signals are integrated early during the vegetative growth in spring rapeseed, and light intensity produces stronger effects than R/FR signals at crop level.