Are Vitis vinifera L. plants blind to see their neighbours?

GONZÁLEZ CARINA V.; VILA HERNÁN; JOFRÉ MARÍA FLORENCIA; BOTTINI RUBÉN; GIORDANO, CARLA V.

Córdoba

Congreso; 16th International Congress on Photobiology; 2014

International Union on Photobiology

Low red:far-red (R:FR) ratios perceived by phytochromes are an indication fo canopy shading and of the proximity of plant neighbors. Many plant species favor stem elongation as part of the shade avoidance síndrome (SAS) to escape from neighbours and succeed in competition for light. Phytochromes also regulate anatomical and physiological parameters involved in plant wáter relations and carbón economy, and participates in responses to different stresses (ei.e. drought, cold, herbivory and pathogens). Thus phytochromes act as integrators of different environment signals. Many crop management decisions and cultural practices can alter the light environment experienced by crops and hence affect important agronomical traits sucha as yield and fruit quality. This study aimed to asses the photomorphogenic performance of the primary cultivated grape species, Vitis vinífera L. in response to different light environments. We evaluated anatomical, morphological and physiological traits involved in plant architecture, wáter and carbón balance and drought tolerance. Pot-gown plants of Syrah and Torrontés Riojano cultivated in a greenhouse were exposed to lateral illumination with FR radiation that reduced the lateral R:FR ratio, mimicking the proximity of other plants. None of the cultivars showed differences in stem growth, internode length, petiole length and angle, leaf área, leaf thickness, photosynthetic pigments, stomata density and stomata indez in response to the light treatment; as well, there were no differences in stomatal conductance (gs), plant conductance (K), stem hydraulic conductivity (Kmax) and in the components of leaf wáter potential estimated through pressure-volume analysis. However, both varieties showed increases of GA1, GA3 and IAA leaf-levels but not in ABA, suggesting that phytochrome light signalling is uncoupled in this species. Grapevines performance under shade conditions and the implications of our results will be discussed in an agronomical context