A mechanistic model for vegetative vigor in grapevine

HUGALDE, I.; AGÜERO, C.; M. A. WALKER; ROMERO, N.; BARRIOS-MASIAS, F.; MCELRONE, A.; NGEN, H.; RIAZ, S.; ARANCIBIA, C.; VILA, H.

VERONA

Simposio; X International Symposium on Grapevine Physiology and Biotechnology; 2016

Mechanistic modelling constitutes a valuable tool for researchers and biophysists to study diversebiological phenomena. This study describes the construction of a theoretical model for plant vigor.The model conceives vigor as the result of the interaction of ambient, external stimuli and plant,physiological behavior. As the ambient stimuli, we consider soil and atmospheric conditions. Soilwater status directly affects root hydraulics. Atmospheric humidity, water vapor pressure deficit,light and temperature will affect leaf water potential and stomatal conductance. These responses toenvironment will influence the plant gas exchange as well as tissue turgor and plant growth. These,also influenced by hormonal signals, will determine the total C assimilation and biomasspartitioning affecting plant growth and vigor. To parameterize and test our model we studied the F1progeny from a cross between Ramsey and Riparia Gloire de Montpellier, rootstocks that conferhigh and low vigor, respectively. We evaluated 138 genotypes from this cross, three replicates each,for 60 days in a greenhouse at UC Davis, California, in the summer of 2014 and 2015. Each plantwas pruned to a single shoot and watered daily. In 2014, after day 45, 50 genotypes were subjectedto a 50% water deficit based from initial weight at full pot capacity. Shoot growth rate, leaf area anddry biomass were measured for the complete population (including the stressed subset), whilehydraulic conductance, stomatal conductance, water potential and chlorophyll content weremeasured for the subset. In 2015, we repeated the same evaluation, adding photosynthesis and roothydraulic conductance measurements for the complete own-rooted population and a grafted subset,with Cabernet sauvignon scion.Future perspective is to complete the model and validate it. Our mechanistic model may constitutean interesting tool for plant growth studies, in grapevine or any other species.