Limited linkages of aboveground and below ground phenology: A study in grape

Authors: RADVILLE, LAURA - PENNSYLVANIA STATE UNIVERSITY; BAUERLE, TARYN - CORNELL UNIVERSITY; Comas, Louise; MARCHETTO, KATHERINE - PENNSYLVANIA STATE UNIVERSITY; LAKSO, ALAN - CORNELL UNIVERSITY; SMART, DAVID - UNIVERSITY OF CALIFORNIA; DUNST, RICHARD - CORNELL UNIVERSITY; EISSENSTAT, DAVID - PENNSYLVANIA STATE UNIVERSITY

Submitted to: American Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2016
Publication Date: 11/8/2016
Citation: Eissenstat, D.M., Bauerle, T.L., Marchetto, K.A., Comas, L.H., Radville, L., Lakso, A.N., Smart, D.R., Dunst, R. 2016. Limited linkages of aboveground and belowground phenology: A study in grape. American Journal of Botany. 10.3732/ajb.1600212.
DOI: https://doi.org/10.3732/ajb.1600212

Interpretive Summary: Plant growth and development has important implications for plant resource use, carbon fluxes, and interactions with other organisms. Although aboveground growth has been well studied, the timing of root growth is not well understood and controls on root growth unclear. We examined root growth of grape vines with cameras in a five year study in Fredonia, New York, and a three year study in Oakville, California. In contrast to previous reports there was a single yearly root flush at both sites but with high variability in timing and amount of root growth among years. In both locations, abiotic variables were generally poor predictors of absolute root growth, suggesting absolute root production is more closely linked to vine physiology. However, using multiple regressions with data from New York, we found strong predictors of relative cumulative root growth by days after bloom and air temperature. Growing degree days and air temperature combined were nearly as strong, and more practical for predictions at off-site locations. The model provided good estimates of timing of cumulative root growth in CA, despite the different climate. Relative cumulative production seems related to increased air temperature, which may be affected with a changing climate.

Technical Abstract: Plant phenology has important implications for plant resource use, carbon fluxes, and interactions with other organisms. Although aboveground phenology has been well studied, the timing of root growth is not well understood, and controls on the timing of growth unclear. We used minirhizotrons to examine the timing of grape root production over five years in Fredonia, New York, under a humid continental climate, and over three years in Oakville, California, a region with a Mediterranean-type climate. In contrast to previous reports of a bimodal root production pattern, at both sites there was typically a single yearly root flush but with high variability in timing and amount of root growth among years. Both in New York and California, abiotic variables were generally poor predictors of absolute root growth. These findings indicate that many factors besides current season’s abiotic conditions affect absolute root production. However, using multiple regression with data from New York, we found strongest predictors of relative cumulative root growth (fraction of total annual production) by days after bloom and air temperature. Degree days and air temperature combined were nearly as strong, and we suggest that for off-site forecasting, these meteorological variables can be more practical for predicting timing of cumulative root growth. Additionally, the model provided a fairly good estimate of timing of cumulative root growth in CA, despite the distinctly different climate. Relative cumulative production seems related to increased air temperature, which may be affected with a changing climate.