Nitrate uptake and transport properties of two grapevine rootstocks with varying vigor

Authors: ROSSDEUTSCH, LANDRY - Oregon State University; Schreiner, Roger; SKINKIS, PATRICIA - Oregon State University; DELUC, LAURENT - Oregon State University

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2020
Publication Date: 1/18/2021
Citation: Rossdeutsch, L., Schreiner, R.P., Skinkis, P.A., Deluc, L. 2021. Nitrate uptake and transport properties of two grapevine rootstocks with varying vigor. Frontiers in Plant Science. 11. Article 608813. https://doi.org/10.3389/fpls.2020.608813.
DOI: https://doi.org/10.3389/fpls.2020.608813

Interpretive Summary: Grapevine rootstocks are used extensively in viticulture and play an important role in how well the scion grows, which is believed to be driven by a rootstocks ability to acquire nitrogen from soil and transport it to the shoot. However, the mechanisms that govern nitrogen uptake and transport to shoots are not understood. We investigated the nitrogen uptake and transport properties of two rootstocks that are known to differ in how well they promote scion growth in a series of studies in grafted grapevines using Pinot noir scions to better understand how rootstocks influence shoot growth. The nitrate uptake kinetics in roots and the expression of key genes in nitrogen utilization pathways in roots were examined along with the transport of nitrate to leaves. The results showed that the rootstock known to impart greater scion growth transported more nitrate to leaves as a result of greater water movement to leaves when nitrogen supply was low or high. The less vigorous rootstock showed lower transport of nitrate to leaves and a greater allocation of vine biomass toward roots when nitrogen was low. These findings indicate that growth promotion of scions by grapevine rootstocks appear to be driven more by transport of nitrogen as compared to uptake kinetics from soil.

Technical Abstract: In viticulture, rootstocks are essential to cope with edaphic constraints. They can also be used to modulate scion growth and development to help improve berry yield and quality. The rootstock contribution to scion growth is not fully understood. Since nitrogen (N) is a significant driver of grapevine growth, rootstock properties associated with N uptake and transport may play a key role in the growth potential of grafted grapevines. We evaluated N uptake and transport in a potted system using two grapevines rootstocks [Riparia Gloire (RG) and 1103 Paulsen (1103P)] grafted to Pinot noir (Pommard clone) scion. Combining results of nitrate induction and steady-state experiments at two N availability levels, we observed different responses in the uptake and utilization of N between the two rootstocks. The low vigor rootstock (RG) exhibited greater nitrate uptake capacity and nitrate assimilation in roots after nitrate resupply than the more vigorous 1103P rootstock. This behavior may be attributed to a greater root carbohydrate status observed in RG for both experiments. However, 1103P demonstrated a higher N translocation rate to shoots regardless of N availability. These distinct rootstock behaviors resulted in significant differences in biomass allocation between roots and shoots under N-limited conditions, although the overall vine biomass was not different. Under sufficient N supply, differences between rootstocks decreased but 1103P stored more N in roots, which may benefit growth in subsequent growing seasons. Overall, greater transpiration of vines grafted to 1103P rootstock causing higher N translocation to shoots could partially explain its known growth-promoting effect to scions under low and high N availability, whereas the low vigor typically conferred to scions by RG may result from the combination of lower N translocation to shoots and a greater allocation of biomass toward roots when N is low.