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Front. Plant Sci. | doi: 10.3389/fpls.2019.00038

Pepper rootstock and scion physiological responses under drought stress

  • 1Instituto Valenciano de Investigaciones Agrarias, Spain
  • 2Institute for Adriatic Crops and Karst Reclamation, Croatia
  • 3Universitat Politècnica de València, Spain

In vegetables, tolerance to drought can be improved by grafting commercial varieties onto drought tolerant rootstocks. Grafting has emerged as a tool that copes with drought stress. In previous results, the A25 pepper rootstock accession showed good tolerance to drought in fruit production terms compared with non grafted plants and other rootstocks. The aim of this work was to study if short-term exposure to drought grafted plants using A25 as a rootstock would show tolerance to drought now. To fulfill this objective, some physiological processes involved in roots (rootstock) and leaves (scion) of grafted pepper plants were analyzed. Pepper plants not grafted (A), self-grafted (A/A) and grafted onto a tolerant pepper rootstock A25 (A/A25) were grown under severe water stress induced by PEG addition (-0.55 MPa) or under control conditions for 7 days in hydroponic pure solution. According to our results, water stress severity was alleviated by using the A25 rootstock in grafted plants (A/A25), which indicated that mechanisms stimulated by roots are essential to withstand stress. A/A25 had a bigger root biomass compared with plants A and A/A that resulted in better water absorption, water retention capacity and a sustained CO2 assimilation rate. Consequently, plants A/A25 had a better carbon balance, supported by greater nitrate reductase activity located mainly in leaves. In the non grafted and self-grafted plants, the photosynthesis rate lowered due to stomatal closure, which limited transpiration. Consequently, part of NO3- uptake was reduced in roots. This condition limited water uptake and CO2 fixation in plants A and A/A under drought stress, and accelerated oxidative damage by producing reactive oxygen species (ROS) and H2O2, which were higher highest in their leaves, indicating great sensitivity to drought stress and induced membrane lipid peroxidation. However, drought deleterious effects were slightly marked in plants A than in A/A. To conclude, the A25 rootstock protects the scion against oxidative stress, which is provoked by drought, and shows better C and N balances that enabled the biomass to be maintained under water stress for short-term exposure, with higher yields in the field.

Keywords: gas exchange, Grafted, Oxidative Stress, Pepper (Capsicum annum L.), rootstock, Water relation, Drought stress

Received: 18 Sep 2018; Accepted: 10 Jan 2019.

Edited by:

Claudio Bonghi, University of Padova, Italy

Reviewed by:

Georgia Ntatsi, Institute of Plant Breeding and Genetic Resources, Hellenic Agricultural Organisation (HAO), Greece
Cherubino M. Leonardi, Università degli Studi di Catania, Italy  

Copyright: © 2019 CALATAYUD, López-Serrano, Canet-Sanchis, Vuletin Selak, PENELLA, San Bautista and López-Galarza. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. ANGELES CALATAYUD, Instituto Valenciano de Investigaciones Agrarias, Moncada(Valencia), Spain, calatayud_ang@gva.es