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Strategies to Avoid Salinity and Hydric Stress of Pepper Grafted Plants

Penella, C., Nebauer, S.G., Bautista, A. San, López-Galarza, S., Calatayud, A.
Procedia Environmental Sciences 2015 v.29 pp. 211-212
Capsicum annuum, Capsicum baccatum, Capsicum chinense, crop yield, cultivars, homeostasis, hydroponics, leaves, lipid peroxidation, nitrate reductase, osmotic pressure, photosynthesis, polyethylene glycol, potassium, proline, roots, rootstocks, salinity, scions, seedlings, semiarid zones, sodium, sodium chloride, stress tolerance, sweet peppers, vegetable crops, water stress
Sweet pepper is one of the most important vegetable crops in arid and semiarid regions. Grafting has been proposed as an interesting strategy that improves the responses of crops under the salinity and hydric deficits occurring in these areas.In a previous work, we selected Capsicum spp accessions with different degrees of salinity and hydric stress tolerance to be used as rootstocks (the highest to lowest): Capsicum chinense Jacq. ‘ECU-973’ (code 12), Capsicum baccatum L. var. pendulum ‘BOL-58’ (code 14) and Capsicum annuum L var. ‘Serrano’ (code 5). The behavior of commercial cultivar seedlings grafted onto these rootstocks was compared during 14 days under water stress (5% polyethylene glycol) and salinity (40mM NaCl) in hydroponic culture.Different physiological parameters were measured to test the hypothesis that tolerance might be related to the role of rootstock in altering the stress perception by the scion and to identify differences in pepper-grafted plants adaptation mechanisms in response to salt and osmotic stresses.At a similar osmotic pressure of the solution, grafted plants onto the 12 and 14 rootstocks activated tolerance mechanisms based on ion specific responses under salinity, whereas osmotic adjustment based on proline accumulation was performed under water stress. The maintenance of the scion's homeostasis under salinity was achieved through the restriction of Cl- transport to leaves and to diminished Na+ loading in roots and leaves, thus favouring K+ uptake. Under both stresses, a minor negative impact on photosynthesis, nitrate reductase activity and lipid peroxidation in scion leaves grafted onto 12 and 14 rootstocks was observed.In conclusion, the results of these works reinforce that the use of tolerant pepper rootstocks is a promising strategy to provide salinity and water stress tolerance and can consequently improve crop yield.