engleski

A new rootstock alleviates polyethylene glycol-induced water stress in grafted pepper: an analysis of root-to-shoot signalling

In agriculture, water stress is one of the most limiting factors for crops growth and development. Suitable commercial fruit characteristics are normally difficult to be combined with resistance to abiotic stress. In addition, there is a lack of public acceptance of genetic engineering, so it is necessary to improve techniques to overcome these stresses. Actually, grafting technique is an environ-friendly-technique to avoid or reduce losses in commercial yields. Based on previous screening studies, we used pepper accession A25 as tolerant rootstock to evaluate the potential mechanisms to cope water stress resulting from grafting. Three pepper combinations were used: Adige commercial variety (A), A grafted onto itself (A/A) and A grafted onto A25 accession (A/A25). Water stress treatment was induced by the addition of 5% PEG. The objective was deep in the rootstock/scion physiological-signalling traits that contribute to improve tolerance to scion through of photosynthesis, signalling molecules level like H2O2, nitrate reductase (NR) and biomass. All measurements were performed at 7 days after the inoculation of stress. In general, it is possible to see maintenance of biomass in A/A25 pepper plants related to ability to limit (or protect) the loss of CO2 assimilation ; a conservative NR activity and a lower H2O2 level. A pronounced decrease in gas exchange measurements in A and A/A combinations closed to a reduction of their biomass and loss of NR activity in leaves join a considerable H2O2 increase. To sum up, the responsible mechanisms of water stress tolerance when plants are grafted onto A25 were the maintenance of the photosynthetic capacity and a sink activity of the growing organs mediated by absence of oxidative damage, probably by a higher buffer capacity of A/A25 plants under water stress.

water stress, grafting, rootstock, photosynthesis, signalling molecules, nitrate reductase, biomass

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