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Elsevier Penella, C.; González Nebauer, S.; Quinones, A.; San Bautista Primo, A.; López Galarza, SV.; Calatayud, A. (2015). Some rootstocks improve pepper tolerance to mild salinity through ionic regulation. Plant Science. 230:12-22. doi:10.1016Science. 230:12-22. doi:10. /j.plantsci.2014 . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 leaves. This work suggests that using tolerant pepper rootstocks that maintain the scion's ion homeostasis is a promising strategy to provide salinity tolerance and can consequently improve crop performance when faced with farmland salinity.

The performance of a salt-tolerant pepper (Capsicum annuum L.) accession (A25) utilized as a rootstock was assessed in two experiments. In a first field experiment under natural salinity conditions, we observed a larger amount of marketable fruit (+75%) and lower Blossom end Root incidence (-31%) plants, which had a constitutive enhanced root apparatus and 2.6-fold higher proline content under salinity, did not show alterations in photosynthesis and growth and MDA levels increased only slightly. Our results underline that salt tolerance in A/A25 grafted plants could be mediate by (I) the maintenance of root sink strength and (II) the markedly increased proline levels that could balance cell osmotic pressure thus protecting enzymatic stability from salttriggered damage.

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Cyperus esculentus L. is known as chufa, yellow nutsedge or tiger nut. lt grows wild as a weed, but also is grown as a crop; sometimes it is also called rush-nut. Although it can be found in cold regions, as Alaska (Holm et al. 1977: 125), it is considered a plant of warm areas, widespread in tropical and temperate zones around the globe (de Vries 1991). It is most troublesome in eastem and southem Africa and in North and Central America. Recently it has also spread to sorne European countries with colder climates such as the Netherlands (Rotteveel 1993;de Vries 1991), Switzerland (Gerhold 1992Schmitt 1995; Schmitt and Sahli 1992), Germany and Austria (Gerhold 1992) and Hungary (Dancza 1994). Kükenthal (1936) distinguished eight botanical varieties of Cyperus esculentus. Recently three of these varieties were rejected and only four wild varieties (esculentus, leptostachyus, macrostachyus, and hermanii) and the cultivated variety sativus are recognized today (ter Borg and Schippers 1992). This can explain the existence of two distinct groups of plants which have a similar morphology but differ widely in application and which are known by the same name: one is a weed and the other, a crop.Since ancient times the chufa tuber has been considered a foodstuff; it was an

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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 in 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 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 compared to 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.