Perennial rhizomatous grasses are regarded as leading energy crops due to their environmental benefits and their suitability to regions with adverse conditions. In this paper, two different experiments were carried out in order to study the salinity (S) and water stress (WS) effects on biomass production in giant reed (Arundo donax L.). In Experiment 1, eight clones of giant reed were subjected to four S and WS treatments: (i) well-watered with nonsaline solution, (ii) water stress with non-saline solution, (iii) well-watered with saline solution and iv) water stress with saline solution. In Experiment 2, five clones of giant reed were subjected to increasing S levels in two locations: University of Catania (UNICT-Italy) (i)well-watered with non-saline solution and (ii)wellwatered with mild saline solution; and University of Barcelona (UB-Spain) (iii)well-watered with non-saline solution and (iv)well-watered with severe saline solution. Photosynthetic and physiological parameters as well as biomass production were measured in these plants. According to our data, giant reed seems to be more tolerant to S than WS. Both stresses mainly affected stomatal closure to prevent dehydration of the plant, and eventually decreasing the photosynthetic rate. The differential performance of the giant reed clones was ranked according to their tolerance to S and WS by using the Stress Susceptibility Index. 'Agrigento' was the most WS resistant clone and 'Martinensis' was the most S resistant. 'Martinensis' and 'Piccoplant' were found to be the most suitable clones for growing under both stress conditions. Moreover, 'Fondachello', 'Cefalú' and 'Licata' were the most resistant clones to increasing S levels.Keywords: Arundo donax L.; biomass; water stress; salinity stress; photosynthesis; Stress Susceptibility Index. ABBREVIATIONSA sat , light saturated net CO 2 assimilation rate (µmol m -2 s -1 ); DLP, complete dry leaves percentage (%); DM, dry matter (g); FC, field capacity; g s , stomatal conductance (mol m -2 s -1 ); gLA, green leaf area (m 2 ); GLP, complete green leaves percentage (%); H, height (cm); LAR, leaf area ratio (m 2 Kg -1 ); LWR, leaf weight ratio (Kg Kg -1 ); NL, number of leaves; NS, number of stems; PPFD, photosynthetic photon flux density; PRG, perennial rhizomatous grasses; RWC, relative water content (%); S, salinity; SA, stem area (m 2 ); SLA, specific leaf area (m 2 Kg -1 ); S/R, shoot/root ratio (g g -1 ); SSI, stress susceptibility index; TDW, total dry weight (g); WS, water stress; YLP, complete yellow leaves percentage (%).3

The reference given here is cited in the text but is missing from the reference list -please make the list complete or remove the reference from the text: "University of Sheffield (2003)". Q1Please confirm that given names and surnames have been identified correctly. Q2The number of keywords provided exceeds the maximum (journal requirement: 3-5 keywords). Please delete extra keywords. Q3Ref. "University of Sheffield (2003)" is cited in the text but not provided in the reference list. Please provide it in the reference list or delete the citation from the text. Q4One or more sponsor names and the sponsor country identifier may have been edited to a standard format that enables better searching and identification of your article. Please check and correct if necessary. Q5Please provide the volume number and page range for the bibliography in Ref. "Bloom et al. (2014)". Q6Please provide complete details for Ref. "NOAA-ESRL (2014)". Q7 Table S4 is cited in the text but the corresponding input is not provided. Please provide it or delete these citations from the text. Q8Please specify the significance of footnote "*, ** and ***" cited in the Jouzel et al., 1993; Cowling and Sage, 1998). SinceAbbreviations: Amax, light and CO2-saturated net assimilation rate; Asat, lightsaturated net assimilation rate; cm, centimeter; Fv/Fm, maximum quantum yield of PSII; F v /F m , efficiency of the capture of excitation energy by open PSII reaction centers; gs, stomatal conductance; HI, Harvest Index; ITE, instantaneous transpiration of efficiency; Jmax, rate of photosynthetic electron transport; NsS, number of spikelets per spike; PSII, Photosystem II;˚PSII, relative quantum yield of PSII; qp, photochemical quenching; qN, non-photochemical quenching coefficient; NPQ, nonphotoquemical quenching; L, leaf; R, root; Rn, dark respiration; S, spike; SL, spike length; SN, spike number; St, stem; StL, stem length; StN, stem number; TFA, total flag area; TLA, total leaf area; TSA, total spike area; TStA, total stem area; Vc, max, maximum carboxylation velocity of Rubisco.* Corresponding author. (Aranjuelo et al., 2009a(Aranjuelo et al., ,b, 2011aPardo et al., 2009 with the continued emission of CO 2 will bring about changes in 106 land suitability and crop yields (IPCC, 2008(IPCC, , 2013. In particular, 107 these negative impacts are predicted to be greater for wheat than 108 for any other crop (IFPRI, 2008(IFPRI, , 2013. 109As was pointed out before, improvement of the quality of the is not yet well understood (Schnyder, 1993

The present study assessed the behavior of four clones of Arundo donax L. (giant reed) as a perennial rhizomatous grass of increasing interest due to its high biomass production and great adaptability to stress conditions. In this study, a molecular, physiological, and biomass characterization was performed in greenhouse conditions on four Mediterranean clones. The majority of physiological and biomass parameters were not significantly different between clones. However, it was possible to observe large differences in the chromosome count for the four clones. In this way, we detected different numbers of chromosomes for each clone (98 to 122), but surprisingly, no correlation was observed between their chromosome numbers and their physiological and biomass responses.

Herbivory is one of the most globally distributed disturbances affecting carbon (C)-cycling in trees, yet our understanding of how it alters tree C-allocation to different functions such as storage, growth or rhizodeposition is still limited. Prioritized C-allocation to storage replenishment vs growth could explain the fast recovery of C-storage pools frequently observed in growth-reduced defoliated trees. We performed continuous 13C-labeling coupled to clipping to quantify the effects of simulated browsing on the growth, leaf morphology and relative allocation of stored vs recently assimilated C to the growth (bulk biomass) and non-structural carbohydrate (NSC) stores (soluble sugars and starch) of the different organs of two tree species: diffuse-porous (Betula pubescens Ehrh.) and ring-porous (Quercus petraea [Matt.] Liebl.). Carbon-transfers from plants to bulk and rhizosphere soil were also evaluated. Clipped birch and oak trees shifted their C-allocation patterns above-ground as a means to recover from defoliation. However, such increased allocation to current-year stems and leaves did not entail reductions in the allocation to the rhizosphere, which remained unchanged between clipped and control trees of both species. Betula pubescens and Q. petraea showed differences in their vulnerability and recovery strategies to clipping, the ring-porous species being less affected in terms of growth and architecture by clipping than the diffuse-porous. These contrasting patterns could be partly explained by differences in their C cycling after clipping. Defoliated oaks showed a faster recovery of their canopy biomass, which was supported by increased allocation of new C, but associated with large decreases in their fine root biomass. Following clipping, both species recovered NSC pools to a larger extent than growth, but the allocation of 13C-labeled photo-assimilates into storage compounds was not increased as compared with controls. Despite their different response to clipping, our results indicate no preventative allocation into storage occurred during the first year after clipping in either of the species.