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Plants employ various strategies to mitigate the impact of herbivory and one such strategy involves the associations with fungal endophytes. Some cool‐season forage grasses benefit from protection against herbivores by Epichloë fungal endophytes. However, since the maintenance of symbiosis relies on the plant, costs of hosting endophytes have been also observed. This becomes particularly crucial when forage varieties, inoculated with endophytes that are nontoxic to livestock but still protect host against insect herbivores, experience significant foliage loss (defoliation). We investigated the impact of a nontoxic Epichloë endophyte on the responses of tall fescue plants to defoliation across two morphotype varieties, Continental and Mediterranean, and different seasonal contexts. Under specific defoliation treatments, endophyte‐symbiotic plants showed reduced postdefoliation recovery, indicating the costs of hosting the endophyte for host plants. However, these conditions were not the most severe for plant growth. Regardless of the endophyte's presence, plants from Continental morphotype exhibited superior recovery than those from Mediterranean morphotype, an effect that was more pronounced in summer. Notably, the endophyte promoted plant growth after defoliation in winter for both morphotypes. Our study offers insights into mitigating endophyte‐associated costs on plant recovery postdefoliation by strategically managing cutting intensity and frequency, considering the seasonal variation. [ABSTRACT FROM AUTHOR]

Biochar is being used with increasing frequency as a soil remediator. However, its impact depends on soil limitations, biochar source and concentration applied. We studied Guadua chacoensis bamboo biochar as a saline-alkaline soil amendment. Aqueous solutions with 0, 2.5 and 5% of bamboo biochar (BC) were used to determine their influence on seed germination rate and radicle length in two horticultural species moderately tolerant to salinity and alkalinity: arugula (Eruca sativa) and radish (Raphanus sativus). Also, we amended a saline-alkaline soil with 0, 0.5 and 2.5% of BC to evaluate its effect on plant height, leaf and root biomass of both horticultural crops. The application of 2.5 and 5% BC solution decreased arugula germination in 3.14% and 5.2%, respectively, compared to 0% BC. The addition of BC decreased radicle length in both species and such reduction was more significant with the higher BC concentration. The addition of 0.5% and 2.5% BC as amendment in a saline-alkaline soil decreased arugula height in 27.32% and 50.33%, respectively, compared to 0% BC, resulting in smaller plants with less leaf and root biomass. The BC amendment did not affect leaf biomass, but 2.5% BC reduced root biomass in 53.85% compared to 0% BC. These results seem to be influenced not only by the BC inherent characteristics but also by the increase in soil pH, caused by the addition of biochar. Further studies may evaluate the impact of BC addition with different properties on saline-alkaline soils, and its use as an amendment in the remediation of acid soils. [ABSTRACT FROM AUTHOR]

Crucial to our understanding of plant ecology is the consideration of the eco‐physiological responses and constraints of plant–fungal symbioses throughout the native distribution range of their host.We examined key eco‐physiological roles of two co‐occurring fungal symbionts [Epichloë endophytes and arbuscular mycorrhizal fungi (AMF)] in the endemic grass Hordeum comosum across a wide bioclimatic gradient and contrasting grazing severity. We sampled H. comosum plants along four humid‐to‐arid transects in Patagonia, Argentina, covering its entire distribution range and determined Epichloë presence, AMF root colonization, nitrogen and phosphorus concentration, intrinsic water‐use efficiency (iWUE, the ratio of photosynthesis to stomatal conductance) and 18O‐enrichment of cellulose in shoots.Root colonization by AMF increased with Epichloë presence. All plants hosted Epichloë in the humid range of the gradient, but symbioses occurrence decreased towards arid sites which also displayed severe grazing symptoms at site level.Symbiosis with Epichloë correlated positively with shoot nitrogen concentration in the centre of the distribution range, and with shoot phosphorus concentration across the entire distribution range.The site‐level relationship of AMF colonization with 18O‐enrichment and iWUE suggested that mycorrhiza boosted stomatal conductance in humid environments but curbed it in arid environments.While the interpretation of interactions and potential causalities from observational studies should be done with caution, this study demonstrates distinct correlations between plant–fungal symbiont associations and key resource parameters (phosphorus, nitrogen and iWUE vs. 18O‐enrichment). Such correlations may suggest particular functional roles for these symbionts in the ecology of their host plant. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Remediation of saline-sodic soils used for cattle breeding is particularly challenging due to the limited alternatives. We hypothesize that introducing salt tolerant and productive forage in a lowland halophytic steppe, typical of saline-sodic soils, increases belowground biomass inputs and activity, generating a series of positive effects on soil biological and chemical properties, and aggregate stability – an accepted indicator of soil degradation resistance. Under natural environmental conditions, we found that the introduction of Panicum coloratum (panicum) increased belowground biomass almost three times, the abundance of mites tended to be greater and that of springtails was 9.4 kg−1 contrasting with none found in the halophytic steppe, after 7 years. The concentration of Ca2+ and Mg2+ increased 26% and 54%, respectively, and that of Na+ was reduced 31% compared with the halophytic steppe. Soil pH decrease 5% and electrical conductivity decreased 37% (changing from moderate to very slightly saline) in panicum compared to the halophytic steppe. However, in panicum, mineral-associated organic matter (MAOM) and aggregate stability decreased 22% and 26%, respectively. We concluded that, although biological and chemical properties improved, aggregate stability – an early indicator of soil recovery – decreased, which was likely determined by MAOM reduction in saline-sodic soils. [ABSTRACT FROM AUTHOR]

Elongation-induced leaf emergence is one wayfor plants to deal with complete submergence by 'escaping' from water. This growth strategy is hypothesised to be more beneficial under single long-term submergence than under repeated short-term submergence events (i.e.fluctuating environment), as costs of repeated plant 'adjustment' would exceed the initial benefits of shoot elongation. To test this idea, 2-week-old plants of Chloris gayana Kunth. cv. Fine Cut (a submergencetolerant cultivar first selected by a screening experiment) were grown for 4 weeks under (i) control conditions, (ii) two 1-week submergence cycles, or (iii) one 2-week submergence cycle. Additionally, a set of plants were placed below nettings to assess the cost of remaining forcedly submerged. Impeding leaves emergence through nettings did not compromise survival when submergence was 1-week long, but determined the death of all plants when extended to 2 weeks. Growth as affected by flooding regime revealed that under one 2-week submergence event, plants accumulated a 2.9-fold higher dry mass than when they experienced the same submergence duration in separate events along 1week. The 'escape' strategy in the grass C. gayana, by which leaf contact with air is re-established, is essential for its survival, and it is more beneficial for plant growth under long-term submergence than under repeated short-term submergence cycles. [ABSTRACT FROM AUTHOR]

Waterlogging imposes severe stress to the plant, and the interplay between root and aerial organs in the adjustment to this stress is poorly understood. A set of recombinant inbred lines ( RILs) of L otus japonicus ( Gifu B-129 × Miyakojima MG-20) was subjected to control and waterlogging conditions for 21 d, and 12 traits related to leaf physiological functioning, root aerenchyma formation, shoot and root morphology, and dry mass accumulation were assessed to generate phenomic networks. The phenomic network became more complex under waterlogging as a result of the incorporation of root aerenchyma and dark-adapted Fv/ Fm. Significant waterlogging-induced variation was found for stomatal conductance, dark-adapted Fv/ Fm and aerenchyma. The RILs with stronger induction of aerenchyma in response to waterlogging tended to show reduced negative impact of this stress on root growth but suffered average impact on shoot growth. The RILs that retained higher stomatal conductance under waterlogging tended to retain higher dark-adapted Fv/ Fm and shoot growth under waterlogging conditions but showed average impact on root traits. We propose a model where, although the stress experienced by the roots during waterlogging is transmitted to the shoot, shoots and roots deal with waterlogging in a less interdependent manner than often assumed. [ABSTRACT FROM AUTHOR]

Belowground biodiversity loss from anthropogenic causes is far less addressed and quantified than aboveground biodiversity loss. Soil fauna supports soil productivity and biogeochemical cycles, and their decline needs further research. We tested the effects of a woodland harvest gradient (0, 30, 50, and 70% biomass removal) on litterfall, mesofauna density, and Oribatida diversity in three sites of northwestern Patagonia (Argentina). Sites contrasted in plant community structure and productivity. Acari from litter and soil were compared. Annual litter production showed a 58% decline at the highest harvest intensity level, which was constant across sites. Litter structural α- diversity decreased with the highest intensity harvest only at the high productivity site. The density of soil-inhabiting Acari did not change with increasing harvest intensity, while the density of Acari inhabiting the litter decreased by 65% at the highest harvest intensity. Within Acari, Oribatida inhabiting the litter had the most significant density decline with increasing harvest intensity. Oribatida richness and α- diversity only differed among sites, suggesting resistance to increasing biomass removal despite shifts in litter production and litter structural diversity. Prostigmata did not respond to increasing biomass removal either in soil or litter. Our study is the first to assess Acari response to an aboveground biomass removal gradient in southern woodlands. Applying high biomass removal to low productivity sites can compromise micro detritivore density and thus, impair its functional role. Site productivity should be considered in management plans entailing conservation of soil fauna in southern woodlands. • Litter mite density declined 65% at high woody biomass removal at the valley floor. • This decline was linked with litter production reduction from woody biomass removal. • In contrast to litter mites, soil mites responded little to woody biomass removal. • Among litter mites, Oribatida showed the greatest sensitivity in density. • Oribatida diversity was insensitive to biomass removal despite litter reduction. [ABSTRACT FROM AUTHOR]

Symbiosis between cool-season grasses and vertically transmitted fungal endophytes are common and significantly impact on ecosystem function. This makes the understanding of the underlying mechanisms to symbiotic individuals frequency in local populations much more interesting. Most studies have been focused on the differential fitness between symbiotic and non-symbiotic counterparts (relative fitness), barely considering other mechanisms. We performed a microcosms experiment to evaluate whether grazing alters the dynamics of the endophyte Neotyphodium occultans in the annual grass Lolium multiflorum by simultaneously modifying the relative fitness and the endophyte efficiency to be transmitted from host plants to seeds. Grazing was simulated by means of clipping and trampling on symbiotic and non-symbiotic plants growing separately, in soils obtained from paddocks, differing in their agronomic management history (natural grassland vs. ryegrass promotion). Seed production showed a complex pattern as it depended on the symbiotic status of the plants, the level of grazing and the agro-ecological context. Grazed plants produced three times fewer seeds than ungrazed plants only in microcosms with endophyte-symbiotic plants in soils from ryegrass promotion. Endophyte benefits on seed production were exclusively observed in ungrazed plants in the same soil. Symbiotic plants produced symbiotic and non-symbiotic seeds in all the treatments. While the production of non-symbiotic seeds by these plants was not affected by grazing and the soil, grazing reduced the production of symbiotic seeds in both contexts. Grazing negative effect on the density of fully infected spikes determined a significant increment in the transmission failures which were not modified by agro-ecological contexts. Therefore, grazing can modulate symbiosis dynamics through reducing seed production and endophyte transmission efficiency. Transmission has been disregarded, but it is a context-dependent process that could lead to a gradual reduction in the symbiotic plants frequency in a population if the mutualism effectiveness does not outweigh transmission failures. [ABSTRACT FROM AUTHOR]

Cool-season grasses commonly harbor fungal endophytes in their aerial tissues. However the effects of these symbionts on soil microbial communities have rarely been investigated. Our objective was to explore microbial community responses in soils conditioned by plants of the annual grass Lolium multiflorum with contrasting levels of infection with the endophyte Neotyphodium occultans. At the end of the host growing season, we estimated the functional capacity of soil microbial communities (via catabolic response profiles), the contribution of fungi and bacteria to soil activity (via selective inhibition with antibiotics), and the structure of both microbial communities by molecular analyses. Soil conditioning by highly infected plants affected soil catabolic profiles and tended to increase soil fungal activity. We detected a shift in bacterial community structure while no changes were observed for fungi. Soil responses became evident even without changes in host plant biomass or soil organic carbon or total nitrogen content, suggesting that the endophyte modified host rhizodepositions during the conditioning phase. Our results have implications for the understanding of the reciprocal interactions between above and belowground communities, suggesting that plant-soil feedbacks can be mediated by this symbiosis. [ABSTRACT FROM AUTHOR]

The management of native forests in Northern Patagonia has great potential to provide multiple products with high market value, whose regional demand is growing continuously. Considering that economic profitability is key to guide sustainable forest management decisions, in this paper the effect of the discounting rate, which is a measure of the opportunity cost of funds and resources used in a project, was evaluated over the profitability of forest management options. Five management alternatives of native mixed shrublands through variable discount rates were analyzed. The costs and revenues were obtained from a woodshed experiment extraction in El Foyel, Río Negro (41°38'48.44" S; 71°29'59.06" O), consultation and local publications. It was found that with lower discount rates to 2.9 % the most attractive management alternative was the management that combined woodshed extractions and afforestation of Austrocedrus chilensis while at a higher discount rate, the most attractive alternative was the woodshed shrub management with intensive extraction. There was no rate that positioned the alternative replacement of the shrubland for afforestation of Pinus ponderosa as the best alternative. This work suggests that there are management alternatives of native forest that would be more profitable than that for single species forest plantations of P. ponderosa. [ABSTRACT FROM AUTHOR]

This study aimed at investigating the effects of an autochthonous microbial inoculant microencapsulated by spray‐drying on fermentation parameters, microbiological composition, mycotoxin level and aerobic stability of maize and lucerne silages. Experiment 1, a completely randomized design with a 2 × 2 × 4 factorial arrangement of treatments, evaluated inoculation (control or Lactobacillus plantarum Hv75, Pediococcus acidilactici 3903 and Lactobacillus buchneri B463), packing density (148.5 kg dry matter (DM)/m3 or 181.5 kg DM/m3) and storage period (0, 1, 30 or 60 days) in maize silage. Lactic acid bacteria (LAB) supplementation produced higher DM and lower acetic acid and deoxynivalenol contents compared to the control (p < 0.05). However, these differences were small in terms of practical applications. Experiment 2 evaluated effects of microbial inoculation (similar as in experiment 1), wilting time (3 or 21 h) and storage period (0, 3, 30 or 60 days) in lucerne silage. LAB supplementation increased DM and lactic acid content, reduced pH and concentrations of acetic acid, ethanol and ammonia nitrogen/total nitrogen compared to the control (p < 0.05). In addition, inoculation increased total LAB population and decreased yeast and mould counts (p < 0.05). Although the strains displayed potential to be used as a bio‐inoculant at different lucerne moisture levels, prolonged wilting positively influenced DM, crude protein and fibre degradation (p < 0.05). Therefore, the addition of this spray‐dried inoculant to lucerne silages with longer wilting could be recommended for the attainment of silage quality. [ABSTRACT FROM AUTHOR]