Influence of arbuscular mycorrhizae on biomass and root morphology of selected strawberry cultivars under salt stress

To investigate the influence of arbuscular mycorrhizal fungi (AMF) on biomass and root morphology, a greenhouse experiment was conducted using three elite strawberry (Fragaria X ananassa Duch.) cultivars ('Kent', 'Jewel', and 'Saint-Pierre'). They were subjected to three NaCl levels (0, 30, and 60 mmol/L) and were inoculated and noninoculated (control) with AMF Glomus irregulare. The presence of AMF significantly changed root morphology and increased root-length percentages of medium (0.5 mm < root diameter φ [less than or equal to] 1.5 mm) and coarse (4 > 1.5 mm) roots, shoot and root tissue biomass, root to shoot ratio (R/S ratio), and specific root length (SRL), regardless of cultivar and salinity. In contrast, salt alone changed root morphology and decreased shoot and root tissue biomass, R/S ratio, and SRL. The AMF colonization rates were reduced linearly and significantly with increasing salinity levels. Cultivars responded differently to AMF than to salt stress. 'Saint-Pierre' seemed to be the most tolerant cultivar to salinity, while 'Kent' was the most sensitive. Consequently, AMF symbiosis highly enhanced salt tolerance of strawberry plants, which confirmed the potential use of mycorrhizal biotechnology in sustainable horticulture in arid areas. Key words: arbuscular mycorrhizae, arid soil, salinity, strawberry, stress. Afin d'examiner l'influence des champignons mycorhiziens arbusculaires (CMA) sur la biomasse et la morphologie des racines, les auteurs ont conduit une experience en serres, en utilisant trois cultivars elites de fraisier (Fragaria X ananassa Duch.) ('Kent', 'Jewel',et 'St-Pierre'). Ils les ont soumis a trois concentrations de NaCl (0, 30, et 60 mmol/L), avec ou sans (temoin) inoculation, avec le CMA Glomus irregulare. La presence du CMA a modifie significativement la morphologie racinaire et a augmente les pourcentages des longueurs des racines moyennes (0,5 mm < diametre racinaire φ [less than or equal to] 1,5 mm) et grosses (φ >1,5 mm), la biomasse des tissus caulinaires et racinaires, le rapport racine tige (rapport R/S) et la longueur specifique des racines (LSR), independamment du cultivar ou de la salinite. Au contraire, le sel pris isolement a egalement modifie la morphologie racinaire et diminue la biomasse des tissus caulinaires et racinaires, le rapport R/S et la LSR. L'augmentation de la salinite a reduit lineairement et significativement la colonisation par le CMA. Le cultivar 'St-Pierre' apparait comme le plus tolerant a la salinite et le cv 'Kent' comme le plus sensible. On conclut que la symbiose CMA augmente fortement la tolerance a la salinite chez les plants de fraisiers, ce qui confirme le potentiel de la biotechnologie mycorhizienne pour l' horticulture en regions arides. Mots-cles : mycorhizes arbusculaires, sol aride, salinite, fraisier, stress. [Traduit par la Redaction]
Introduction Plants are frequently exposed to adverse environmental conditions that have negative effects on development, productivity, and plant survival. Among environmental stresses, salinity is considered as the most important limiting [...]