Efectos de rizobacterias promotoras del crecimiento vegetal en rasgos fisiológicos y anatómicos de triticum aestivum l. en respuesta al déficit hídrico.
Loading...
Date
2025
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
La sequía limita crecientemente la productividad del trigo (Triticum aestivum L.). En este contexto, los ecosistemas de media montaña andina, cuya flora xerofítica y microbioma están adaptados al déficit hídrico, ofrecen un modelo y reservorio microbiano para enfrentar esta limitación. Con este antecedente, se evaluó el efecto de cuatro cepas rizobacterianas promotoras del crecimiento vegetal (PGPR) aisladas de Azorella prolifera: Bacillus pumilus (B), Streptomyces virginiae (S), Rahnella sp. (R) y Peribacillus simplex (P), empleando dos estrategias de inoculación: macroencapsulación de refuerzo en la línea de siembra y priming de semillas, esta última empleada con las tres cepas que mostraron mayor viabilidad (S, R y P).
En una cámara de crecimiento se sometieron las plántulas a riego deficitario (30 % humedad gravimétrica), midiendo biomasa fresca y seca aérea-radicular, área y volumen de raíces, contenido de clorofila (SPAD), área foliar específica (AFE), contenido relativo de agua y proporción de materia seca, así como longitud y diámetro de tallo, número de hojas y porcentaje de espigación. El priming con P. simplex destacó: mantuvo biomasa fresca aérea y radicular 27 % y 34 % superiores al testigo, conservó área y volumen radicular, sostuvo índices fisiológicos estables y elevó la espigación al 80 %. Bajo el mismo método, S. virginae mostró efectos intermedios, mientras que Rahnella sp. presentó un establecimiento tardío. En contraste, la macroencapsulación produjo respuestas poco consistentes. Estos resultados indican que el priming con P. simplex es la combinación más prometedora para mejorar la tolerancia del trigo al déficit hídrico, abriendo paso a ensayos de campo y a la formulación de bioproductos adaptados a la agricultura en zonas áridas.
Drought increasingly limits the productivity of wheat (Triticum aestivum L.). In this context, Andean mid-mountain ecosystems, whose xerophytic flora and microbiome are adapted to water shortages, offer a model and microbial reservoir to address this limitation. Against this background, the effect of four plant growth-promoting rhizobacterial (PGPR) strains isolated from Azorella prolifera: Bacillus pumilus (B), Streptomyces virginiae (S), Rahnella sp. (R), and Peribacillus simplex (P) was evaluated using two inoculation strategies: booster macroencapsulation at the sowing line and seed priming, the latter used with the three strains that showed the highest viability (S, R, and P). In a growth chamber, seedlings were subjected to deficit irrigation (30% gravimetric humidity), and fresh and dry aboveground root biomass, root area and volume, chlorophyll content (SPAD), specific leaf area (SLA), relative water content and dry matter ratio, as well as stem length and diameter, leaf number, and bolting percentage were measured. Priming with P. simplex was notable: it maintained fresh aboveground and root biomass 27% and 34% higher than the control, conserved root area and volume, maintained stable physiological indices, and increased bolting to 80%. Under the same method, S. virginiae showed intermediate effects, while Rahnella sp. showed delayed establishment. In contrast, macroencapsulation produced inconsistent responses. These results indicate that priming with P. simplex is the most promising combination for improving wheat's tolerance to water stress, paving the way for field trials and the development of bioproducts adapted to agriculture in arid zones.
Drought increasingly limits the productivity of wheat (Triticum aestivum L.). In this context, Andean mid-mountain ecosystems, whose xerophytic flora and microbiome are adapted to water shortages, offer a model and microbial reservoir to address this limitation. Against this background, the effect of four plant growth-promoting rhizobacterial (PGPR) strains isolated from Azorella prolifera: Bacillus pumilus (B), Streptomyces virginiae (S), Rahnella sp. (R), and Peribacillus simplex (P) was evaluated using two inoculation strategies: booster macroencapsulation at the sowing line and seed priming, the latter used with the three strains that showed the highest viability (S, R, and P). In a growth chamber, seedlings were subjected to deficit irrigation (30% gravimetric humidity), and fresh and dry aboveground root biomass, root area and volume, chlorophyll content (SPAD), specific leaf area (SLA), relative water content and dry matter ratio, as well as stem length and diameter, leaf number, and bolting percentage were measured. Priming with P. simplex was notable: it maintained fresh aboveground and root biomass 27% and 34% higher than the control, conserved root area and volume, maintained stable physiological indices, and increased bolting to 80%. Under the same method, S. virginiae showed intermediate effects, while Rahnella sp. showed delayed establishment. In contrast, macroencapsulation produced inconsistent responses. These results indicate that priming with P. simplex is the most promising combination for improving wheat's tolerance to water stress, paving the way for field trials and the development of bioproducts adapted to agriculture in arid zones.
Description
Tesis presentada para optar al título de Ingeniero en Biotecnología Vegetal.
Keywords
Crecimiento (Plantas), Trigo, Sequías