Synergism between calcium nitrate applications and fungal endophytes to increase sugar concentration in Festuca sinensis under cold stress

Epichloe endophytes have been shown to increase tolerance to biotic and abiotic stresses in many cool-season grasses. We investigated the impact of endophyte infection of Festuca sinensis, on root metabolic activity, photosynthetic pigments, leaf relative water content (RWC) and soluble carbohydrates in a field experiment carried out during chilling and irrigation with Ca(NO3)(2). A highly significant (P < 0.001) correlation for Epichloe endophytes was observed for root metabolic activity. Ca(NO3)(2) affected very significantly root metabolic activity and total chlorophyll (P < 0.001). Low temperature led to highly significant (P < 0.001) reductions in root metabolic activity, RWC, total chlorophyll, chlorophyll a/b ratio, and carotenoid contents. In addition, the fructose concentrations of shoots were greater on the 14th day than on the 28th day and before treatment, whilst the glucose concentration of roots was much higher on the 28th day than before and after 14 days treatment. Moreover, our results indicated that the addition of calcium nitrate contributed to higher levels of total chlorophylls, soluble sugars, sucrose, fructose or glucose in the shoots and roots in both E+ and E- plants during long periods of chilling. These results suggest that Epichloe endophyte infection and/or exogenous calcium nitrate can confer better tolerance to cold stress.

Automated summary

The study shows that Epichloe endophyte infection can enhance the tolerance of Festuca sinensis to biotic and abiotic stresses, while the addition of exogenous calcium nitrate can increase the levels of chlorophyll and soluble sugars in plants.