Growth and Physiological Responses of Strawberry (Fragaria × Ananassa Duch.) to Waterlogging Stress

Abstract

Changes in strawberry vegetative growth, carbon assimilation, tissue hydration and membrane integrity caused by waterlogging limit strawberry performance. Secondary analysis of the strawberry response data was used to investigate growth and physiological response for 5 durations of waterlogging. The treatments were freely drained control and root-zone waterlogging for 2, 4, 6 or 8 days with 8 plants per treatment and common day 8 endpoint. Growth, biomass, gas exchange, chlorophyll, fluorescence, relative water content, electrolyte leakage, malondialdehyde and proline were estimated. Finally, statistical approaches included one-way analysis of variance, Tukey comparisons, Benjamini–Hochberg adjustment and duration regressions with HC3 uncertainty estimates. After adjustment, 22 out of 23 outcomes had significant effects of the treatments, except for final plant height. Waterlogging for 8 days resulted in 61.6% reduction in net photosynthesis, 30.3% reduction in leaf area, 29.8% shorter root, and 25.0% reduction in total dry weight when compared with the control. The RWC decreased from 91.21% to 75.14%, while the electrolyte leakage increased from 14.84% to 45.60%. There was a significant rise in the concentrations of malondialdehyde (2.84-fold) and proline (3.76-fold). Fv/Fm did not change after 2 days but after longer exposure it dropped to lower levels like in the control. The overall results show good linear lack of fit for Fv/Fm and relative water content, indicating that the response did not fit constant daily changes. The results reveal a synergic performance reduction in strawberry growth related to time of exposure and show the importance of combining growth, photosynthetic, hydration and membrane parameters in the assessment of waterlogging responses.