Physiological responses of Carex schmidtii Meinsh to alternating flooding-drought conditions in the Momoge wetland, northeast China

摘要

Alternating flooding-drought conditions have been shown to be an effective water-saving method to restore wetland plants in arid and semi-arid regions. Carex schmidtii is a critical plant species for the restoration of degraded wetlands in the Momoge National Nature Reserve (MNNR) in northeast China. Comparative studies of plant leaves, under permanent inundation condition (AF condition) and 30 d cycles of alternate flooding-drought conditions (A30), were carried out. Plant leaf morphology and biomass, as well as physiological traits and nutrient stoichiometry, were analyzed to understand the mechanism of C. schmidtii to environmental factors. It was well demonstrated that growth of plants under A30 condition achieved significantly higher length and the ratio of leaf withering (by 9.02 and 6.73 times, respectively), compared with those obtained under AF condition. Dry leaf matter content, varying between 37.8% and 44.6% under the A30 condition was 18.1% greater than those obtained under the AF condition. Initial plant treatment was found to greatly increase chlorophyll content and superoxide dismutase activity. The proline content of C. schmidtii under A30 condition was significantly higher, whereas plant leaf nitrogen and phosphorus contents under A30 condition were only slight lower than under AF condition. Hence, alternating flooding-drought conditions initiated in the early growth stage had a beneficial effect on their adaptability to environment changes; assisting plant growth and biomass accumulation when water supply reduced. Overall, the results provide supporting information for the restoration and management of C. schmidtii tussocks in degraded wetlands in semi-arid regions.