Abstract: Soil water content could influence the growth and physiological traits of wetland plants. To investigate the growth and physiological conditions of Typha orientalis in response to the variations of soil moisture, we established seven treatments with soil water contents of 9%, 14%, 19%, 22%, 33%, 36% and 38%. The growth and physiological indicators of T. orientalis were measured. The results showed that: (1) The growth of T. orientalis was sensitive to changes in soil water content. Based on a comprehensive analysis of growth and physiological indicators, the suitable soil water content for T. orientalis ranged from 22% to 36%. The maximum plant height and basal diameter were observed at 36% soil water content, reaching 184.20 cm and 12.74 mm, respectively. Moreover, T. orientalis tolerated soil water contents of 9% for 36 days and 14% for 114 days, indicating a strong short-term drought tolerance. (2) Total biomass of T. orientalis initially increased and then decreased with increasing soil water content, reaching a maximum of 8.95 g·plant^-1 on day 90 in the treatment of 36% soil water content. (3) Chlorophyll a content in T. orientalis reached its maximum value of 1.76 mg·g^-1 on day 30 under 33% soil water content, whereas chlorophyll b and carotenoid contents reached their maximum values of 0.62 and 0.27 mg·g^-1, respectively, on day 60 under 22% and 38% soil water content. (4) On day 120, peroxidase (POD) activity reached a maximum of 36.61 U·g^-1·min^-1 in the 38% soil water content treatment, while superoxide dismutase (SOD) and catalase (CAT) activities peaked under 36% and 33% soil water content, with values of 188.32 U·g^-1 and 46.01 U·g^-1·min^-1, respectively. In conclusion, the soil water content of 22% to 36% is most suitable for the growth of T. orientalis. These findings are helpful for reasonably regulating soil water content during wetland ecological restoration, promoting the healthy growth of T. orientalis, and thereby maintaining the health of wetland ecosystems.

Key words: soil water content, growth characteristics, physiological characteristics, wetland ecology