Eco-physiological responses of Schima superba seedlings from two provenances to drought and rewatering

Abstract

In the context of global climate change, the research on eco-physiological responses to drought and rewatering among provenances of trees species will help to understand the effect of climate conditions of provenances on drought resistance of trees, further providing theoretical references for cultivation and management of forests in the future. In this study, Schima superba from two provenances in southern China were selected. Potted seedlings were subjected to simulated drought and rewatering conditions. Eco-physiological traits (photosynthesis traits, hydraulic traits, non-structural carbohydrates-NSC, proline concentrations-Pro and superoxide dismutase-SOD activity) of seedlings were examined. The results were as follows: (1) Under well-watered condition, stem xylem water potential (Ψxylem), leaf relative water content (RWC), photosynthetic rate (Asat) and stomatal conductance (Gs) were lower in seedlings from Guangdong provenance compared with Fujian provenance. (2) Responses of hydraulic traits, Pro and SOD to drought and rewatering were consistent between the two provenances. Ψxylem, RWC and Pro could recover to control values rapidly, while percent of stem xylem embolism and SOD could not recover to control values in the end. (3) Asat was more sensitive to drought from Fujian provenance than Guangdong provenance, and it took more time to recover to control in Fujian provenance. (4) The recovery rate of NSC from Fujian provenance was faster than Guangdong provenance. Collectively, seedlings from both provenances could not repair their embolized xylem in the short-term rewatering period (30 days). Although photosynthesis rate in Guangdong provenance could recover to control faster than from Fujian provenance, it was lower than that from Fujian provenance. Furthermore, the recovery rate of NSC was slower in Guangdong provenance than Fujian provenance, indicating that growth and survivals of seedlings from Guangdong provenance may experience greater risk in future characterized with increasing drought stress.

Keywords

• drought-rewatering
• photosynthetic traits
• hydraulic traits
• schima superba
• intra-specific differences