Experimental warming and drought treatments reduce physiological activities and increase mortality of Pinus koraiensis seedlings

Autor: Yujin Roh, Hanna Chang, Yowhan Son, Jiae An
Rok vydání: 2020
Předmět:
Zdroj: Plant Ecology. 221:515-527
ISSN: 1573-5052
1385-0237
DOI: 10.1007/s11258-020-01030-3
Popis: This study was conducted to investigate physiological responses and mortality of P. koraiensis seedlings under warming and drought treatments. In May 2016, 90 P. koraiensis seedlings (aged 2 years) were planted in each plot (n = 20), and exposed to a combination of + 3 °C warming and − 30% drought, with 5 replicates. Net photosynthetic rate (A), stomatal conductance (gs), transpiration (E), and maximal photochemical efficiency of photosystem II (Fv/Fm) were measured from April 2017 to December 2018. Seedling mortality was measured eight times during the study period at irregular intervals. A, gs, and E decreased by − 21.99%, − 34.58%, and − 33.6% under the warming treatment, and by − 5.82%, − 11.03%, and − 8.56% under the drought treatment, respectively, in response to decreasing soil water content and increasing soil and leaf temperature. There was no significant difference in the overall Fv/Fm by the warming and drought treatments. The long-term reduction in photosynthesis by the warming treatment might cause carbon starvation, resulting in a 7.43-fold increase in seedling mortality. Moreover, under the drought treatment, seedling mortality was unaffected since its effects on A were occasional and small as compared to the warming treatment. Due to the unusually high temperature in summer of 2018, leaf temperature was 38.28 °C and seedlings were exposed to temperature above 45 °C for 10.7 h under the warming treatment. Fv/Fm in August 2018 decreased sharply by − 11.79% and seedling mortality increased by 15.31-fold during summer, under the warming treatment. Thus, leaf damage by severe heat stress may have triggered a rapid increase in seedling mortality.
Databáze: OpenAIRE
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