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Journal of Arid Land

Article Title

Size- and leaf age-dependent effects on the photosynthetic and physiological responses of Artemisia ordosica to drought stress

Authors

WANG Chunyuan, 1 Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
YU Minghan, 1 Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, ChinaFollow
DING Guodong, 1 Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, ChinaFollow
GAO Guanglei, 1 Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China; 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
ZHANG Linlin, 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
HE Yingying, 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
LIU Wei, 2 Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China

Abstract

Drought is one of the most significant natural disasters in the arid and semi-arid areas of China. Populations or plant organs often differ in their responses to drought and other adversities at different growth stages. At present, little is known about the size- and leaf age-dependent differences in the mechanisms of shrub-related drought resistance in the deserts of China. Here, we evaluated the photosynthetic and physiological responses of Artemisia ordosica Krasch. to drought stress using a field experiment in Mu Us Sandy Land, Ningxia Hui Autonomous Region, China in 2018. Rainfall was manipulated by installing outdoor shelters, with four rainfall treatments applied to 12 plots (5 m×5 m). There were four rainfall levels, including a control and rainfall reductions of 30%, 50% and 70%, each with three replications. Taking individual crown size as the dividing basis, we measured the responses of A. ordosica photosynthetic and physiological responses to drought at different growth stages, i.e., large-sized (>0.5 m2) and small-sized (≤0.5 m2) plants. The leaves of A. ordosica were divided into old leaves and young leaves for separate measurement. Results showed that: (1) under drought stress, the transfer efficiency of light energy captured by antenna pigments to the photosystem II (PSII) reaction center decreased, and the heat dissipation capacity increased simultaneously. To resist the photosynthetic system damage caused by drought, A. ordosica enhanced its free radical scavenging capacity by activating its antioxidant enzyme system; and (2) growth stage and leaf age had effects on the reaction of the photosynthetic system to drought. Small A. ordosica plants could not withstand severe drought stress (70% rainfall reduction), whereas large A. ordosica individuals could absorb deep soil water to ensure their survival in severe drought stressed condition. Under 30% and 50% rainfall reduction conditions, young leaves had a greater ability to resist drought than old leaves, whereas the latter were more resistant to severe drought stress. The response of A. ordosica photosynthetic system reflected the trade-off at different growth stages and leaf ages of photosynthetic production under different degrees of drought. This study provides a more comprehensive and systematic perspective for understanding the drought resistance mechanisms of desert plants.

Keywords

drought stress, age difference, plant size, photosynthesis, physiological response, survival strategy

First Page

744

Last Page

758

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