LI Huan1,2, WU Yanyou1
(1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China；
2. China; and University of Chinese Academy of Sciences, Beijing 100049, China)
Abstract: The responses of photosynthetic and photorespiration characteristics of two plants of Moraceae (Broussonetia papyrifera and Morus alba.) to the drought stress were studied by applying 150 g/L polyethylene glycol (PEG) to simulate the arid environment. The relevant chemical parameters of the culture medium and the photosynthetic parameters of leaves were measured. The arid environment was found to have less effect on the water absorption capacity of Broussonetia papyrifera than that of Morus alba. The Broussonetia papyrifera adapted to the arid environment by moderate photosynthesis, low transpiration and high water use efficiency, while the Morus alba by low photosynthetic, low transpiration and high water use efficiency. In the simulated drought environment, the Broussonetia papyrifera adapted to external stress by stable carboxylation efficiency, high photosynthetic capacity, high photosynthetic capacity utilization share, while the Morus alba by low carboxylation efficiency, low light respiration rate and low light respiration utilization share. The mulberry tree showed a higher adaptive capacity to the external drought stress than Morus alba. This adaptive mechanism of Broussonetia papyrifera may be related to its higher photorespiration rate and the ability of utilizing bicarbonate ions. The "consuming carbon for water" mechanism may be an important mechanism for plants to adapt for the karst drought.
Key words: polyethylene glycol; Broussonetia papyrifera; Morus alba; drought stress; photosynthetic parameters; photorespiration.
EARTH AND ENVIRONMENT Vol.47, No.2, Tot No.328, 2019, Page 141-150
