Chin J Plant Ecol ›› 2019, Vol. 43 ›› Issue (11): 988-998.DOI: 10.17521/cjpe.2019.0128

• Research Articles • Previous Articles     Next Articles

Effects of simulated changes in precipitation pattern on sap flux in two tree species in subtropical region

ZHANG Zhen-Zhen1,*(),YANG Ke-Jia1,GU Yu-Lu1,ZHAO Ping2,OUYANG Lei2   

  1. 1College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321000, China
    2South China Botanical Garden, Chinese Academy of Sciences, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Chinese Academy of Sciences, Guangdong Provincial Key Laboratory of Applied Botany, Guangzhou 510650, China
  • Received:2019-05-28 Accepted:2019-11-07 Online:2019-11-20 Published:2020-03-26
  • Contact: ZHANG Zhen-Zhen
  • Supported by:
    Supported by the National Natural Science Foundation of China(41630752);Supported by the National Natural Science Foundation of China(41701226);the Zhejiang Province Public Welfare Technology Application Research Project(LGF19C030002)

Abstract:

Aims Over the past decades, the precipitation patterns in subtropical regions markedly changed in response to global climate change. The impacts of changing precipitation patterns on plant growths and forest water balance remain unclear. In this study, the effects of varying precipitation patterns on whole tree water were tested in a natural forest in South China.Methods The study was conducted in the Heshan National Field Research Station of Forest Ecosystem in Guangdong Province, from September 2012 to December 2014. Throughfalls were intercepted by installing rain-shelters underneath the tree canopy and transferred to a nearby water reservior in dry season (from October to March of the next year), which were then reapplied to the field plots in equal quantity of the interception in wet season (from April to September), to simulate changed rainfall pattern to drier dry season and wetter wet season (DD). Sap flux density was continually measured on two tree species, Schima superba and Michelia macclurei. Student t-test was used to determine the significance of differences in mean maximum sap flux density (¯JS) between the two species in the control plots (AC), and between AC and DD treatments during the experiment.Important findings The average ¯JS was (49.5 ± 1.7) mL∙m -2∙s -1in M. macclurei and (43.6 ± 2.0) mL∙m -2∙s -1 in S. superba in the AC treatment when the active photosynthetic radiation (PAR) was greater than 1 100 μmol·m -2·s -1. M. macclurei showed higher sensitivity to increasing PAR. The ¯JS ratio (DD/AC) in both species initially increased significantly, followed by a short-term decrease. In S. superba, the ratio decreased from 0.74 to 0.68 in DD from October 2012 to March 2013, and then increased to 0.93 in March 2014 and 1.04 in November 2014. In M. macclurei, the ratio decreased from 1.00 to 0.94 in DD from October 2012 to March 2013, and then increased to 1.06 in March 2014. We found that S. superba could maintain higher ¯JS in response to the increasing PAR and vapor pressure deficit (VPD) in the DD treatment. Our results showed that the short-term drought would lead to a decline in tree transpiration; but in the long run, plants tended to compensate for the drought induced growth loss by elevating the ¯JS. Compared to M. macclurei, S. superba could maintain higher water transport capacity due to its more extensive ¯JS plasticity in response to the extended drought.

Key words: changed precipitation patterns, water use strategy, sap flux density, water stress