Changes in Photosynthetic Performance and Water Relation Parameters in the Seedlings of Korean Dendropanax Subjected to Drought Stress
2018
Lee, K.C., Division of Botanic Research and Management, NIE, Seocheon, Republic of Korea
Background: This study aimed to investigate out the influence of drought stress on the physiological responses of Dendropanax morbifera seedlings. Methods and Results: Drought stress was induced by discontinuing water supply for 30 days. Under drought stress, photosynthetic activity was significantly reduced with decreasing soil water content (SWC), as revealed by the parameters such as Fv/Fm, maximum photosynthetic rate (PNmax), stomatal conductance (gs), stomatal transpiration rate (E), and intercellular CO2 concentration (Ci). However, water use efficiency (WUE) was increased by 2.5 times because of the decrease in gs to reduce transpiration. Particularly, E and gs were remarkably decreased when water was withheld for 21 days at 6.2% of SWC. Dendropanax morbifera leaves showed osmotic adjustment of −0.30MPa at full turgor and −0.13 MPa at zero turgor. In contrast, the maximum bulk modulus of elasticity (Emax) did not change significantly. Thus, Dendropanax morbifera seedlings could tolerate drought stress via osmotic adjustment. Conclusions: Drought avoidance mechanisms of D. morbifera involve reduction in water loss from plants, through the control of stomatal transpiration, and reduction in cellular osmotic potential. Notably photosynthetic activity was remarkably reduced, to approximately 6% of the SWC.
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