Aspen Bibliography
Recovery of Populus tremuloides seedlings following severe drought causing total leaf mortality and extreme stem embolism
Document Type
Article
Journal/Book Title/Conference
Physiologia Plantarum
Volume
140
Issue
3
First Page
246
Last Page
257
Publication Date
2010
Abstract
In contrast with other native Populus species in North America, Populus tremuloides (aspen) can successfully establish itself in drought-prone areas, yet no comprehensive analysis has been performed on the ability of seedlings to withstand and recover from a severe drought resulting in complete leaf mortality. Here, we subjected 4-month-old aspen seedlings grown in two contrasting soil media to a progressive drought until total leaf mortality, followed by a rewatering cycle. Stomatal conductance (gs), photosynthesis and transpiration followed a sigmoid decline with declining fraction of extractable soil water values. Cessation of leaf expansion occurred close to the end of the linear-decrease phase, when gs was reduced by 95%. Leaf mortality started after gs reached the lowest values, which corresponded to a stem–xylem pressure potential (Ψxp) of −2.0 MPa and a percent loss of stem hydraulic conductivity (PLC) of 50%. In plants with 50% leaf mortality, PLC values remained around 50%. Complete leaf mortality occurred at an average stem PLC of 90%, but all seedlings were able to resprout after 6–10 days of being rewatered. Plants decapitated at soil level before rewatering developed root suckers, while those left with a 4-cm stump or with their stems intact resprouted exclusively from axillary buds. Resprouting was accompanied by recovery of stem hydraulic conductivity, with PLC values around 30%. The percentage of resprouted buds was negatively correlated with the stem %PLC. Thus, the recovery of stem hydraulic conductivity appears as an important factor in the resprouting capacity of aspen seedlings following a severe drought.
Recommended Citation
Lu, Y.; Equiza, M.A.; Denga, X.; Tyree, M.T. 2010. Recovery of Populus tremuloides seedlings following severe drought causing total leaf mortality and extreme stem embolism. Physiologia Plantarum 140: 246-257.
