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Prior exposure to freezing stress enhances the survival and recovery of Poa pratensis exposed to severe drought
Author(s) -
Kong Ricky S.,
Henry Hugh A. L.
Publication year - 2016
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.1600176
Subject(s) - biology , poa pratensis , herbaceous plant , temperate climate , sugar , agronomy , dehydration , drought stress , biomass (ecology) , drought tolerance , sucrose , frost (temperature) , fructose , snow , poaceae , botany , horticulture , biochemistry , physics , geomorphology , meteorology , geology
PREMISE OF THE STUDY: Both freezing and drought cause cellular dehydration, and they elicit similar increases in protective compounds, which suggests that these stresses could potentially interact. We examined whether the physiological changes that occur in response to freezing in the fall and spring could affect subsequent survival and growth after summer drought. METHODS: We froze Poa pratensis tillers in the late fall, early spring, or late spring at 0, −5, or −10°C for 3 d and then subjected them to no drought (−0.025 MPa), moderate drought (−0.140 MPa), or severe drought (−0.250 MPa) for 3 wk in the summer. We quantified survival and total biomass after a 3‐wk recovery period, and we determined leaf soluble sugar concentrations before and then 0, 30, and 55 d after freezing. KEY RESULTS: For survival and biomass, there were significant interactions between freezing and drought. Spring frozen tillers had the highest biomass and survival following severe drought, whereas fall freezing did not significantly increase the biomass of tillers following the severe drought. Increased drought tolerance after spring freezing did not appear to be associated with increased soluble sugar content, given that the freezing effects on leaf glucose, fructose, and sucrose content were absent 55 d post freezing. CONCLUSIONS: Our results demonstrate that multiple stresses that occur over different seasons can interact; this interaction is highly relevant to herbaceous species in northern temperate regions that are experiencing more intense and frequent stress as a result of changes in snow cover and extreme climatic events.