Identification and Measurement of Summer Dormancy in Temperate Perennial Grasses
- Mark R. Norton *a,
- F. Volaireb,
- F. Lelièvreb and
- S. Fukaic
- a Industry and Investment NSW, GPO Box 1600, Canberra ACT 2601, Australia, and Future Farm Industries Cooperative Research Centre, The Univ. of Western Australia, 35 Stirling Hwy., Crawley, WA 6009, Australia
b Institut National de Recherche Agronomique (INRA), UMR SYSTEM, 2 place Viala, 34060 Montpellier, France
c Univ. of Queensland, School of Land, Crop and Food Sciences, Brisbane, QLD 4072, Australia
There is an apparent increase in frequency of prolonged droughts in regions with Mediterranean climates. This has rekindled interest in the summer dormancy trait for improving drought resistance of temperate perennial pasture grasses. In orchardgrass (Dactylis glomerata L.), tall fescue [Lolium arundinaceum (Schreb.) Darbysh.], and phalaris (Phalaris aquatica L.), identification of the three common drought resistance traits of vascular plants, dehydration avoidance (or delay), dehydration tolerance, and summer dormancy, is often confused. Summer dormancy, the least common of these traits, is found in cool-season grasses from semiarid and arid Mediterranean climates and provides an enhanced level of drought resistance. It is best measured in field-grown plants previously exposed to low winter temperatures and short photoperiods. Those perennial grasses not exhibiting summer dormancy survive drought by avoiding and/or tolerating dehydration and express this as a response to water deficit irrespective of the season. Here we review three summer water-supply environments, full irrigation, midsummer storm, and summer drought, for their precision and repeatability in measuring dormancy. Full irrigation and midsummer storm can be recommended, but measurement of dormancy under prolonged drought caused inconsistencies.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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