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- Title
Evidence of population variation in drought tolerance during seed germination in four Banksia (Proteaceae) species from Western Australia.
- Authors
Cochrane, J. Anne; Hoyle, Gemma L.; Colin J., Yates; Wood, Jeff; Nicotra, Adrienne B.
- Abstract
Given the predicted changes in rainfall patterns for many Mediterranean climate regions, identifying seed tolerance to moisture stress in the earliest phase of plant development is an important consideration for species conservation, management and restoration. Here, we used polyethylene glycol (PEG 8000) to induce plant water deficit similar to drought stress in a field situation. Seeds of four Western Australia Banksia R.Br. (Proteaceae) species were incubated at seven levels of moisture potential (0 to -1.5 MPa) and three constant temperatures (10°C, 15°C and 20°C). In the absence of moisture stress, germination was uniformly high, but increasing drought stress led to reduced and delayed germination in all species. Overall, the threshold moisture potential value for a significant decline, and delay, in germination was -0.25 MPa. Results suggested that one species (B. coccinea) is likely to be most vulnerable to germination failure under predicted changes in rainfall patterns, whereas another (B. media) is likely to be less vulnerable. There was significant variation in population response to drought stress. However, this variation could not be explained by rainfall across species distributions. We discuss the PEG approach for assessing seed sensitivity to moisture stress, particularly in the context of shifting rainfall under climate change. Declining rainfall will heavily affect seed germination in many species in seasonal Mediterranean climates. Seeds of four Western Australia Banksia species were exposed to moisture-stress conditions during incubation, with results demonstrating how vulnerability to moisture stress varies across species and populations. Identifying drought tolerance during early developmental stages in a plant's life cycle is vital for conserving species in situ and for effective restoration in a warming, drying world.
- Publication
Australian Journal of Botany, 2014, Vol 62, Issue 6, p481
- ISSN
0067-1924
- Publication type
Article
- DOI
10.1071/BT14132