Pre- and post-harvest influences on physiological dormancy alleviation of an AustralianAsteraceaespecies:Actinobole uliginosum(A. Gray) H. Eichler

Abstract

2008). Pre-and post-harvest inuences on physiological dormancy alleviation of an Australian Asteraceae species: Actinobole uliginosum (A. Gray) H. AbstractThe effects of maternal air temperature and soil moisture upon seed physiological dormancy (PD) alleviation of an Australian native Asteraceae were investigated. From the onset of flowering, Actinobole uliginosum plants growing ex situ were subjected to either a warm (mean 268C) or cool (mean 178C) temperature regime, with adequate or limited water availability. In the warm environment, the reproductive phase was accelerated, and plants yielded fewer seeds over a shorter, earlier harvest period, when compared to those in the cool environment. Initial germination of all seeds was low (, 20% at 158C) due to PD, which was gradually alleviated by a dry afterripening (DAR) treatment (34/208C, 40% relative humidity, in darkness). Seeds from plants grown in the warm environment were more responsive to DAR than seeds from the cool environment, but maternal plant water availability had little effect on dormancy status. Germination was higher at 158C than at 25/158C, reaching a plateau of c. 80% germination after 20 weeks DAR. Before DAR, application of GA 3 had little impact on seeds, which would consequently be classified as having deep PD if tested at the time of dispersal. However, DAR caused seeds to become increasingly responsive to GA 3 , reaching 97% germination at 158C following just 4 weeks of DAR, which would indicate non-deep PD if seeds were tested following a period of warm, dry storage. Maternal air temperature regulates PD status of A. uliginosum, such that seeds collected from a warmer environment are likely to be more responsive to DAR. Post-harvest storage in an environment suitable for DAR affects seed response to GA 3 , which has implications for germination stimulation and dormancy classification.

Warmer seed environments increase germination fractions in Australian winter annual plant species

“…These results were relatively insensitive to water reduction treatments for both species, indicating that temperature, rather than moisture stress, is the most influential component of the maternal environment on primary dormancy (Hoyle et al. , c). Our results for the five native species were consistent with this maternal temperature effect, although we were unable to account for genetic differences between the maternal populations of each species.…”

“…Recent experimental work on two Australian PD species, Actinobole uliginosum (Asteraceae, common in YGJW) and Goodenia fascicularis (Goodeniaceae), revealed that warmer maternal environments accelerate the reproductive period and reduce the levels of primary dormancy in freshly dispersed seeds (Hoyle et al. , c). These results were relatively insensitive to water reduction treatments for both species, indicating that temperature, rather than moisture stress, is the most influential component of the maternal environment on primary dormancy (Hoyle et al.…”

Cyclic population dynamics and density‐dependent intransitivity as pathways to coexistence between co‐occurring annual plants

“…data). Seeds of all focal species were collected from the study site in 2010 and underwent a 2-week dry-after-ripening treatment at 40°C to alleviate dormancy (Hoyle, Daws, Steadman, & Adkins, 2008). Seeds were placed on sterilised germination paper in culture plates exposed to one of three constant temperature: 7°C, 14°C and 25°C.…”

Harvesting as an Alternative to Burning for Managing Spinifex Grasslands in Australia

“…Prior to germination, seeds were placed at 35 ∘ C overnight since annual plants from semiarid climates often require dry hot conditions to break dormancy [25]. Twenty seeds of each species were used in three replicates per treatment.…”