Overcoming physiological dormancy in Prostanthera eurybioides (Lamiaceae), a nationally endangered Australian shrub species

2008 ◽  
Vol 56 (3) ◽  
pp. 214 ◽  
Author(s):  
P. J. Ainsley ◽  
M. K. Jones ◽  
T. E. Erickson
Keyword(s):  
South Australia ◽  
Physical Dormancy ◽  
Shrub Species ◽  
Dry Heat ◽  
Pulse Heat ◽  
Germination Process ◽  
Physiological Dormancy ◽  
Continuous Application ◽  
Persistent Calyx

Prostanthera eurybioides (Lamiaceae) is an endangered shrub endemic to South Australia. Fruits consist of four mericarps enclosed by a persistent calyx, with each seed characterised by the presence of what we are defining as a mericarp plug. Research focussed on understanding the role of the mericarp plug in the germination process, determining seed dormancy classification and germination cues. Treatments tested included combinations of pulse dry heat (60–120°C) for up to 60 min, continuous application of gibberellic acid (100 mg L–1), smoked water (10% (v/v)) and excision of the mericarp plug. Seed imbibition experiments dispelled the presence of physical dormancy. The mericarp plug was found to be acting as a mechanical barrier preventing germination. Pulse dry heat (80°C) significantly improved germination, as did removal of the mericarp plug. Smoked water inhibited germination. Based on germination response, seeds have been classified as having non-deep physiological dormancy, with maximum germination (86%) observed following a pulse heat treatment (80°C, 10 min) and removal of the mericarp plug. Natural mechanisms for overcoming dormancy are proposed.

Sensitivity cycling and its ecological role in seeds with physical dormancy

2009 ◽  
Vol 19 (1) ◽  
pp. 3-13 ◽  
Author(s):  
K.M.G. Gehan Jayasuriya ◽  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Life Cycle ◽  
Environmental Conditions ◽  
Common Phenomenon ◽  
Ecological Role ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Physiological Dormancy ◽  
Seed Coats

AbstractCycling of physically dormant (PY) seeds between states insensitive and sensitive to dormancy-breaking factors in the environment has recently been demonstrated inFabaceaeandConvolvulaceae, and it may be a common phenomenon in seeds with water-impermeable seed coats. In contrast to seeds of many species with physiological dormancy (PD), those with PY cannot cycle between dormancy and non-dormancy (ND). In this paper, we evaluate the role of sensitivity cycling in controlling the timing of germination of seeds with PY in nature, and show that sensitivity cycling in seeds with PY serves the same ecological role as dormancy cycling in seeds with PD. Thus, sensitivity cycling in seeds with PY ensures that germination in nature occurs only at (a) time(s) of the year when environmental conditions for growth are, and are likely to remain, suitable long enough for the plant to complete its life cycle or to form a perennating structure. Further, we describe the experimental procedures necessary to determine whether sensitivity cycling is occurring, and discuss briefly the possible relevance of sensitivity cycling to dormancy classification.

Dormancy-breaking and germination requirements for seeds of Acacia papyrocarpa, Acacia oswaldii and Senna artemisioides ssp.×coriacea, three Australian arid-zone Fabaceae species

2014 ◽  
Vol 62 (7) ◽  
pp. 546 ◽  
Author(s):  
Leanne M. Pound ◽  
Phillip J. Ainsley ◽  
José M. Facelli
Keyword(s):  
Arid Zone ◽  
South Australia ◽  
Dormancy Breaking ◽  
Physical Dormancy ◽  
Dry Heat ◽  
Seed Mortality ◽  
Wet Heat ◽  
Pre Treatment ◽  
Unpredictable Environment ◽  
Germination Requirements

Physical dormancy is common in seeds of arid-land legumes. Improved understanding of germination requirements of hard-seeded species will further our understanding of arid lands and aid restoration projects. We studied the germination responses of Acacia papyrocarpa (Benth.), A. oswaldii (F.Muell) and Senna artemisioides (Gaudich. ex DC.) Randell ssp. × coriacea (Benth.) Randell from a chenopod shrubland in South Australia. Imbibition testing indicated that all three species had physical dormancy, but the proportion of dormant seeds was lower in A. oswaldii. This corresponded to a thinner testa in this species. Mechanisms tested to scarify seeds included mechanical scarification and different durations of wet or dry heat. Mechanically scarified seeds germinated readily, reaching maximum numbers in 10–15 days, independently of incubation temperatures, with the exception of S. artemisioides seeds, which germinated at a slower rate in cooler temperatures. Overall, wet heat was more effective than dry heat to alleviate physical dormancy, whereas dry heat in some cases resulted in seed mortality. On the basis of these results, it is recommended that seeds of A. papyrocarpa and S. artemisoides be pretreated with wet heat in future restoration programs. No pre-treatment is required for dormancy loss in A. oswaldii seeds. The different responses of seeds of these species suggest that their populations have varying strategies for persistence in this unpredictable environment.

Characterization of dormancy behaviour in seeds of the model legume Medicago truncatula

2010 ◽  
Vol 20 (2) ◽  
pp. 97-107 ◽  
Author(s):  
William Bolingue ◽  
Benoit Ly Vu ◽  
Olivier Leprince ◽  
Julia Buitink
Keyword(s):  
Medicago Truncatula ◽  
Initial Water Content ◽  
Physical Dormancy ◽  
Initial Water ◽  
Model Legume ◽  
Physiological Dormancy ◽  
Germination Behaviour ◽  
Kinetics Of

AbstractSeeds of Medicago truncatula, a genomic model species for legumes, exhibit physiological and physical dormancy. Here, the factors influencing the germination behaviour of freshly harvested and stored seeds were investigated using several genotypes. Hardseededness is promoted when mature seeds are equilibrated at relative humidities (RH) below 75%. The release of physical dormancy during imbibition was dependent on the initial water content/RH that the seeds were dried to: the drier the seeds, the longer the imbibition time needed to break physical dormancy. The kinetics of physical dormancy release was slower than that of physiological dormancy, making it possible to uncouple both phenomena. Freshly harvested embryos without seed coverings germinated at the same speed as afterripened seeds. The depth of dormancy varied between different M. truncatula genotypes, from more to less dormant: DZA315.16>A17 (Jemalong)>R108>DZA45.5. This difference was eliminated by removing the endosperm. Collectively, these observations indicate that the endosperm is likely the main factor in the reduced germination of freshly harvested seeds. White light decreased germination speed of dormant seeds whereas it had no effect on non-dormant seeds. Recently harvested seeds were most dormant at temperatures above 17°C, whereas afterripened seeds germinated over a wider range of temperature. Fluridone could efficiently break dormancy, reinforcing the role of abscisic acid (ABA) synthesis. However, dormancy was not affected by gibberellic acid (100 μM GA3) or nitrate. The particular dormancy features unravelled here for M. truncatula, combined with the available genomic resources, make it a new, useful model for genetic and molecular studies which can complement those developed for Arabidopsis.

Characterisation of seed dormancy of 12 Chilean species of Nolana (Solanaceae) from the coastal Atacama Desert

2020 ◽  
pp. 1-10
Author(s):  
Josefina Hepp ◽  
Miguel Gómez ◽  
Pedro León-Lobos ◽  
Gloria Montenegro ◽  
Luis Vilalobos ◽  
...  
Keyword(s):  
Seed Dormancy ◽  
Atacama Desert ◽  
Distilled Water ◽  
Latitudinal Distribution ◽  
Physical Dormancy ◽  
Physiological Dormancy ◽  
Arid Habitat ◽  
The Relationship ◽  
Germination Requirements

Abstract The genus Nolana (Solanaceae) comprises numerous species endemic to the coastal Atacama Desert of Chile and Peru of high ornamental potential and conservation value. The environments in which these species have evolved and are present today correspond to particular conditions in the midst of a hyper-arid habitat, so the study of their germination requirements and characterisation of seed dormancy becomes important in terms of conservation but also for ecological and evolutionary purposes. Different treatments were performed on mericarps of 12 species of Nolana: control (intact seeds imbibed in distilled water), scarification in funicular plug and distilled water and scarification in funicular plug and addition of GA3 (500 ppm); their permeability to water was also tested. It was determined that the species did not present physical dormancy, as had been previously reported, but rather physiological dormancy (PD). Germination results after treatments were not homogeneous among all 12 species, indicating differences in their dormancy levels. Also, the important role of the endosperm in the prevention of germination for the studied Nolana species was highlighted. Regarding the relationship between the level of PD (expressed as the percentage of germination for the most successful treatment) and the latitudinal distribution of the species or their phylogenetic closeness, it was determined that, for the studied species, their proximity in terms of clades was more relevant than their latitudinal distribution.

“Consideration of patients as networked units to identify opportunities and motivation to enhance capability”: A mixed methods study to explore a personalised Digital Health Hub Model of Care for hip fractures in South Australia (Preprint)

2021 ◽  
Author(s):  
Lalit Yadav ◽  
Tiffany K Gill ◽  
Anita Taylor ◽  
Jen DeYoung ◽  
Mellick J Chehade
Keyword(s):  
Hip Fractures ◽  
Digital Health ◽  
Family Members ◽  
South Australia ◽  
Aged Care ◽  
Mixed Methods Study ◽  
Residential Aged Care ◽  
Model Of Care ◽  
Factors Influencing

UNSTRUCTURED Introduction Majority of older people with hip fractures once admitted to acute hospital care are unable to return to their pre-fracture level of independence and a significant number are either newly admitted or return to residential aged care. Patient education involves family members and/or residential aged care staff as networked units, crucial for empowerment through improving health literacy. Advancement of digital technology has led to evolving solutions around optimising health care including self-management of chronic disease conditions and telerehabilitation. The aim of this study is to understand perspectives of older patients with hip fractures, their family members and residential aged carers, to inform the development of a digitally enabled model of care using a personalised digital health hub (pDHH). Methods A mixed methods study was conducted at a public tertiary care hospital in South Australia involving patients aged 50 years and above along with their family members and residential aged carers. Quantitative data, including basic demographic characteristics, access to computers and Internet were analysed using descriptive statistics. Spearman’s Rank Order Correlation was used to examine correlations between the perceived role of a pDHH in improving health and likelihood of subsequent usage. Whereas qualitative data included series of open-ended questions and findings were interpreted using constructs of capability, opportunity and motivation to help understand the factors influencing the likelihood of potential pDHH use Results Overall, 100 people were recruited in the study, representing 55 patients, 13 family members and 32 residential aged carers. The mean age of patients was 76.4 years (SD-8.4, age range 54-88) and females represented 60% of patients. Although a moderate negative correlation existed with increasing age and likelihood of pDHH usage (ρ= -0.50, p<0.001) the perceived role of the DHH in improving health had a strong positive correlation with the likelihood of pDHH usage by self (ρ=0.71, p<0.001) and by society, including friends and family members (ρ=0.75, p<0.001). Of particular note, almost all the patients (98%) believed they had a family member or friend /carer who would be able to help them to use a digital health platform. Whereas our qualitative findings suggest emphasising on complex interplay of capability, opportunity and motivation as crucial factors while designing a pDHH enabled model of care for hip fractures at a local context level. Conclusion Findings from this study contributed to understand the dynamics around capabilities, motivation and opportunities of patients, family members and formal carers as a “patient networked unit”. Future research recommendation must involve co-creation guided by iterative processes through improving understanding of factors influencing development and successful integration of complex digital healthcare interventions in real-world scenarios.

Studies on the control of water-dropwort (Oenanthe pimpinelloides) in South Australia

1995 ◽  
Vol 35 (4) ◽  
pp. 483
Author(s):  
GJ Mitchell ◽  
RJ Carter ◽  
SR Chinner
Keyword(s):  
Stem Elongation ◽  
South Australia ◽  
Perennial Herb ◽  
Metsulfuron Methyl ◽  
Rate Of Spread ◽  
Herbicide Treatments ◽  
Direct Drilling ◽  
Water Dropwort

Water-dropwort (Oenanthe pimpinelloides L.), a tuberous perennial herb, is currently known in South Australia from only a single locality in the Mount Lofty Ranges. There is little information on water-dropwort control, and 2 experiments were conducted to assess the effects of sowing pasture, with or without presowing herbicides, on the control of this weed. Phalaris (Phalaris aquatica L.) and perennial clovers were successfully introduced into infested pastures by direct drilling in autumn. Water-dropwort regenerated from seed more densely in unsown plots than plots of established perennial pasture, suggesting that upgrading pastures may be a strategy to reduce the rate of spread by seed of this weed. A range of herbicide treatments applied to waterdropwort at the stem elongation stage in spring before autumn sowing of pastures provided effective shortterm control. The best short-term control was provided by glyphosate at 1440 g a.i./ha; metsulfuron methyl at 6, 12, and 36 g a.i./ha; and metsulfuron methyl at 12 g a.i./ha tank-mixed with glyphosate or 2,4-D amine at 720 or 1000 g a.i./ha, respectively. These treatments, and chlorsulfuron at 21 g a.i./ha, also significantly (P<0.05) reduced water-dropwort abundance (relative to untreated areas) for up to 18 months after sowing and initially improved the density of sown pasture species, but these improvements were not evident 14 months after resowing. Although prior season herbicide treatments controlled water-dropwort in newly sown pastures, 2 separate applications of herbicides, in May and October, gave no better control of water-dropwort than a single herbicide application in spring. Water-dropwort infestations do not appear to prevent successful direct drilling of phalaris and perennial clovers. Although pasture renovation did not provide long-term suppression of water-dropwort, the maintenance of vigorous pastures may reduce the rate of population growth from seedlings of this weed. Recropping restrictions may limit the role of chlorsulfuron for water-dropwort control in pasture renovation situations.

scholarly journals Using hydraulic head, chloride and electrical conductivity data to distinguish between mountain-front and mountain-block recharge to basin aquifers

2018 ◽  
Vol 22 (2) ◽  
pp. 1629-1648 ◽  
Author(s):  
Etienne Bresciani ◽  
Roger H. Cranswick ◽  
Eddie W. Banks ◽  
Jordi Batlle-Aguilar ◽  
Peter G. Cook ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Arid Regions ◽  
South Australia ◽  
Hydraulic Head ◽  
Mountain Front ◽  
Quaternary Aquifers ◽  
Groundwater Systems ◽  
Flow Directions ◽  
Electrical Conductivity Data

Abstract. Numerous basin aquifers in arid and semi-arid regions of the world derive a significant portion of their recharge from adjacent mountains. Such recharge can effectively occur through either stream infiltration in the mountain-front zone (mountain-front recharge, MFR) or subsurface flow from the mountain (mountain-block recharge, MBR). While a thorough understanding of recharge mechanisms is critical for conceptualizing and managing groundwater systems, distinguishing between MFR and MBR is difficult. We present an approach that uses hydraulic head, chloride and electrical conductivity (EC) data to distinguish between MFR and MBR. These variables are inexpensive to measure, and may be readily available from hydrogeological databases in many cases. Hydraulic heads can provide information on groundwater flow directions and stream–aquifer interactions, while chloride concentrations and EC values can be used to distinguish between different water sources if these have a distinct signature. Such information can provide evidence for the occurrence or absence of MFR and MBR. This approach is tested through application to the Adelaide Plains basin, South Australia. The recharge mechanisms of this basin have long been debated, in part due to difficulties in understanding the hydraulic role of faults. Both hydraulic head and chloride (equivalently, EC) data consistently suggest that streams are gaining in the adjacent Mount Lofty Ranges and losing when entering the basin. Moreover, the data indicate that not only the Quaternary aquifers but also the deeper Tertiary aquifers are recharged through MFR and not MBR. It is expected that this finding will have a significant impact on the management of water resources in the region. This study demonstrates the relevance of using hydraulic head, chloride and EC data to distinguish between MFR and MBR.

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