Germination of selected Australian native grass species, with potential for minesite rehabilitation

2013 ◽  
Vol 61 (4) ◽  
pp. 283 ◽  
Author(s):  
Grus J. Farley ◽  
Sean M. Bellairs ◽  
Stephen W. Adkins

Native grasses have become increasingly important in the post-mining landscape where land rehabilitators try to reconstruct vegetation communities similar to those present before land clearing. So as to include native grasses in these communities, there is a requirement to understand their germination biology, because in the past, many grasses have typically been hard to establish in the final community. The present study found that poor germination of 13 native grass species was due to (1) low percentage of seed fill, (2) low seed viability of filled seeds and/or (3) seed dormancy. Eight species had dormancy treatments investigated. Most were found to exhibit at least one form of dormancy that was either located in the hull structures immediately external to the caryopsis (i.e. the lemma, palea and glumes), within the seed coat (i.e. testa and pericarp, tissues that are found inside the hull, but external to the embryo and endosperm) and/or within the embryo. Seven of the grass species tested were found to have a dormancy mechanism present in two or more locations of their dispersal unit. Germination of the selected native grass species could be improved by (1) processing seeds to enrich the percentage of seeds that are filled, (2) testing viability to ensure a high proportion of the seeds are likely to germinate or (3) using methods to help overcome dormancy and promote germination.

1999 ◽  
Vol 47 (4) ◽  
pp. 563 ◽  
Author(s):  
Tamara R. Read ◽  
Sean M. Bellairs

The germination responses to plant-derived smoke of seeds of 20 native grass species from New South Wales, Australia, were tested under laboratory conditions. The species belonged to 14 genera including Bothriochloa, Chloris, Cymbopogon, Danthonia, Dichanthium, Digitaria, Eragrostis, Eriochloa, Microlaena, Panicum, Paspalidium, Poa, Stipa and Themeda. The interaction between smoke and husk-imposed dormancy was examined by removing the floral structures surrounding the seeds, when sufficient seeds were available. Smoke was shown to be an important environmental stimulus for breaking the dormancy of native grasses; however, the response differed considerably between different genera and between species of the same genus. For almost half of the species, smoke significantly increased the germination percentage. Panicum decompositum showed the greatest response, with germination increasing from 7.7 to 63.1% when smoke was applied. Panicum effusum had no germination in the absence of smoke, but 16.7% germination when smoke was applied. Stipa scabra subsp. scabra had germination significantly reduced by smoke from 30.2 to 19.9%. Five species had their germination rate, but not the final germination percentage, affected by smoke, and a third of the species were unaffected by smoke. For five of the species, Chloris ventricosa, Dichanthium sericeum, Panicum decompositum, Poa labillardieri and Stipa scabra subsp. falcata, this is the first report of a smoke-stimulated germination response. For those species with germination promoted by smoke, retention of the covering structures did not prevent smoke stimulation of germination. Sowing smoke-treated husked seeds is likely to be preferable as it would still promote greater germination, whereas dehusking seeds can result in the seeds being more susceptible to desiccation and fungal attack in the field. It is suggested that other grassland communities that respond to pyric conditions may also contain species that respond to smoke.


2019 ◽  
Vol 70 (12) ◽  
pp. 1044
Author(s):  
M. L. Mitchell ◽  
M. R. McCaskill ◽  
R. D. Armstrong

Approximately 3.1 Mha (22%) of the agricultural area of south-eastern Australia can be classified as native pasture. There is the assumption that, owing to the widespread occurrence of low-fertility soils in Australia, native grass species do not respond to increased phosphorus (P) fertility. Currently, there are no industry recommendations of target soil-test P values for native-grass-based pastures. This paper reviews the responses of perennial native pasture species endemic to south-eastern Australia to P application in controlled environments, surveys, replicated experiments and paired-paddock trials. Eighty-seven site-years of trial data where different levels of P were applied, conducted over the last two decades, on native-based pastures in south-eastern Australia are reviewed. Data indicate that application of P fertilisers to native grass pastures can increase dry matter (DM) production and maintain pasture stability. However, minimum targets for herbage mass (800 kg DM/ha) and groundcover (80%) are required to ensure persistence of perennial native grasses. Stocking rates also need to match carrying capacity of the pasture. Based on previous research, we recommend target soil-test (Olsen; 0–10 cm) P levels for fertility-tolerant native grass pastures, based on Microlaena stipoides, Rytidosperma caespitosum, R. fulvum, R. richardsonii, R. duttonianum and R. racemosum, of 10–13 mg/kg, whereas for pastures based on fertility-intolerant species such as Themeda triandra, lower levels of <6 mg/kg are required to ensure botanical stability.


2019 ◽  
Vol 67 (4) ◽  
pp. 309 ◽  
Author(s):  
Annette M. Cavanagh ◽  
Robert C. Godfree ◽  
John W. Morgan

Australia has a large diversity of native grasses. The diaspores of many species possess awns that vary considerably in their number and shape. Some variations of awn shape have been found to be effective at diaspore dispersal. Although morphological descriptions of awns exist for most native grass species, the number of species that possess awns and the extent of awn variation is unknown. This makes it difficult to determine the evolutionary importance of awns and the potential function of the various morphologies. The aim of this study was to construct an awn typology based on morphological descriptions collated from published flora databases that will quantify the awn type diversity of all native grass species in Australia, and will inform awn type relationships and help to clarify the role of differing awn morphologies in diaspore dispersal. We found that 42.1% of 1000 Australian native grasses with a single awn type were determined to have a ‘significant’ awn. These could be classified into one of 20 awn types, the most common being (1) single, apical, geniculate (once-sharply bent) awns (93 species; 28 genera, especially Iseilema), (2) three, apically-attached, straight awns (59 species, mainly Aristida) and (3) single, apical, bigeniculate (twice-sharply bent) awns (46 species, mainly Austrostipa). Among Australian grasses, slightly (though significantly) more C3 species (49.2%) had awns than C4 species (39.9%), although the most common awn types in both contained sharply bent awns (bigeniculate and geniculate respectively). Our classification system will help to improve our understanding of the amount of awn morphological variation in Australian grasses and will enable further investigation into the important ecological role of awns in species fitness.


2000 ◽  
Vol 40 (8) ◽  
pp. 1081 ◽  
Author(s):  
D. L. Garden ◽  
P. M. Dowling ◽  
D. A. Eddy ◽  
H. I. Nicol

Results are presented of a survey of pastoral properties on the Central, Southern and Monaro Tablelands of New South Wales carried out during 1991—92. Landholders were interviewed to obtain information on property size, enterprise types, grazing management, tree clearing, fertiliser history and carrying capacity. In addition, familiarity with native grass species, and knowledge of their value were determined. The main grazing enterprises were wool and beef. The most common form of livestock management was continuous grazing. Most properties had been extensively cleared of trees (average cleared area 80%), and there had been a significant amount of disturbance of the original pastures. This varied from 40% of total property area for the Central and Monaro Tablelands to 60% for the Southern Tablelands. The main form of disturbance was cultivation for pasture sowing or fodder cropping. Landholders had used 80% more fertiliser on disturbed areas than on undisturbed areas, with most fertiliser applied on the Southern Tablelands and least on the Monaro Tablelands. The average carrying capacities of undisturbed and disturbed pastures over the tablelands were 4.3 and 7.7 dry sheep equivalents per hectare, respectively. While most landholders were satisfied with the performance of their sown pastures, there was a lack of knowledge of the contribution of native perennial grasses to pasture production. Using survey data, it was estimated that pastures with native grasses as the major components covered a minimum of 1.38 million hectares or 40% of the surveyed area. With such a large contribution to production, there is a need to assist landholders to identify native perennial grasses so that their potential value can be more fully realised.


2021 ◽  
Vol 2 ◽  
Author(s):  
Rajender Kumar Sharma

Abstract Seeds of Abrus precatorius L. (Fabaceae) were used as weight measure by Indigenous people. Where, the seeds were referred as Ratti; a traditional Indian unit of mass measurement. Seed weight fluctuates depending upon age, moisture, storage-period/conditions. Therefore, use of seeds as a weighing unit become dubious and need to be validated. For this purpose, seeds of A. precatorious were subjected to different moisture conditions and periodically monitored. Surprisingly, there was no change in seed weight was observed, indicating the impermeability of seed coat. The later was confirmed by scarification of seed coat which resulted in 53% increase in seed weight against 0% in control. Further, presence of a potent toxin (abrin) in the seed coat protects it from pests and microbes, and contributes to the maintenance of impermeability for longer period of time. The data validates the use of A. precatorious seeds as a weighing unit (ratti) by the indigenous people and discussed.


2012 ◽  
Vol 87 (9) ◽  
pp. 1335-1341 ◽  
Author(s):  
Sabitry Bordoloi ◽  
Budhadev Basumatary ◽  
Rubul Saikia ◽  
Hamendra Chandra Das

2016 ◽  
Vol 8 (2) ◽  
pp. 77
Author(s):  
Stephen I. Mensah ◽  
Chimezie Ekeke

<p class="1Body">The seed dormancy of <em>Senna obtusifolia</em> was investigated through various methods, namely pretreatments in concentrated sulfuric acid, 2% potassium nitrate (KNO<sub>3</sub>), 99% ethanol, 99% methanol, and in hydrogen perioxide; examination of the seed coverings; and the determination of water uptake by the seeds in order to ascertain the most effective technique for breaking dormancy and also determine the dormancy type. The results showed that sulfuric acid treatment recorded the highest germination (100%); followed by 2% hydrogen peroxide treatment (24%) in 15minutes immersion. The methanol and ethanol pretreatments gave 18.33% and 16.5% germinations respectively. Pretreatment in 2% potassium nitrate gave the lowest germination (8.50%), while the intact seeds of <em>S. obtusifiolia</em> (control) gave 0% germination. The anatomy of the seed coat indicated the presence of hard, thickened and specialized cells of cuticle, macrosclereids, osteoscereids, and disintegrated parenchyma layers. The water uptake of intact seeds was low (13.5%) after 24 hr imbibitions. These findings revealed that the seed coat acts as barrier to germination by preventing water absorption, possibly gaseous diffusion in and out of the seed and conferring mechanical resistance to the protrusion of embryo. Pretreatments, such as immersion in H<sub>2</sub>SO<sub>4 </sub>will soften the seed coat and permit germination. Seed dormancy in <em>S. obtusifolia </em>can be considered of physical nature and classified as physical dormancy. The results obtained in this study may serve as useful information in the production and improvement of <em>S. obtusifolia </em>seedlings, as knowledge on seed dormancy and germination is a critical factor and requirements to the understanding of the propagation of this plant either in situ or ex-situ, in view of the economic potentials/attributes of this species.</p>


Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.


2008 ◽  
Vol 1 (1) ◽  
pp. 50-58 ◽  
Author(s):  
Bryan A. Endress ◽  
Catherine G. Parks ◽  
Bridgett J. Naylor ◽  
Steven R. Radosevich

AbstractSulfur cinquefoil is an exotic, perennial forb that invades a wide range of ecosystems in western North America. It forms dense populations and often threatens native plant species and communities. In this study, we address the following questions: (1) what herbicides, rates, and application times are most effective at reducing sulfur cinquefoil abundance while having the least impact on native plants; and (2) does postherbicide seeding with native grass species increase native plant abundance? In 2002, we experimentally examined the effects of five herbicides (dicamba + 2,4-D; metsulfuron-methyl; triclopyr; glyphosate; and picloram) at two rates of application (low and high), three application times (early summer, fall, and a combined early summer–fall treatment), and two postherbicide seed addition treatments (seeded or not seeded) on sulfur cinquefoil abundance, plant community composition, and species richness. Experimental plots were monitored through 2005. Picloram was the most effective herbicide at reducing sulfur cinquefoil density, the proportion of remaining adult plants, and seed production. The effects of picloram continued to be evident after 3 yr, with 80% reduction of sulfur cinquefoil in 2005. In addition, seeding of native grass seeds alone (no herbicide application) reduced the proportion of sulfur cinquefoil plants that were reproductively active. Despite reductions in sulfur cinquefoil abundance, all treatments remained dominated by exotic species because treated areas transitioned from exotic forb- to exotic grass-dominated communities. However, a one-time herbicide application controlled sulfur cinquefoil for at least 3 yr, and therefore might provide a foundation to begin ecological restoration. Herbicide applications alone likely are to be insufficient for long-term sulfur cinquefoil control without further modification of sites through native grass or forb seeding. Integrating herbicides with native plant seeding to promote the development of plant communities that are resistant to sulfur cinquefoil invasion is a promising management approach to ecological restoration.


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