Resource Allocation to Asexual Gemma Production and Sexual Reproduction in South-Western Australian Pygmy and Micro Stilt-Form Species of Sundew (Drosera spp, Droseraceae)

1992 ◽  
Vol 40 (3) ◽  
pp. 353 ◽  
Author(s):  
PS Karlsson ◽  
JS Pate
Keyword(s):  
Resource Allocation ◽  
Sexual Reproduction ◽  
Seed Production ◽  
Asexual Reproduction ◽  
Western Australia ◽  
Dry Matter ◽  
Late Season ◽  
Plant Resource ◽  
Total Plant ◽  
Western Australian

Proportional allocations of current total dry matter (DM), N and P to early season asexual gemma production and late-season flowering and seed production were compared for eight pygmy rosette form and three micro stilt-form perennial pygmy sundews (Drosera spp.) in native habitat in south-western Australia. Mean allocations to gemmae for the smaller rosette species were 22% for DM, 60% for N and 38% for P versus 8, 20 and 23% (DM, N, P) respectively for the micro stilt forms. Allocations to mature fully formed seeds were extremely low, 1-8, 4.0 and 5.4% (DM, N, P) for the rosette forms, 0.7, 3-0 and 2.3% respectively for the micro stilt forms. The above values reflect the heavy bias towards gemma production, (8-52 propagules per plant per season across the 11 species) as opposed to that for seed (0-8 fully formed seeds per plant per season). Comparable information for the annual nongemmiferous pygmy sundew D. glanduligera showed end of season allocation of 66, 37 and 29% (DM, N, P) of total plant resource to inflorescences minus seeds, and additional amounts equivalent to 30, 59 and 69% to the 60 seeds produced per plant of this species in the study season. A detailed phenology of resource allocation across a full season of growth in second, third and fourth season plants of the rosette perennial D. closterostigma showed net seasonal losses in the total vegetative resource of N and of P in older plants attributable to apparent over commitment to asexual reproduction during the season of study.

The levels of copper, molybdenum and inorganic sulphate in some Western Australian pastures. A contribution to the study of copper deficiency diseases in ruminants

1962 ◽  
Vol 2 (4) ◽  
pp. 40 ◽  
Author(s):  
AB Beck
Keyword(s):  
Western Australia ◽  
Dry Matter ◽  
Copper Deficiency ◽  
Copper Level ◽  
Growing Period ◽  
Inorganic Sulphate ◽  
Deficiency Diseases ◽  
Western Australian

Levels of copper, molybdenum, and inorganic sulphate are reported for samples of Western Australian pastures from areas where copper deficiency diseases in ruminants have occurred and from unaffected areas. The copper contents of the pastures were determined previously. It was found that the copper deficiency diseases commonly occurred where pastures contained less than 3 p.p.m. Cu in the dty matter during the growing period, while such diseases were absent where the pastures contained more than 6 p.p.m. Cu. Values between 3 and 6 p.p.m Cu were classified as marginal. The molybdenum and inorganic sulphate contents of the original pasture samples have now been determined. The molybdenum contents of the three classes of pasture were found to lie within the same range (0.1 to 4 p.p.m. Mo in the dry matter, with the majority less than 1 p.p.m.). These values are similar to those recorded by overseas workers for normal pastures. Inorganic sulphate contents of the three classes of pasture also lay within the same range (0.1 to 0.9 per cent SO4, with the majorio between 0.2 and 0.4 per cent). The results for the pastures examined suggest that in Western Australia the low copper level is the constant and the most significant factor associated with enzootic ataxia in sheep and falling disease in cattle.

Phenology, Reproductive-Biology and Seed Development in Four Rush and Sedge Species From Western Australia

1988 ◽  
Vol 36 (6) ◽  
pp. 711 ◽  
Author(s):  
KA Meney ◽  
KW Dixon
Keyword(s):  
Seed Production ◽  
Western Australia ◽  
Dry Matter ◽  
Matter Content ◽  
Dry Matter Content ◽  
Dry Matter Accumulation ◽  
Tissue Water ◽  
Dry Matter Partitioning ◽  
Study Species

Four species of Restionaceae and Cyperaceae from the Mediterranean-type climate region of Western Australia were studied to determine factor(s) limiting their reproductive performance. Ecdeiocolea monostachya (Ecdeiocoleaceae), Lepidobolus chaetocephalus (Restionaceae), Restio aff. sphacelatus (Restionaceae) and Mesomelaena pseudostygia (Cyperaceae) differed in the pattern of dry matter partitioning and phenological patterns. All species were moderately efficient at remobilising dry matter from senescing vegetative organs, maintaining constant tissue water to dry matter content in mature organs over the study period regardless of soil moisture availability. In situ nutrient and water supplements of study species did not elicit improved seed production or significant increases in dry matter accumulation (except for current and old culms of E. monostachya and spikelets of L. chaetocephalus). For all study species except L. chaetocephalus, seed production was low, while herbivore activity, insect predation andlor infection by a smut (Tolyposporium lepidiboli) reduced seed production potential in L. chaetocephalus and E. monostachya. Attempts at seed germination for all study species were not successful. Extracted embryos from mature seed of all species cultured in vitro grew rapidly, providing a reliable method for propagation of study species.

Factors Limiting the Recruitment of Eucalyptus salmonophloia in Remnant Woodlands .I. Pattern of Flowering, Seed Production and Seed Fall

1994 ◽  
Vol 42 (5) ◽  
pp. 531 ◽  
Author(s):  
CJ Yates ◽  
RJ Hobbs ◽  
RW Bell
Keyword(s):  
Seed Production ◽  
Western Australia ◽  
Seed Viability ◽  
Fragmented Landscape ◽  
Viable Seed ◽  
Seed Fall ◽  
Individual Trees ◽  
Western Australian ◽  
Remnant Population ◽  
Conservation Of Biodiversity

Woodlands dominated by Eucalyptus salmonophloia F. Muell. occur throughout the fragmented landscape of the Western Australian wheatbelt. In most of these remnant woodlands, there is no regeneration of E. salmonophloia and this has become a concern for the conservation of biodiversity in the region. This study examined seed production, seed viability and pattern of seed fall in four remnant populations of E. salmonophloia in the central wheatbelt of Western Australia, to determine whether these factors are limiting recruitment. Surveys of flowering, seed production and seed fall were conducted over a two-year-period which included three potential flowering seasons. Individual trees flowered once over this period and the intensity of flowering and the proportion of flowers which set seed varied greatly between remnants. Seed from up to two consecutive flowering seasons was stored in the canopy, thus, E. salmonophloia formed substantial canopy seed stores. Seeds were released from this store throughout the year and seed fall showed only a weak winter decline. The viability of seeds released from the canopy store in each remnant population was high. These results indicate that the availability of viable seed is unlikely to be responsible for the lack of E. salmonophloia recruitment in remnant woodlands.

Impact of insects and fungi on doublegee (Emex australis) in the Western Australian wheatbelt

1998 ◽  
Vol 49 (5) ◽  
pp. 767 ◽  
Author(s):  
John K. Scott ◽  
Roger G. Shivas
Keyword(s):  
Biological Control ◽  
Seed Production ◽  
Western Australia ◽  
Seed Quality ◽  
Dry Weight ◽  
High Density ◽  
Exclusion Experiment ◽  
Emex Australis ◽  
Study Sites ◽  
Western Australian

Biotic influences on doublegee(Emex australis Steinheil) seed production wereinvestigated as a precursor to the introduction of new insect biologicalcontrol agents for this weed, and to investigate the cause of doublegeedecline in the northern and central wheatbelt of Western Australia since 1990.The symptoms of the decline are doublegee plants of reduced size withdistorted leaves, collapsed stems, and smaller achenes(the spiny seed-bearing fruit) that crumble when mature.Three sites were investigated in 1992 by surveys for insects and fungi, andinsect and fungus exclusion experiments.Emex stem blight (Phomopsis emicis R. G. Shivas) waspresent at the 3 study sites. The Watheroo site had comparatively high levelsof dock aphids (Brachycaudus rumexicolens Patch) ondoublegee plants, the Badgingarra site had a comparatively high density ofdock sawfly (Lophyrotoma analis Costa) on doublegee, andvery few insects were present on doublegee at the Wongan Hills site. Viruseswere not detected in samples of plants showing the effects of decline.The exclusion experiment showed a significant effect of removing insects andfungi on achene dry weight at the Watheroo site. There was no treatment effectat the Badgingarra and Wongan Hills sites. The biology of the fungus and theaphid lead to the conclusion that the primary cause of doublegee decline isthe dock aphid. This indicates that biological control againstE. australis might be achieved by using insects thatindirectly affect seed quality.

Defoliation regrowth and dry matter partitioning in the two arid zone grasses, Aristida armata and Thyridolepis mitchelliana

1987 ◽  
Vol 38 (5) ◽  
pp. 881 ◽  
Author(s):  
RF Brown
Keyword(s):  
Seed Production ◽  
Dry Matter ◽  
Arid Zone ◽  
Plant Production ◽  
Pasture Management ◽  
Leaf Production ◽  
Dry Matter Partitioning ◽  
Intact Plants ◽  
Domestic Livestock ◽  
Total Plant

Plants of the desirable rangeland grass, Thyridolepis mitchelliana, and its undesirable companion, Aristida armata, were defoliated at various ages, and their subsequent regrowth and seed production compared with that of intact plants. Young plants of T. mitchelliana, but not A. armata, often failed to survive severe defoliation. Seed production by A. armata greatly exceeded that of T. mitchelliana and was much less affected by defoliation. In both defoliated and intact plants, the proportion of dry matter in inflorescences was several times greater for A. armata than T. mitchelliana, but the reverse occurred with leaf production. Root growth was little affected by defoliation, and there was no evidence of export of root material to support tops regrowth. Total plant production of both species was unaffected by the loss of half the tops, but was depressed by more severe defoliation. The differences between the two species in their reaction to defoliation seem sufficient to explain the displacement of T. mitchelliana by A. armata which followed the introduction of domestic livestock. Under grazing, A. armata is likely to have a reproductive advantage, and the implications of this for pasture management are examined.

Growth and seed yield of vetches (Vicia spp.) in south-western Australia

1996 ◽  
Vol 36 (5) ◽  
pp. 587 ◽  
Author(s):  
KHM Siddique ◽  
SP Loss
Keyword(s):  
Seed Yield ◽  
Western Australia ◽  
Dry Matter ◽  
Rapid Development ◽  
Farming Systems ◽  
Grain Legumes ◽  
Poor Growth ◽  
Breeding Programs ◽  
Seed Yields ◽  
Western Australian

The growth and seed yield of 5 vetch (Vicia) cultivars representing Vicia sativa, V. benghalensis and V. villosa were compared at 8 sites over 2 years in south-western Australia. The vetches showed considerable potential as grain and forage legume crops in the low to medium rainfall areas of the Western Australian cereal belt. Cultivars of V. sativa showed the most potential in terms of dry matter and seed yield, and on average across sites and seasons both Languedoc and Blanchefleur produced over 2.5 t/ha of dry matter at flowering: Machine-harvested seed yields were over 1.6 t/ha. Cultivars of V. benghalensis and V. villosa produced considerably less dry matter at flowering and had lower harvest index (0.14-0.42) and seed yield < 4 t/ha) when compared with the V. sativa cultivars, possibly due to their poor growth rates and delayed phenology. Early Purple, an early flowering and maturing selection from the V. benghalensis cultivar Popany, showed improved adaptation and seed yield at many low rainfall sites. Nevertheless, Languedoc, Blanchefleur and Early Popany are all considered late flowering (up to 126 days) compared with grain legumes adapted to this environment, and further improvement in vetch species could be achieved by selecting for more rapid development. Both soft-seededness and non-shattering pods should also be high priorities for vetch selection and/or breeding programs. It is concluded that vetch species may have a role in farming systems in Western Australia for the production of fodder, hay, grain or green manure while providing the other rotational benefits of legumes on fine-textured neutral to alkaline and shallow duplex soils where narrow-leafed lupin is poorly adapted.

Molecular basis of adaptive evolution of sperm motility involved in in vivo fertilization of terrestrial animals

Impact ◽  
2020 ◽  
Vol 2020 (6) ◽  
pp. 73-75
Author(s):  
Akihiko Watanabe
Keyword(s):  
Sexual Reproduction ◽  
Sperm Motility ◽  
Asexual Reproduction ◽  
Acrosome Reaction ◽  
Sperm Morphology ◽  
Adaptive Potential ◽  
Selective Pressures ◽  
The Face ◽  
Genetic Profiles

One of the unifying traits of life on this planet is reproduction, or life's ability to make copies of itself. The mode of reproduction has evolved over time, having almost certainly begun with simple asexual reproduction when the ancestral single celled organism divided into two. Since these beginnings' life has tried out numerous strategies, and perhaps one of the most important and successful has been sexual reproduction. This form of reproduction relies on the union of gametes, otherwise known as sperm and egg. Evolutionarily, sexual reproduction allows for greater adaptive potential because the genes of two unique individuals have a chance to recombine and mix in order to produce a new individual. Unlike asexual reproduction which produces genetically-identical clones of the parent individual, sex produces offspring with novel genes and combinations of genes. Therefore, in the face of new selective pressures there is a higher chance that one of these novel genetic profiles will produce an adaptation that is advantageous in the new circumstances. Dr Akihiko Watanabe is a reproductive biologist based in the Department of Biology, Faculty of Science Yamagata University in Japan, he is currently working on three research projects; a comparative study on the signalling pathways for inducing sperm motility and acrosome reaction in amphibians, the mechanism behind the adaptive modification of sperm morphology and motility, and the origin of sperm motility initiating substance (SMIS).

Factors that contribute to urban–rural gradients in risk of schizophrenia: Comparing Danish and Western Australian registers

2021 ◽  
pp. 000486742110096
Author(s):  
Oleguer Plana-Ripoll ◽  
Patsy Di Prinzio ◽  
John J McGrath ◽  
Preben B Mortensen ◽  
Vera A Morgan
Keyword(s):  
Confidence Interval ◽  
Western Australia ◽  
Urban Areas ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Hazard Ratio ◽  
Indigenous Status ◽  
Increased Risk ◽  
The Relationship ◽  
Western Australian

Introduction: An association between schizophrenia and urbanicity has long been observed, with studies in many countries, including several from Denmark, reporting that individuals born/raised in densely populated urban settings have an increased risk of developing schizophrenia compared to those born/raised in rural settings. However, these findings have not been replicated in all studies. In particular, a Western Australian study showed a gradient in the opposite direction which disappeared after adjustment for covariates. Given the different findings for Denmark and Western Australia, our aim was to investigate the relationship between schizophrenia and urbanicity in these two regions to determine which factors may be influencing the relationship. Methods: We used population-based cohorts of children born alive between 1980 and 2001 in Western Australia ( N = 428,784) and Denmark ( N = 1,357,874). Children were categorised according to the level of urbanicity of their mother’s residence at time of birth and followed-up through to 30 June 2015. Linkage to State-based registers provided information on schizophrenia diagnosis and a range of covariates. Rates of being diagnosed with schizophrenia for each category of urbanicity were estimated using Cox proportional hazards models adjusted for covariates. Results: During follow-up, 1618 (0.4%) children in Western Australia and 11,875 (0.9%) children in Denmark were diagnosed with schizophrenia. In Western Australia, those born in the most remote areas did not experience lower rates of schizophrenia than those born in the most urban areas (hazard ratio = 1.02 [95% confidence interval: 0.81, 1.29]), unlike their Danish counterparts (hazard ratio = 0.62 [95% confidence interval: 0.58, 0.66]). However, when the Western Australian cohort was restricted to children of non-Aboriginal Indigenous status, results were consistent with Danish findings (hazard ratio = 0.46 [95% confidence interval: 0.29, 0.72]). Discussion: Our study highlights the potential for disadvantaged subgroups to mask the contribution of urban-related risk factors to risk of schizophrenia and the importance of stratified analysis in such cases.

scholarly journals Paclobutrazol Improves Sesame Yield by Increasing Dry Matter Accumulation and Reducing Seed Shattering Under Rainfed Conditions

2021 ◽  
Author(s):  
Muhammad Zeeshan Mehmood ◽  
Ghulam Qadir ◽  
Obaid Afzal ◽  
Atta Mohi Ud Din ◽  
Muhammad Ali Raza ◽  
...  
Keyword(s):  
Leaf Area ◽  
Seed Production ◽  
Seed Yield ◽  
Dry Matter ◽  
Biomass Accumulation ◽  
Total Biomass ◽  
Dry Matter Accumulation ◽  
Seed Shattering ◽  
Rainfed Conditions ◽  
Leaf Greenness

AbstractSeveral biotic and abiotic stresses significantly decrease the biomass accumulation and seed yield of sesame crops under rainfed areas. However, plant growth regulators (such as Paclobutrazol) can improve the total dry matter and seed production of the sesame crop. The effects of the paclobutrazol application on dry matter accumulation and seed yield had not been studied before in sesame under rainfed conditions. Therefore, a two-year field study during 2018 and 2019 was conducted with key objectives to assess the impacts of paclobutrazol on leaf greenness, leaf area, total dry matter production and partitioning, seed shattering, and seed yield of sesame. Two sesame cultivars (TS-5 and TS-3) were treated with four paclobutrazol concentrations (P0 = Control, P1 = 100 mg L−1, P2 = 200 mg L−1, P3 = 300 mg L−1). The experiment was executed in RCBD-factorial design with three replications. Compared with P0, treatment P3 improved the leaf greenness of sesame by 17%, 38%, and 60% at 45, 85, and 125 days after sowing, respectively. However, P3 treatment decreased the leaf area of sesame by 14% and 20% at 45 and 85 days after sowing than P0, respectively. Compared with P0, treatment P3 increased the leaf area by 46% at 125 days after sowing. On average, treatment P3 also improved the total biomass production by 21% and partitioning in roots, stems, leaves, capsules, and seeds by 23%, 19%, 23%, 22%, and 40%, respectively, in the whole growing seasons as compared to P0. Moreover, under P3 treatment, sesame attained the highest seed yield and lowest seed shattering by 27% and 30%, respectively, compared to P0. This study indicated that by applying the paclobutrazol concentration at the rate of 300 mg L−1 in sesame, the leaf greenness, leaf areas, biomass accumulation, partitioning, seed yield, and shatter resistance could be improved. Thus, the optimum paclobutrazol level could enhance the dry matter accumulation and seed production capacity of sesame by decreasing shattering losses under rainfed conditions.

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