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Indigenous plants and artificial nectar sources facilitate urban adjustment of avian pollinators in Cape Town
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Abstracts
The aqueous and ethyl acetate extracts (but not the chloroform or hexane extracts) also significantly inhibited carcinoma proliferation, albeit with substantially lower potency. Subsequent analysis of the T. sericea leaf extracts by GC-MS headspace analysis highlighted several interesting volatile compounds. All extracts were shown to be non-toxic in the Artemia nauplii bioassay. The lack of toxicity of these extracts and their anti-proliferative bioactivity against Caco-2 and HeLa carcinoma cells indicates their potential in the treatment of some cancers. doi:10.1016/j.sajb.2017.01.038
Indigenous plants and artificial nectar sources facilitate urban adjustment of avian pollinators in Cape Town A. Coetzeea, P. Barnardb,c, A. Pauwa a Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa b Climate Change and BioAdaptation, South African National Biodiversity Institute, Private Bag X7, Claremont 7735, South Africa c DST/NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa E-mail address: [email protected] (A. Coetzee) Urban areas are growing rapidly and often result in habitat loss and fragmentation. This poses a threat to plants that depend on animal pollinators. Plant populations remaining in fragments may suffer lower pollination success if their pollinators do not adjust to these novel urban habitats. We investigated how avian pollinators in fynbos adjust to Cape Town urban habitats by testing which of their biological traits and which garden traits facilitate or hinder their visitation frequencies in gardens. A questionnaire was used to obtain information about garden traits and frequencies of nine nectarivorous bird species from 193 gardens around the Cape Town metropole. Information on biological traits was gathered from published literature. Nectar specialist birds were less frequent than expected based on their frequencies in a nearby natural area, suggesting that their urban adjustment is limited. Bird species with greater habitat generalisation were more numerous in gardens. Birds were attracted to gardens with a high diversity of indigenous plants as well as with sugar water feeders. This suggests that the provisioning of natural and artificial nectar resources may aid pollinators’ adjustment and provide stepping stones of habitat in rapidly changing landscapes. However, this raises questions on whether and how natural plant populations will be affected through changing pollinator visitation frequencies and the presence of cultivated plants. doi:10.1016/j.sajb.2017.01.039
The effects of herbicides on soil chemical and soil microbial characteristics of riparian fynbos ecosystems L.S. Cogill, S.M. Jacobs, K. Jacobs Department of Conservation Ecology and Entomology, University of Stellenbosch, Private Bag X1, Stellenbosch 7602, South Africa E-mail address: [email protected] (L.S. Cogill) The WfW is a public agency under the jurisdiction of DWAF (Department of Water Affairs and Forestry) whose mandate includes putting their efforts into both ecological restoration through alien
invasive clearing as well as public poverty relief. The WfW makes use of various herbicides to manage IAP (Invasive Alien Plant) encroachment and re-invasions in many natural ecosystems, particularly for that of riparian fynbos in the Western Cape. The herbicides used could however have unforeseen detrimental impacts on the ecosystem and hinder long term ecological restoration. Certain herbicides and the active ingredients they contain could be potentially detrimental to the quality of the soil and alter soil microbial community structure. The study is aimed at determining the effects of herbicides on soil chemical characteristics and soil microbial community structure over time. Soil chemical characteristics such as nutrient availability, microbial enzyme activity, and pH were analyzed over time after applying different herbicide treatments. In addition, potential effects on microbial community structure were monitored via ARISA (Automated Ribosomal Intergenic Spacer Analysis) and the Biolog-plate technique. The active ingredients namely, glyphosate, triclopyr, and fluroxypyr and picloram tend to have an acidifying effect on the soil where the soil-pH levels decrease consistently with herbicide treatment. Furthermore, an increase in soil available nitrogen seems to occur with certain concentrations of herbicide. No significant effects on microbial activity and diversity were expressed. Further soil microbial analysis (such as species-specific identification) will have to be included in future research and at different time intervals in order to show for the effects of herbicide on specific microbial genera that are important and prevalent in riparian fynbos ecosystems. doi:10.1016/j.sajb.2017.01.040
Orthodox seeds and resurrection plants: Two of a kind? M.-C.D. Costaa, J.M. Farranta, H.W.M. Hilhorstb a Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa b Laboratory of Plant Physiology, Wageningen University, Wageningen, The Netherlands E-mail address: [email protected] (M.-C.D. Costa) Although staple crops do not survive extended periods of drought, their seeds survive almost complete dehydration (desiccation). These seeds are desiccation tolerant (DT). There are some 135 Angiosperm species, termed “resurrection plants”, whose seeds and vegetative tissues are DT. Vegetative DT first arose with the transition from aquatic to terrestrial life forms, but was lost as plants acquired mechanisms for water deficit (drought) resistance. DT was then confined to seeds, spores and pollen grains. It has been proposed that resurrection plants have appropriated DT from seeds, reactivating such mechanisms in vegetative tissues through mechanisms not yet completely understood. A better understanding of these mechanisms will aid the development of crop varieties better able to survive extreme drought conditions. Xerophyta viscosa is probably among the most resilient resurrection species and its genome has recently been sequenced. The mechanisms for vegetative DT in X. viscosa bear remarkable resemblance with those of seeds. X. viscosa is poikilochlorophyllous and, like maturing seeds, it dismantles the thylakoid membrane systems and loses chlorophyll during dehydration, these processes being restored on rehydration. This strategy minimizes the generation of reactive oxygen species during drying and subsequent long periods of storage in the dry state. During dismantling of its photosynthetic machinery, X. viscosa engages antisenescence mechanisms in a similar manner as maturing seeds. The transcription factor ABI5 and LEA proteins are strongly associated with the acquisition of longevity in orthodox seeds. ABI5 may be a regulator
Abstracts
The aqueous and ethyl acetate extracts (but not the chloroform or hexane extracts) also significantly inhibited carcinoma proliferation, albeit with substantially lower potency. Subsequent analysis of the T. sericea leaf extracts by GC-MS headspace analysis highlighted several interesting volatile compounds. All extracts were shown to be non-toxic in the Artemia nauplii bioassay. The lack of toxicity of these extracts and their anti-proliferative bioactivity against Caco-2 and HeLa carcinoma cells indicates their potential in the treatment of some cancers. doi:10.1016/j.sajb.2017.01.038
Indigenous plants and artificial nectar sources facilitate urban adjustment of avian pollinators in Cape Town A. Coetzeea, P. Barnardb,c, A. Pauwa a Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa b Climate Change and BioAdaptation, South African National Biodiversity Institute, Private Bag X7, Claremont 7735, South Africa c DST/NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa E-mail address: [email protected] (A. Coetzee) Urban areas are growing rapidly and often result in habitat loss and fragmentation. This poses a threat to plants that depend on animal pollinators. Plant populations remaining in fragments may suffer lower pollination success if their pollinators do not adjust to these novel urban habitats. We investigated how avian pollinators in fynbos adjust to Cape Town urban habitats by testing which of their biological traits and which garden traits facilitate or hinder their visitation frequencies in gardens. A questionnaire was used to obtain information about garden traits and frequencies of nine nectarivorous bird species from 193 gardens around the Cape Town metropole. Information on biological traits was gathered from published literature. Nectar specialist birds were less frequent than expected based on their frequencies in a nearby natural area, suggesting that their urban adjustment is limited. Bird species with greater habitat generalisation were more numerous in gardens. Birds were attracted to gardens with a high diversity of indigenous plants as well as with sugar water feeders. This suggests that the provisioning of natural and artificial nectar resources may aid pollinators’ adjustment and provide stepping stones of habitat in rapidly changing landscapes. However, this raises questions on whether and how natural plant populations will be affected through changing pollinator visitation frequencies and the presence of cultivated plants. doi:10.1016/j.sajb.2017.01.039
The effects of herbicides on soil chemical and soil microbial characteristics of riparian fynbos ecosystems L.S. Cogill, S.M. Jacobs, K. Jacobs Department of Conservation Ecology and Entomology, University of Stellenbosch, Private Bag X1, Stellenbosch 7602, South Africa E-mail address: [email protected] (L.S. Cogill) The WfW is a public agency under the jurisdiction of DWAF (Department of Water Affairs and Forestry) whose mandate includes putting their efforts into both ecological restoration through alien
invasive clearing as well as public poverty relief. The WfW makes use of various herbicides to manage IAP (Invasive Alien Plant) encroachment and re-invasions in many natural ecosystems, particularly for that of riparian fynbos in the Western Cape. The herbicides used could however have unforeseen detrimental impacts on the ecosystem and hinder long term ecological restoration. Certain herbicides and the active ingredients they contain could be potentially detrimental to the quality of the soil and alter soil microbial community structure. The study is aimed at determining the effects of herbicides on soil chemical characteristics and soil microbial community structure over time. Soil chemical characteristics such as nutrient availability, microbial enzyme activity, and pH were analyzed over time after applying different herbicide treatments. In addition, potential effects on microbial community structure were monitored via ARISA (Automated Ribosomal Intergenic Spacer Analysis) and the Biolog-plate technique. The active ingredients namely, glyphosate, triclopyr, and fluroxypyr and picloram tend to have an acidifying effect on the soil where the soil-pH levels decrease consistently with herbicide treatment. Furthermore, an increase in soil available nitrogen seems to occur with certain concentrations of herbicide. No significant effects on microbial activity and diversity were expressed. Further soil microbial analysis (such as species-specific identification) will have to be included in future research and at different time intervals in order to show for the effects of herbicide on specific microbial genera that are important and prevalent in riparian fynbos ecosystems. doi:10.1016/j.sajb.2017.01.040
Orthodox seeds and resurrection plants: Two of a kind? M.-C.D. Costaa, J.M. Farranta, H.W.M. Hilhorstb a Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa b Laboratory of Plant Physiology, Wageningen University, Wageningen, The Netherlands E-mail address: [email protected] (M.-C.D. Costa) Although staple crops do not survive extended periods of drought, their seeds survive almost complete dehydration (desiccation). These seeds are desiccation tolerant (DT). There are some 135 Angiosperm species, termed “resurrection plants”, whose seeds and vegetative tissues are DT. Vegetative DT first arose with the transition from aquatic to terrestrial life forms, but was lost as plants acquired mechanisms for water deficit (drought) resistance. DT was then confined to seeds, spores and pollen grains. It has been proposed that resurrection plants have appropriated DT from seeds, reactivating such mechanisms in vegetative tissues through mechanisms not yet completely understood. A better understanding of these mechanisms will aid the development of crop varieties better able to survive extreme drought conditions. Xerophyta viscosa is probably among the most resilient resurrection species and its genome has recently been sequenced. The mechanisms for vegetative DT in X. viscosa bear remarkable resemblance with those of seeds. X. viscosa is poikilochlorophyllous and, like maturing seeds, it dismantles the thylakoid membrane systems and loses chlorophyll during dehydration, these processes being restored on rehydration. This strategy minimizes the generation of reactive oxygen species during drying and subsequent long periods of storage in the dry state. During dismantling of its photosynthetic machinery, X. viscosa engages antisenescence mechanisms in a similar manner as maturing seeds. The transcription factor ABI5 and LEA proteins are strongly associated with the acquisition of longevity in orthodox seeds. ABI5 may be a regulator