title: Synergistic defensive effects of silicon and Epichloë endophytes on insect pests of agricultural grasses in New Zealand

authors: van Amsterdam, Sarah

subjects: Silicon

abstract: New Zealand has several insect pasture pests which cause economic losses of between $1.7 B and $2.3 B annually in the dairy, and ‘sheep and beef’ industries. Research on grass species defence provides insights into methods to reduce this economic impact. Epichloë endophytes and silicon accumulation are two well-studied mechanisms of reducing phytophagous insect damage in grass species, but their potential synergies have not been investigated. Previous research has hypothesised that plants infected with endophyte may accumulate more silicon than their non endophyte infected counterparts, suggesting multi-tiered defences. Of specific interest to this thesis is the potential impact of silicon supplementation on the alkaloid profiles of novel grass-endophyte associations. This research aimed to investigate changes to silicon concentration over time, endophyte growth and alkaloid concentration in two cool season grass species from the sub-family Pooideae and subsequent effects of these variables on major New Zealand insect pests. This interaction was investigated through the use of whole plant glasshouse trials, excised root bioassays, and artificial diet experiments using a range of above- and below ground phytophagous pasture pests (Listronotus bonariensis, Wiseana copularis and Costelytra giveni) as well as a generalist herbivore model study organism (Epiphyas postvittana). The two grass species included; Lolium perenne infected with a novel association with an endophyte naturally found in Festuca arundinacea (Epichloë coenophiala), and Festuca pratensis infected with its naturally occurring endophyte (Epichloë unicatum). 
Results from this research do not indicate that, in the grass endophyte associations studied, endophyte infection is linked to an increase in plant silicon content. There is evidence to suggest that the herbage material of L. perenne endophyte-infected plants has less silicon than endophyte free plants. There were no direct correlations between plant silicon content and the production of bioactive secondary metabolite alkaloids (lolines) or endophytic mycelial mass in F. pratensis and L. perenne. Although silicon supplementation was not linked to a direct increase in plant silicon content, there was an increase in loline production in the herbage of L. perenne, indicating a potential role of silicon in either modulating the soil environment or influencing plant biochemical reactions potentially leading to a change in production of lolines. This study also found negative effects of endophyte alkaloids on insect performance and feeding which correlate to previous literature but was not able to accept nor reject the initial hypothesis of synergistic effects of the two defences studied. Interestingly, results suggested differential allocation of silicon between plant species and lolines within individual plant tissues. Silicon was higher in the root material of L. perenne than F. pratensis and the opposite was true for the herbage material. Also, the proportion of each loline in the root and herbage of F. pratensis differed. In summary, this research has provided insights into the temporal interactions between silicon and endophyte infection. However, further research is required to investigate the multi tiered effects of these two plant defences on economically important phytophagous insects.

text: Synergistic defensive effects of silicon and Epichloë endophytes on insect pests of agricultural grasses in New Zealand New Zealand has several insect pasture pests which cause economic losses of between $1.7 B and $2.3 B annually in the dairy, and ‘sheep and beef’ industries. Research on grass species defence provides insights into methods to reduce this economic impact. Epichloë endophytes and silicon accumulation are two well-studied mechanisms of reducing phytophagous insect damage in grass species, but their potential synergies have not been investigated. Previous research has hypothesised that plants infected with endophyte may accumulate more silicon than their non endophyte infected counterparts, suggesting multi-tiered defences. Of specific interest to this thesis is the potential impact of silicon supplementation on the alkaloid profiles of novel grass-endophyte associations. This research aimed to investigate changes to silicon concentration over time, endophyte growth and alkaloid concentration in two cool season grass species from the sub-family Pooideae and subsequent effects of these variables on major New Zealand insect pests. This interaction was investigated through the use of whole plant glasshouse trials, excised root bioassays, and artificial diet experiments using a range of above- and below ground phytophagous pasture pests (Listronotus bonariensis, Wiseana copularis and Costelytra giveni) as well as a generalist herbivore model study organism (Epiphyas postvittana). The two grass species included; Lolium perenne infected with a novel association with an endophyte naturally found in Festuca arundinacea (Epichloë coenophiala), and Festuca pratensis infected with its naturally occurring endophyte (Epichloë unicatum). 
Results from this research do not indicate that, in the grass endophyte associations studied, endophyte infection is linked to an increase in plant silicon content. There is evidence to suggest that the herbage material of L. perenne endophyte-infected plants has less silicon than endophyte free plants. There were no direct correlations between plant silicon content and the production of bioactive secondary metabolite alkaloids (lolines) or endophytic mycelial mass in F. pratensis and L. perenne. Although silicon supplementation was not linked to a direct increase in plant silicon content, there was an increase in loline production in the herbage of L. perenne, indicating a potential role of silicon in either modulating the soil environment or influencing plant biochemical reactions potentially leading to a change in production of lolines. This study also found negative effects of endophyte alkaloids on insect performance and feeding which correlate to previous literature but was not able to accept nor reject the initial hypothesis of synergistic effects of the two defences studied. Interestingly, results suggested differential allocation of silicon between plant species and lolines within individual plant tissues. Silicon was higher in the root material of L. perenne than F. pratensis and the opposite was true for the herbage material. Also, the proportion of each loline in the root and herbage of F. pratensis differed. In summary, this research has provided insights into the temporal interactions between silicon and endophyte infection. However, further research is required to investigate the multi tiered effects of these two plant defences on economically important phytophagous insects.

year: 2020

title: The Te Aroha silver and gold mining company: the introduction of Australian capital to Waiorongomai

authors: Hart, Philip

abstract: William Robert Wilson, one of the founders of B.H.P., visited New Zealand on several occasions both to obtain relief for his rheumatism and to acquire racehorses. In 1888, after Josiah Clifton Firth and Henry Hopper Adams extolled the wonders of the Waiorongomai goldfield, he visited it, took samples for testing, and expressed confidence in its great future. Upon his return to Australia he formed the Te Aroha Silver and Gold Mining Company on terms that benefited the promoters but did not provide adequate working capital. 
The new company developed some of the existing mines and did some prospecting of nearby areas. The battery, completely overhauled on the American pattern under the supervision of American experts, was the best plant in Australasia. When it operated, after obtaining some very positive results it ran out of both suitable ore and fluxes and had to close, and mining ceased. The company then sought a government subsidy to drive an expensive low-level tunnel to provide cheaper access to the lodes at depth, threatening to dismantle the plant and remove it to Australia if the subsidy was not provided. As Cabinet did not want to set a precedent, its request was declined; accordingly, the plant was dismantled and sent to Australia. For a time its mines were held under protection, to the annoyance of local miners, but were then abandoned.
The company failed because its plant had an inappropriate process for the complex and refractory local ore, did not have cheap fluxes, and there was insufficient high-grade ore. Post mortems agreed it should have spent more time developing the mines and testing the ore before erecting such an expensive plant. The collapse of this company held back the development of the field for years.

text: The Te Aroha silver and gold mining company: the introduction of Australian capital to Waiorongomai William Robert Wilson, one of the founders of B.H.P., visited New Zealand on several occasions both to obtain relief for his rheumatism and to acquire racehorses. In 1888, after Josiah Clifton Firth and Henry Hopper Adams extolled the wonders of the Waiorongomai goldfield, he visited it, took samples for testing, and expressed confidence in its great future. Upon his return to Australia he formed the Te Aroha Silver and Gold Mining Company on terms that benefited the promoters but did not provide adequate working capital. 
The new company developed some of the existing mines and did some prospecting of nearby areas. The battery, completely overhauled on the American pattern under the supervision of American experts, was the best plant in Australasia. When it operated, after obtaining some very positive results it ran out of both suitable ore and fluxes and had to close, and mining ceased. The company then sought a government subsidy to drive an expensive low-level tunnel to provide cheaper access to the lodes at depth, threatening to dismantle the plant and remove it to Australia if the subsidy was not provided. As Cabinet did not want to set a precedent, its request was declined; accordingly, the plant was dismantled and sent to Australia. For a time its mines were held under protection, to the annoyance of local miners, but were then abandoned.
The company failed because its plant had an inappropriate process for the complex and refractory local ore, did not have cheap fluxes, and there was insufficient high-grade ore. Post mortems agreed it should have spent more time developing the mines and testing the ore before erecting such an expensive plant. The collapse of this company held back the development of the field for years.

year: 2016

title: Te kākahu whakataratara o Ngāi Tūhoe: Ko te reo ōkawa, ko te reo o te marae

authors: McFarland, Agnes

subjects: Reo Māori

abstract: Ko te reo ōkawa ara ko te reo o te marae, he reo hōhonu. Ka mutu, he tapu katoa ōna āhuatanga katoa. E rua ngā kōrero whakatau o runga i te marae. Ko te karanga me te whaikōrero. Kai roto i wēneki reo e rua, ka ahu mai te kupu nei te poroporoaki. Ka āta tirohia te poroporoaki i roto i ngā whakaaro e pā ana ki ngā tikanga o te karanga. Whai muri ka titiro ki te wāhanga o te poroporoaki i roto i te whaikōrero. Mā wēneki tikanga e rua, ka whakaputaina ngā whakaaro me te hōhonutanga o te mamae o te ngākau pōuri ka ea hoki te mamae. Ka tiro ake tātau ki ngā take i whakaputaina, ngā tohutohu ā rātau mā me ngā rongo o te wairua o te kupu kōrero. Tae atu hoki ki te tohungatanga ki te whakatakoto i te rerenga kupu mai i ngā whatumanawa o ngā kuia me ngā kaumātua ō Ngāi Tūhoe. Nō reira, ka titiro ake tātau ki ngā momo āhuatanga katoa o te karanga. Whai muri ko ngā tikanga e pā ana ki te whaikōrero. Whai muri, ko wētahi atu tūmomo tauira mō te poroporoaki.

text: Te kākahu whakataratara o Ngāi Tūhoe: Ko te reo ōkawa, ko te reo o te marae Ko te reo ōkawa ara ko te reo o te marae, he reo hōhonu. Ka mutu, he tapu katoa ōna āhuatanga katoa. E rua ngā kōrero whakatau o runga i te marae. Ko te karanga me te whaikōrero. Kai roto i wēneki reo e rua, ka ahu mai te kupu nei te poroporoaki. Ka āta tirohia te poroporoaki i roto i ngā whakaaro e pā ana ki ngā tikanga o te karanga. Whai muri ka titiro ki te wāhanga o te poroporoaki i roto i te whaikōrero. Mā wēneki tikanga e rua, ka whakaputaina ngā whakaaro me te hōhonutanga o te mamae o te ngākau pōuri ka ea hoki te mamae. Ka tiro ake tātau ki ngā take i whakaputaina, ngā tohutohu ā rātau mā me ngā rongo o te wairua o te kupu kōrero. Tae atu hoki ki te tohungatanga ki te whakatakoto i te rerenga kupu mai i ngā whatumanawa o ngā kuia me ngā kaumātua ō Ngāi Tūhoe. Nō reira, ka titiro ake tātau ki ngā momo āhuatanga katoa o te karanga. Whai muri ko ngā tikanga e pā ana ki te whaikōrero. Whai muri, ko wētahi atu tūmomo tauira mō te poroporoaki.

year: 2012-05