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Ecological, genetic and cultural status of Solanum aviculare, poroporo (Solanaceae)

Solanum aviculare, endemic to Australasia, is an opportunist pioneer secondary successional plant occupying disturbed and open lowland habitats, and was an important medicinal and cultural species to Māori known as poroporo. It is currently in 'decline', the ecological decline appearing to correspond to a decline in knowledge and cultural use of the species. To gain understanding of the reasons for the decline, enhance ecological knowledge, assist conservation and cultural restoration of Solanum aviculare this research documented the successional role and cycle of regeneration dynamics and tactics, established morphological characteristics, investigated the genetic diversity and recorded cultural and conservation information. The successional status and role was identified. Growth data identified cohort development and inter-site differences, metadata found height and crown spread growth to be significantly correlated and likely part of an early reproduction and dispersal strategy. Germination of soil cores from differing depths confirmed a viable seed bank exists sufficient for species maintenance. Viable seed spread via animal gut passage was determined by germination and chemical tests, results showed rats passed higher rates of viable seed than birds. Seed germination trials with stratified and fresh seed confirmed temporal and depth behaviour, flowering observation documented temporal differences with the closely allied species Solanum laciniatum, indicating a relationship to stasis induction. Leaf morphology studies documented differences between the two allied species and proposed further nomenclature. Genetic diversity was investigated through the use of PCR/ISSR techniques. Chloroplast DNA was extracted by CTAB and DNA kit protocols. CTAB extraction was unable to effectively remove RNA, although use of DNA samples with high quantities of RNA confirmed that RNA was not an inhibiting factor in PCR production. The production of consistent reliable ISSR bands proved difficult, with no technical explanation found. ISSR findings indicate that Solanum aviculare is highly monomorphic, consisting of predominant invariant monomorphic loci. Twenty primers were tested with no polymorphic loci identified and no intra species variation documented. Indications were also that Solanum aviculare and Solanum laciniatum are inter species invariant on monomorphic loci. Monomorphic loci may possibly be the evolutionary markers of generic differentiation within Solanum. Surveys identified Solanum aviculare as uncommon and rare, existing mainly as single plants or small groups in the majority of areas surveyed. The Threatened and Uncommon Plant listing of Solanum aviculare as an 'at risk declining' species is confirmed and a further Recommendation category proposed. Ecological decline and corresponding decline in cultural use and knowledge of Solanum aviculare was identified through specialist interviews; appearing to be related to removal from Māori of control over their land. The name poroporo being now associated mainly with non indigenous Solanum species. Māori cultural concepts in practice were highlighted as fundamentally important to reversing the decline, with an example of a successful traditional practice based (tikanga) integrative collaborative restoration program being documented. This research forwards that optimal collaborative solutions, programs integrating scientific and tikanga knowledge and practices, provide the best opportunity of reversing the declining trend and for increasing and maintaining knowledge associated with the traditional role of poroporo.
Type of thesis
Weavers, G. M. (2010). Ecological, genetic and cultural status of Solanum aviculare, poroporo (Solanaceae) (Thesis, Master of Science (MSc)). The University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/5008
The University of Waikato
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