Seed Production and Processing of the Indigenous Coastal Sand-Binding Plant Spinifexsericeus

摘要

Spinifex sericeus R.Br is an important indigenous sand-binding grass growing on coastal foredunes throughout the North Island and northern South Island of New Zealand. Utilising seed rather than vegetative propagation techniques has typically been more successful in establishing plants for sand dune stabilisation in New Zealand. Since 1998, caryopses (naked "seeds") have been mechanically extracted at Massey University from 43 collections (or sub-collections) sent by interested parties from 16 NorthIsland beaches. Although most collections received were from five beaches of the south western coast of the North Island (25), especially Hokio beach near Levin, a number were also received from a further five west coast and six east coast beaches. Weights of extracted whole seeds ranged from as little as 2.9 g (approximately 210 seeds) to 142 g (approximately 11,270 seeds) per "packed" fertiliser bag of spinifex seedheads (ave. 51.1 g, about 3790 seeds).The ten highest yields obtained were collectionsfrom Hokio (8), Foxton (1), and Himatangi (1) beaches. Low yields were more typical of east coast beaches, although the lowest yields recorded were from the west coast beach of Oakura, near New Plymouth. Fungal smut or rodents were identified as causes of low seed yield in some cases. Thousand seed weight varied from 11.7 g (Patea) to 15.6 g (Muriwai). A relationship of declining seed weight with increasing seed yield was only prevalent from the combined Hokio and Kapiti collections (r~2= 76%).