Germination behaviour of seeds of the New Zealand woody species Alseuosmia macrophylla, A. pusilla, Cordyline banksii, Geniostoma rupestre, Myrtus bullata, and Solanum aviculare

Abstract

Seeds from freshly collected fruit were tested to examine germination period in relation to season, germination rates, and degree of success, in conditions similar to those that they could experience after dispersal in nature. In a relatively well lit, moist treatment seeds germinated in autumn‐winter, or winter‐spring(‐summer). Germination of a few Alseuosmia macrophylla seeds was delayed until spring of the second year. Success was high (97–100%) for all species except Solanum (72–82%). Germination in the dark was nil for Alseuosmia macrophylla but for the other species ranged from 82% (Solanum) to 100% (Cordyline); Alseuosmia macrophylla seeds germinated when brought into the light (96% success). Germination on soil was much more variable and usually the degree of success was lower than in the well lit treatments, except for Cordyline and Myrtus. Germination success in‐fruit was nil for all species except Cordyline, for which it was very poor.

Drying for several months substantially lowered seed viability for Alseuosmia spp. and Myrtus, but the viability of seeds of the other species tested was relatively unimpaired. When buried, only Cordyline sent (relatively few) shoots to the soil surface; Geniostoma and Solanum seeds went dormant and many (Solanum), or all (Geniostoma) germinated when unearthed. Buried Myrtus seeds germinated but died underground.

Germination behaviour of the seeds of the respective species generally matches the ecological habit of the plants, Geniostoma and Solanum, colonisers of disturbed sites, being the most versatile. The effect of pre‐conditioning of seeds on their subsequent germination behaviour is emphasised. Secondary dormancy effects may be induced by darkness alone (Alseuosmia macrophylla), or burial, involving both darkness and probably the gaseous environment (Geniostoma and Solanum), and possibly by drying (Alseuosmia macrophylla, Cordyline, Solanum).

Keywords:

• high viability
• varied treatments
• diverse germination responses
• seed storage
• pre‐conditioning