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Gap‐detecting mechanism in the seed germination of Mallotus japonicus (Thunb.) Muell. Arg., a common pioneer tree of secondary succession in temperate Japan
Author(s) -
Washitani Izumi,
Takenaka Akio
Publication year - 1987
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/bf02349773
Subject(s) - germination , biology , ecological succession , temperate climate , botany , horticulture
Germination responses of Mallotus japonicus (Thumb). Muell. Arg. seeds to temperature revealed a gap‐detecting mechanism in the seed germination of the species. Among various constant and alternating temperatures examined in the range from 12–40°C, only very limited temperature regimes were found to be favourable for seed germination, specifically, alternating temperatures between 18–32°C and 28–40°C. A single several‐hour higher‐temperature (32–40°C) treatment could also induce the germination of seeds which had been imbibed for several days at a constant temperature in the range of 20–26°C, suggesting that there is a process requiring higher temperature among the overal germination processes. Seeds located at or near the surface of denuded soil would have a good chance of experiencing such a temperature change when several rainy days are followed by fine weather, while seeds beneath close vegetation would not. On the other hand, the pressence or absence of light or a simulated ‘canopy ligh’ had little effect on the germination. Therefore, it was concluded that the seeds of M. japonicus have a ‘gapdetecting mechanism’ in the form of a higher‐temperature requirement of a certain process involved in the overall germination processes.