New Zealand Journal of Botany abstract
Germination behaviour of the seeds of seven New Zealand vine species
C. J. BURROWS
Department of Plant and Microbial Sciences
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
Abstract Germination rates, percentage germination success,
and phenomena related to germination delay were determined for seeds from
freshly collected fruit (summer-autumn) of Calystegia tuguriorum,
Clematis foetida, Muehlenbeckia australis, Parsonsia
heterophylla, Ripogonum scandens, Rubus cissoides, and
Tetrapathaea tetrandra. The experimental treatments simulated natural
conditions that the seeds might experience after dispersal. In the standard
treatment (seeds cleaned, moist, well-lit) seeds of each species behaved
differently. Ripogonum seeds germinated through autumn and winter; in
late-collected fruit some had germinated viviparously. The large seeds have a
very thin testa and are killed by drying. Some Muehlenbeckia seeds
germinated in autumn, the rest did not do so until early spring.
Clematis and Tetrapathaea seeds did not start germinating until
late winter (when temperatures were rising) and all viable seeds had germinated
within two months. A few Rubus and Parsonsia seeds germinated,
respectively, in autumn and spring. Germination of the remaining seeds occurred
at a slow, steady rate for Rubus, for two years, and during warm periods
for Parsonsia, for three years. Sporadic germination of
hard-coated Calystegia seeds occurred over five years. The amount of
germination success was high (89-98%) for Clematis, Ripogonum,
Muehlenbeckia, and Tetrapathaea, but only 18, 73, and
82%, respectively, for Calystegia, Parsonsia, and
Rubus.
In the dark treatment most Tetrapathaea and Parsonsia seeds
germinated, but only moderate numbers of Ripogonum,
Muehlenbeckia, and Rubus seeds and none of Clematis.
In the soil treatment germination success was lower than in the standard
treatment and germination rates were slower. The same applied to seeds in the
in-fruit treatment for Muehlenbeckia, Parsonsia, and
Rubus. No radicles emerged in the in-fruit treatment for
Ripogonum, but the embryos of many developed, viviparously, to
the immediate pre-emergence stage.
Ripogonum, Calystegia, Clematis, Muehlenbeckia,
and Tetrapathaea can all maintain short-term seed banks, in fruit,
on the parents (for two months or more). Rubus, Parsonsia,
and Calystegia seeds can persist in soil seed banks for more than a
year. Ripogonum does not maintain soil seed banks. It is not known
whether seeds of Clematis and Tetrapathaea can do so. Generally
the seed germination phenomena accord well with the habitat preferences of the
respective species.
Keywords seeds; dry fruit; fleshy fruit; germination delays;
different patterns; vivipary; seed banks; environmental correlations
B95010
Received 28 February 1995; accepted 13 August 1995
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