Abstract:
Floriculture and traditional medicine are two main industries that depend on wild plant
species heavily. Lack of knowledge on propagation of wild species is one main
drawback in utilizing wild plants in these two industries. If the seed biology information
of ornamentally and medicinally important wild plants could be elucidated, those
findings would be useful in effective utilization of these plants in the commercial
production. Thus, the main objective of this study was to determine the seed storage
behaviour, dormancy and germination of fourteen selected plant species in wet zone
lowland rainforests in Sri Lanka. Fruits were collected from four rainforest reserves in
Sri Lanka; Sinharaja, Kanneliya, Yagirala and Pituwala. The study assessed seed
germination, embryo length: seed length ratio, embryo morphology and effect of
gibberellic acid (GA3) on seed germination. Additionally, seed storage behaviour was
experimentally determined through the hundred seed method. During the study, 6 non
dormant and 8 dormant species were identified. Seeds of 8 species had fully developed
embryos, while 6 species had underdeveloped embryos including 4
morphophysiologically and 2 morphologically dormant species. Treatment with GA3
indicated that 2 species exhibited physiological dormancy. Hundred seed method
identified 2 desiccation-sensitive and 12 desiccation-tolerant seed-producing species.
This study provides useful information on germination and dormancy breaking of 14
plant species which can be applied to develop suitable seed propagation systems for
them. Most of the desiccation-tolerant species identified in this study also have high
conservation value. As desiccation-tolerant seeds can easily be stored, seed banking can
be recommended as an ex-situ conservation strategy for these species. As the studied
species include five endemic plants which showed a limited distribution and are
currently facing anthropogenic threats, the above information could be utilized in
commercial cultivation of those ornamentally and medicinally important plants.
Thereby, the pressure of over-exploitation of these species from their natural habitats
can be restricted.
