Seed biology of Symplocos cochinchinensis, towards reforestation of degraded submontane forests in Sri Lanka
Postgraduate Institute Of Science, University Of Peradeniya, Peradeniya, Sri Lanka
Athugala Y. S. , Jayasuriya K. M. G. G., Gunaratne A. M. T. A.
Introduction: What conservation problem or question does your study address?
Symplocos cochinchinensis is an important pioneer tree species with a high medicinal value. This native tree species can be used effectively for restoration of degraded lands. However, it is difficult to collect adequate number of seedling from the wild populations. this study was conducted to gather the basic seed biological information of S. cochinchinensis to aid forest restoration on degraded lands.
Methods: What were the main research methods you used?
Initial seed moisture content (MC) and viability of seeds were used to determine the seed storage behaviour. Germination of mature intact S. cochinchinensis seeds at 25 oC in light/ dark (14h/ 10 h) and imbibition of nonscarified (NS) and manually scarified (MS) seeds was assessed to determine the presence of physiological (PD) and/or physical dormancy. Cross and longitudinal sections of the seeds were used to assess the condition of the embryo (underdeveloped or not). Manual scarification, gibberellic acid (GA3) treatment, acid scarification treatments were conducted to determine the level of PD. Effect of temperature (at 15, 25 and 35 oC) and of complete darkness on seed germination was studied. Time taken for shoot emergence from radicle emergence was monitored to evaluate the presence of epicotyl dormancy.
Results: What are your most important results?
Initial MC was 11.6 %. In standard germination test, only 9 % of seeds germinated after 90 days. MS & NS seeds have a similar pattern of imbibition. GA3 500 ppm treated seeds gave the highest germination. The embryo was fully developed. 51.0 % of the seeds germinated within 80 days at 15 oC, while none of the seeds germinated at 25 oC and 35 oC. Under dark condition, seeds germinated under dark as well.. Shoot emergence delayed significantly after radicle emergence.
Discussion: What are your important discussion points and what is the relevance of your results to conservation (if any)?
S. cochinchinensis produce orthodox seeds. Seeds are dormant and they are physiologically dormant. Epicotyl of Symplocos also dormant. Therefore S. cochinchinensis has physiological epicotyl dormancy.GA3 treatment is a best possible treatment that can be used to produce seedlings within a short time for restoration activities. Cold stratification may be the natural PD breaking treatment. Light is not a requirement for seed germination.