A review of dipterocarps - Center for International Forestry Research

Seed Physiology 69
Dipterocarp seed of the OLDA type has a shorter
storage life than seed of crop species if compared at the
same moisture content. Thus, it has been estimated that
the relevant K E and, C W viability constants (which
indicate seed longevity) are, respectively, only 6.4 and
2.9 on the average for dipterocarp seed (Table 6),
compared with 8.4 and 4.7 (Tompsett 1994) for
herbaceous crops. Further research is needed to extend
these findings to other OLDA dipterocarp species.
The stage of fruit development at harvest is important
to ensure optimum desiccation tolerance, and
consequently to ensure maximum storage potential.
Further research is needed for dipterocarps in order to
closely assess the relationship between harvest
condition, postharvest handling, and desiccation
tolerance.
Studies are needed to increase knowledge of the
optimum moisture and temperature conditions for
storage of recalcitrant seeds, employing controlled
conditions. Especially, research is needed in relation to
the chilling injury. Studies to quantify chilling damage
in relation to moisture content are needed. Also, research
is required to determine its relationship to underlying
biochemical processes.
Although the database DABATTS (Tompsett and
Kemp 1996a, b) includes a large amount of previously
unpublished information on dipterocarp seed, a high
proportion of its contents are the results produced by
the authors. Unpublished information from other sources
needs to be databased, building on DABATTS and
increasing the total sum of research results readily
available.
Research on the induction of flowering is necessary
to improve knowledge of the causes underlying the
irregular flowering of dipterocarps. Such research may
provide artificial means for the induction of flowering
in relation to breeding and to seed production in nonmast
years.
These approaches might with benefit be extended to
other tropical tree families such as the Palmae and
Sapotaceae.
Relevant Institutions
As described in Chapter 4 and above (in the work of
Sasaki, Mori, Tang, Tamari and Yap), Forest Research
Institute Malaysia (FRIM) has played a leading role in
early dipterocarp seed research, particularly in the areas
of germination ecology and storage research. Current
work at FRIM on cryopreservation and seedling storage
is referred to elsewhere. Over the last decade, the seed
physiological studies at the Royal Botanic Gardens Kew
have contributed basic knowledge, creating a firm
foundation for practical recommendations. The Forest
Research Centre, Sandakan, Malaysia, has a seed research
laboratory constructed under an FAO aid programme and
has undertaken significant dipterocarp research.
In Thailand the Royal Forest Department’s ASEAN
Tree Seed Centre, Muak Lek, has been involved in
dipterocarp studies for a number of years and has good
facilities; additionally, the central laboratory in Bangkok
has an active research team on the topic.
The Ecosystems Research and Development Bureau,
Republic of the Philippines, is engaged in dipterocarp
seed research, as are the Forest Research and
Development Centre, the Biotechnology Centre and
BIOTROP in Bogor, Indonesia. In India, research on
biochemical aspects has been recently conducted at the
High Altitude Plant Physiology Research Centre of
Garhwal University, Srinagar and the Forest Research
Institute, Dehra Dun has been involved in dipterocarp
research in the recent past.
In China, biochemical, ultrastuctural and
physiological research on dipterocarp species has been
performed by staff of the Tropical Forest Research
Institute, Chinese Academy of Forestry, Guangdong.
Although not involved in dipterocarp research, the
Agriculture and Horticulture Department at Reading
University, UK, is developing experience in the area of
tropical tree seed physiology. Other institutes have
contributed information in this field, but space available
limits the numbers that can be included.
Acknowledgements
I thank the Royal Botanic Gardens Kew and the Center
for International Forestry Research for facilities and
financial support
References
Berjak, P. and Pammenter, N.W. 1996. Recalcitrant
(desiccation-sensitive) seeds. In: Olesen, K. (ed.)
Innovations in tropical tree seed technology, 14-29.
Danida Forest Seed Centre, Humlebaek.
Chin, H.F., Hor, Y.L. and Mohd Lassim, M.B. 1984.
Identification of recalcitrant seeds. Seed Science and
Technology 12: 429-436.