A review of dipterocarps - Center for International Forestry Research

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Seed Handling 83 (Pence 1992). In addition, material from the recalcitrant seed of the tropical forest tree Araucaria hunsteinii can be cryopreserved; storage of species for four years at -20°C has been achieved, viability being measured in terms of callus production (Pritchard et al. 1995). Growth occurred from the radicle end of the embryo axis. Some results achieved by Krishnapillay and colleagues (unpublished) are described. Studies were conducted on the recalcitrant-seeded dipterocarp species Hopea odorata and Dryobalanops aromatica. Embryos were first subjected to cryoprotection treatment using sucrose and dimethyl sulphoxide; following this, the embryos were partially dried to a moisture content near 14-15%. The temperature of the material was then taken to -30°C at the rate of 1°C per minute, finally being reduced to -196°C by plunging into LN. After one week the embryo axes were removed, thawed at 40°C and evaluated for survival. About 5% showed signs of swelling and/or the emergence of growth initials. These post-thawing changes were observed in the epicotylar region; no development was observed in the radicle region and none of the embryonic axes were able to grow into whole plants. Improvements to the protocol are being sought. A total of 50 excised embryo axes were used in 5 replicates for each study and for each species. Cryopreservation has also been used for whole seeds of Dipterocarpus alatus and D. intricatus (Krishnapillay and Marzalina, unpublished). However, these species are basically orthodox in storage physiology (Tompsett 1987). Cryopreservation is not recommended for species of this storage physiology type because of the comparative practical benefits of using conventional seedbank storage at -20°C (Pritchard 1995). The greatest proven uses of this approach have been with small pieces of tissue. Complete success in the production of entire seedlings after freezing of tissues may require the development of in vitro culture methods (see Chapter 3). In addition, nursery techniques for weaning the developed plantlets are required. Considerable investment of research time and resources may thus be needed to assess if the method can be useful in practice for recalcitrant-seeded material. Summary of Seed Handling Methods For South and Southeast Asian Dipterocarpaceae, the following current seed handling recommendations have been made (Tompsett and Kemp 1996a, b). Collection Recommendations Check a small sample of seeds before collecting, since insect infestation may be excessive. Collect seeds from the tree when the wings are turning from green to brown. Collection is best accomplished by shaking or plucking branches; a climber may be needed where branches are inaccessible from the ground. Plan the collection to minimise the period of time (preferably a maximum of three days) between harvest and either nursery sowing or short-term storage at the seed centre. Transport Recommendations Recalcitrant and OLDA seeds are considered separately. Recalcitrant seeds should be transported moist and in ventilated containers; they should be kept as cool as possible but not below 18°C. If the wings are left intact, a reservoir of air is created which provides oxygen for respiration. This method reduces both the imbibition of moisture in the container and the accumulation of heat produced by respiration, thereby limiting the chance of germination during transport. Possible containers include open, folded-over polythene bags, closed polythene bags with small ventilation holes, and open-weave sacks. Where greater rigidity is required, the bags or sacks should be enclosed in cardboard or wooden boxes with ventilation holes. Care should be taken to avoid overheating by exposure of the containers to direct sunlight. Additionally, seed should be retained above its lowest-safe moisture content For species with OLDA storage physiology seeds, collections may sometimes need to be made from the ground with moisture contents at or below 12%. Dry seed of this type should be transported as follows. For use in the short-term, transport the seed at a cool temperature above 2°C; for use in the long term, transport material at as low a temperature as possible, but not below -20°C. Retain the dry seed in sealed containers during transport. For moist OLDA seed, follow the methods described for transport of recalcitrant seed. Processing Recommendations Remove wings for ease of handling and to reduce storage bulk for all species. Other processing applies to OLDA species. Seeds of this type will dry well in 20°C or higher with a low relative humidity. Material should be transferred to the appropriate storage conditions as soon as the desired moisture content is reached. Retaining seeds in a monolayer in a flow of
Seed Handling 84 air will ensure rapid drying, thereby reducing the risk of seed ageing. Careful removal of the calyx can further reduce bulk for dry storage. However, this procedure is time consuming and may only be economic for longerterm (conservation) storage. Storage Recommendations Procedures are recommended separately for small and large quantities of recalcitrant seeds and for OLDA seeds. For larger quantities of recalcitrant seeds, material should be kept at near the harvest moisture content and in media such as sawdust and perlite. Seed moisture content should be checked at the start and then periodically during storage; any wide fluctuations observed should be counteracted by increasing or decreasing the moisture content of the medium. This careful moisture content monitoring and management can reduce the rate of pre-germination. Excess moisture in the medium causes the seeds to become anoxic, whilst too little moisture lowers seed moisture content and leads to desiccation damage. Suitable containers include open-weave sacks or bags. Storage in a high-humidity room at 18 o C is recommended. The optimal condition for storage of smaller quantities of recalcitrant seed is retention within inflated polythene bags in a 99% relative humidity incubator at 18 o C and at a moisture content near that of the seed at harvest. Polythene bags with rib-channel closure provide suitable packaging; alternatively, loosely-tied, thin-gauge polythene bags may be employed. Insertion of a rigid object helps to maintain an air space. Ventilation at least weekly is essential; use of air at a high relative humidity would be desirable for this purpose. Moisture content should be checked at the start and then periodically during storage; fluctuations should be counteracted by increasing or decreasing the relative humidity around the seed, if possible. Different handling is required for OLDA species; the summarised methods for collection, processing and transport described above must be followed closely if the three storage methods below are to be effective. a) Before sowing in the nursery, seed storage of OLDA species at about 40-50% moisture content is suitable over very short periods of about fifteen days. Moist storage avoids the risk of partial loss of viability on drying. Temperatures employed should be no lower than 18 o C. The seed containers described above in relation to recalcitrant species for smaller and larger seedlots are suitable. b) In the case of longer-term storage any initial, partial loss on drying may be outweighed by the improved final longevity achieved. Storage for conservation is possible if seed is dried to approximately 12% moisture content; material should be sealed in suitable rigid containers (e.g. Kilner jars) and retained at -20 o C. Further relevant information is given in the summarised processing method above. c) For medium-term storage periods (between 2 weeks and 24 months), OLDA seed should be retained at 2°C with other conditions as prescribed for longerterm storage. Germination Recommendations Remove seed wings prior to sowing in order to ensure good contact with the germination medium and germinate at approximately 26 o C -31 o C. In the case of dry, decoated OLDA seeds (de-coating is recommended for conservation storage), slow imbibition is essential. This can be achieved by retaining the material in 100% humidity for 24 hours before sowing. Research Priorities Changes are occurring in relation to reforestation and afforestation programmes in the regions where dipterocarps are grown. The emphasis is now on the use of indigenous species in combination with exotics. It follows that suitable planting material will be increasingly in demand. Hence, there is a necessity to increase research in the areas described below: 1. Optimising methods for the collection, processing, storage and germination of forest seeds so that seed storage life is maximised, taking into account the need for retaining the viability of seeds that germinate during storage. More detailed suggestions are given in Chapter 3. 2. When the seed storage physiology is known, other information is required. In particular, practical methods for large-scale drying are required in the case of OLDA species, and methods for the storage of bulky recalcitrant material need improvement. 3. Identification of seed-predating insects leading to assessment of their behaviour, especially in the seasonal zones, is desirable. This would complement studies undertaken already in the aseasonal areas.
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A Review of Dipterocarps Taxonomy,
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ã 1998 by Center for International
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Authors S. Appanah Forest Research
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SPINs Species Improvement Network T
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Foreword The Center for Internation
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Introduction As a consequence, much
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Introduction each project that is m
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Biogeography and Evolutionary Syste
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Page 39 and 40: Biogeography and Evolutionary Syste
Page 55 and 56: Conservation of Genetic Resources i
Page 65 and 66: Seed Physiology P.B. Tompsett Seed
Page 67 and 68: Seed Physiology 59 (Sasaki 1980, Ya
Page 69 and 70: Seed Physiology 61 § orthodox; and
Page 71 and 72: Seed Physiology 63 Table 4. Lowest-
Page 73 and 74: Seed Physiology 65 Table 5. (contin
Page 75 and 76: Seed Physiology 67 Table 6. Viabili
Page 77 and 78: Seed Physiology 69 Dipterocarp seed
Page 79 and 80: Seed Physiology 71 Roberts, E.H. 19
Page 81 and 82: Seed Handling 74 viability of the s
Page 83 and 84: Seed Handling 76 the basic activiti
Page 85 and 86: Seed Handling 78 Table 2. Seed (fru
Page 87 and 88: Seed Handling 80 Table 3. Mean inse
Page 89: Seed Handling 82 Seedling storage u
Page 93 and 94: Seed Handling 86 ASEAN Forest Tree
Page 95 and 96: Seed Handling 88 Tompsett, P.B. and
Page 97 and 98: Seedling Ecology of Mixed-Dipteroca
Page 107 and 108: Root Symbiosis and Nutrition Table
Page 109 and 110: Root Symbiosis and Nutrition Table
Page 111 and 112: Root Symbiosis and Nutrition specie
Page 113 and 114: Root Symbiosis and Nutrition in Sab
Page 115 and 116: Root Symbiosis and Nutrition where
Page 117 and 118: Root Symbiosis and Nutrition 5. Lim
Page 119 and 120: Root Symbiosis and Nutrition Group
Page 121 and 122: Root Symbiosis and Nutrition Takaha
Page 123 and 124: Pests and Diseases of Dipterocarpac
Page 139 and 140: Management of Natural Forests S. Ap
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Management of Natural Forests about
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Management of Natural Forests 4. Cl
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Management of Natural Forests were
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Management of Natural Forests incre
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Management of Natural Forests 1. He
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Management of Natural Forests which
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Management of Natural Forests Cheng
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Management of Natural Forests Uebel
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Plantations 152 macrocarpa, V. indi
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Plantations 154 are: Dipterocarpus
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Plantations 156 and no longer in ne
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Plantations 158 able to store them
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Plantations 160 ‘Predictive Test
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Plantations 162 Qureshi et al. (196
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Plantations 164 Tomboc and Basada (
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Plantations 166 are removed. Anothe
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Plantations 168 intervention. Sange
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Plantations 170 mono-layered. The r
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Plantations 172 diameter of 46.3 m
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Plantations 174 Ang, L.H., Maruyama
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Plantations 176 Cheah, L.C. 1971. A
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Plantations 178 Kadambi, K. 1957. B
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Plantations 180 Moura-Costa, P. 199
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Plantations 182 Regional Workshop o
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Plantations 184 Conference on Dipte
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Non-Timber Forest Products from Dip
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Scientific Index BIXALES, 25 BOLETA
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Scientific Index EPHEMEROPTERA, 119
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Scientific Index Ovalis section, 8,
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Scientific Index Shorea leptoderma,
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Scientific Index VATERINAE sub-trib
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General Index barus kapur, 192-3 ba
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General Index endangered species, i
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General Index distribution, 15 enda
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General Index nurse crops, 161, 165
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General Index seed material, cryopr
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General Index TPI, 139 tractors, 15
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