A review of dipterocarps - Center for International Forestry Research

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Conservation of Genetic Resources in the dipterocarpaceae 47 Table 2. Breeding systems of Dipterocarps. Species/Section Percent Fruit Set Inferred Breeding References Selfed Crossed System Shorea cordifolia Section Doona 0.5 21.0 Self-incompatible 1 S. disticha Section Doona 0.0 10.0 Self-incompatible 1 S. trapezifolia Section Doona 0.8 3.8 Self-incompatible 1 S. trapezifolia Section Doona 0.5 11.3 Self-incompatible 1 S. hemsleyana Section Muticae 0.0 15.2 Self-incompatible 2 S. macroptera Section Muticae 2.5 19.9 Self-incompatible 2 S. lepidota Section Muticae 1.7 24.4 Self-incompatible 2 S. acuminata Section Muticae 1.1 34.1 Self-incompatible 2 S. leprosula Section Muticae 1.6 17.0 Self-incompatible 2 S. splendida Section Pachycarpae 0.0 37.5 Self-incompatible 2 S. stenoptera Section Pachycarpae n/a n/a Self-incompatible 2 S. ovalis Section Ovales 16.2 17.6 Self-compatible 2 Dipterocarpus oblongifolius 69.3 64.0 Self-compatible 2 Dryobalanops lanceolata n/a n/a Self-incompatible 3 Hopea glabra n/a n/a Self-compatible or 2 Section Richetioides apomictic S. maxima Section Richetioides n/a n/a Self-incompatible 2 S. multiflora n/a n/a Self-incompatible 2 1: Dayanandan et al. (1990); 2: Chan (1981); 3: Mamose et al. (1994). Outcrossing Rates More recently genetic markers in the form of allozymes have been used to quantify mating systems in species of Dryobalanops, Hopea, Shorea, and Stemonoporus. Analysis of mating systems on the basis of markers allows examination of the progeny arrays of many trees in the population. Moreover, outcrossing rate (tm) can be quantified between zero and one; zero representing complete selfing and one indicating 100% outcrossing. Mating systems of species examined so far are shown in Table 3. The outcrossing rates range from 0.617 in Shorea trapezifolia to 0.898 in Stemonoporus oblongifolius. The average rates expressed in Table 3 mask considerable variation among trees and years. The rate varied from 0.49 to 1.00 among trees in Shorea congestiflora (Murawski et al. 1994a, b). S. megistophylla trees in the logged forests had a lower outcrossing rate than trees in undisturbed forests (Murawski et al. 1994b). The difference seems to be dependent on the density of reproductive trees. Such density-dependent differences in outcrossing rates have also been shown in several other
Conservation of Genetic Resources in the dipterocarpaceae 48 Table 3. Outcrossing rates of Dipterocarps. Species Outcrossing Rate tm (± standard error) tropical tree species (Murawski and Hamrick 1990, 1991). Apparently, the low density of trees in logged stands reduces the inter-tree movement of pollinators and promotes self-pollination. Selfing, in part, may be aided by a weak self-incompatibility system. Kitamura et al. (1994) compared outcrossing rates of Dryobalanops aromatica in primary and secondary forests but found no significant differences. Self-incompatibility as well as mating system studies suggest that dipterocarps are predominantly outcrossed. Outcrossing in large populations can allow populations to harbour considerable genetic variation. In dipterocarps, mass flowering is also likely to enhance outcrossing by allowing exchange of gametes among a very large number of individuals. Not surprisingly, therefore, populations of dipterocarps show considerable genetic variation (see below). Although the analysis of mating systems shows that the rates of outcrossing are high, it is also clear that there is a considerable potential for selfing in almost all species examined so far. Moreover, apomixis has been reported in several species (see below). While outcrossing continuously generates new genetic variation, potential for self-pollination and apomixis allows occasional new variants to spread in the population or colonise new sites, and thereby promote differentiation of taxa. Pollen and Seed Dispersal Pollen dispersal influences the mating system, and both pollen and seed dispersal affect population genetic structure. Limited dispersal results in inbreeding, small effective population sizes, and a high level of differentiation among populations. Extensive dispersal has the opposite effect. Outcrossing in dipterocarps is achieved through a wide variety of pollinators that differ in their foraging References Dryobalanops 0.794 (±0.059) – Kitamura et al. (1994) aromatica 0.856 (±0.063) Shorea congestiflora 0.874 (±0.021) Murawski et al. (1994) S. megistophylla 0.860 (±0.058) Murawski et al. (1994) S. trapezifolia 0.617 (±0.033) Murawski et al. (1994) Stemonoporus 0.898 (±0.022) Murawski & Bawa oblongifolius (1993) ranges and therefore disperse pollen over varying distances. Appanah and Chan (1981) implicated thrips as pollen vectors for several species of Malaysian species of Shorea, section Muticae. The thrips breed in flower buds of the species they pollinate and, as flowering progresses, they multiply in number. The adult thrips feed on stamens and petals. As the petals of the flowers are shed from the tree the thrips fall on the ground and then move to a new cohort of subsequently opened flowers. The distances over which thrips move are not known but, because of their relatively small body size, they apparently do not fly over long distances. It is presumed that their restricted movement is not a drawback in their effectiveness as pollinators because the species they pollinate are relatively abundant. Dayanandan et al. (1990) present evidence for pollination of Shorea megistophylla (section Doona) and Vateria copallifera by bees (Apis spp.). They also observed a wide variety of other insect floral visitors including thrips. However, the thrips acted as flower predators rather than pollinators, particularly in V. copallifera. More recently, Momose et al. (1994) have presented evidence for pollination of Dryobalanops lanceolata, a large canopy tree species in Sarawak, by medium sized, stingless bees (Trigona spp.). They also noted the presence of many other types of flower visitors (Coleoptera and Diptera). Momose et al. suggest that medium sized, stingless bees constitute an important group of pollen vectors for canopy and subcanopy trees in Sarawak (see also Chan and Appanah 1980). Clearly, the dipterocarps are pollinated by a wide variety of insects. The three detailed studies, respectively by Appanah and Chan (1981), Dayanandan et al. (1990), and Momose et al. (1994) have revealed three different classes of pollinators. Ashton (1982) in his extensive review also lists beetles and moths as flower visitors, although their role in pollination has not yet been demonstrated. Among the pollinators implicated so far, all, except thrips, are capable of moving pollen over long distances. The extent of gene flow via pollen (and seeds) is further discussed in subsequent sections. Seed dispersal in most dipterocarps is by wind (Ashton 1982). In most species, sepals are modified into
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A Review of Dipterocarps Taxonomy,
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ã 1998 by Center for International
Page 5 and 6: Authors S. Appanah Forest Research
Page 7 and 8: SPINs Species Improvement Network T
Page 9 and 10: Foreword The Center for Internation
Page 11 and 12: Introduction As a consequence, much
Page 13 and 14: Introduction each project that is m
Page 15 and 16: Biogeography and Evolutionary Syste
Page 55: Conservation of Genetic Resources i
Page 59 and 60: 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 and 90: Seed Handling 82 Seedling storage u
Page 91 and 92: Seed Handling 84 air will ensure ra
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
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Root Symbiosis and Nutrition Table
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Root Symbiosis and Nutrition Table
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Root Symbiosis and Nutrition specie
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Root Symbiosis and Nutrition in Sab
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Root Symbiosis and Nutrition where
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Root Symbiosis and Nutrition 5. Lim
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Root Symbiosis and Nutrition Group
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Root Symbiosis and Nutrition Takaha
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Pests and Diseases of Dipterocarpac
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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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