A. Prasetyo, H. Aiso, F. Ishiguri, I. Wahyudi, I. Wijaya, J. Ohshima, S. Yokota
Fast-growing tree species are being considered as an alternative source of timber to augment the supply in southern Asian countries. Eucalyptus is one of the most promising genus because its fast-growing characteristics and hybridization among species can produce superior characteristics valuable to both the pulp and timber industries. To evaluate the possibility of using it for timber, growth characteristics and wood properties were investigated for three nine-year-old Eucalyptus species (E. urophylla, E. grandis, and E. pellita) planted for pulpwood in Indonesia. E. pellita showed superior growth characteristics and wood properties compared to the other two species. No negative correlation coefficients were observed between growth characteristics and wood properties in any of the species, indicating that improvement of wood properties might not reduce the growth characteristics. The hybrids from E. pellita and E. urophylla might produce a next generation with better growth characteristics, resistance to pests and diseases, tolerance to low soil fertility, and relatively good wood properties. In addition, based on the obtained results, hybridization between E. grandis and E. urophylla or E. pellita might improve the relatively low wood properties of E. grandis.
{"title":"Variations on growth characteristics and wood properties of three Eucalyptus species planted for pulpwood in Indonesia","authors":"A. Prasetyo, H. Aiso, F. Ishiguri, I. Wahyudi, I. Wijaya, J. Ohshima, S. Yokota","doi":"10.3759/TROPICS.MS16-15","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-15","url":null,"abstract":"Fast-growing tree species are being considered as an alternative source of timber to augment the supply in southern Asian countries. Eucalyptus is one of the most promising genus because its fast-growing characteristics and hybridization among species can produce superior characteristics valuable to both the pulp and timber industries. To evaluate the possibility of using it for timber, growth characteristics and wood properties were investigated for three nine-year-old Eucalyptus species (E. urophylla, E. grandis, and E. pellita) planted for pulpwood in Indonesia. E. pellita showed superior growth characteristics and wood properties compared to the other two species. No negative correlation coefficients were observed between growth characteristics and wood properties in any of the species, indicating that improvement of wood properties might not reduce the growth characteristics. The hybrids from E. pellita and E. urophylla might produce a next generation with better growth characteristics, resistance to pests and diseases, tolerance to low soil fertility, and relatively good wood properties. In addition, based on the obtained results, hybridization between E. grandis and E. urophylla or E. pellita might improve the relatively low wood properties of E. grandis.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Panida Kachina, H. Kurokawa, Michio Oguro, T. Nakashizuka, Hiroshi Tanaka, Satid Thinkampheang, S. Sungkaew, Samroeng Panuthai, Dokrak Marod
To understand the effect of forest fire on the regeneration of Cephalostachyum pergracile Munro bamboo, we compared the culm dynamics in the early regeneration stage for 3 years between a site protected from natural fires since 1995 and a site that had been burnt almost annually in a mixed deciduous forest in Thailand. Although the repeated fires distinctly decreased the number and basal area of culms per clump and the proportion of surviving culms throughout the study period, this bamboo species basically represents an adaptation to fire disturbance. A greater number of thin culms and many small branches produced by the fire-disturbed bamboos may have maximized photosynthesis with minimum allocation of photosynthate after they lose their aboveground parts. Further, the ratio of surviving clumps was higher at the unprotected site than at the protected site where selfthinning among clumps occurred. In contrast to these dynamic responses of bamboos against the fire disturbances, the number of individual clumps and their sizes remained smaller at the unprotected site than at the protected site. These results indicate that the intensity and frequency of fires primarily determine the dynamics of the bamboo population, having potential to alter the forest succession to either less or more bamboo dominating forest community. Further studies are required to elucidate the role of fire on the interaction between bamboo and tree species, specifically at the middle and matured stages of bamboo life history and along a gradient of fire regimes for better understanding assembly of the MDF community.
{"title":"Effect of Forest fire on the regeneration of a bamboo species (Cephalostachyum pergracile Munro) at a mixed deciduous forest in Mae Klong Watershed Research Station, Thailand","authors":"Panida Kachina, H. Kurokawa, Michio Oguro, T. Nakashizuka, Hiroshi Tanaka, Satid Thinkampheang, S. Sungkaew, Samroeng Panuthai, Dokrak Marod","doi":"10.3759/TROPICS.MS16-09","DOIUrl":"https://doi.org/10.3759/TROPICS.MS16-09","url":null,"abstract":"To understand the effect of forest fire on the regeneration of Cephalostachyum pergracile Munro bamboo, we compared the culm dynamics in the early regeneration stage for 3 years between a site protected from natural fires since 1995 and a site that had been burnt almost annually in a mixed deciduous forest in Thailand. Although the repeated fires distinctly decreased the number and basal area of culms per clump and the proportion of surviving culms throughout the study period, this bamboo species basically represents an adaptation to fire disturbance. A greater number of thin culms and many small branches produced by the fire-disturbed bamboos may have maximized photosynthesis with minimum allocation of photosynthate after they lose their aboveground parts. Further, the ratio of surviving clumps was higher at the unprotected site than at the protected site where selfthinning among clumps occurred. In contrast to these dynamic responses of bamboos against the fire disturbances, the number of individual clumps and their sizes remained smaller at the unprotected site than at the protected site. These results indicate that the intensity and frequency of fires primarily determine the dynamics of the bamboo population, having potential to alter the forest succession to either less or more bamboo dominating forest community. Further studies are required to elucidate the role of fire on the interaction between bamboo and tree species, specifically at the middle and matured stages of bamboo life history and along a gradient of fire regimes for better understanding assembly of the MDF community.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS16-09","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Satomi Baba, A. Ohtaka, N. Koiwa, Mio Takahashi, K. Katsukawa, Nichanapit Tippakdee
Vegetational change was studied during 2010-2015 in the coral-gravelly barrier spit that appeared in 2007 in association with the 2004 Indian Ocean Tsunami at Pakarang Cape, southwestern Thailand, related to topographical changes. No lichens, liverworts, or ferns were found during the study period, although lithophytic algae were widespread over the coral gravel. Several woody species, along with several creeping herbaceous species, colonized the area soon after appearance of the barrier spit. Coral gravel covering the ground surface prevented the sand movement, facilitating colonization by drifting seeds. In all, 37 species of vascular plants, comprising 21 woody and 16 herbaceous species, were recorded through 2015. Annual monitoring of the plant covered area, location, and height of all the trees taller than 20 cm along with formation process of the barrier split using highresolution GPS revealed that vegetation was affected strongly by topographical changes. In accordance with easterly movement of the barrier spit, vegetation largely disappeared in the western part, although it developed in the eastern part. Casuarina equisetifolia increased and grew significantly faster than other species, producing a thick forest in the stable central part of the barrier spit during the study period.
{"title":"Vegetational changes in the coral-gravelly barrier spit appearing after the 2004 Indian Ocean Tsunami at Pakarang Cape, southwestern Thailand, related to topographical changes","authors":"Satomi Baba, A. Ohtaka, N. Koiwa, Mio Takahashi, K. Katsukawa, Nichanapit Tippakdee","doi":"10.3759/TROPICS.MS15-22","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-22","url":null,"abstract":"Vegetational change was studied during 2010-2015 in the coral-gravelly barrier spit that appeared in 2007 in association with the 2004 Indian Ocean Tsunami at Pakarang Cape, southwestern Thailand, related to topographical changes. No lichens, liverworts, or ferns were found during the study period, although lithophytic algae were widespread over the coral gravel. Several woody species, along with several creeping herbaceous species, colonized the area soon after appearance of the barrier spit. Coral gravel covering the ground surface prevented the sand movement, facilitating colonization by drifting seeds. In all, 37 species of vascular plants, comprising 21 woody and 16 herbaceous species, were recorded through 2015. Annual monitoring of the plant covered area, location, and height of all the trees taller than 20 cm along with formation process of the barrier split using highresolution GPS revealed that vegetation was affected strongly by topographical changes. In accordance with easterly movement of the barrier spit, vegetation largely disappeared in the western part, although it developed in the eastern part. Casuarina equisetifolia increased and grew significantly faster than other species, producing a thick forest in the stable central part of the barrier spit during the study period.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-22","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the Southeast Asian tropics, the tree genus Macaranga includes many myrmecophytic species that associate with ‘plant-ants’ nesting in their domatia spaces. Plant-ants on Macaranga myrmecophytes protect their host-plants against herbivores. Because interspecific differences in ant defense intensities among Macaranga myrmecophytes affect the host-plant use by herbivorous insects, they need to be studied to better understand the ecology and evolution of herbivores on Macaranga myrmecophytes. In this study, to examine whether larvae of a lycaenid species, Arhopala major, which potentially feeds on some Macaranga myrmecophytes, can be used for a bioassay that assesses relative ant aggressiveness towards general herbivores on Macaranga plants, we experimentally introduced A. major larvae onto leaves of three Macaranga myrmecophytic species. We measured (1) the time required for the first touch by plant-ants on an introduced larva and (2) the number of plant-ant workers aggregating 3 min after the first touch. The order of three Macaranga species in ant defense intensity, as estimated by the two measurements, corresponded with the results of previous studies investigating the interspecific differences in ant defense intensities using ant-exclusion experiments. This suggests that the bioassay using A. major larvae is valid for the assessment of relative intensities of ant defenses on Macaranga species. As time and labor cost are low and standardization is easier, compared with the other methods, such as ant-exclusion experiments, the bioassay tested in this study is practical for assessing ant defense intensities on Macaranga plants.
{"title":"A bioassay for measuring the intensities of ant defenses on Macaranga myrmecophytes","authors":"Usun Shimizu-Kaya, Tadahiro Okubo, T. Itioka","doi":"10.3759/TROPICS.MS15-19","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-19","url":null,"abstract":"In the Southeast Asian tropics, the tree genus Macaranga includes many myrmecophytic species that associate with ‘plant-ants’ nesting in their domatia spaces. Plant-ants on Macaranga myrmecophytes protect their host-plants against herbivores. Because interspecific differences in ant defense intensities among Macaranga myrmecophytes affect the host-plant use by herbivorous insects, they need to be studied to better understand the ecology and evolution of herbivores on Macaranga myrmecophytes. In this study, to examine whether larvae of a lycaenid species, Arhopala major, which potentially feeds on some Macaranga myrmecophytes, can be used for a bioassay that assesses relative ant aggressiveness towards general herbivores on Macaranga plants, we experimentally introduced A. major larvae onto leaves of three Macaranga myrmecophytic species. We measured (1) the time required for the first touch by plant-ants on an introduced larva and (2) the number of plant-ant workers aggregating 3 min after the first touch. The order of three Macaranga species in ant defense intensity, as estimated by the two measurements, corresponded with the results of previous studies investigating the interspecific differences in ant defense intensities using ant-exclusion experiments. This suggests that the bioassay using A. major larvae is valid for the assessment of relative intensities of ant defenses on Macaranga species. As time and labor cost are low and standardization is easier, compared with the other methods, such as ant-exclusion experiments, the bioassay tested in this study is practical for assessing ant defense intensities on Macaranga plants.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-19","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taiki Mori, S. Ishizuka, R. Konda, A. Wicaksono, J. Heriyanto, A. Hardjono, S. Ohta
Effects of phosphorus (P) addition on nitrous oxide (N2O) emissions from an Acacia mangium plantation soil was examined in relatively aerobic condition with carbon (C) and nitrogen (N) addition. We hypothesized that P addition reduced N2O emissions through stimulated microbial N immobilization and subsequent decrease in inorganic N resources for producing N2O. We prepared the following four experimental sets; high C (glucose 2000 μg C g soil ) and water-filled pore space (WFPS) 40 % (H40), low C (glucose 100 μg C g soil) and WFPS 40 % (L40), high C and WFPS 60 % (H60), and low C and WFPS 60 % (L60). Nitrogen (NH4NO3, 20 μg N g soil ) was also added to all soils. We prepared P-added soils (Ca(H2PO4)2, 20 μg P g soil ) and non-added control to test the effects of P addition on N2O emissions. Contrary to our hypothesis, P addition did not reduce N2O emissions, although soil microbial N immobilization was stimulated by P addition in soils with low C addition. Stimulated total N cycling by P addition probably offset the decrease in soil inorganic N. Meanwhile P addition reduced soil microbial biomass N (MBN) content in H60, where N2O emissions increased significantly by P addition. It was possible that the microbial growth reached its peak and started dying more quickly in P-added soils in H60 due to the favorable condition for microbes (higher C and water content). Thus we concluded that (i) P addition did not necessarily stimulate soil microbial N immobilization, and (ii) N2O emissions might not decrease even if P addition stimulated soil microbial N immobilization.
在相对好氧条件下，研究了添加磷(P)对锰相思人工林土壤氧化亚氮(N2O)排放的影响，同时添加碳(C)和氮(N)。我们假设P的添加通过刺激微生物N固定和随后产生N2O的无机N资源减少来减少N2O的排放。我们准备了以下四组实验;高碳(葡萄糖2000 μ C g土壤)和充水孔隙(WFPS) 40% (H40)，低碳(葡萄糖100 μ C g土壤)和充水孔隙(WFPS) 40% (L40)，高碳和充水孔隙(WFPS) 60% (H60)，低碳和充水孔隙(WFPS) 60% (L60)。所有土壤均添加氮(NH4NO3, 20 μg N g土壤)。制备了加磷土壤(Ca(H2PO4)2, 20 μ P g土壤)和未加磷对照，考察了加磷对N2O排放的影响。与我们的假设相反，添加P并没有减少N2O的排放，尽管在低碳添加的土壤中，添加P可以促进土壤微生物的N固定。施磷促进了土壤总氮循环，可能抵消了土壤无机氮的减少，同时施磷降低了H60土壤微生物生物量N (MBN)含量，其中N2O排放量显著增加。在H60加磷土壤中，微生物生长达到峰值，开始死亡的速度更快，可能是由于微生物的有利条件(较高的C和含水量)。因此，我们得出结论:(1)添加磷并不一定促进土壤微生物氮的固定;(2)即使添加磷促进土壤微生物氮的固定，N2O的排放也可能不会减少。
{"title":"Effects of phosphorus addition on N2O emissions from an Acacia mangium soil in relatively aerobic condition","authors":"Taiki Mori, S. Ishizuka, R. Konda, A. Wicaksono, J. Heriyanto, A. Hardjono, S. Ohta","doi":"10.3759/TROPICS.MS15-15","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-15","url":null,"abstract":"Effects of phosphorus (P) addition on nitrous oxide (N2O) emissions from an Acacia mangium plantation soil was examined in relatively aerobic condition with carbon (C) and nitrogen (N) addition. We hypothesized that P addition reduced N2O emissions through stimulated microbial N immobilization and subsequent decrease in inorganic N resources for producing N2O. We prepared the following four experimental sets; high C (glucose 2000 μg C g soil ) and water-filled pore space (WFPS) 40 % (H40), low C (glucose 100 μg C g soil) and WFPS 40 % (L40), high C and WFPS 60 % (H60), and low C and WFPS 60 % (L60). Nitrogen (NH4NO3, 20 μg N g soil ) was also added to all soils. We prepared P-added soils (Ca(H2PO4)2, 20 μg P g soil ) and non-added control to test the effects of P addition on N2O emissions. Contrary to our hypothesis, P addition did not reduce N2O emissions, although soil microbial N immobilization was stimulated by P addition in soils with low C addition. Stimulated total N cycling by P addition probably offset the decrease in soil inorganic N. Meanwhile P addition reduced soil microbial biomass N (MBN) content in H60, where N2O emissions increased significantly by P addition. It was possible that the microbial growth reached its peak and started dying more quickly in P-added soils in H60 due to the favorable condition for microbes (higher C and water content). Thus we concluded that (i) P addition did not necessarily stimulate soil microbial N immobilization, and (ii) N2O emissions might not decrease even if P addition stimulated soil microbial N immobilization.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ryosuke Takeuchi, I. Wahyudi, H. Aiso, F. Ishiguri, W. T. Istikowati, T. Ohkubo, J. Ohshima, K. Iizuka, S. Yokota
The utilization of wood resources from unutilized fast-growing tree species found in secondary forests was investigated by studying the wood properties, including anatomical characteristics, of two Macaranga species—M. bancana and M. pearsonii—growing naturally in secondary forests in Central Kalimantan, Indonesia. Several wood properties related to pulp and paper quality were also evaluated, including the Runkel ratio, Luce's shape factor, flexibility coefficient, slenderness ratio, solid factor, and wall coverage ratio. The mean basic density of these two species ranged from 0.23 to 0.31 g cm, while the mean values of vessel diameter, vessel element length, fiber diameter, fiber wall thickness, and fiber length ranged from 126 to 192 μm, 0.88 to 1.19 mm, 24.5 to 29.8 μm, 0.99 to 1.14 μm, and 1.42 to 1.69 mm, respectively. The lignin content of M. bancana and M. pearsonii wood was 27.2 and 28.0%, respectively. Almost all wood properties related to pulp quality showed better values than those reported for Acacia and Eucalyptus species, although sheet density of paper might be lower due to higher solids factor and possibility of occurrence of vessel picking was probably higher due to longer vessel element length and larger vessel diameter. Based on the results, the wood from these two Macaranga species can be used as pulpwood.
{"title":"Wood properties related to pulp and paper quality in two Macaranga species naturally regenerated in secondary forests, Central Kalimantan, Indonesia","authors":"Ryosuke Takeuchi, I. Wahyudi, H. Aiso, F. Ishiguri, W. T. Istikowati, T. Ohkubo, J. Ohshima, K. Iizuka, S. Yokota","doi":"10.3759/TROPICS.MS15-23","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-23","url":null,"abstract":"The utilization of wood resources from unutilized fast-growing tree species found in secondary forests was investigated by studying the wood properties, including anatomical characteristics, of two Macaranga species—M. bancana and M. pearsonii—growing naturally in secondary forests in Central Kalimantan, Indonesia. Several wood properties related to pulp and paper quality were also evaluated, including the Runkel ratio, Luce's shape factor, flexibility coefficient, slenderness ratio, solid factor, and wall coverage ratio. The mean basic density of these two species ranged from 0.23 to 0.31 g cm, while the mean values of vessel diameter, vessel element length, fiber diameter, fiber wall thickness, and fiber length ranged from 126 to 192 μm, 0.88 to 1.19 mm, 24.5 to 29.8 μm, 0.99 to 1.14 μm, and 1.42 to 1.69 mm, respectively. The lignin content of M. bancana and M. pearsonii wood was 27.2 and 28.0%, respectively. Almost all wood properties related to pulp quality showed better values than those reported for Acacia and Eucalyptus species, although sheet density of paper might be lower due to higher solids factor and possibility of occurrence of vessel picking was probably higher due to longer vessel element length and larger vessel diameter. Based on the results, the wood from these two Macaranga species can be used as pulpwood.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-23","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70009953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Doan, A. Sano, H. Tamaki, H. Pham, Y. Terashima
Oil-degrading filamentous fungi (ODF) were enumerated and isolated from two islands, Iriomote, Japan, and Con Dao, Vietnam. Iriomote has a subtropical and Con Dao a tropical climate. The counts of total fungi and ODF in sediment samples from supratidal and intertidal zones on Iriomote were statistically higher than on Con Dao. Water samples from seawater, however, gave a reverse result. In total, 23 ODF including 11 isolates in 5 genera from Iriomote and 12 isolates in 4 genera from Con Dao were isolated. On Iriomote, the isolates which showed the highest potential of oil degradation were 2 Penicillium isolates and one Trichoderma, however they did not grow at 37°C nor survived at 37°C. One Candida isolate has higher potential of oil-degradation, and grew and survived at temperature 42°C. On the contrary, on Con Dao, 2 Aspergillus, one Penicillium and one Trichoderma isolates had potential of oil-degradation, and grew and survived at temperature 42°C. This result suggests that comparing with subtropical Iriomote, the tropical Con Dao maintains more oil-degrading fungi which have higher-temperature resistance.
摘要从日本伊里奥摩岛和越南孔岛分离到一种油降解丝状真菌(ODF)。伊里奥莫特属亚热带气候，孔岛属热带气候。伊里奥莫特岛潮上带和潮间带沉积物样品中真菌总数和ODF计数均显著高于Con岛。然而，来自海水的水样给出了相反的结果。共分离到23株ODF，其中Iriomote 5属11株，Con Dao 4属12株。在Iriomote上，表现出最高降解潜力的分离株是2株青霉和1株木霉，但它们在37°C下不能生长，也不能存活。一个分离的念珠菌具有较高的油降解潜力，并在42°C的温度下生长和存活。相反，在Con岛上，2株曲霉、1株青霉和1株木霉具有油降解潜力，并在42℃的温度下生长和存活。结果表明，热带Con Dao与亚热带Iriomote相比，保留了更多耐高温的油降解真菌。
{"title":"Comparison of distribution of oil-degrading filamentous fungi on subtropical Iriomote Island, Japan, and tropical Con Dao Island, Vietnam","authors":"C. Doan, A. Sano, H. Tamaki, H. Pham, Y. Terashima","doi":"10.3759/TROPICS.MS15-11","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-11","url":null,"abstract":"Oil-degrading filamentous fungi (ODF) were enumerated and isolated from two islands, Iriomote, Japan, and Con Dao, Vietnam. Iriomote has a subtropical and Con Dao a tropical climate. The counts of total fungi and ODF in sediment samples from supratidal and intertidal zones on Iriomote were statistically higher than on Con Dao. Water samples from seawater, however, gave a reverse result. In total, 23 ODF including 11 isolates in 5 genera from Iriomote and 12 isolates in 4 genera from Con Dao were isolated. On Iriomote, the isolates which showed the highest potential of oil degradation were 2 Penicillium isolates and one Trichoderma, however they did not grow at 37°C nor survived at 37°C. One Candida isolate has higher potential of oil-degradation, and grew and survived at temperature 42°C. On the contrary, on Con Dao, 2 Aspergillus, one Penicillium and one Trichoderma isolates had potential of oil-degradation, and grew and survived at temperature 42°C. This result suggests that comparing with subtropical Iriomote, the tropical Con Dao maintains more oil-degrading fungi which have higher-temperature resistance.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-11","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many studies have reported the presence of soil respiration hot spots, which are areas of extremely high soil respiration, but little is known about their causes. Because previous studies implied that they were caused by macrofauna, we conducted a field survey in a Malaysian lowland rainforest to examine whether increased soil respiration was induced by the activities of macrofauna such as termites, ants and earthworms. Soil respiration was measured in a grid system of 10 m intervals in a 1 ha plot. We measured soil respiration again three or four days after the first measurement to examine the spatiotemporal change in hot spots. After the second measurement, we excavated soil to a depth of 20 cm at the five points showing the highest soil respiration rates (hot spots) and their neighboring points as controls and visually searched for macrofauna. The average soil respiration for two measurements did not differ significantly (8.21 and 7.93 μmol CO2 m s, respectively). Four hot spots were revealed in each of the two measurements, but only one appeared in both measurements. Several ants (100-500 individuals, Lophomyrmex sp.) were observed in soil under soil respiration chamber areas at one hot spot and one control point, respectively. This suggests that the hot spots in the study site were not located near active nests or intensively active areas of macrofauna, and it is possible that the hot spots may represent the points of mass CO2flux transport events.
许多研究报告了土壤呼吸热点的存在，这些热点是土壤呼吸极高的地区，但对其原因知之甚少。由于以往的研究表明土壤呼吸增加是由大型动物引起的，因此我们在马来西亚低地雨林进行了实地调查，以研究白蚁、蚂蚁和蚯蚓等大型动物的活动是否引起土壤呼吸增加。在1公顷土地上以10 m间隔的网格系统测量土壤呼吸。我们在第一次测量后的3 - 4天再次测量土壤呼吸，以检验热点地区的时空变化。在第二次测量后，我们在土壤呼吸速率最高的5个点(热点)及其邻近点挖掘土壤至20 cm深，并作为对照，目测寻找大型动物。两个测量的土壤呼吸平均值差异不显著(分别为8.21 μmol CO2 m s和7.93 μmol CO2 m s)。在两次测量中，每次都发现了四个热点，但两次测量中只出现了一个热点。在1个热点和1个控制点土壤呼吸室区土壤中分别观察到数只蚂蚁(100 ~ 500只，Lophomyrmex sp.)。这表明研究点的热点并不位于大型动物活跃巢穴附近或密集活动区域，热点可能代表了大量co2通量输送事件的点。
{"title":"Spatial and temporal variations in soil respiration hot spots in a lowland tropical rain forest, Peninsular Malaysia","authors":"Momo Takada, T. Yamada, W. R. Kadir, T. Okuda","doi":"10.3759/TROPICS.MS15-17","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-17","url":null,"abstract":"Many studies have reported the presence of soil respiration hot spots, which are areas of extremely high soil respiration, but little is known about their causes. Because previous studies implied that they were caused by macrofauna, we conducted a field survey in a Malaysian lowland rainforest to examine whether increased soil respiration was induced by the activities of macrofauna such as termites, ants and earthworms. Soil respiration was measured in a grid system of 10 m intervals in a 1 ha plot. We measured soil respiration again three or four days after the first measurement to examine the spatiotemporal change in hot spots. After the second measurement, we excavated soil to a depth of 20 cm at the five points showing the highest soil respiration rates (hot spots) and their neighboring points as controls and visually searched for macrofauna. The average soil respiration for two measurements did not differ significantly (8.21 and 7.93 μmol CO2 m s, respectively). Four hot spots were revealed in each of the two measurements, but only one appeared in both measurements. Several ants (100-500 individuals, Lophomyrmex sp.) were observed in soil under soil respiration chamber areas at one hot spot and one control point, respectively. This suggests that the hot spots in the study site were not located near active nests or intensively active areas of macrofauna, and it is possible that the hot spots may represent the points of mass CO2flux transport events.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-17","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil nutrient concentrations and tree dynamics were examined in two Bornean tropical forests on contrasting geological substrates, one on volcanic and the other on sedimentary rocks. Concentrations of P extracted by the Hadley fractionation method and inorganic N of topsoils were much greater in the volcanic site than in the sedimentary site. Dipterocarps showed greater relative growth rates in the volcanic site than in the sedimentary site at the smallest size class (10 cm ≤ diameter at breast height<20 cm), but not at larger size classes. Dipterocarps in the two sites demonstrated the same values of crown position index (a surrogate of light conditions), implying that the greater tree growth in the volcanic site was associated with the greater soil nutrient availability, but not with light availability. On the other hand, relative growth rates of non-dipterocarps did not differ between the sites at all size classes despite the considerable differences in the soil nutrient concentrations, suggesting that factors other than N and P availabilities limit the growth of these trees. Contrary to growth rate, annual mortality rate was greater in the volcanic site at all size classes for all phylogenetic groups. Our results suggest that the volcanic site is characterized as high soil nutrient availability and a greater tree turnover, and that tree size is an important factor that differentiates tree growth between the two tropical forests with contrasting nutrient availabilities.
{"title":"Soil nutrients and size-dependent tree dynamics of tropical lowland forests on volcanic and sedimentary substrates in Sabah, Malaysian Borneo","authors":"Ryota Aoyagi, N. Imai, T. Seino, K. Kitayama","doi":"10.3759/TROPICS.MS15-13","DOIUrl":"https://doi.org/10.3759/TROPICS.MS15-13","url":null,"abstract":"Soil nutrient concentrations and tree dynamics were examined in two Bornean tropical forests on contrasting geological substrates, one on volcanic and the other on sedimentary rocks. Concentrations of P extracted by the Hadley fractionation method and inorganic N of topsoils were much greater in the volcanic site than in the sedimentary site. Dipterocarps showed greater relative growth rates in the volcanic site than in the sedimentary site at the smallest size class (10 cm ≤ diameter at breast height<20 cm), but not at larger size classes. Dipterocarps in the two sites demonstrated the same values of crown position index (a surrogate of light conditions), implying that the greater tree growth in the volcanic site was associated with the greater soil nutrient availability, but not with light availability. On the other hand, relative growth rates of non-dipterocarps did not differ between the sites at all size classes despite the considerable differences in the soil nutrient concentrations, suggesting that factors other than N and P availabilities limit the growth of these trees. Contrary to growth rate, annual mortality rate was greater in the volcanic site at all size classes for all phylogenetic groups. Our results suggest that the volcanic site is characterized as high soil nutrient availability and a greater tree turnover, and that tree size is an important factor that differentiates tree growth between the two tropical forests with contrasting nutrient availabilities.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MS15-13","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-08-01DOI: 10.3759/TROPICS.MSMS15-18
Taiki Mori, C. Wachrinrat, D. Staporn, Ponthep Meunpong, Warawich Suebsai, Khitja Boonsri, K. Kitayama
Since microbial biomass is a key factor controlling nutrient dynamics in the soil through mineralization of soil organic nutrients or microbial turnover, investigating the seasonal changes of microbial activities and biomass is essential for better understanding the nutrient dynamics in tree plantation. We investigated the seasonal changes in soil respiration, microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) in five tropical tree plantation stands. Although CO2 emissions and MBN contents were high in hot-rainy season and low in cool-dry season, MBC contents in cool-dry season kept in the same level as rainy season. We assumed that the different response of MBC and MBN to cool-dry condition was because of the changes in microbial fauna or individual adaptation for drought. The influence of the microbial dynamics observed in the present study on soil nutrient dynamics needs to be studied in the future.
{"title":"Seasonal changes in soil respiration and microbial biomass in five tropical tree plantations in Thailand","authors":"Taiki Mori, C. Wachrinrat, D. Staporn, Ponthep Meunpong, Warawich Suebsai, Khitja Boonsri, K. Kitayama","doi":"10.3759/TROPICS.MSMS15-18","DOIUrl":"https://doi.org/10.3759/TROPICS.MSMS15-18","url":null,"abstract":"Since microbial biomass is a key factor controlling nutrient dynamics in the soil through mineralization of soil organic nutrients or microbial turnover, investigating the seasonal changes of microbial activities and biomass is essential for better understanding the nutrient dynamics in tree plantation. We investigated the seasonal changes in soil respiration, microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) in five tropical tree plantation stands. Although CO2 emissions and MBN contents were high in hot-rainy season and low in cool-dry season, MBC contents in cool-dry season kept in the same level as rainy season. We assumed that the different response of MBC and MBN to cool-dry condition was because of the changes in microbial fauna or individual adaptation for drought. The influence of the microbial dynamics observed in the present study on soil nutrient dynamics needs to be studied in the future.","PeriodicalId":51890,"journal":{"name":"Tropics","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2016-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3759/TROPICS.MSMS15-18","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70010611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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