排序方式： 共有8条查询结果，搜索用时 15 毫秒
1
1.
We examined the carbon stock and rate of carbon sequestration in a tropical deciduous forest dominated by Dipterocarpus tuberculatus in Manipur,North East India.Estimation of aboveground biomass was determined by harvest method and multiplied with density of tree species.The aboveground biomass was between18.27–21.922 t ha-1and the carbon stock ranged from9.13 to 10.96 t C ha-1across forest stands.Aboveground biomass and carbon stock increased with the increase in tree girth.The rate of carbon sequestration varied from1.4722 to 4.64136 t ha-1year-1among the dominant tree species in forest stands in tropical deciduous forest area.The rate of carbon sequestration depends on species composition,the density of large trees in different girth classes,and anthropogenic disturbances in the present forest ecosystem.Further work is required to identify tree species having the highest potential to sequester CO2 from the atmosphere,which could lead to recommendations for tree plantations in a degraded ecosystem. 相似文献
2.
不同光照和土壤水分对3种龙脑香科植物种子发芽的影响 总被引：1，自引：0，他引：1
2007和2008连续两年的1月、10月,分别采集云南龙脑香科的东京龙脑香、望天树、狭叶坡垒的种子,将种子在不同光照(20%、40%、60%和80%)和不同土壤水分(土壤含水量20%、40%、60%和80%)条件下进行种子萌发试验,研究不同光照和土壤水分对3种植物种子发芽率和苗木生长的影响。结果表明,龙脑香科植物种子发芽率在光照强度为20%、40%时较高,80%时较低;种子发芽率在土壤含水率60%时较高,80%和20%均较低;在同等条件下,狭叶坡垒种子发芽率最高,最高时可达88%,东京龙脑香种子发芽率最低,最低时仅为9%;在相同条件下,3种云南龙脑香科植物苗木生长最快的为狭叶坡垒,15个月苗龄苗高为86 cm,地径达1.23 cm。 相似文献
3.
Wood samples of apitong (Dipterocarpus grandiflorua) and ilang-ilang (Ilang-Ilang C. dadloyi) and feces of termites [Cryptotermes brevis (Walker)] fed on these woods were collected from University of the Philippines, Los Baňos. Lignin of each sample was isolated by Björkman’s procedure. There was no significant difference in 1H nuclear magnetic resonance (NMR) spectra or in the methoxyl content between Björkman lignins from original woods and termite feces. Differences were detected in the contents of aliphatic and unconjugated phenolic hydroxyl groups, suggesting minor structural changes of lignin during digestion by termites. In addition, the ratio of syringyl to guaiacyl nuclei of Björkman lignin from termite feces determined by 1H NMR spectra was higher than those from the original woods. The molar ratio of syringyl to guaiacyl nuclei of termite feces was higher than those from the original woods as determined by alkaline nitrobenzene oxidation. These results suggest that the structural changes of lignin in the termite gut are due to the insignificant formation of C-C linkages in guaiacyl nuclei. It was concluded that there were minor changes in the structural features of lignin under mostly anaerobic conditions, in contrast to the significant changes that occur through biological modification under aerobic conditions. 相似文献
4.
Muhtadi Hakim EH Juliawaty LD Syah YM Achmad SA Latip J Ghisalberti EL 《Fitoterapia》2006,77(7-8):550-555
A new resveratrol tetramer, named diptoindonesin E, was isolated from the acetone extract of the tree bark of Dipterocarpus hasseltii, together with five known resveratrol oligomers (-)-epsilon-viniferin, laevifonol, (-)-alpha-viniferin, vaticanol B, (-)-hopeaphenol, and a coumarin, scopoletin. The structures of these compounds were determined from spectroscopic evidence. Cytotoxicity test of the isolated compounds showed that hopeaphenol strongly inhibited murine leukemia P-388 cells. 相似文献
5.
本文论述了孟加拉国吉大港大学校园里,不同年龄(5、10、20年)的羯布罗香(Dipterocarpus turbinatus Gaertn. F)人工林内,距树木基部不同距离(1、2、3、4米)处,外生侵染菌根的水平分布状况.在山的3个部位(顶部、中部和下部)对各人工林外生侵染菌根的侵染进行了测定.在不同水平分布距离处的树下采集了1000cm3的根际土壤样本,不同距离和山高处的外生侵染菌根浸染率差异显著.在5年和10年林龄的人工林内,浸染率随着距树的距离的增加而快速下降,而在20年林龄的人工林内,浸染率随着距树基部距离的增加而急剧增加.山下部20年生人工林内距树4m处的浸染率最高(81.3%),山顶部5年生人工林内距树4m处的浸染率最低(55.33%).图6参32. 相似文献
6.
7.
引种泰国的小瘤龙脑香经22年的栽培观测表明,该树种在引种地中国的西双版纳生长迅速,超过原产地部分地区;开花结果正常,用种子已繁殖出一批新植株;对其落叶量和林下土壤养分的测定表明,该树种具有保持水土、改良土壤的作用.本文还就小瘤龙脑香的造林的环境条件要求以及国外种植情况及其经济效益等方面,分析了该树种在我国热带地区大面积发展的可行性. 相似文献
8.
本文论述了孟加拉国吉大港大学校园里,不同年龄(5、10、20年)的羯布罗香(DipterocarpusturbinatusGaertn.F)人工林内,距树木基部不同距离(1、2、3、4米)处,外生侵染菌根的水平分布状况。在山的3个部位(顶部、中部和下部)对各人工林外生侵染菌根的侵染进行了测定。在不同水平分布距离处的树下采集了1000cm3的根际土壤样本,不同距离和山高处的外生侵染菌根浸染率差异显著。在5年和10年林龄的人工林内,浸染率随着距树的距离的增加而快速下降,而在20年林龄的人工林内,浸染率随着距树基部距离的增加而急剧增加。山下部20年生人工林内距树4m处的浸染率最高(81.3%),山顶部5年生人工林内距树4m处的浸染率最低(55.33%)。 相似文献
1