{"created":"2023-05-15T09:59:49.415264+00:00","id":4047,"links":{},"metadata":{"_buckets":{"deposit":"fa61dfc9-f685-4e79-a159-53dc2dc1e104"},"_deposit":{"created_by":9,"id":"4047","owner":"9","owners":[9],"pid":{"revision_id":0,"type":"depid","value":"4047"},"status":"published"},"_oai":{"id":"oai:miyazaki-u.repo.nii.ac.jp:00004047","sets":["74","74:59"]},"author_link":["21374"],"item_10006_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"木材資源-の過度な依存によるアフリカ熱帯林の減少に対して､近年関心が高まっている｡しかし､ガーナを含む多くのアフリカの国々での植林を成功させるための課題の一つは､環境条件の異なる立地で植林に用いる樹種､特に郷土種の生理生態的な特性の情報が不足していることである｡本研究では､ガーナの森林再生に有用と考えられる数種の熱帯樹について土壌水分､土壌養分及び光環境をコントロールした条件下での､生長及び生理生態的反応を調べた｡\n1.まず､ガーナの半落葉樹林帯の異なる立地に生育する2種のアフリカマホガニー(Khaya anthotheca and K. ivorensis)の実生苗を､ガラス室内で3レベルの土壌水分条件(過湿､適潤及び乾燥)で育て､苗高､乾物重､物質配分に対する土壌水分の影響を調べた｡K. ivorensisでは土壌水分の不足は､乾物重を著しく減少させ､乾燥に対する順応戦略によって葉と根の物質配分を変化させた｡K.anthotheca の実生苗は､適潤及び乾燥処理においてK.ivorensisの実生苗よりも乾物重が多かった｡これらの結果からK.anthothecaはアフリカ湿潤熱帯の中で4-5ケ月の乾期のある立地での造林樹種に､K.ivorensisは同地域の低地など土壌の乾燥が起こりにくい立地の造林樹種に適していると考えられる｡\n2.次に､乾燥半落葉樹林帯からサバンナまでのより乾燥ストレスの大きい地域での多様な植林目的に適する樹種を検討した.Cadrela odorata､Cassia siamea, Khaya senegalensisの実生苗の耐乾性を､土壌の乾燥過程での蒸散速度､気孔コンダクタンス及びクロロフィル蛍光の変化から比較した結果､C.siameaとK.senegalensisはより強い耐乾性を示し､C.odoramaは乾燥回避性を示し土壌水分減少の早い段階から消費水分の減少が見られた｡この結果から､この地域の中で強い乾燥ストレスとなる立地ではC.siameaとK.senegalensisを植栽する方が有利である｡\n3.立地の光環境との関係を検討するために､3樹種の実生苗を相対照度(RLI)10､22､45､100%の光条件下で育て､乾物重､物質分配､最大光合成速度(Amax)､水分利用効率(WUE)､光飽和点(LSE)及び最大光量子収率(Fv/Fm)から比較した｡先駆種であるTerminalia superba は､RLI100%でAmax､WUE､LSE及びFv/Fnの平均値が最も高く､RLI10%では､Amax、WUE､LSEの平均値は最も低くなった。遷移中期種であるCedlela odorataはRLI22%でMansonia altissimaより高いAmax 及びLSEを示した｡また､3樹種ともRLI45%で乾物重は最も大きくなった｡全光下及び日陰の条件下における葉と根-の物質分配は､典型的なパターンを示した。これらの結果からT.superbaは全光条件となる立地､C.odorataは光に関して広い適応域を持ち林内の広いギャップから全光条件下まで､M altissimaは林内での小さなギャップ-の造林樹種に適していると考えられる｡\n4.初期生長-の施肥の効果をCedrela oforataとTerminalia superba の実生苗を用いて光環境(RLI33%および100%)との関係で調べた｡両種とも施肥､RLI33%で高い相対成長率を示し､乾物重は施肥､RLI100%で最も高くなった｡施肥で両種の葉の窒素濃度と相対クロロフィル含有量が増加し､無施肥ではRLI100%でクロロフィル含有量が低下した｡また施肥は､RLI100%でのC.odorataのFv/Fmを増加させ､光阻害の影響を低減させるなど､初期生長への施肥の大きな効果が認められた｡\nこの研究により､ガーナの森林再生に有望な樹種の光､土壌水分､養分などの立地条件に対する反応特性が明らかになり､研究の成果はこれからの西アフリカ地域での､森林再生､造林の際の立地に応じた樹種選択に実際に適用できると考えられる｡","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"\\nDeforestation of African tropical forests as a result of greater dependence on wood resources is a growing concern. However, one of the challenges to successful reforestation efforts in many African countries, including Ghana, is the lack of knowledge on ecophysiological traits of potential plantation species, especially native species, under different site conditions.\nA series of experiments were conducted under controlled conditions to examine morphological and/ or physiological responses of some selected tropical tree species to soil water, nutrient and/ or light treatments.\nFirst, soil water availability on seedling height, dry matter production and allocation were investigated for two African mahogany species (Khaya anthotheca and K. ivorensis) from contrasting semi-deciduous forest sub-types of Ghana. Seedlings of the two species were subjected to three soil watering treatments, which were termed wet, moderate and dry treatment, in a glass house facility. Soil water deficit greatly reduced total dry matter production in K. ivorensis and altered proportional allocation to leaves and roots as a possible strategy for acclimation. In the moderate and dry treatments, K. anthotheca seedlings had greater total plant dry matter than K. ivorensis seedlings, which suggests that K. anthotheca have considerable potential for plantation forestry in the humid tropics ofAfrica where distinct drought periods (4-5 months) occur.\nSecond, drought resistance in seedlings of Cedrela odorata, Cassia siamea and Khaya senegalensis were estimated through measurements of transpiration rate, stomatal conductance and chlorophyll fluorescence, and growth responses under drought conditions of a greenhouse experiment.\nThis study was conducted in order to assess the suitability of these species for plantation forestry in semi arid and drier sites of Ghana. Results of this study indicated that C. siamea and K. senegalensis exhibited stronger drought resistance, whereas C. odorata followed a drought-avoiding strategy and was more conservative in its water use. At soil water potential of -0.4 MPa (mild drought condition), C. odorata showed restricted growth and lowered physiological traits. In contrast, C. siamea and K. senegalensis showed reduced growth and physiological traits at -1.0 and -0.8 MPa, respectively, conferring greater advantage to them than C.\nodorata as plantation forestry species in semi-dry environments.\nThird, containerized seedlings of three tropical species were grown under four different light treatments [i.e., 100, 45, 22 and 10% sunlight].\nPhotosynthetic properties and growth analysis reflected the species successional status with Terminalia superba, the pioneer species showing largest mean light-saturated photosynthesis (Amax), light saturation estimates (LSE), intrinsic water-use efficiency (WUE) and maximal quantum yield of photosystem II (Fv/Fm) at 100% sunlight, whereas at 10% sunlight, it showed the lowest Amax, WUE and LSE. At 22% sunlight, Cedrela odorata, an intermediate successional species had greater Amax and LSE than Mansonia altissima, a non-pioneer light demander and T. superba. Superior biomass production was found at 45% sunlight for all the species. Allocation to leaf and root followed patterns typical of plants growing in sun or shade conditions. Light requirement for species growth and physiological functions may be specie-specific. This study therefore, suggests that T. superba may have greater potential in plantation forestry at exposed sites; C. odorata has broad ecological amplitude making it suitable for planting in medium gaps and exposed sites; M altissima may be suitable for enrichment planting in smaller gaps.\nFurthermore, growth responses to fertilization in seedlings of Cedrela odorata and Terminalia superba were studied under 100 and 33% sunlight. Both species attained greatest relative height growth rate at 33% sunlight with fertilization and showed superior biomass production at 100% sunlight with fertilization. N fertilization enhanced foliar N concentration and relative Chl content of both species and without fertilization, 100% sunlight-grown foliage of C. odorata showed reduced Chl content. At 100% sunlight, fertilization enhanced Fv/Fm of C. odorata and thus, reduced the specie's susceptibility to photoinhibition. Enhancing acclimation of C. odorata and T. superba seedlings through longer hardening periods plus nutrient additions in an exposed nursery conditions may stimulate their initial growth when planted in the field.\nResults from these experimental studies may have practical use in screening tropical tree species for use in reforestation and plantation forestry in degraded forest sites of West Africa where site resources such as soil water, light and nutrient availability may vary considerably.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_10006_textarea_22":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_textarea_value":"鹿児島大学大学院連合農学研究科博士論文"},{"subitem_textarea_language":"ja"}]},"item_10006_version_type_18":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_ab4af688f83e57aa","subitem_version_type":"AM"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Richard, Gyimah","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2020-06-21"}],"displaytype":"detail","filename":"DT_GymahRichard.pdf","filesize":[{"value":"10.9 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"DT_GymahRichard.pdf","url":"https://miyazaki-u.repo.nii.ac.jp/record/4047/files/DT_GymahRichard.pdf"},"version_id":"36424a23-b4e7-47a5-88bf-8131a22480dd"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Studies on growth  and ecophysiological characteristics of tropical tree species useful in Ghana","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Studies on growth  and ecophysiological characteristics of tropical tree species useful in Ghana","subitem_title_language":"en"},{"subitem_title":"ガーナにおける有用熱帯樹木の生長と生理生態的特性に関する研究","subitem_title_language":"ja"}]},"item_type_id":"10006","owner":"9","path":["74","59"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2007-11-26"},"publish_date":"2007-11-26","publish_status":"0","recid":"4047","relation_version_is_last":true,"title":["Studies on growth  and ecophysiological characteristics of tropical tree species useful in Ghana"],"weko_creator_id":"9","weko_shared_id":-1},"updated":"2023-07-30T23:00:58.002580+00:00"}