Time bound physiological stress responses of fresh water aquatic plant species to water flow, irradiance and heavy metal toxic environments

• 資料種別: 博士論文
• タイトル: Time bound physiological stress responses of fresh water aquatic plant species to water flow, irradiance and heavy metal toxic environments
• 著者・編者: VIRAJ, PRASANNA RANAWAKAGE
• 著者標目: VIRAJ, PRASANNA RANAWAKAGE
• 出版事項: 埼玉大学大学院理工学研究科
• 出版年月日等: 2020
• 出版年（W3CDTF）: 2020
• 並列タイトル等: 淡水水生植物の水流、放射照度および重金属毒性に対する生理学的ストレス応答
• タイトル（掲載誌）: 博士論文（埼玉大学大学院理工学研究科（博士後期課程））
• 授与機関名: 埼玉大学
• 授与年月日: 2020-09-23
• 授与年月日（W3CDTF）: 2020-09-23
• 報告番号: 甲第1190号
• 学位: 博士(工学)
• 博論授与番号: 甲第1190号
• 本文の言語コード: eng
• 対象利用者: 一般
• 一般注記: type:text; Abiotic stressors exerted on macrophytes are more complex process in nature and understanding each stressor time interrelation with biochemical activities are not yet fully discovered. Although one particular stress variable provides limited knowledge to ecological perspective compared to the conceptual studies focus on several stress factors. Considering the anthropogenic activity related issues, on present aquatic environment appropriate stressors such as flow movement, irradiance variation and heavy metal exposure were selected for study. Thus the present thesis work specifically assesses the temporal scale biochemical activity fluctuations to define how particular stressor effect mediates by aquatic plants. The main objective of study was to evaluate the flow and irradiance effect on macrophyte species during different diurnal time points for understands suitable habitat niches. For achieve this objective flow and irradiance conditions were simulated with outdoor flume channel integrating two flow conditions and two irradiance levels. Then in order to understand the different flow velocities effect on macrophyte antioxidative activities and scavenging capabilities by two velocity gradient and stagnant flow compared with fully shaded condition on Egeria densa macrophyte. Third and fourth objectives were concern on heavy metal effect on biochemical activities of Ceratophyllum demersum and Chara braunii, respectively considering time interactions. The flow and irradiance experiment results showed that compared to the other treatments, the open-flow treatments had the highest hydrogen peroxide (H₂O₂) concentration which occurred with the acceleration of antioxidant activity at midday, mainly due to the independent effect of irradiance and flow movement. The plant diurnal H₂O₂ and antioxidant activity rhythms had varying fluctuations, and peroxidase (POD) activity showed a rapid response to oxidative stress. The increase in POD activity followed a more similar pattern aligned with H₂O₂ synthesis, while catalase (CAT) and ascorbate peroxidase (APX) activities were dominant in the late hours of the day. Concerning the velocity gradient experiment, between the two mean flow velocity generated H₂O₂ content there was no any significant difference. However, compared to the stagnant and shaded treatments velocity effect was significantly contributed to the ROS synthesis at midday time. Although antioxidative activities and chlorophyll pigments, fluctuated with the 12hr day duration and stabilized at evening phase. Oxidative stress related cellular starch granule accumulation was pronounced within high flow velocity, low flow velocity and shade treated E. densa plants while bigger starch granules observed from same treatments respectively.In heavy metal study C. demersum macrophyte was exposed to two heavy metal (Cu and Zn) gradients in order to test the hypothesis whether biochemical activities may vary over time. The heavy metal concentrations were arranged as 0 to 10 mg L-¹. The concentration of H₂O₂ accumulation was found to be accelerated with short duration and higher concentration of Cu and Zn whereas afterward it was appeared to decline. With upregulated H₂O₂ content, indole acetic acid IAA content decreased significantly in all Cu treatments whereas only 5 and 10mg L-¹ of Zn caused the IAA changes. The oxidative stress was not observed at 1 mg L-¹ of Zn, whereas all Cu gradients caused dramatic damage to the antioxidative activities (POD and CAT). In addition, chlorophyll pigments were negatively influenced by both heavy metals suggesting that the chlorophyll destruction was inevitable with metal accumulation. Furthermore, the IAA reduction with heavy metal stress made C. demersum antioxidative potential in to lower level. These results suggest that C. demersum may grow well at 1mg L-¹ threshold Zn polluted water bodies through regulating the antioxidative system whereas the plant species seems not suitable for phytoremediation in Cu polluted water with a range of 1 to 10mg L-¹. Although, Chara braunii, H₂O₂ synthesis rapidly accelerated with the high Cu concentrations and time exposure. This oxidative stress leads to the higher Catalase activity and Guaiacol peroxidase activity in shorter durations thus afterwards it reduced to the lower concentration. Considering the overall experimental results flow and irradiance fluctuation caused more prominent effect on both macrophyte species biochemical activities. These fluctuations might be associated with morphological characteristics of two macrophytes and based on flow resistance which they can survive in each flow movements by regulating biochemical activities. However, heavy metal exposure should be limited to the required range of heavy metal and shorter time durations for maintain optimum biochemical activities of C. demersum and Chara braunii.; ACKNOWLEDGEMENT ..................................................................................................... iABSTRACT ........................................................................................................... iiTABLE OF CONTENT ................................................................................................... ivLIST OF FIGURES .................................................................................................. viiiLIST OF TABLES ...................................................................................................... x1 General Introduction and Literature review ........................................................................ 11.1 Freshwater aquatic plant species and corresponding diverse function of the ecosystem ............................ 11.2 Main abiotic stressors and growth distribution of the fresh water plants......................................... 31.3 Flow mediated growth changes on aquatic plants .................................................................. 41.4 Role of solar irradiance on aquatic ecosystem ................................................................... 61.5 Heavy metals effect on freshwater plants growth and physiological responses ..................................... 71.6 Selected plant species for study ................................................................................ 91.6.1 Ceratophyllum demersum ........................................................................................ 91.6.2 Egeria densa ................................................................................................. 101.6.3 Chara braunii................................................................................................. 112 Macrophytes biochemical responses for solar irradiance, flow regimes and heavy metals ............................ 122.1 Metabolism of reactive oxygen species and abiotic stress ....................................................... 122.2 Antioxidants and scavenging process ............................................................................ 132.3 Auxin induced stress responses ................................................................................. 142.4 Photosynthesis pigments concentration fluctuation and stress physiology ........................................ 152.5 Pulse amplitude modulation and photosynthesis measurements...................................................... 163 Objectives of the study .......................................................................................... 173.1 Significance of the study ...................................................................................... 173.2 Objectives ..................................................................................................... 183.3 Hypotheses ..................................................................................................... 184 Evaluation of the physiological alterations in Ceratophyllum demersum L along a diurnally changing solar irradiance gradient ........................................................................................................... 194.1 Introduction ................................................................................................... 194.2 Methodology .................................................................................................... 214.2.1 Plant materials .............................................................................................. 214.2.2 Experimental setup............................................................................................ 224.2.3 Photosynthesis measurements .................................................................................. 244.2.4 Photosynthetic pigment analysis .............................................................................. 254.2.5 Antioxidant enzyme analysis .................................................................................. 254.2.6 Statistical analyses ......................................................................................... 264.3 Results ........................................................................................................ 264.3.1 Photosynthesis responses ..................................................................................... 264.3.2 Pigment concentration ........................................................................................ 294.3.3 Reactive oxygen species ...................................................................................... 314.3.4 Antioxidant enzymatic activities.............................................................................. 324.4 Discussion ..................................................................................................... 345 Different flow velocities effect on invasive macrophyte Egeria densa antioxidative activities and cellular hydrogenperoxide synthesis. ................................................................................................ 385.1 Introduction and objectives .................................................................................... 385.2 Materials and methods .......................................................................................... 395.2.1 Biochemical analysis ......................................................................................... 395.2.2 Transmission electron microscopy ............................................................................. 395.2.3 Statistical analysis ......................................................................................... 395.3 Results ........................................................................................................ 405.3.1 Flow velocity effect on photosynthetic pigments .............................................................. 405.3.2 Flow induced effect on chlorophyll fluorescence .............................................................. 425.3.3 Flow induced effect on generation of hydrogen peroxide (H₂O₂) ................................................ 435.3.4 Flow induced effect on cell ultrastructure ................................................................... 465.4 Discussion ..................................................................................................... 476 Reactive oxygen species and endogenous indole acetic acid synthesis induced by Zn and Cu in the fresh water macrophyte Ceratophyllum demersum L. ......................................................................................... 506.1 Introduction ................................................................................................... 506.2 Material and methods ........................................................................................... 526.2.1 Plant materials and growth conditions ........................................................................ 526.2.2 Experimental design........................................................................................... 526.2.3 Sampling and extract preparation ............................................................................. 536.2.4 Chlorophyll pigment analysis ................................................................................. 536.2.5 Determination of hydrogen peroxide (H₂O₂) content ............................................................ 536.2.6 Determination of indole acetic acid (IAA) content ............................................................ 536.2.7 Determination of antioxidative activity ...................................................................... 546.2.8 Statistical analysis ......................................................................................... 546.3 Results ........................................................................................................ 546.3.1 Effects on photosynthetic pigments and Chlorophyll a/b ratio ................................................. 546.3.2 Effect on reactive oxygen species (ROS) ...................................................................... 576.3.3 Effect on the synthesis of IAA hormones ...................................................................... 586.3.4 Effect on antioxidant enzyme activities ...................................................................... 596.4 Discussion ..................................................................................................... 617 Copper contaminated water mediated biochemical changes on charophyte species Chara braunii ....................... 657.1 Introduction ................................................................................................... 657.2 Materials and methods .......................................................................................... 667.2.1 Sampling and extracts preparation ........................................................................... 667.3 Results ........................................................................................................ 677.4 Discussion ..................................................................................................... 718 Conclusions and Recommendations................................................................................... 738.1 Conclusions .................................................................................................... 738.2 Recommendations ................................................................................................ 74References ......................................................................................................... 76; 指導教員 : 藤野毅
• DOI: 10.24561/00019368; https://doi.org/10.24561/00019368
• 国立国会図書館永続的識別子: info:ndljp/pid/11865175; https://dl.ndl.go.jp/pid/11865175
• コレクション（共通）: 障害者向け資料
• コレクション（障害者向け資料：レベル1）: テキストデータ
• コレクション（個別）: 国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文; https://dl.ndl.go.jp/collections/A00014
• 収集根拠: 博士論文（自動収集）
• 受理日（W3CDTF）: 2021-11-08T14:10:24+09:00
• 作成日（W3CDTF）: 2021-09-16
• 記録形式（IMT）: application/pdf
• オンライン閲覧公開範囲: 国立国会図書館内限定公開
• デジタル化資料送信: 図書館・個人送信対象外
• 遠隔複写可否（NDL）: 可
• 掲載誌（URI）: http://dx.doi.org/10.24561/00019368; http://id.nii.ac.jp/1586/00019368/
• 連携機関・データベース: 国立国会図書館 : 国立国会図書館デジタルコレクション; https://dl.ndl.go.jp