| 摘要: |
| 干露胁迫强度决定着海草床在潮间带的分布,植物的生理特性是反映其环境胁迫效应的重要依据。为探索潮汐周期内不同时长的光热干露胁迫对海草生理特性的影响,该文以热带优势海草泰来草(Thalassia hemprichii)为对象,通过在日光温室内模拟高温(41.0～44.5 ℃)和强光(633～1 682 μmol·m-2·s-1)环境条件,研究不同露空时间(0、10、20、40、60、90 min·d-1,连续7 d)对泰来草叶片生长速率、光合色素含量和光合荧光参数,以及对叶片和根部抗氧化酶活性、非结构碳水化合物和次生代谢产物含量的影响。结果表明:(1)≤10 min·d-1的日周期光热干露对泰来草的生长速率和生理特性未产生显著影响(P>0.05)。(2)在光热干露条件下,随露空时间的延长,泰来草叶片损伤逐渐加重,颜色由绿色变为褐色且生长速率降低,光合色素含量、叶绿素a/叶绿素b、叶绿素荧光参数均呈下降趋势; 叶片和根的MDA、可溶性糖含量以及POD、SOD、CAT酶活性呈升高趋势; 叶片淀粉、总酚和总黄酮含量呈先升高后降低的趋势。(3)90 min·d-1的日周期光热干露是泰来草叶绿体PS Ⅱ光合反应中心不完全失活的承受极限。综上认为,潮汐周期内较长时间的光热干露胁迫会对泰来草的生长和生理特性产生负面影响,该研究结果为了解热带海草在潮间带的分布规律以及海草床生态修复时的位置选择提供了依据。 |
| 关键词: 泰来草, 光热干露, 露空时间, 生理特性, 叶绿素荧光, 抗氧化酶 |
| DOI：10.11931/guihaia.gxzw202208038 |
| 分类号:Q948.1 |
| 文章编号:1000-3142(2023)11-1965-10 |
| Fund project:海南崖州湾重大科技计划项目(2022CXYZD002-02); 海南省研究生创新科研项目(Qhys2021-391,Qhys2021-393); 大学生创新创业训练计划项目(202111100016, S202111100039)。 |
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| Effects of diurnal periodic photothermal desiccation stress on physiological characteristics of Thalassia hemprichii |
|
LI Zhaoyang1,3, SHI Yunfeng2*, CAI Jiali1,3, ZHAO Muqiu2,
SHI Zhiqiang1, LUO Huijue3, HAN Qiuying1
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1. Yazhouwan Innovation Research Institute of Hainan Tropical Oceanography University, Sanya 572022, Hainan, China;2. Hainan
Modern Marine Ranch Engineering Research Center, Sanya 572022, Hainan, China;3. Key Laboratory of Coastal
Marine Ecological Environment Process and Carbon Sink of Hainan, Sanya 572022, Hainan, China
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| Abstract: |
| The distribution of seagrass meadows in intertidal zone is determined by the intensity of desiccation stress. The physiological characteristics of plants are the important basis to reflect their environmental stress effects. In order to explore the effects of the duration of photothermal desiccation stress on the physiological characteristics of seagrass during the tidal cycle, taking the tropical dominant seagrass Thalassia hemprichii as the research object, a simulation experiment was carried out in a solar greenhouse with high temperature(41.0-44.5 ℃)and strong light(633-1 682 μmol·m-2·s-1)environmental conditions. The effects of different desiccation time(0, 10, 20, 40, 60, 90 min·d-1, continuous for 7 d)on the growth rate, photosynthetic pigment content and photosynthetic fluorescence parameters of the leaves, as well as on the activities of antioxidant enzymes and the contents of nonstructural carbohydrates and secondary metabolites of leaves and roots were studied. The results were as follows:(1)The diurnal periodic photothermal desiccation of ≤10 min·d-1 had no significant effect on the growth rate and physiological characteristics of T. hemprichii(P>0.05).(2)Under the photothermal desiccation conditions, the damage of T. hemprichii leaves increased, the color of leaves changed from green to brown, and the growth rate of leaves decreased with the extension of desiccation time. Meanwhile, the photosynthetic pigment content, chlorophyll a/chlorophyll b and the chlorophyll fluorescence parameters of leaves showed a downward trend; the contents of MDA and soluble sugar and the activities of POD, SOD and CAT of leaves and roots showed an upward trend; whereas the contents of starch, total phenol and total flavonoids in leaves increased first and then decreased.(3)The diurnal periodic photothermal desiccation of 90 min·d-1 was the upper limit of incomplete inactivation for T. hemprichii chloroplast PS Ⅱ photosynthetic reaction center. In summary, a long term photothermal desiccation stress during tidal cycle has negative impacts on the growth and physiological characteristics for T. hemprichii. The results provide the reference for understanding the distribution of tropical seagrasses in the intertidal zone and the location selection of seagrass meadows for ecological restoration. |
| Key words: Thalassia hemprichii, photothermal desiccation, desiccation time, physiological characteristic, chlorophyll fluorescence, antioxidant enzyme |
