【摘要】 以1年生鼓节竹分株苗为材料,采用盆栽试验,设置对照组（CK）（土壤含水量为33.0%～35.2%）、轻度干旱胁迫组（土壤含水量为24.2%～26.4%）、中度干旱胁迫组（土壤含水量为17.6%～19.8%）、重度干旱胁迫组（土壤含水量为8.8%～11.0%）,通过人工模拟干旱胁迫研究鼓节竹光合特性及叶绿素荧光参数的变化规律,以揭示干旱胁迫条件下鼓节竹的适应能力和适应机制.结果表明:（1）鼓节竹叶片的净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（T_r）随着干旱胁迫时间的增加及胁迫强度的增大呈下降的趋势;胞间二氧化碳浓度（C_i）随着干旱胁迫时间的增加呈先下降后上升的趋势,分别在轻度干旱胁迫21 d、中度干旱胁迫14 d、重度干旱胁迫7 d时达到最小值;气孔限制值（L_s）在干旱胁迫下随着胁迫时间的增加呈先上升后下降的趋势;水分利用效率（WUE）在轻度、中度干旱胁迫下随着胁迫时间的增加呈先上升后下降的趋势,而在重度干旱胁迫下呈下降的趋势.（2）干旱胁迫对鼓节竹叶片叶绿素荧光参数均产生了影响,其中,最大荧光产量（F_m）、最大光化学效率（F_v/F_m）、潜在活性（F_v/F₀）、实际光化学效率(Φ_PSⅡ)、光合电子传递速率（ETR）、光化学猝灭系数（qP）在干旱胁迫下随着胁迫时间的增加均呈下降的趋势;初始荧光产量（F₀）在干旱胁迫下随着胁迫时间的增加呈先上升后下降的趋势;非光化学猝灭系数（qN）在轻度、中度干旱胁迫下随着胁迫时间的增加呈显著上升的趋势,而在重度干旱胁迫下呈先下降后上升的趋势.本试验结果显示:在干旱胁迫下,鼓节竹可通过改变自身叶片的形态来抵御干旱胁迫带来的伤害,从而在轻度、中度干旱胁迫下表现出一定的抗旱性;干旱胁迫对鼓节竹光合特性和叶绿素荧光参数的影响明显,气孔和非气孔因素都是影响光合速率下降的因素;鼓节竹可通过降低qP、Φ_PSⅡ以及增加qN来降低PSⅡ反应中心的开放程度,从而降低反应中心在干旱胁迫下的伤害,表现出一定的耐旱性;维持鼓节竹具有较高WUE的土壤含水量为17.6%～26.4%.更多还原

【Abstract】 To reveal the adaptability and adaptation mechanism of Bambusa tuldoides ‘Swolleninternode’under drought stress, 3 levels of drought stress, namely light drought stress [24.2%-26.4% soil moisture content（SMC）], moderate drought stress（17.6%-19.8% SMC）, and severe drought stress（8.8%-11.0% SMC） were applied to one-year-old B.tuldoides ‘Swolleninternode’ramet seedlings grown in pots, and group with SMC ranging between 33.0%-35.2% was set as the control. Artificial drought stress simulation was conducted to evaluate the photosynthetic characteristics and chlorophyll fluorescence characteristics of B.tuldoides ‘Swolleninternode’. The results showed that net photosynthetic rate（P_n）, stomatal conductance（G_s）, transpiration rate（T_r） decreased with intensified drought stress and increased stress time. Intercellular CO₂ concentration（C_i） started with an increase and then decreased, reaching minimums on day 21, 14, and 7 under light, moderate and severe drought stress, respectively. Stomatal limit value（L_s） all increased first and then declined during 3 levels of drought stress, and water use efficiency（WUE） also increased first and then decreased under light and moderate drought stress while it went down all the way under severe drought stress.（2） Drought stress affected the chlorophyll fluorescence parameters of B.tuldoides ‘Swolleninternode’. Maximum fluorescence（F_m）, maximum PSⅡ photochemical efficiency（F_v/F_m）, PSⅡ potential activity（F_v/F₀）, actual photochemical efficiency(Φ_PSⅡ), apparent photosynthetic electron transport rate（ETR） and photochemical quenching（qP） all dropped under drought stress. Minimal fluorescence（F₀） showed a downward trend after rising. Non photochemical quenching（qN） increased notably under light and moderate drought stress, while it declined first and then rose under severe drought stress. It can be included that B.tuldoides ‘Swolleninternode’demonstrates a certain degree of drought resistance under light to moderate drought stress by adjusting leaf morphology. Drought stress adversely affects photosynthetic and chlorophyll fluorescence characteristics of B.tuldoides ‘Swolleninternode’, which were attributed from both stomatal and non stomatal factors. B.tuldoides ‘Swolleninternode’can lower the open degree of PSⅡ reaction center by decreasing qP and PSⅡ and increasing qN, thus damages to reaction center are reduced under drought stress. It suggests that B.tuldoides ‘Swolleninternode’maintains a high level of WUE at soil moisture of 17.6%-26.4%.更多还原