淹水胁迫下江南牡丹生长及光合特性研究

以3年生江南牡丹品种‘凤丹白’为材料,利用盆栽淹水法,设置正常管理、轻度胁迫和重度胁迫3个水平,研究不同淹水胁迫水平对牡丹生长和光合特性的影响。结果表明：经过30 d胁迫后,正常管理、轻度胁迫和重度胁迫下的江南牡丹苗高生长量分别为3.6、1.1和0.73 cm,地径生长量分别为0.21、0.11和0.06 cm,植株总生物量增加量分别为7.0、3.0和2.75 g,淹水胁迫和正常生长差异显著,淹水胁迫严重影响了江南牡丹的生长。同时,在正常管理时,牡丹总叶绿素含量升高,而在淹水胁迫下呈下降趋势。淹水胁迫不同时间根系活力均呈下降趋势且随着胁迫程度的增加下降越大。正常管理下光合速率逐渐增加而胁迫条件下光合速率逐渐降低。同时胁迫条件下,牡丹蒸腾速率、气孔导度均明显下降；轻度淹水胁迫下胞间CO2浓度先升高后降低；而重度胁迫下胞间CO2浓度呈现逐渐升高的变化趋势。淹水胁迫对牡丹根系活力、茎段生长和叶片光合特性影响较大。该研究结果为江南牡丹耐涝胁迫机理研究奠定了理论基础。

Effects of flooding stress on growth and photosynthesis of Paeonia suffruticosa

Growth and photosynthesis of three-year-old seedlings of Paeonia suffruticosa“fengdanbai” were investigated in a 30-day flooding experiment. Three treatment levels were set in this experiment:normal management, mild stress and severe stress levels. The results showed that after 30 d of the above three treatments accordingly, the height growth of P. suffruticosa was 3.6, 1.1 and 0.73 cm, the ground diameter growth of P. suffruticosa was 0.21, 0.11 and 0.06 cm. The increase in total plant biomass was 7.0, 3.0 and 2.75 g. The difference was remarkable between flooding stress and nor-mal growth, the growth of P. suffruticosa was seriously affected by flooding stress. At the same time, total chlorophyll content increased under normal management, but declined under stress conditions. The root activity decreased when trea-ted with flooding at different times. Meanwhile, under flooding stress, the transpiration rate and stomatal conductance of P. suffruticosa also decreased. Under mild flooding stress, the intercellular carbon dioxide concentration first increased and then decreased, but increased under severe flooding stress. The study suggests that flooding stress affects the P. suf-fruticosa root vigor, stem, leaf growth and photosynthetic characteristics. This study will provide the information for stress mechanism of jiangnan P. suffruticosa.