干旱胁迫下石灰花楸幼苗叶片的解剖结构和光合生理响应

Leaf Anatomical Structure and Photosynthetic Physiology Responses of Sorbus folgneri Seedlings under Drought Stress

采用盆栽控水设置4种水分梯度,研究1年生石灰花楸幼苗叶片解剖结构和光合生理指标对干旱胁迫的响应。结果显示:(1)干旱胁迫下,石灰花楸叶片逐渐变薄,轻度和中度胁迫下栅海比显著升高,而重度胁迫下显著降低。(2)干旱胁迫抑制了光合色素合成,降低了叶绿素和类胡萝卜素含量,同时使叶绿素a/b和叶绿素/类胡萝卜素值升高。(3)随干旱程度加剧,净光合速率、蒸腾速率和气孔导度日变化整体下降,胞间CO2浓度整体上升,光合限制以非气孔因素为主。研究表明,石灰花楸能根据水分亏缺程度调整叶片结构和光合生理特征以维持生存和生长,具有较强的耐旱性。

Four levels of drought stress were applied to 1-year-old potted seedhngs ot 5orOus ：otgnerz to In- vestigate the effects of drought on leaf anatomical structure and photosynthetic characteristics. The results showed that： （1）Drought stress had induced significant reduction in leaf thickness,caused higher palisade to spongy ratio in light and moderate,lower ratio in severe stress. （2）Drought depressed synthesis of pho- tosynthetic pigments, reduced the tissue concentrations of chlorophylls and carotenoids,caused higher chlo- rophyll a to b and chlorophyll to carotenoids ratio. （3）The diurnal variation of net photosynthetic rate,transpiration rate, stomatal conductance decreased, but intercellular CO2 density increased with drought stress increasing. The limitation of photosynthesis was mainly caused by non-stomatal factors. In summary, S. folgneri demonstrated to be drought-resistant,it could adjust its leaf anatomical structure and net pho- tosynthetic capacity according to levels of drought stress to maintain survival and growth.