We examined the responses of physiological and leaf anatomic structural characteristics of six Helleborus orientalis cultivars to different degrees of drought stress. A membership function was used to evaluate drought resis-tance and identify physiological and leaf anatomical indicators that exhibited a stronger correlation with drought tolerance. The results showed that leaf thickness, leaf area per unit mass and soluble protein levels of the six cultivars significantly decreased with the increases of drought stress. Net photosynthetic rate, stomatal conductance, and transpiration rate of leaves increased first and then decreased, while the intercellular CO2 concentration decreased. The relative electrical conductivity, MDA, and H2O2 contents of leaves were increased. Soluble saccharide and proline contents, and antioxidant enzyme activities were first elevated and then decreased. With the increases of drought stress, the ratio of palisade tissue thickness to sponge tissue thickness and stomatal density increased. Key indicators and relativities in evaluating drought resistance of those cultivars were proline, soluble sugars, and the ratio of palisade tissue thickness to sponge tissue thickness. H. orientalis 'Anemone Red' and H. orientalis 'Ane-mone Red spotted' had better drought resistance, which could be the excellent parental materials for the cultivation of new drought-resistant cultivars in the future.
研究人工控水模拟干旱胁迫条件下6个东方铁筷子品种的生理和叶片解剖结构的变化特征,并利用隶属函数法对其抗旱性进行评价,筛选出与抗旱性关联较大的生理及叶片解剖结构指标。结果表明: 随着干旱胁迫程度增加,6个东方铁筷子品种的叶片厚度、单位质量叶面积和可溶性蛋白水平显著下降,净光合速率、气孔导度和蒸腾速率均先上升后降低,胞间CO2浓度下降,叶片相对电导率、丙二醛和过氧化氢含量均升高,可溶性糖、脯氨酸含量和抗氧化酶活性均先升高后降低。随着干旱胁迫程度增加,栅栏组织厚度与海绵组织厚度比以及气孔密度均增加。脯氨酸、可溶性糖、栅栏组织厚度与海绵组织厚度比等指标与抗旱性关系密切,可作为评价东方铁筷子抗旱性的重要指标。‘银莲花红’和‘银莲花红斑’抗旱能力优异,可为未来的抗旱新品种培育提供优良亲本材料。.
Keywords: antioxidant system; drought stress; leaf anatomy; osmotic regulation; photosynthesis.