Abstract:

Potentilla leucophylla and Potentilla verticillaris were taken as testing materials to research their anatomical structures and physiological indexes include chlorophyll contents of leaves under drought stress, further to compare and analyze the drought-tolerant capabilities of two Potentilla species. The results indicated that the thicknesses of leaves, upper and lower epidermis, spongy tissue gradually decreased with the increase of drought stress, whereas the thicknesses of palisade tissue increased and the ratio of palisade tissue to spongy tissue gradually increased. Compared with the initial stress, the chlorophyll content of Potentilla leucophylla and Potentilla verticillaris was gradually decreased 35.62% and 31.72%, respectively; the MDA and free proline contents of both species increased; the SOD activities of both first increased and then decreased, the maximum SOD activities were at the 20 th and 25 th days, respectively. With the increase of drought stress, the rangeability of physiological indexes of Potentilla verticillaris was lower than that of Potentilla leucophylla indicating that the drought tolerance of Potentilla verticillar was stronger than Potentilla leucophylla. Therefore, the anatomical structure and physiological changes of leaves can be used as the evaluation indexes of plant drought resistance.

Key words: Drought stress, Potentilla leucophylla, Potentilla verticillaris, Anatomical structures, Physiological indexes, Physiological response

摘要：

以白叶委陵菜(Potentilla leucophylla)和轮叶委陵菜(Potentilla verticillaris)为试验材料,通过干旱胁迫处理研究2种委陵菜叶片的解剖结构和叶绿素含量等生理指标的变化情况,进而比较分析2种委陵菜的耐干旱能力,以期为耐旱植物的选育奠定基础.结果表明:随着干旱胁迫增强,2种植物的叶片、上下表皮和海绵组织厚度逐渐减小,栅栏组织厚度逐渐增加,且栅栏组织与海绵组织厚度比值呈逐渐增长趋势;与胁迫初期相比,白叶和轮叶委陵菜叶绿素含量逐渐下降,下降幅度分别为35.62%, 31.72%;丙二醛(MDA)和游离脯氨酸含量上升,MDA含量的增长幅度分别为572%, 458%;超氧化物歧化酶(SOD)活性先上升后下降,SOD活性分别在胁迫的第20 d和25 d达到最大值.干旱胁迫处理期间,轮叶委陵菜各项指标的变化幅度稍小,说明轮叶委陵菜适应干旱的能力强于白叶委陵菜,植物叶片的解剖结构和生理指标变化可以作为植物耐旱能力的评价指标.

关键词: 干旱胁迫, 白叶委陵菜, 轮叶委陵菜, 解剖结构, 生理指标, 生理响应