不同系统梨品种抗旱性初步评价

Preliminary Evaluation of Drought-Resistance Among Pears Cultivars

以5大梨系统20个梨品种的2年生盆栽梨苗为试材,研究水分胁迫及复水条件下膜脂过氧化物质、渗透调节物质及抗氧化酶活性的变化特征。结果表明,秋子梨系统梨品种具有较高的净光合速率、气孔导度和水分利用效率,较低的蒸腾速率和叶面饱和蒸汽压亏缺,抗旱性强于其他品种;砂梨抗旱性最弱。随着水分胁迫时间的延长,抗旱性较弱的西洋梨和砂梨MDA和O_2^-含量迅速增加,膜系统受到严重伤害。西洋梨和白梨随着干旱胁迫的加重脯氨酸大量积累,启动渗透调节来缓解水分胁迫造成的伤害。水分胁迫前期不同系统梨品种SOD和POD活性呈持续上升趋势,胁迫过重则活性降低,且抗氧化酶增加的幅度与梨品种的抗旱性呈正相关关系。综合评价认为,秋子梨、新疆梨及白梨系统品种的抗旱性较强,适宜在干旱、半干旱地区发展,西洋梨和砂梨则抗旱性较弱,适宜在湿润、半湿润地区发展。

Two years old pear trees in 20 cultivars of five species in pot were selected as experimental. The variation characteristics of membrane lipid peroxidation substance,osmotic adjustment substance and antioxidant enzyme activity under drought stress and rewatering conditions were studied. The results showed that the drought resistance of Pyrus ussuriensiswas stronger than other species. Pyrus ussuriensis had a higher net photosynthetic rate,stomatal conductance and water use efficiency and lower transpiration rate and saturation vapor pressure deficit. Drought resistance of Pyrus pyrifolia was the weakest. With the prolong of water stress time,The MDA and O_2^- contents of Pyrus communis and Pyrus pyrifolia increased rapidly. Their membrane system was hurt seriously. Proline of Pyrus communis and Pyrus bretschneideri accumulated with the aggravation of drought stress and alleviated the water stress damage by osmotic adjustment. SOD and POD activity of pear cultivarsin creased in the earlier water stress and decreased in the later. A positive correlation was observed between increasing extent of antioxidant enzymes and drought resistance of pear. In results,Pyrus ussuriensis,Pyrus sinkiangensis and bretschneideri had a stronger drought resistance,which was suitable for planting in arid and semi-arid Region. Pyrus communis and Pyrus pyrifolia had a weaker drought resistance,which was suitable for planting in humid and semi-humid Region.