砧木的抗旱能力直接影响桃品种生长发育，选择适宜抗旱性桃砧木对桃产业发展有积极的促进作用。为阐明不同桃砧木对干旱胁迫生理响应机制，以5种桃砧木扦插苗为试材，通过盆栽控水方式，研究不同程度干旱胁迫下5种桃自根砧的叶片水分特性、渗透调节物质、抗氧化物酶及叶绿素含量变化。结果表明，随着干旱程度加重，5种砧木相对含水量、临界含水量下降，自然饱和亏、临界饱和亏及需水程度上升，组织密度和自由水含量逐渐减少，束缚水含量则增大，持水能力、组织水势和耐旱系数下降。各干旱胁迫处理的丙二醛(MDA)含量、 游离脯氨酸(Pro)含量、可溶性糖含量和叶绿素含量均增加；过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性提高，其中随干旱程度加重，丙二醛(MDA)含量、游离脯氨酸(Pro)含量均呈增加趋势，SOD活性、CAT活性也均呈提升趋势，可溶性糖含量、叶绿素含量、POD活性变化不尽相同。综合隶属函数分析可知，桃自根砧品种间抗旱性由强到弱依次为樱桃李5号、RA、樱桃李3号、GF677、樱桃李1号。

Drought-resistant ability of rootstocks has a direct impact on the growth and development of peach varieties.Toclarify the physiological response mechanism of different peach rootstocks under drought stress, this experiment analyzed changes in moisture characteristics, osmotic adjustment substances, antioxidant enzymes, and chlorophyll fluorescence in leaves of five peach rootstocks by means ofpot experiment. The resultsshowed that with the aggravation of drought, compared with the respective controls,relative water content and critical water content of 5 rootstocks decreased, while natural saturation deficit, critical saturation deficit and water demand increased, the tissue density and freewater content gradually decreased, while the bound water content increased, and the water holding capacity, tissue water potential and drought tolerance coefficient decreased, and were less than their respective controls. Malondialdehyde(MDA) and free proline(Pro) contents, soluble sugar and chlorophyll contents were increased comparedwith their respective controls under different drought treatments, and increased activities of peroxidase (POD), superoxide dismutase (SOD) and catalase(CAT) were detected. But with the aggravation of drought, contents of MDA, Pro and activities of SOD and CAT showed the tendency of increase, while soluble sugar and chlorophyll contents and activity of POD showed diverse tendency of change. Under long-term drought stress, rootstock stimulates the activity of antioxidant enzymes by regulating the water potential and water holding capacity of leaf tissue, which prevents a large amount of MDA production and increases the content of osmoregulation substances, and enhances the ability to resist drought stress, thus improving the drought tolerance.

S646；S759.81

国家桃产业技术体系种苗扩繁与生产技术岗位 (CARS-30-1-6)；农业农村部西北地区果树科学观测实验站(S-10-18)；甘肃省农业科学院科技成果转化项目(2022GAAS-CGZH06)。