干旱胁迫对海棠幼苗生长及生理特性的影响

采用盆栽试验法研究轻度、中度、重度干旱胁迫(土壤相对含水量分别为50%、35%、20%)对5种海棠幼苗生长及生理特性的影响,以期为园林绿化和苹果砧木的筛选提供优良的海棠品种。结果表明:随干旱胁迫程度加重,各海棠幼苗新梢相对生长量和根系活力均呈现下降趋势,在重度干旱胁迫下八棱海棠仍能维持高达79.649%的相对生长量,而红果海棠仅为34.820%;重度干旱胁迫下的八棱海棠根系活力降幅最小,为35.71%;重度干旱胁迫下,除八棱海棠外,其他品种丙二醛(MDA)含量均极显著高于对照(土壤相对含水量60%~80%),红果海棠最高,为对照的3.077倍;重度干旱胁迫下,珠美海棠超氧化物歧化酶(SOD)活性上升最快,为对照的1.119倍。综合各项指标和隶属函数分析结果,5种海棠幼苗耐旱性强弱依次为八棱海棠西府海棠平顶海棠珠美海棠红果海棠。

Effect of Drought Stress on the Growth and Physiological Characteristics of Begonia Seedlings

Potted seedlings of five species of begonia were used as materials to study the effects of drought stress on the growth and physiological characteristics,in order to provide excellent varieties of begonia for landscaping and the selection of apple rootstock.The results showed that with the increase of drought stress,the shoot relative growth and root activity displayed a downward trend of each begonia seedlings.Under severe drought stress,M.robusta could still maintain a relative growth of up to 79.649%,while M.komarovii was only 34.820%.And the root activity of M.robusta was the least affected,which was 35.71%.Under severe drought stress,except M.robusta the MDA contents of the others were higher than CK significantly.M.komarovii was the highest,reaching 3.077 times of CK.Under severe drought stress,the SOD activity of M.zumi rose the fastest,which was 1.119 times of CK.According to comprehensive analysis and subordinate function,the drought resistance level of five species of begonia seedlings was as following:M.robusta>M.micromalus>M.prunifolia>M.zumi>M.komarovii.