低温胁迫下新疆野苹果离体叶片生理特性分析

新疆野苹果是我国珍贵的野生果树资源,具有亲和力强、种源丰富、抗性强等优良特性。为了解其低温胁迫下的生理特性,本研究通过低温胁迫(4℃)处理新疆野苹果离体叶片,分别测定不同胁迫天数下苹果叶片的过氧化物酶(POD)活性、脯氨酸含量、丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性等生理指标。结果表明:随着低温胁迫天数的增加,苹果叶片中MDA含量呈递增趋势;POD活性、SOD活性呈先升高后下降的趋势;脯氨酸含量出现先增加后缓慢降低的趋势;而叶绿素含量在处理1 d时略有下降,接着呈先升高后降低的变化趋势。低温胁迫对相关生理指标的影响均达到显著水平。相关性分析结果显示,低温胁迫天数与MDA含量、SOD活性呈极显著正相关;与POD活性、脯氨酸含量、叶绿素含量之间有一定相关性。本研究为进一步阐明新疆野苹果的抗寒机理以及选育耐寒品种提供了实验依据。

Physiological Analysis of Leaves in Vitro ofMalus sieversi under Low Temperature Stress

Malussieversiiis precious resource of wild fruit trees in China, with strong affinity, rich provenance, strong resistance and other excellent features. In order to analyze its physiological characters under low temperature stress, peroxidase（POD） activity, proline content, malondialdehyde（MDA） content and superoxide dismutase（SOD） activity were tested after treated leavesin vitro with low temperature（4℃）. The results show that with the increase of the low temperature stress days, theMDA content showed a trend of increasing,POD,SOD activity showed a decreased trend after the first enhancement, proline content increased at first and then reduced slowly, and chlorophyll content was slightly lower at the first day, and then reduced after the first increase. Low temperature stress on all physiological indexes related to these effects reached significant level. Correlation analyses show that the days of low temperature stress were positively correlated withMDA content andSOD activity significantly, while there was a certain correlation withPOD activity, proline content and chlorophyll content. This study provides the experimental data for elucidating the mechanism of cold resistance and breeding cold resistant variety ofMalus sieversii.