甜瓜幼苗对逆境胁迫的生理响应及抗逆性综合评价

Physiological Responses of Muskmelon Seedlings to Different Adversity Stresses and Synthetical Evaluation of Stress Resistance

为阐明逆胁迫对甜瓜幼苗伤害的生理机制及综合抗逆性品种选育筛选与应用提供理论依据,以熟性不同的薄皮甜瓜F13-18、F14-20为试验材料,测定了幼苗期不同逆境胁迫条件下与抗逆性有关的可溶性蛋白质(SP)、叶绿素(Chl)、游离脯氨酸(Pro)、丙二醛(MDA)的含量和保护性酶活性等生理指标。结果表明,苗期逆境胁迫增加了SP、Pro、MDA含量及细胞膜的透性(TDS),提高了超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性,降低了Chl含量及叶绿素a与叶绿素b的比值(Chla/b),但不同逆境胁迫的生理机制有差异,整体表现为干旱、水分胁迫对叶片渗透调节物质含量及光合特性的影响较大,低温、盐胁迫对叶片保护性酶活性影响较大。利用主成分分析对苗期抗逆性生理指标进行评价,Chl、Chla/b、POD、SOD可作为早熟品种F13-18苗期综合抗逆性的鉴定指标,Chl、Pro、TDS、POD可作为中晚熟品种F14-20苗期综合抗逆性的鉴定指标。

The physiological mechanism of injury on Muskmelon under adversity stresses was elucidated to provide theoretical basis for screen- ing and application of resistant variety. Early-maturing variety F13-18 and middle-late variety F14-20 were used as the test materials, con- tents ofsoluble protein, chlorophyll, free proline, malondialdehyde and protective enzyme connected with resistance by cold, drought, salt and water stress at the seedlings stage were determined. Adversitystress of seedlings stage increased the contents of soluble protein, chloro- phyll, free proline, malondialdehyde, raised the activity of SOD and POD, reduced the content of chlorophyll and Chla./b. But there were different coping mechanisms between different types of adversity stresses,in a whole, cold and water stress had larger effects on osmoregulation matters content and photosynthetic characteristics, and drought and salt stress had larger effects onprotective enzyme activity. The physiologi- cal indexes of stress resistance were evaluated by principal component analysis. The contents of chlorophyll, Chla./b and the activity of SOD and POD could be used as the indicators of Stress resistance identification at the seedlingsstage of Early-maturing variety F13-18, and the contents of chlorophyll, free proline, permeability of cell membrane and PODactivity could be used as ones of middle-late variety F14-20.