烟草花叶病毒对烟草叶片光合特征和POD表达的影响

以烤烟(Nicotiana tabacum L.)品种'中烟5号'为实验材料,对烟草健康株与感染烟草花叶病毒(TMV)株的叶绿素、光合速率、光合速率对光强的响应曲线、光暗反应荧光特征、POD活性及其表达等进行研究,以探讨TMV感染对烟草植株生理生态特征的影响.结果显示:病株的叶绿素a(Chl a)和叶绿素b(Chl b)含量显著低于健康株,但Chl a/Chl b值基本相同;病株暗中初始荧光(F0)、暗中最大荧光(Fm)、暗中可变荧光(Fv)、光下初始荧光(F0′)、光下最大荧光(Fm′)、光下可变荧光(Fv′)、非光化学猝灭系数(NPQ)、PSⅡ捕光效率(Fv′/Fm′)、PSⅡ实际光化学效率(ФPSⅡ)及光饱和点显著低于健康株;净光合速率在光强较大(＞1 500 μmol·m-2·s-1)时病株比健康株低,光强适中(1 500 μmol·m-2·s-1左右)时两者相差不大,光强较弱(＜1 500 μmol·m-2·s-1左右)时病株比健康株高;病株叶片的过氧化物酶(POD)活性显著升高,POD同工酶中一些大分子量蛋白分子表达量加大.研究表明,感染TMV使烟草植株对光抑制更为敏感,叶片的荧光激发能力和热耗散能力下降,PSⅡ反应中心捕光效率和光化学反应效率降低,光合电子传递能力和碳同化能力受到抑制;POD活性提高和表达量增加可能是诱导烟草抗病性的一个关键生理过程.

Photosynthesis Characters and Peroxidase Activities of Tobacco Leaves Infected by Tobacco Mosaic Virus

The chlorophyll content,photosynthsis rates,response curves of photosynthesis-light,fluorescence parameters of light and dark reaction,peroxidase (POD) activities of healthy and sick (infected by TMV) leaves of tobacco were studied for investigating the influence of TMV infected on physio-ecology characters of tobacco.The results showed that the contents of chlorophyll a (Chl a) and chlorophyll b (Chl b) in sick leaves were lower than in the healthy ones;but the values of Chl a/Chl b were identical.Minimal,...