马铃薯植株感染Y病毒后生理指标变化与抗病性的关系

Changes in Physiological Index and Its Relation to Resistance of Potato Plants Infected with Potato Virus Y

本研究分别以对PVY感病、过敏和极端抗性的品种脱毒试管苗为材料,比较了接种PVY后不同时间内超氧化物歧化酶(SOD)和游离脯氨酸含量2个指标的变化。从整体上看,未接种PVY条件下,感病品种(Superior)植株的SOD活性较极端抗性品种(IVP35)和过敏型品种(Desiree)低。接种后,IVP35的SOD活性下降;Desiree在接种前期0.5～1 d SOD的活性下降,2～7 d后SOD活性上升,再后7～14 d又下降;Superior接种PVY后,SOD活性有上升趋势,且在接种2～3 d变化率出现最大值。另外,IVP35和Desiree在接种PVY后SOD变化率小,变化范围分别为-13.4%～4.6%和-17.8%～8.7%;Superior接种PVY后,SOD活性变幅较大,范围为5.1%～79.2%。被测的3个品种无论接种与否,极端抗性品种和过敏型品种其植株内部游离脯氨酸含量均明显高于感病品种。正常情况下,IVP35和Desiree的游离脯氨酸含量为41.39～48.77μg.g-1干重和33.42～39.11μg.g-1干重,而Superior仅为8.91～10.72μg.g-1干重。接种PVY后,Superior的游离脯氨酸含量明显上升,达到11.23～21.54μg.g-1干重;虽然IVP35和Desiree的游离脯氨酸含量也呈上升趋势,但上升幅度小,含量分别为48.92～72.13μg.g-1干重和42.46～71.34μg.g-1干重。

Superoxide dismutase and free praline contents were compared in potato plants derived from plantlets in vitro of three potato cultivars, Superior （susceptible）, IVP 35 （extremely resistant）, and Desiree （hypersensitive） before and after inoculation with potato virus Y （PVY）. In general, before inoculation, the superoxide dismutase content was lower in the susceptible cultivar Superior than in the resistant cultivar IVP 35 and hypersensitive cuhivar Desiree. After inoculation with PVY, the superoxide dismutase content in IVP 35 decreased. For Desiree, the superoxide dismutase content decreased in the early stage of inoculation （0.5-1 days after inoculation）, then increased later （2-7 days after inoculation）, and finally decreased again （7-14 days after inoculation）. As for Superior, the superoxide dismutase content tended to increase and had a maximal value of the rate of change 2-3 days after inoculation. In addition, the cultivars, IVP 35 and Desiree, had a small rate of change after inoculation, ranging -13.4%-4.6% and -17.8%-8.7%, respectively, while for the susceptible cuhivar Superior the rate of change was large, 5.1%-79.2%. The proline contents of IVP 35 and Desiree were higher than that of Superior no matter whether the potato plants were inoculated or not. Before inoculation, the proline content of IVP 35 and Desiree were 41.39-48.77 μg·g^-1 DW and 33.42-39.11 μg·g^-1 DW, respectively, while the proline content of Superior was only 8.91-10.72 μg·g^-1 DW. However, after inoculation the proline content of Superior raised obviously, and 11.23～21.54 μg·g^-1 DW were observed. The proline contents of IVP 35 and Desiree were also raised after inoculation, but only to less extent, with the values of 48.92～72.13 μg·g^-1 DW and 42.46～71.34μg·g^-1 DW, respectively.