UV-B辐射和干旱胁迫对烟草逆境生理指标的影响

以2个烤烟品种(红花大金元和K326)为供试作物,研究增强UV-B辐射、干旱及交叉胁迫对烟草活性氧水平、膜质过氧化、膜稳定性、抗氧化酶活性等逆境生理指标的影响,旨在揭示植物对紫外和干旱交叉胁迫的适应机制。结果表明:UV-B辐射和干旱胁迫可导致烟草H2O2含量上升,膜稳定性相应下降。当2种胁迫同时发生时,烟草氧化损伤程度低于单因子胁迫或处于2种单因子胁迫之间。产生这种交叉适应性的原因可能是UV-B辐射诱导的抗氧化酶活性增强和干旱诱导的渗透调节物含量增加产生叠加作用,增强了植株的抗氧化能力,从而缓解了彼此对植物体造成的氧化损伤。红大品种获得交叉适应性的能力高于K326。

Effects of UV-B Radiation and Drought on Stress Physiological Index of Tobacco

n the present study, we explored the influence of elevated UV-B radiation, drought and the combined stress on physiological characteristics, including ROS levels, membrane lipid peroxidation, membrane stability and antioxidase activity, in two tobacco(Nicotiana tabacum L.)cultivars Hongda and K326. The purpose of the study was to understand the mechanism of cross adaptation of plant induced by UV-B radiation and drought. Results showed that, both UV-B radiation and drought caused a significant increase in H2O2 content in tobacco leaves, while the membrane stability declined significantly. When exposed in both UV-B radiation and drought, the extent of oxidative injury of tobacco was either lower than the single factor stress or similar to the single factor stress. The cross adaptation may be the superposition effect of the enhanced antioxidant enzyme activity stimulated by UV-B radiation and the increase of osmotic adjustment substance content induced by drought, which could alleviate the oxidative damage. The study also demonstrated that tobacco cultivar Hongda exhibited better cross adaptation than K326 under the combined stress by UV-B and drought stress.