摘要
以盆栽平邑甜茶(Malus hupehensis)幼苗为试材,探讨连作对叶片光系统功能的伤害机制及对活性氧含量、抗氧化酶活性的影响。结果表明,连作条件下,平邑甜茶幼苗生物量减少,叶片净光合速率降低,PSⅡ受到损伤,其响应机制是:PSⅡ供体侧放氧复合体受到损伤,QA被过度还原,光合电子传递链中的QA-大量积累,PSⅡ反应中心和受体侧均受到显著性伤害,受体侧由QA向QB的传递受阻,电子传递链受到损害,大量能量积累导致光能过剩及活性氧浓度上升,对光系统造成氧化破坏,抑制光合作用。同时,以吸收光能为基础的性能指数降低,实际光化学效率减弱,PSⅡ激发能分配方式发生改变,植株叶片通过增加热耗散等消耗过多激发能来适应连作带来的胁迫环境。连作条件下,平邑甜茶幼苗叶片抗氧化酶系统与活性氧之间动态平衡被打破,加剧了脂膜过氧化程度,加重了对叶片的伤害。
The Malus hupehensis Rehd. seedlings were selected as the tested materials. The purpose of this study was to investigate the effects of continuous cropping stress on photosynthetic activities and reactive oxygen species and protective enzymes activities. The results showed that under continuous cropping conditions, the biomass of Malus hupehensis Rehd.seedlings decreased, the net photosynthetic rate of leaves decreased, and the PSⅡwas damaged. The response mechanism was that the oxygen-evolving complex(OEC) of the PSⅡwas damaged, QAwas over-reduced, QA-in the photosynthetic electron transfer chain was accumulated, the reaction center and accepter side of PS Ⅱ were significantly damaged, the transfer from QAto QBat the accepter side was blocked, and the electron transfer chain was damaged, a large amount of energy accumulation leads to the excess of light energy and the increase of reactive oxygen concentration, which causes oxidative damage to the light system and inhibits photosynthesis. At the same time, the performance index based on absorption of light energy decreased, the actual photochemical efficiency weakened, the distribution mode of PSⅡexcitation energy changed, and the plant leaves adapted to the stress environment brought by continuous cropping by increasing heat dissipation and consuming too much excitation energy. Under continuous cropping conditions, the dynamic balance between protective enzyme system and reactive oxygen species in leaves of Malus hupehensis Rehd. seedlings was broken, which aggravated the degree of lipid membrane peroxidation and aggravated the damage to leaves.
作者
吕毅
LU Yi(Weihai Academy of Agricultural Sciences,Shandong 264200)
出处
《中国果树》
北大核心
2023年第3期12-17,共6页
China Fruits
基金
山东省果品产业技术体系项目(SDAIT-06-19)。
关键词
连作
平邑甜茶
幼苗
光系统Ⅱ
活性氧
抗氧化酶
continuous cropping
Malus hupehensis Rehd.
seedlings
PSⅡ
reactive oxygen species
protective enzymes
