植物抗热性与叶绿体的关系

与其它细胞器相比,叶绿体对热敏感的多,PSH比PSI对热敏感.各种光合反应中,放氧过程对热最敏感。高温下功能性Mn~(2 )的解离,抑制光合放氧。高温胁迫下,叶绿体膜脂的特性是否与抗热性有关,目前看法不一,有些资料表明,叶绿体在热适应过程中,类囊体中产生热保护因子,其性质不甚明了。HSPs可能参与热保护作用。叶绿体中含有丰富的抗氧化物质和自由基清除酶系,目前有很多资料显示,耐热与热敏植物品种或植物在不同的热处理条件下,其各种活性氧含量或活性氧清除能力存在差异。

THE RELATIONSHIP BETWEEN THE THERMAL STABILITY AND CHLOROPLAST IN PLANT

Chioroplast is more sensitive to high temperautre than other cellorganelles. PSII is much more sensitive to heat than PSI. PSI is very heat-stable. Among the various reactions of PSII, the oxygen-evolving process is particularly sensitive to heat. Releasing Mn2 from the PSII particles results in heat inactivation of oxygen evolution, whether the properties of chloroplast membrane lipids are related to the thermo-resistant ability is un-clear. Some data suggested that unknown factors responsible for thermal stability remain in isolated thylakoid membranes. Heat shock proteins (HSPs) may play a role in enhanc-ing the thermal stability of photosynthesis. Antioxidant and enzymes that scavenge oxygen radicals are bound to chloroplast. Studies have demonstrated as yet that the thermo-resis-tant cultivars differ from the thermo-sensitive culsitivars in contents of active oxygen and in ability to scavenge oxygen radicals.