Soto Adriana, Hernández Laura, Quiles María José
Departamento de Biología Vegetal, Facultad de Biología, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain.
Departamento de Biología Vegetal, Facultad de Biología, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain.
Plant Sci. 2014 Oct;227:84-9. doi: 10.1016/j.plantsci.2014.07.004. Epub 2014 Jul 11.
Spathiphyllum wallisii plants were sensitive to temperature stress under high illumination, although the susceptibility of leaves to stress may be modified by root temperature. Leaves showed higher tolerance to high illumination, in both cold and heat conditions, when the roots were cooled, probably because the chloroplast were protected by excess excitation energy dissipation mechanisms such as cyclic electron transport. When the roots were cooled both the activity of electron donation by NADPH and ferredoxin to plastoquinone and the amount of PGR5 polypeptide, an essential component of cyclic electron flow around PSI, increased. However, when the stems were heated or cooled under high illumination, but the roots were heated, the quantum yield of PSII decreased considerably and neither the electron donation activity by NADPH and ferredoxin to plastoquinone nor the amount of PGR5 polypeptide increased. In such conditions, the cyclic electron flow cannot be enhanced by high light and PSII is damaged as a result of insufficient dissipation of excess light energy. Additionally, the damage to PSII induced the increase in both chlororespiratory enzymes, NDH complex and PTOX.
在高光照条件下，白鹤芋植株对温度胁迫敏感，尽管叶片对胁迫的敏感性可能会因根温而改变。当根部冷却时，叶片在寒冷和炎热条件下对高光照均表现出更高的耐受性，这可能是因为叶绿体受到了诸如循环电子传递等过剩激发能耗散机制的保护。当根部冷却时，NADPH和铁氧还蛋白向质体醌的电子供体活性以及PSI周围循环电子流的必需成分PGR5多肽的量均增加。然而，当在高光照下加热或冷却茎部，但加热根部时，PSII的量子产率会大幅下降，NADPH和铁氧还蛋白向质体醌的电子供体活性以及PGR5多肽的量均不会增加。在这种条件下，高光无法增强循环电子流，并且由于过剩光能的耗散不足，PSII会受到损伤。此外，PSII的损伤导致了两种氯呼吸酶（NDH复合体和PTOX）的增加。
