入侵植物互花米草(Spartina alterniflora)叶绿素荧光对淹水胁迫的响应

在上海崇明东滩国家级鸟类自然保护区生态修复示范样地中,开展了持续淹水技术治理入侵植物互花米草的物理控制实验.同时,应用叶绿素荧光技术,分别研究了连续2年持续水淹和淹水1年后排水恢复自然生境条件下,外来入侵植物互花米草叶绿素荧光动力学参数及叶绿素含量的动态变化.结果表明,第1年持续淹水降低了互花米草体内的叶绿素含量和PSⅡ最大光化学效率(Fv/Fm)、PSⅡ的潜在活性(Fv/Fo)、光合电子传递速率(ETR)和光化学猝灭(qP)等叶绿素荧光动力参数值,抑制了互花米草的光合作用.随着淹水时间的延长,到第2年生长季节时互花米草已可以通过调节热耗散或其他生理生态指标来适应淹水环境,满足其生长繁殖的需要.一旦解除淹水胁迫,互花米草的光合活性可迅速恢复,甚至超过对照,表现出很强的恢复能力.持续淹水胁迫仅能在初期抑制互花米草的光合作用,随着淹水时间的延长,互花米草可以通过调节其他生理指标来适应淹水环境,保障光合作用的正常进行.

Responses of chlorophyll fluorescence of an invasive plant Spartina alterniflora to continuous waterlogging

Aphysical control measure of continuous waterlogging was conducted to investigate an invasive plant Spartina alterniflora at a demonstration site of the Chongming Dongtan nature reserve. In this study,the responses of Spartina alterniflora in terms of the parameters of chlorophyll fluorescence and chlorophyll content to continuous waterlogging for two years and to restoring after continuous waterlogging for one year were investigated. The results showed that in the first year of waterlogging,the chlorophyll contents and the parameters of Fv/Fm,Fv/Fo,ETRand qPof S. alterniflora reduced considerably and its photosynthesis could be inhibited. But during the second year of waterlogging,S. alterniflora could adapt to the waterlogging conditions by adjusting heat dissipation and other physiological parameters to meet its growth and reproduction requirements. Once S. alterniflora was released from the waterlogging stress,the photosynthetic activity could recover quickly and even exceed the control,showing over-compensation. Continuous waterlogging stress could inhibit the growth and reproduction of S. alterniflora,but this invasive plant could effectively adapt to the stress by adjusting its physiological parameters to meet the requirements of photosynthesis.