盐度和水淹对海三棱藨草种子萌发及幼苗生长的影响

Effects of salinity and duration of submergence on seed germination and seedling growth of Scirpus mariqueter

研究海三棱藨草(Scirpus mariqueter)种子和幼苗在盐度和水淹时长作用下的生存机制,为长江口滨海湿地生态修复提供重要的科学依据。通过模拟潮汐控制不同水淹时长(8、10、12、14 h/d)和盐度(0、5、10、15)进行实验,分析其对发芽率、发芽指数、叶绿素、超氧化物歧化酶(SOD)和丙二醛(MDA)等生长生理指标的影响。结果表明:盐度对海三棱藨草种子发芽率、发芽指数和海三棱藨草幼苗MDA影响最大;盐度和水淹时长的交互作用对海三棱藨草幼苗叶绿素和SOD影响最大。在盐度为0、水淹时长为12 h/d时发芽率最高;盐度15是海三棱藨草种子萌发的临界盐度;盐度为10、水淹时长12 h/d分株数最高;叶绿素在0盐度和12 h水淹时长交互处理下最高;SOD总活性在盐度为10、8 h/d水淹时长处理下最高;盐度为10、12 h/d水淹时长处理下MDA含量最低。这说明海三棱藨草在中等盐度(5、10)和中等水淹时长(10、12 h/d)时适应性最强。

The survival mechanisms of seeds and seedlings of Scirpus mariqueter under the effect of salinity and flooding time were studied to provide an important scientific basis to the ecological restoration of coastal wetlands in the Yangtze Estuary. Different flooding time(8 h/d, h/d 10, 12 h/d, 14 h/d) and salinity(0,5,10,15) were controlled through the simulation of tidal, then the impact of physiological indexes, such as germination rate, germination index, chlorophyll, superoxide dismutase(SOD) and malondialdehyde(MDA) were analyzed. Among them, salinity had the greatest influence on germination rate, germination index and MDA of seedling. Chlorophyll and SOD were mostly influenced in the interaction between salinity and submergence. The results showed that the germination rate reached to the highest when the salinity at 0, and the flooding time at 8 h/d. The critical salinity of the seed germination was 15‰, and the number of turns was the highest at 10‰ and 12 h/d. Chlorophyll was the highest under the interactive treatment of salinity at 0‰ and flooding time of 12 h. What’s more, the total activity of SOD was the highest at 10‰ of salinity and 8 h/d of flooding time, and MDA was the lowest at 10‰ and 12 h/d. The results showed that the Scirpus mariqueter was most adaptable to moderate salinity(5, 10) and moderate flooding time(10 h/d, 12 h/d).