Department of Biology, University of North Florida, Jacksonville, FL 32224, USA.
Plant Physiol Biochem. 2011 Sep;49(9):1051-8. doi: 10.1016/j.plaphy.2011.06.006. Epub 2011 Jun 25.
Seagrass meadows are a vital component of coastal ecosystems and have experienced declines in abundance due to a series of environmental stressors including elevated salinity and incidence of disease. This study evaluated the impacts of short-term hypersalinity stress on the early stages of infection in Thalassia testudinum Banks ex König by assessing changes in cellular physiology and metabolism. Seagrass short shoots were exposed to ambient (30 psu) and elevated (45 psu) salinities for 7 days and subsequently infected for one week by the causative pathogen of wasting disease, Labyrinthula sp. The occurrence of wasting disease was significantly lower in the hypersalinity treatments. Additionally, while exposure to elevated salinity caused a reduction in chlorophyll a and b content, T. testudinum's health, in terms of photochemical efficiency, was not significantly compromised by hypersalinity or infection. In contrast, plant respiratory demand was significantly enhanced as a function of infection. Elevated salinity caused T. testudinum to significantly increase its in vivo H(2)O(2) concentrations to levels that exceeded those which inhibited Labyrinthula growth in a liquid in vitro assay. The results suggest that while short-term exposure to hypersalinity alters selected cellular processes this does not necessarily lead to an immediate increase in wasting disease susceptibility.
海草草地是沿海生态系统的重要组成部分，但由于一系列环境胁迫因素的影响，包括盐度升高和疾病的发生，其丰度有所下降。本研究通过评估细胞生理和代谢的变化，评估了短期高盐度胁迫对塔希利亚测试丁um 银行克斯国王感染早期阶段的影响。将海草草短枝在环境（30 psu）和升高（45 psu）盐度下暴露 7 天，然后用导致消瘦病的病原体 Labyrinthula sp. 感染一周。在高盐度处理中，消瘦病的发生明显较低。此外，尽管暴露于高盐度会导致叶绿素 a 和 b 含量减少，但 T. testudinum 的健康状况（就光化学效率而言）并未因高盐度或感染而受到显著损害。相比之下，感染会显著增加植物的呼吸需求。高盐度导致 T. testudinum 的体内 H(2)O(2)浓度显著增加，超过了在体外液体测定中抑制 Labyrinthula 生长的浓度。研究结果表明，虽然短期暴露于高盐度会改变某些细胞过程，但这并不一定会导致消瘦病易感性的立即增加。
