Australian Rivers Institute & Griffith School of Environment, Griffith University, Nathan, QLD, Australia.
Griffith School of Environment, Griffith University, Nathan, QLD, Australia.
Chemosphere. 2017 Oct;184:969-980. doi: 10.1016/j.chemosphere.2017.06.063. Epub 2017 Jun 17.
Here we link plant source phylogeny to its chemical characteristics and determine parameters useful for predicting DOM phytotoxicity towards algal monocultures. We found that DOM characterised using UV-visible spectroscopic indices and elemental analysis is useful for distinguishing DOM plant sources. Specifically, combined values of absorbance at 440 nm and coefficients for the spectral slope ratio, were used to distinguish between gymnosperm-leached DOM and that from angiosperms. In our bioassays, DOM leached from 4 g leaf L resulted in over 40% inhibition of photosynthetic yield for the cyanobacterium, Cylindrospermopsis raciborskii, for eight of the nine plants tested. Significant variables for predicting inhibition of yield were DOM exposure time and plant source, or using an alternate model, exposure time and spectroscopic and elemental measures. Our study proposes spectroscopic indices which can estimate a plant source's contribution to aquatic DOM, may provide insights into ecological outcomes, such as phytotoxicity to algae. The cyanobacterium (C. raciborskii) was more sensitive to DOM than a green algae (Monoraphidium spp.), as identified in a subsequent dose-response experiment with five different DOM plant sources. Low level additions of angiosperm derived-DOM (i.e. 0.5 g L) were slight phytotoxic to Monoraphidium spp. causing 30% inhibition of yield, while C. raciborskii was not affected. Higher DOM additions (i.e. 2 g L) caused 100% inhibition of yield for C. raciborskii, while Monoraphidium spp. inhibition remained under 30%. The divergence in algal sensitivity to DOM indicates that in aquatic systems, DOM derived from catchment vegetation has the potential to affect algal assemblages.
在这里，我们将植物源系统发育与化学特征联系起来，并确定了用于预测 DOM 对藻类纯培养物植物毒性的有用参数。我们发现，使用紫外可见光谱指数和元素分析对 DOM 进行特征描述有助于区分 DOM 的植物来源。具体来说，440nm 处的吸光度与光谱斜率比系数的组合值可用于区分裸子植物淋溶的 DOM 和被子植物来源的 DOM。在我们的生物测定中，从 4g 叶片淋滤出的 DOM 导致 9 种测试植物中的 8 种，对蓝藻 Cylindrospermopsis raciborskii 的光合作用产量抑制超过 40%。预测产量抑制的显著变量是 DOM 暴露时间和植物源，或者使用替代模型，即暴露时间和光谱及元素测量。我们的研究提出了可以估计植物源对水生 DOM 贡献的光谱指数，可能为生态结果（如藻类毒性）提供深入了解。在随后的五个不同 DOM 植物源的剂量反应实验中，与绿藻（Monoraphidium spp.）相比，蓝藻（C. raciborskii）对 DOM 更敏感。低水平添加被子植物衍生的 DOM（即 0.5g/L）对 Monoraphidium spp. 略有植物毒性，导致产量抑制 30%，而 C. raciborskii 不受影响。较高的 DOM 添加量（即 2g/L）导致 C. raciborskii 的产量抑制率达到 100%，而 Monoraphidium spp. 的抑制率仍低于 30%。藻类对 DOM 的敏感性差异表明，在水生系统中，集水区植被产生的 DOM 有可能影响藻类组合。
