Hock Maria, Plos Carolin, Sporbert Maria, Erfmeier Alexandra
Kiel University, Institute for Ecosystem Research / Geobotany, Olshausenstr. 75, 24118 Kiel, Germany.
Martin Luther University Halle-Wittenberg, Institute of Biology / Geobotany and Botanical Garden, Am Kirchtor 1, 06108 Halle, Germany.
Plants (Basel). 2020 Feb 18;9(2):269. doi: 10.3390/plants9020269.
During plant invasions, exotic species have to face new environmental challenges and are affected by interacting components of global change, which may include more stressful environmental conditions. We investigated an invasive species of New Zealand grasslands, commonly exposed to two concomitant and limiting abiotic factors-high levels of ultraviolet-B radiation and drought. The extent to which may respond to these interacting stress factors via adaptive responses was assessed in a greenhouse experiment comprising native German plants and plants of exotic New Zealand origins. Plants from both origins were grown within four treatments resulting from the crossed combinations of two levels of UV-B and drought. Over twelve weeks, we recorded growth, morphological characteristics, physiological responses and productivity. The results showed that drought stress had the strongest effect on biomass, morphology and physiology. Significant effects of UV-B radiation were restricted to variables of leaf morphology and physiology. We found neither evidence for additive effects of UV-B and drought nor origin-dependent stress responses that would indicate local adaptation of native or exotic populations. We conclude that drought-resistant plant species might be predisposed to handle high UV-B levels, but emphasize the importance of setting comparable magnitudes in stress levels when testing experimentally for antagonistic interaction effects between two manipulated factors.
在植物入侵过程中，外来物种必须面对新的环境挑战，并受到全球变化相互作用因素的影响，其中可能包括压力更大的环境条件。我们研究了新西兰草原的一种入侵物种，该物种通常会受到两种同时存在且具有限制作用的非生物因素——高水平的紫外线B辐射和干旱——的影响。在一项温室实验中，我们评估了该物种通过适应性反应对这些相互作用的胁迫因素作出反应的程度，实验中包括德国本土植物和新西兰外来植物。两种来源的植物在紫外线B和干旱两个水平的交叉组合产生的四种处理条件下生长。在十二周的时间里，我们记录了植物的生长、形态特征、生理反应和生产力。结果表明，干旱胁迫对生物量、形态和生理的影响最大。紫外线B辐射的显著影响仅限于叶片形态和生理变量。我们既没有发现紫外线B和干旱的叠加效应的证据，也没有发现表明本地或外来种群局部适应的起源依赖性胁迫反应的证据。我们得出结论，抗旱植物物种可能易于应对高水平的紫外线B，但强调在通过实验测试两个控制因素之间的拮抗相互作用效应时，设定可比胁迫水平幅度的重要性。
