Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, New Zealand.
Plant Biol (Stuttg). 2011 Nov;13(6):896-901. doi: 10.1111/j.1438-8677.2011.00458.x. Epub 2011 Mar 14.
This study used nine populations of Trifolium repens L. (white clover) to investigate possible relationships between plant morphological attributes and responses to ultraviolet-B (UV-B) radiation. Plants were exposed to 0 or 13.3 kJ·m(-2) ·day(-1) UV-B for 12 weeks. Drought was applied in parallel to these treatments during the last 4 weeks of the experiment to test whether limited moisture availability would alter morphological UV-B responses. UV-B affected plant morphology under well-watered conditions, reducing leaf size by 15%, leaf number by 5% and stolon elongation by 19%. The number of leaf primordia in the apical bud was decreased by 4% under UV-B, and by 12% under drought. In drought-exposed plants, leaf size was reduced by 50%, leaf number by 30% and stolon elongation by 60%. In addition, drought reduced specific leaf area (SLA) by 33% and increased leaf percentage dry mass (PDM) by 40%. UV-B-induced reduction in plant biomass in the T. repens populations was associated with higher plant productivity and this was further linked to larger leaf size as well as to lower PDM. In conclusion, the findings suggest that morphological attributes conferring fast potential growth under productive conditions carry a cost in the form of lower biomass accumulation under UV-B.
本研究利用九种群的白车轴草（Trifolium repens L.）来探究植物形态特征与其对紫外线-B（UV-B）辐射响应之间的可能关系。植物接受 0 或 13.3 kJ·m(-2) ·day(-1) 的 UV-B 辐射，共 12 周。在实验的最后 4 周，平行于这些处理进行干旱处理，以检验水分有限是否会改变形态对 UV-B 的响应。在水分充足的条件下，UV-B 会影响植物形态，使叶片大小减小 15%，叶片数量减少 5%，匍匐茎伸长减少 19%。UV-B 使顶芽叶原基数量减少 4%，干旱使叶原基数量减少 12%。在干旱处理的植物中，叶片大小减小 50%，叶片数量减少 30%，匍匐茎伸长减少 60%。此外，干旱使比叶面积（SLA）减少 33%，叶片干重百分比（PDM）增加 40%。在白车轴草种群中，UV-B 诱导的植物生物量减少与更高的植物生产力有关，这与更大的叶片大小以及更低的 PDM 有关。总之，研究结果表明，在高生产力条件下赋予快速潜在生长能力的形态特征在 UV-B 下会导致生物量积累减少。
