Pociecha E, Rapacz M, Dziurka M, Kolasińska I
Department of Plant Physiology, University of Agriculture in Krakow, Podłużna 3, 30-239 Kraków, Poland.
Department of Plant Physiology, University of Agriculture in Krakow, Podłużna 3, 30-239 Kraków, Poland.
Plant Physiol Biochem. 2016 Jul;104:45-53. doi: 10.1016/j.plaphy.2016.03.016. Epub 2016 Mar 12.
In terms of climate changes and global warming, winter hardiness could be determined by unfavorable environmental conditions other than frost. These could include flooding from melting snow and/or rain, coincident with fungal diseases. Therefore, we designed an experiment to identify potential common mechanisms of flooding tolerance and snow mold resistance, involving the regulation of photosynthetic efficiency and carbohydrate metabolism at low temperatures. Snow mold-resistant and susceptible winter rye (Secale cereale) plants were characterized by considerably different patterns of response to flooding. These differences were clearer at low temperature, thus confirming a possible role of the observed changes in snow mold tolerance. The resistant plants were characterized by lower PSII quantum yields at low temperature, combined with much higher energy flux for energy dissipation from the PSII reaction center. During flooding, the level of soluble carbohydrates increased in the resistant plants and decreased in the susceptible ones. Thus increase in resistant line was connected with a decrease in the energy dissipation rate in PSII/increased photosynthetic activity (energy flux for electron transport), a lower rate of starch degradation and higher rates of sucrose metabolism in leaves. The resistant lines accumulated larger amounts of total soluble carbohydrates in the crowns than in the leaves. Irrespective of flooding treatment, the resistant lines allocated more sugars for cell wall composition, both in the leaves and crowns. Our results clearly indicated that studies on carbohydrate changes at low temperatures or during anoxia should investigate not only the alterations in water-soluble and storage carbohydrates, but also cell wall carbohydrates. The patterns of changes observed after low and high-temperature flooding were different, indicating separate control mechanisms of these responses. These included changes in the photosynthetic apparatus, starch accumulation and cell wall carbohydrate accumulation.
就气候变化和全球变暖而言，冬季耐寒性可能由除霜冻以外的不利环境条件决定。这些条件可能包括融雪和/或降雨引发的洪水，以及同时发生的真菌病害。因此，我们设计了一项实验，以确定耐涝性和抗雪腐病的潜在共同机制，该机制涉及低温下光合效率和碳水化合物代谢的调节。抗雪腐病和易感染雪腐病的冬黑麦（Secale cereale）植株对洪水的反应模式有显著差异。这些差异在低温下更为明显，从而证实了观察到的变化在雪腐病耐受性方面可能发挥的作用。抗性植株的特点是在低温下PSII量子产率较低，同时PSII反应中心能量耗散的能量通量要高得多。在遭受洪水期间，抗性植株中可溶性碳水化合物水平增加，而感病植株中则下降。因此，抗性品系中这种增加与PSII中能量耗散率降低/光合活性增加（电子传递的能量通量）、叶片中淀粉降解速率降低以及蔗糖代谢速率提高有关。抗性品系在冠部积累的总可溶性碳水化合物比在叶片中更多。无论是否进行洪水处理，抗性品系在叶片和冠部都将更多的糖分分配用于细胞壁组成。我们的结果清楚地表明，关于低温或缺氧期间碳水化合物变化的研究不仅应调查水溶性和储存性碳水化合物的变化，还应调查细胞壁碳水化合物的变化。低温和高温洪水后观察到的变化模式不同，表明这些反应有各自独立的控制机制。这些机制包括光合机构的变化、淀粉积累和细胞壁碳水化合物积累。
