Key message

Two months of drought or waterlogging conditions did not induce carbon starvation in Castanea sativa. Carbohydrate dynamics in treated plants provide evidence of why this species adapts well to dry but not to waterlogging conditions.

Abstract

Drought and flooding events, which cause water and oxygen deprivation in tree roots, are expected to occur more frequently due to climate change. The effects of drought and waterlogging on physiology, growth and N content of Castanea sativa Mill. were explored. Through a manipulative experiment, we induced growth-limiting conditions in C. sativa seedlings to identify differences in the dynamics of soluble sugars, starch and total non-structural carbohydrates (NSC) in leaves, stems and roots. Two-year-old seedlings were subjected for 2 months to regular watering, drought and waterlogging treatments. Drought and waterlogging induced similar effects on plants, including reduced stomatal conductance, net photosynthesis and growth. However, chlorophyll degradation was detected only in plants subjected to waterlogging. N content and C/N ratios differed between treatments and were highest in leaves of drought stressed plants and roots of control plants, respectively. Under drought, starch was rapidly depleted to yield soluble sugars and afterwards remained constant, and no change in total NSC was observed, probably allowing plants to reverse drought-induced xylem embolisms. Under waterlogging, a net gain of NSC over time in plant stems and roots was observed, suggesting that plants were unable to utilise them. This is the first study to report different strategies of carbon use in C. sativa trees subjected to drought and waterlogging. NSC dynamics in C. sativa plants provide evidence of why this species adapts well to dry but not to waterlogging conditions.

中文翻译：

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干旱和涝渍引起的锥栗碳水化合物的变化

关键信息

两个月的干旱或涝渍条件没有引起栗树的碳饥饿。经过处理的植物中的碳水化合物动态提供了该物种为何很好地适应干旱而不适合涝灾条件的证据。

抽象

由于气候变化，导致树根中水和氧气缺乏的干旱和洪水事件预计会更频繁地发生。干旱和涝渍对栗木生理，生长和氮含量的影响。被探索了。通过操纵性实验，我们诱导了苜蓿圆线虫的生长限制条件幼苗，以确定叶，茎和根中可溶性糖，淀粉和总非结构性碳水化合物（NSC）动态的差异。对2岁大的幼苗进行2个月的常规浇水，干旱和涝渍处理。干旱和涝灾对植物产生相似的影响，包括气孔导度降低，净光合作用和生长。但是，仅在遭受涝渍的植物中检测到叶绿素降解。氮素含量和碳氮比在不同处理之间有所不同，分别在干旱胁迫植物的叶子和对照植物的根中最高。在干旱下，淀粉迅速耗尽，产生可溶性糖，此后保持恒定，并且未观察到总NSC的变化，可能使植物逆转了干旱引起的木质部栓塞。在淹水的情况下 随着时间的推移，观察到了植物茎和根中NSC的净增加，表明植物无法利用它们。这是第一个报告不同碳使用策略的研究。苜蓿遭受干旱和涝灾。紫花苜蓿植物中的NSC动态提供了该物种为何很好地适应干旱而不适合涝灾条件的证据。