Drought affects the fate of non-structural carbohydrates in hinoki cypress
Drought affects the fate of non-structural carbohydrates in hinoki cypress
复制标题
干旱影响扁柏中非结构碳水化合物的命运
DOI：
10.1093/treephys/tpab135
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发表时间：
2021
期刊：
影响因子：
4
通讯作者：
Epron Daniel
中科院分区：
文献类型：
--
作者：
Tsuji Chiaki;Dannoura Masako;Desalme Dorine;Angeli Nicolas;Takanashi Satoru;Kominami Yuji;Epron Daniel
在干旱条件下提早关闭气孔的树种可能会因光合作用减少和代谢需求减少而导致有限的碳水化合物供应失衡。我们的目的是澄清非结构性碳水化合物的动态响应干旱的节水物种，扁柏（Chamaparis obtusaSieb。et Zucc.）。为此，我们用13CO210天后的干旱处理开始脉冲标记的幼树。树木收获7天后，在干旱进展的早期，86天后，当他们遭受了长期和严重的干旱。标记碳（C）在韧皮部提取物、所有器官的有机质和淀粉以及代谢最活跃的器官（叶、绿色枝和细根）的可溶性糖（蔗糖、葡萄糖和果糖）中被追踪。没有干旱相关的变化，地下和地上器官之间的标记C分配观察。非结构性碳水化合物之间的C分配在干旱进展的早期改变：淀粉浓度降低一半的光合器官，而几乎所有的可溶性糖的浓度往往增加。标记C的优先分配葡萄糖和果糖反映了增加的需求，可溶性糖渗透调节。经过3个月的致命干旱，可溶性糖和淀粉的浓度在干旱胁迫的树木比对照低，但非结构性碳水化合物的池是远远没有完全耗尽。然而，分配到存储已受损的干旱，光合作用和糖转运率也减少了干旱。未能维持细胞膨压通过光合调节和重新填充栓塞木质部由于可溶性糖的消耗在根中可能导致树死亡扁柏，虽然总池的碳水化合物并没有完全耗尽。
Tree species that close stomata early in response to drought are likely to suffer from an imbalance between limited carbohydrate supply due to reduced photosynthesis and metabolic demand. Our objective was to clarify the dynamic responses of non-structural carbohydrates to drought in a water-saving species, the hinoki cypress (Chamaecyparis obtusaSieb. et Zucc.). To this end, we pulse-labeled young trees with13CO210 days after the beginning of the drought treatment. Trees were harvested 7 days later, early during drought progression, and 86 days later when they had suffered from a long and severe drought. The labeled carbon (C) was traced in phloem extract, in the organic matter and starch of all the organs, and in the soluble sugars (sucrose, glucose and fructose) of the most metabolically active organs (foliage, green branches and fine roots). No drought-related changes in labeled C partitioning between belowground and aboveground organs were observed. The C allocation between non-structural carbohydrates was altered early during drought progression: starch concentration was lower by half in the photosynthetic organs, while the concentration of almost all soluble sugars tended to increase. The preferential allocation of labeled C to glucose and fructose reflected an increased demand for soluble sugars for osmotic adjustment. After 3 months of a lethal drought, the concentrations of soluble sugars and starch were admittedly lower in drought-stressed trees than in the controls, but the pool of non-structural carbohydrates was far from completely depleted. However, the allocation to storage had been impaired by drought; photosynthesis and the sugar translocation rate had also been reduced by drought. Failure to maintain cell turgor through osmoregulation and to refill embolized xylem due to the depletion in soluble sugars in the roots could have resulted in tree mortality in hinoki cypress, though the total pool of carbohydrate was not completely depleted.