PDF(Pubmed)
Abstract：
The hydrogen isotopic composition (δ2H) of plant compounds is increasingly used as a hydroclimatic proxy; however, the interpretation of δ2H values is hampered by potential coeffecting biochemical and biophysical processes. Here, we studied δ2H values of water and carbohydrates in leaves and roots, and of leaf n-alkanes, in two distinct tobacco (Nicotiana sylvestris) experiments. Large differences in plant performance and biochemistry resulted from (a) soil fertilization with varying nitrogen (N) species ratios and (b) knockout-induced starch deficiency. We observed a strong 2H-enrichment in sugars and starch with a decreasing performance induced by increasing NO3-/NH4+ ratios and starch deficiency, as well as from leaves to roots. However, δ2H values of cellulose and n-alkanes were less affected. We show that relative concentrations of sugars and starch, interlinked with leaf gas exchange, shape δ2H values of carbohydrates. We thus provide insights into drivers of hydrogen isotopic composition of plant compounds and into the mechanistic modeling of plant cellulose δ2H values.
摘要：
植物化合物的氢同位素组成（δ2H）越来越多地用作水文气候代表；但是，对δ2H值的解释受到潜在的生化和生物物理过程共同作用的阻碍。这里,我们研究了叶片和根部的水和碳水化合物的δ2H值，和叶正烷烃，在两个不同的烟草（Nicotianasylvestris）实验中。植物性能和生物化学的巨大差异是由于（a）不同氮（N）物种比例的土壤施肥和（b）敲除诱导的淀粉缺乏。我们观察到糖和淀粉中强烈的2H富集，由于NO3-/NH4比例增加和淀粉缺乏而导致性能下降。从叶子到根。然而,纤维素和正构烷烃的δ2H值受影响较小。我们发现糖和淀粉的相对浓度，与叶气交换相连，形状δ2H值的碳水化合物。因此，我们提供了有关植物化合物的氢同位素组成的驱动因素以及植物纤维素δ2H值的机理建模的见解。
