Online investigation of respiratory quotients in Pinus sylvestris and Picea abies during drought and shading by means of cavity-enhanced Raman multi-gas spectrometry

Abstract

Photosynthesis and respiration are major components of the plant carbon balance. During stress, like drought, carbohydrate supply from photosynthesis is reduced and the Krebs cycle respiration must be fueled with other stored carbon compounds. However, the dynamics of storage use are still unknown. The respiratory quotient (RQ, CO2 released per O2 consumed during respiration) is an excellent indicator of the nature of the respiration substrate. In plant science, however, online RQ measurements have been challenging or even impossible so far due to very small gas exchange fluxes during respiration. Here we apply cavity-enhanced multi-gas Raman spectrometry (CERS) for online in situ RQ measurements in drought-tolerant pine (Pinus sylvestris [L.]) and drought-intolerant spruce (Picea abies [L. H. Karst]). Two different treatments, drought and shading, were applied to reduce photosynthesis and force dependency on stored substrates. Changes in respiration rates and RQ values were continuously monitored over periods of several days with low levels of variance. The results show that both species switched from COH-dominated respiration (RQ = 1.0) to a mixture of substrates during shading (RQ = 0.77-0.81), while during drought only pine did so (RQ = 0.75). The gas phase measurements were complemented by concentration measurements of non-structural carbohydrates and lipids. These first results suggest a physiological explanation for greater drought tolerance in pine. CERS was proven as powerful technique for non-consumptive and precise real-time monitoring of respiration rates and respirational quotients for the investigation of plant metabolism under drought stress conditions that are predicted to increase with future climate change.

Leaf Transcriptome Analysis of Medicago Ruthenica, Revealing Its Response and Adaptive Strategy to Drought Stress and Rehydration

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“…1). The percentage of unigenes with length of 200-500 bp, 500-1k bp, 1k-2k bp and longer than 2k bp in total unigenes were 34.63%(106,812), 32.91%(101,494), 23.98% (73,961) and 8.49% (26,182), respectively.…”

Understanding the roles of nonstructural carbohydrates in forest trees – from what we can measure to what we want to know

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Highly Sensitive Detection of the Antibiotic Ciprofloxacin by Means of Fiber Enhanced Raman Spectroscopy

“…Raman spectroscopy is an arising technique [15][16][17][18][19][20][21][22][23], which is based on the vibrations of molecules [24][25][26][27][28] and provides high chemical selectivity [29][30][31][32]. This direct method is non-destructive and can be applied for quantitative measurements [33][34][35][36][37].…”