Plant cells, tissues and organs are composed of various biomolecules arranged as structurally diverse units, which represent heterogeneity at microscopic levels. Molecular knowledge about those constituents with their localization in such complexity is very crucial for both basic and applied plant sciences. In this context, infrared imaging techniques have advantages over conventional methods to investigate heterogeneous plant structures in providing quantitative and qualitative analyses with spatial distribution of the components. Thus, particularly, with the use of proper analytical approaches and sampling methods, these technologies offer significant information for the studies on plant classification, physiology, ecology, genetics, pathology and other related disciplines. This review aims to present a general perspective about near-infrared and mid-infrared imaging/microspectroscopy in plant research. It is addressed to compare potentialities of these methodologies with their advantages and limitations. With regard to the organization of the document, the first section will introduce the respective underlying principles followed by instrumentation, sampling techniques, sample preparations, measurement, and an overview of spectral pre-processing and multivariate analysis. The last section will review selected applications in the literature.

Background/Objectives The lipid solubility of antiepileptic drugs directly affects central nervous system availability. In relation to this, the interactions of gabapentin and levetiracetam with dipalmitoylphosphatidylcholine lipids depending on concentrations were comparatively investigated in the present study. Methods The effects of gabapentin and levetricetam as a function of concentration (1–5–10–20 mol%) on biophysical parameters of dipalmitoylphosphatidylcholine multilammelar vesicles were studied by differential scanning calorimetry and fourier transform infrared spectroscopy. Results The data revealed that gabapentin at all concentrations and levetiracetam at 1–5 mol% lowered main transition temperature, enthalpy, cooperativity, lipid fluidity, lipid order, and increased hydrogen binding capacity of glycerol and phosphate groups. However, 10–20 mol% of levetiracetam tend to show different effect on transition temperature, which could also reflect its opposing effect on lipid order and glycerol and phosphate group’s hydrations. Conclusions According to the corresponding findings depending on concentrations both drugs incorporate into phosphatidylcholines, perturbing the packing of lipids and affecting their thermotropic properties. Their binding affinity to acyl chains and hydrophilic parts of lipids was found to highly correlate with lipid-water partition and their solubility degree in water. Hence, the obtained results may offer evaluation of partition profile of the drugs into biological membranes depending on concentration.

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BACKGROUND Glucomannan (GM) is a polysaccharide of the mannan family of compounds found in some plant species. The dried and powdered tubers of some orchid species, collectively known as ‘salep powder,’ are a commercially important crop for human consumption and are one of the primary sources of GM. GM content is the primary indicator for the yield and quality of salep powder. We hypothesized that it would be more practical and accurate to measure GM content within tuber powder directly, prior to any purification or pre‐processing. The GM content of tubers of 14 different orchid species was evaluated and compared using Fourier transform infrared (FTIR) spectroscopy and an enzymatic colorimetric method. RESULTS Among the analyzed modes, the sum of the peak areas at 873 and 812 cm−1, which represent the CH bending attributed to the β‐pyranose form of d‐glucose and d‐mannose, respectively, gave the only confirmation using colorimetric methods. It was found that the tubers of Himantoglossum caprinum and Serapias vomeracea had the highest GM concentrations among the analyzed species. After conducting different pre‐processing steps on Serapias vomeracea tubers, it was found that treating the tubers with milk, or high temperature resulted in an apparent increase in GM concentrations. CONCLUSION Himantoglossum caprinum and Serapias vomeracea give the highest yields of GM and should be used for commercial horticulture. GM estimation should be made prior to any pre‐processing. FTIR spectroscopy is effective and reliable for directly comparing GM content of different orchid species, without the need for any purification or pre‐processing. © 2019 Society of Chemical Industry

Amsonia orientalis Decne. (syn. Rhazya orientalis (Decne.) A. DC.) is only cultivated as an ornamental plant but also has a medicinal merit. The natural populations of the species were taken under conservation as per the Bern Convention by European Council. As one of the most common plant growth regulators and synthetic agricultural fertilizers, the effects of 6-benzylaminopurine (BAP) at different concentrations on primary metabolites of in vitro propagated A. orientalis have been investigated by using Fourier transform infrared (FT-IR) spectroscopy. Among all applied concentrations, 2.0 mg l -1 BAP resulted in increment of hydrogen bonded polysaccharide and proteins concentrations, lipid structure and membrane fluidity. Treatments of 2.0 and 4.0 mg l -1 BAP increased the existence of ferulic acid which also indicates the linkage of xylan and both cellulose and hemicellulose content. There was a significant decrease in the area of the peak which indicated the C=O stretching of proteins and pectins for 0.5 and 1.0 mg l -1 BAP while there was a significant increase for 2.0 and 4.0 mg l -1 of BAP treatments. The evaluation of molecular data from FT-IR spectroscopy as in the current study might help to estimate different physiological changes at the molecular level in plants depending on plant growth regulator and/or fertilizer applications. Thus, this FT-IR based method can be applied to in vitro propagation studies and also to studies focused on effects of pesticide and/or herbicide applications on plants to understand the metabolic changes in target species.