The chemical composition of 1052 samples covering 49 plant species is summarized in this paper. The analyzed biomasses offer a wide range of chemical compositions, monosaccharidic compositions of hemicelluloses, enzymatically digestible organic matter, and bioethanol potential. Nevertheless, their thermal energy value remains in a narrow range on a dry matter basis. Biomasses that were identified as best suited for anaerobic digestion are characterized by low contents of cellulose, hemicelluloses, and lignin and high contents of non-structural constituents. Biomasses most suited for combustion present the lowest content of mineral compounds, and the most adequate biomasses for bioethanol conversion have high contents of total carbohydrates. Interestingly, the observed chemical compositions tend to cluster the biomasses in composition groups that also correspond to phylogenetic groups: commelinids, non-commelinid magnoliophyta, and pinophyta species. Some groups can clearly be subdivided into fibrous and moderately fibrous biomasses.

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Potato tubers (Solanum tuberosum L. cv Bintje and Désirée) were stored for 12 months under three different storage conditions: 4 °C, 20 °C with sprout inhibitor and 20 °C without sprout inhibitor. Independent of the storage conditions, our results show that the increase of membrane permeability, as revealed by electrolyte leakage, is not correlated with the lipid saturation status. Moreover, there is no simple correlation between cold sweetening and membrane permeability or lipid saturation status. During storage at 20 °C without sprout inhibitor, the increase in membrane permeability is inversely correlated to sucrose accumulation, but this is not the case when tubers were stored with sprout inhibitors. Lipoxygenase (LOX) is often proposed as responsible for peroxidative damage to membrane lipids. The gradual peroxidation resulting in double bond index decrease is regarded as a cause of senescence sweetening. Our results revealed that the role of LOX in aging and senescence of potato tubers is far from clear. LOX activity and gene expression are not correlated with the fatty acids composition of the membrane. Moreover, LOX activity and fatty acid hydroperoxide content are low in older tubers, whatever the storage conditions or the varieties. On the basis of our results, the correlation between sugar accumulation (low temperature and senescence sweetening) and peroxidative damage occurring during storage of potato tubers is discussed.

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