Effects of nitrogen source and water availability on stem carbohydrates and cellulosic bioethanol traits of alfalfa plants

Abstract

Symbiotic association of legumes with rhizobia frequently results in higher photosynthesis and soluble carbohydrates in comparison with nitrate-fed plants, which might improve its potential for biomass conversion into bioethanol. A greenhouse experiment was conducted to examine the effects of nitrogen source and water availability on stem characteristics and on relationships between carbohydrates, phenolic metabolism activity and cell wall composition in alfalfa (Medicago sativa L. cv. Aragón). The experiment included three treatments: (1) plants fed with ammonium nitrate (AN); (2) plants inoculated with rhizobia (R); and (3) plants inoculated with rhizobia and amended with sewage sludge (RS). Two levels of irrigation were imposed: (1) well-watered and (2) drought stress. Under well-watered conditions, nitrogen-fixing plants have increased photosynthesis and stem fermentable carbohydrate concentrations, which result in higher potential for biomass conversion to bioethanol than in AN plants. The latter had higher lignin due to enhanced activities of phenolic metabolism-related enzymes. Under drought conditions, the potential for bioethanol conversion decreased to a similar level in all treatments. Drought-stressed nitrogen-fixing plants have high concentrations of fermentable carbohydrates and cell wall cellulose, but ammonium nitrate-fed plants produced higher plant and stem biomass, which might compensate the decreasing stem carbohydrates and cellulose concentrations.

Coffee response to nitrogen and soil water content during the early growth stage

“…Fiasconaro et al. () state that forage (leaf and stem) quality in alfalfa was higher in water‐stressed plants compared to non‐stressed plants. Cellulose concentration decreased whereas hemicellulose increased in both leaves and stems under drier conditions due to a delay in plant maturity, an increase in the leaf to stem weight ratio, and a reduction in fiber concentration.…”

Genes and gene clusters related to genotype and drought-induced variation in saccharification potential, lignin content and wood anatomical traits in Populus nigra†

“…The saccharification potential of wood is also affected by environmental conditions such as drought ( Fiasconaro et al 2012 , van der Weijde et al 2016 ). Drought brings about changes in cell wall composition including an increased abundance of hemicellulose, pectins and lignin, which results in strengthening of the cell wall ( Moore et al 2008 , Le Gall et al 2015 ).…”

“…Drought brings about changes in cell wall composition including an increased abundance of hemicellulose, pectins and lignin, which results in strengthening of the cell wall ( Moore et al 2008 , Le Gall et al 2015 ). Fiasconaro et al (2012) reported that the potential for biofuel conversion in drought-treated alfalfa plants decreased due to a higher lignin content compared with the well-watered plants. On the other hand, in a study comprising 50 different Miscanthus genotypes, drought treatment caused a reduction of cell wall cellulose content and an increase in cell wall hemicellulose content, but nevertheless resulted in a higher efficiency of the conversion of cellulose to glucose during saccharification ( van der Weijde et al 2016 ).…”

Aislamiento, caracterización molecular y evaluación de cepas fijadoras de nitrógeno en la promoción del crecimiento de frijol

“…Los cambios fisiológicos y bioquímicos observados en plantas de frijol inoculadas con el aislado de Ramlibacter sp., podría explicarse también a través del número de nódulos formados en las plantas inoculadas con esta bacteria, ya que estas plantas presentaron 2 y 4 veces mas formación de nódulos con respecto a Sinorhizobium sp., y sinorhizobium fredii respectivamente, lo cual favorece la fijación de nitrógeno atmosférico y por ende el incremento en el área radicular y vegetativa (Yadegari et al, 2008;Fiasconaro et al, 2012).…”

“…Physiological and biochemical changes observed in bean plants inoculated with isolate Ramlibacter sp., could be explained through the number of nodules formed in plants inoculated with the bacteria, since these plants had 2 to 4 more times nodule formation regarding Sinorhizobium sp., and sinorhizobium fredii respectively, which favors atmospheric nitrogen-fixation and therefore an increase in root and vegetative area (Yadegari et al, 2008;Fiasconaro et al, 2012).…”