Effect of D₂O on Growth Properties and Chemical Structure of Annual Ryegrass (Lolium multiflorum)

Abstract

The development of deuterated biomass is essential for effective neutron scattering studies on biomass, which can provide key insights into the complex biomass conversion processes. A method for optimized production of deuterated annual ryegrass (Lolium multiflorum) was developed by growing the plants in 50% D2O in perfused hydroponic chambers. Deuterium incorporation of 36.9% was found in the annual rye grown in 50% D2O. Further, deuterium incorporation of 60% was achieved by germinating the rye seedlings in H2O and growing in 50% D2O inside the perfusion chambers. The characteristics related to enzymatic hydrolysis such as biomass composition, degree of polymerization, and cellulose crystallinity were compared with its control protiated counterpart. The cellulose molecular weight indicated slight variation while hemicellulose molecular weights and cellulose crystallinity remain unaffected with the deuteration.

Ultrastructure and Enzymatic Hydrolysis of Deuterated Switchgrass

“…Approximately 34% deuterium incorporation was calculated from 2 H/ 1 H ratio from 2 H and 1 H NMR spectra of deuterated switchgrass grown in 50% D 2 O medium 4,6 . Switchgrass cultivated by this method exhibited gross morphology and growth rates similar to controls grown in H 2 O 4 , in contrast to the slower growth and dwarfing observed for winter rye 7 , annual rye grass 8 , Arabidopsis 9,10 , and other species 11 . Such deuterated plants for fundamental studies need to be investigated for any possible alterations to physical and chemical characteristics due to stress caused by growth in deuterated media.…”

“…Tillers were cut from the root crowns of the established switchgrass and incubated in plant jars containing sterile Schenk and Hildebrandt’s basal salts in H 2 O until appearance of roots after 5–10 days. The rooted tiller cuttings were transferred to growth chambers assembled from 1 L graduated cylinders fitted with rubber closures with inflow and outflow tubes perfused with dry ambient air using an aquarium pump and in-line desiccant tubes as described previously 8 . After one to eleven months growth, hydroponic plants were transferred to growth medium containing 50% D 2 O for deuteration, while control plants were maintained in H 2 O medium.…”

Supra-Optimal Temperature: An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri

“…Deuterium in deuterated water is known to increase cell stress via several mechanisms [ 43 , 44 ], including greater bond dissociation and activation energies [ 46 ]. Its presence affects the entire metabolism, and its specific effects range from disrupting signaling [ 47 ] and energy production in mitochondria and chloroplasts [ 48 , 49 ] to disrupting cell division [ 50 , 51 ]. Given the very low concentrations of deuterium (or deuterated water) in nature, its application in high concentrations is artificial, and is also quite expensive.…”

Effect of in Vivo Deuteration on Structure of Switchgrass Lignin

“…The structure of lignocellulose plant cell walls contributes to biomass recalcitrance, and it has been characterized by a variety of analytical techniques. − Small-angle neutron scattering (SANS) has been proposed and used for the characterization of lignocellulosic substrates as a nondestructive promising technique due to its unique sensitivity to hydrogen and ability to exchange thermal energies with the materials. , Hydrogen (H) and deuterium (D) interact with neutrons quite differently, and substituting the hydrogen atoms with deuterium greatly enhances the potential of SANS due to the fact that contrast variation significantly depends on the differential scattering power of the D compared to H . Therefore, production of deuterated plant materials is crucial for SANS studies as it makes it possible to separate different biomass components such as cellulose, hemicellulose, and lignin within intact structures by phase contrast variation, enabling simultaneous observation of each component, particularly if one component has been enriched in D. , Unlike isotopic labeling of synthetic polymers, biomass can directly incorporate labeled material from D 2 O in the environment via photosynthesis. Even when plants are grown in natural abundance water which has a concentration of D 2 O ranging from 0.0145 to 0.0149 mol %, the incorporation of D into plant tissues has been used to determine the differences in carbon fixation and transpiration between plants. , As the D 2 O concentration increased, the unique properties of D 2 O such as higher viscosity begin to affect cell growth and metabolism.…”

“…Even when plants are grown in natural abundance water which has a concentration of D 2 O ranging from 0.0145 to 0.0149 mol %, the incorporation of D into plant tissues has been used to determine the differences in carbon fixation and transpiration between plants. , As the D 2 O concentration increased, the unique properties of D 2 O such as higher viscosity begin to affect cell growth and metabolism. Thus, production of deuterated biomass is usually accomplished via deuterium enriched hydroponic cultures. , Various deuterated biological materials from plants including switchgrass, winter grain rye, and annual rye grass have been obtained by hydroponic cultivation using growth medium consisting of basal mineral salts in different levels of D 2 O. ,, …”