Nitrogen Recycling and Flowering Time in Perennial Bioenergy Crops

Abstract

Perennials have a number of traits important for profitability and sustainability of a biofuel crop. Perennialism is generally defined as the ability to grow and reproduce in multiple years. In temperate climates, many perennial plants enter dormancy during winter and recycle nutrients, such as nitrogen, to below ground structures for the next growing season. Nitrogen is expensive to produce and application of nitrogen increases the potent greenhouse gas NOx. Perennial bioenergy crops have been evaluated for biomass yields with nitrogen fertilization, location, year, and genotype as variables. Flowering time and dormancy are closely related to the N recycling program. Substantial variation for flowering time and dormancy has been identified in the switchgrass (Panicum virgatum L.) species, which provides a source to identify the genetic components of N recycling, and for use in breeding programs. Some studies have addressed recycling specifically, but flowering time and developmental differences were largely ignored, complicating interpretation of the results. Future studies on recycling need to appreciate plant developmental stage to allow comparison between experiments. A perennial/annual model(s) and more environmentally controlled experiments would be useful to determine the genetic components of nitrogen recycling. Increasing biomass yield per unit of nitrogen by maximizing recycling might mean the difference for profitability of a biofuel crop and has the added benefit of minimizing negative environmental effects from agriculture.

Genetic mapping of biomass yield in three interconnected Miscanthus populations

“…Cinnamoyl Coa reductase 1 is the first committed enzyme of the lignin branch biosynthetic pathway (Lacombe et al ., ) and was located within the confidence intervals of QTLs on LG 10 for basal circumference, ratio of compressed circumference to basal circumference, culm basal internode diameter, culm dry weight, culm volume and yield per plant. Mineral transporters are key players in mineral acquisition, transport and recycling in plants (Schwartz & Amasino, ; Palmer et al ., ). In this study, mineral transporters such as potassium transporter 2, zinc transporter 3 precursor, high‐affinity K + transporter 1, nitrate transporter 2.4, sulphate transporter 2 were found within QTL confidence intervals for basal circumference, culm node number, plant height and yield per footprint.…”

Nitrogen remobilization and conservation, and underlying senescence‐associated gene expression in the perennial switchgrass Panicum virgatum

“…b). Total shoot N decreased during senescence, presumably as a means of conserving N elsewhere in the plant, especially in underground organs (Schwartz & Amasino, ). Consistent with this idea, the total N content in the root and crown increased by a similar amount during shoot senescence (Figs c, S3a).…”

Soil Quality and Region Influence Performance and Ranking of Switchgrass Genotypes

“…The most effective way for breeders to accomplish this goal may be to conduct selection under conditions where N is either limiting or just barely adequate for biomass production-this is a hypothesis that should be tested. This approach could help to ensure that roots and rhizomes act as an efficient sink for aboveground N (Clark, 1977;Schwartz and Amasino, 2013;de Vries and Bardgett, 2016).…”