Volenec conducts research on physiological processes that influence productivity of crops, with an emphasis on perennial species used for forage and biomass. Stress tolerance is of particular importance in these cropping systems because of the need to survive winter and to withstand complete periodic defoliation during the growing season. In addition, perennial forages and biomass species are generally relegated to lands deemed marginal for row-crop production. Thus, they often encounter less-than-ideal levels of soil nutrients, water, drainage, and other edaphic factors. By understanding mechanisms by which plants tolerate these severe stresses, Dr. Volenec hopes to be able to identify selection criteria for use by plant breeders and/or management strategies that improve productivity and long-term persistence. Examples of Volenec’s research include:
- Starch Reserves, Growth and Persistence. Perennial plants accumulate organic reserves that provide nutrients necessary for initial shoot growth in spring and for shoot regrowth if plants are defoliated in summer. Starch accumulates in the large carrot-like taproots of perennial legume species and in rhizomes or stolons of warm-season perennial grasses. Volenec has focused much of his research on taproot physiology and starch metabolism of alfalfa – the most important forage legume grown worldwide. Volenec and his students were the first to show that high levels of taproot starch does not necessarily lead to rapid regrowth after defoliation. Plants with as little as 5% starch in their taproots regrow as fast as or faster than comparable high-starch plants after harvest. Subsequent work indicated that the activity of certain starch-degrading enzymes (a-amylases) rather than the quantity of starch, has the greatest impact on rate of shoot regeneration following defoliation. Contrary to popular belief, β-amylase appears not to participate in starch hydrolysis in alfalfa taproots, but may instead serve as a storage protein (see below). Anatomical studies also reveal control of starch breakdown is highly regulated at the cellular level. Cells located a few millimeters from each other can have vastly different rates of starch breakdown.
- Nitrogen Reserves and Agronomic Performance. Cold soils in spring inhibit nitrogen fixation and lead to an initial N deficiency in perennial legumes like alfalfa. In addition, nitrogen fixation is markedly reduced after defoliation, these agronomic systems are rarely fertilized with N. Volenec, and co-workers have explored the role of taproot proteins in mediating regrowth and persistence of perennial legumes. These studies have shown that a large decline in taproot protein concentration occurs during initial shoot growth in the spring and after each forage harvest in summer. More importantly, Volenec and his students have discovered specific proteins (including β-amylase) that comprise as much as 50% of the taproot protein pool that are preferentially degraded to provide N to regrowing shoots. These proteins are considered vegetative storage proteins (VSP’s). Working with mutants lacking these VSP’s, Volenec and his students have shown that regrowth rate of -VSP plants is less half that of their +VSP counterparts following defoliation. Recent results have extended these findings to perennial grasses including those used for biomass like Miscanthus and shown a strong dependency of growth of these species on rhizome protein pools.
- Fall Dormancy and Winterhardiness. Fall dormancy also has been a research topic emphasized in Volenec’s research program. It has been recognized for some time that plants with reduced shoot growth in autumn are more winter hardy than are plants that continue shoot growth late into fall. Our understanding of the biological mechanisms underlying fall dormancy is virtually nonexistent. This is despite the fact that, more than any other single feature, fall dormancy is used to predict winter survival of important crop species like alfalfa. The goal of this research is to identify and understand the nature of genes and gene products essential for winter hardiness of alfalfa. For example, Volenec and co-worked have isolated and characterized cold acclimation-responsive genes in alfalfa and showed that nondormant alfalfa lines that winterkill do not express these genes. Other work has focused on accumulation of raffinose family oligosaccharides that accumulate in taproots of winter hardy alfalfa lines, but not those that winterkill. Volenec’s work is unique in that it uses germplasms that differ in fall growth habit and winter hardiness, but which are otherwise closely related. This approach has enabled Volenec and his associates to identify key genetic and physiological differences controlling shoot growth in autumn and winter hardiness.
- Plant Nutrition. Proper plant nutrition, especially nitrogen (N), potassium (K) and phosphorus (P) is critical for high yield and stress tolerance. Volenec and his students are evaluating the interactions of these nutrients on agronomic performance (yield, yield components), and as importantly, the underlying physiological basis of greater growth and persistence. Improved plant persistence often occurs on K-fertilized plots, while fertilization with P without addition of K fertilizer can reduce plant persistence and yield. Changes in root starches, sugars, and N pools like proteins and amino acids are informing our knowledge of how these nutrients impact crop performance. These findings will result in improved diagnostic tools (soil tests, tissue tests) that will be helpful in managing N, P and K for improved agronomic performance, while protecting the environment.
- Sustainable Biomass Production. Renewed in interest in production of herbaceous biomass for bioenergy has resulted in new opportunities for Volenec and collaborators to study the environmental consequences and changes in ecosystem services that occur when perennial crops are used for biofuels. Studies are PU’s Water Quality Field Station (WQFS), a field laboratory comprised of forty-eight 24 m x 9 m drainage lysimeters, permit simultaneous quantification of nutrient losses from the field to surface and ground waters, and emission of greenhouse gasses like methane, carbon dioxide and nitrous oxide. WQFS treatments were modified to include perennial biomass treatments like a low-input big bluestem prairie, Miscanthus, and switchgrass compared to continuous corn with stover biomass removal; all compared to traditional corn-soybean production that currently dominates the Midwest US cornbelt. Our goal is to quantify the N, C, and water balances for candidate biofuels cropping systems knowing that these will be critical drivers of biomass production and sustainability.
- Data and Evidence-based Agriculture. Volenec and collaborators have been at the forefront of Ag data issues for a decade. As Program Planning Officer for the American Society of Agronomy, Volenec organized in 2010 the first-ever Big Data symposium including Simon Liu, then leader of the National Agricultural Library. Working with collaborators Ron Turco and Sylvie Brouder, Volenec co-organized an invite-only meeting in 2013 called “Smart Ag” in Washington DC to bring Ag data issues to our nation’s thought leaders in Ag. Volenec later testified in Washington on data issues following the release of the memo from the Obama administration requiring open access of all data finding by the Federal Government. He also has served as the leader of the data taskforce convened by the Alliance of Crop, Soils and Environmental Science Societies, a coalition of professional societies including Crop Science Society of America, the Soil Science Society of America, and the American Society of Agronomy. He and colleagues view data as an asset and should be freely available for repurposing. They continue to work with science librarians, industry partners, the USDA, and professional societies to create workflows, tools and repositories available for data curation. Recently they have been funded to curate data in the Purdue University Research Repository for several large multi-institutional grants, and have a standing Memorandum of Agreement with the National Agricultural Library that also focuses on curation of Ag data.
- Crop physiology and ecology
Current N-related Projects:
- N cycling in agro-ecosystems
Volenec, J.J., and C.J. Nelson. 1983. Response of tall fescue leaf meristems to N fertilization and harvest frequency. Crop Sci. 23:720-724.
Volenec, J.J., and C.J. Nelson. 1984. Carbohydrate metabolism in leaf meristems of tall fescue. II. Relationship to leaf elongation rates modified by nitrogen fertilization. Plant Physiol. 74:595-600.
Cherney, J.H., K.D. Johnson, J.J. Volenec, and K.S. Anliker. 1988. Chemical composition of herbaceous grass and legume species grown for maximum biomass production. Biomass 17:215-238.
MacAdam, J.W., J.J. Volenec, and C.J. Nelson. 1989. Effects of nitrogen on mesophyll cell division and epidermal cell elongation in tall fescue leaf blades. Plant Physiol. 89:549-556.
Hendershot, K.L., and J.J. Volenec. 1993. Taproot nitrogen accumulation and use in overwintering alfalfa (Medicago sativa L.). J. Plant Physiol. 141:68-74.
Hendershot, K.L., and J.J. Volenec. 1993. Nitrogen pools in taproots of Medicago sativa L. after defoliation. J. Plant Physiol. 141:129-135.
Volenec, J.J., and S.M. Cunningham. 1995. Effect of applied nitrogen on seedling growth and cotyledon protein utilization of effective and ineffective nodulating alfalfa. J. Plant Nutr. 18:1519-1534.
Cunningham, S.M., and J.J. Volenec. 1996. Purification and characterization of vegetative storage proteins from alfalfa (Medicago sativa L.) taproots. J. Plant Physiol. 147:625-632.
Li, R., J.J. Volenec, B.C. Joern, and S.M. Cunningham. 1996. Seasonal changes in nonstructural carbohydrates, protein, and macronutrients in roots of alfalfa, red clover, sweetclover, and birdsfoot trefoil. Crop Sci. 36:617-623.
Volenec, J.J., A. Ourry, and B.C. Joern. 1996. A role for nitrogen reserves in forage regrowth and stress tolerance. Physiol. Plant. 97:185-193.
Avice, J-C., A. Ourry, J.J. Volenec, G. Lemaire, and J. Boucaud. 1996. Defoliation-induced changes in abundance and immuno-localization of vegetative storage proteins in taproots of Medicago sativa. Plant Physiol. Biochem. 34:561-570.
Barber, L.D., B.C. Joern, J.J. Volenec, and S.M. Cunningham. 1996. Supplemental nitrogen effects on alfalfa regrowth and nitrogen mobilization from roots. Crop Sci. 36:1217-1223.
Li, R., J.J. Volenec, B.C. Joern, and S.M. Cunningham. 1997. Potassium and nitrogen effects on carbohydrate and protein metabolism in alfalfa roots. J. Plant Nutrition 20:511-529.
Kalengamaliro, N.E., J.J. Volenec, B.C. Joern, and S.M. Cunningham. 1997. Seedling development and deposition of starch and storage proteins in alfalfa roots. Crop Sci. 37:1194-1200.
Avice, J.C., A. Ourry, G. Lemaire, J.J. Volenec, and J. Boucaud. 1997. Root protein and vegetative storage protein are key organic nutrients for alfalfa shoot regrowth. Crop Sci. 37:1187-1193.
Li, R., J.J. Volenec, B.C. Joern, and S.M. Cunningham. 1998. Effects of phosphorus nutrition on carbohydrate and protein metabolism in alfalfa roots. J. Plant Nutrition 21:459-474.
Cunningham, S.M., and J.J. Volenec. 1998. Seasonal carbohydrate and protein metabolism in roots of contrasting alfalfa (Medicago sativa L.) cultivars. J. Plant Physiol. 153:220-225.
Noquet, C., J.C. Avice, A. Ourry, J.J. Volenec, S.M. Cunningham and J. Boucaud. 2001. Effects of environmental factors and endogenous signals on N uptake, N partitioning and taproot vegetative storage protein accumulation in Medicago sativa. Aust. J. Plant Physiol. 28:279-288.
Justes, E., P. Thiebeau, J-C. Avice, G. Lemaire, J.J. Volenec, and A. Ourry. 2002. Influence of summer sowing dates, N fertilization and irrigation on autumn VSP accumulation and dynamics of spring regrowth in alfalfa (Medicago sativa L.). J. Exp. Bot. 53:111-121.
Meuriot, F., J.-C. Avice, M.-L. Decau, J.-C. Simon, P. Laine, J.J. Volenec, and A. Ourry. 2003. Accumulation of N reserves and vegetative storage protein (VSP) in taproots of non-nodulated alfalfa (Medicago sativa L.) are affected by mineral N availability. Plant Sci. 165:709-718.
Noquet, C., F. Meuriot, J.-C. Avice, A. Ourry, S.M. Cunningham, and J.J. Volenec. 2003. Short-day photoperiod induced changes in N uptake, N partitioning and accumulation of vegetative storage proteins in two Medicago sativa L. cultivars. Func. Plant Biol. 30:853-863.
Avice, J-C., F. Le-Dily, E. Goulas, C. Noquet, F. Meuriot, J.J. Volenec, S.M. Cunningham, T.G. Sors, C. Dhont, Y. Castonguay, P. Nadeau, G. Belanger, F-P. Chalifour, and A. Ourry. 2004. Vegetative storage proteins in overwintering storage organs of forage legumes: roles and regulation. Can. J. Bot. 81:1198-1212.
Meuriot, F., C. Noquet, J.C. Avice, J.J. Volenec, S.M. Cunningham, T. Sors, S. Caillot, and A. Ourry. 2004. Methyl jasmonate alters N partitioning, N reserves accumulation and induces gene expression of a 32-kDa vegetative storage protein that possess chitinase activity in Medicago sativa L. taproots. Physiol. Plant. 120:113-123.
Meuriot, F., M.-L. Decau, A. Morvan-Bertrand, M.-P. Prud’homme, F. Gastal, J.-C. Simon, J.J. Volenec, and J.-C. Avice. 2005. Contribution of initial C and N reserves in Medicago sativa recovering from defoliation: impact of cutting height and residual leaf area. Func. Plant Biol. 32:321-334.
Patton, A.J., S.M. Cunningham, J.J. Volenec, and Z.J. Reicher. 2007. Differences in freeze tolerance of zoysiagrasses. I. Role of Proteins. Crop Sci. 47:2162-2169.
Brouder, S.M. and J.J. Volenec. 2008. Impact of climate change on crop nutrient and water use efficiencies. Physiol. Plant. 133:705-724.
Berg, W.K., S.M. Cunningham, S.M. Brouder, B.C. Joern, K.D. Johnson, J.J. Volenec. 2009. Influence of phosphorus and potassium on alfalfa yield, taproot C and N pools, and transcript levels of key genes after defoliation. Crop Sci. 49:974-982.
Pembleton, K.G., S.M. Cunningham, and J.J Volenec. 2010. Effect of summer irrigation on seasonal changes in taproot reserves and the expression of winter dormancy/activity in four contrasting lucerne cultivars. Crop Pasture Sci. 61:873-884.
Dierking, R.M., D. Allen, S.M. Brouder, and J.J. Volenec. 2016. Yield, biomass composition, and N use efficiency during establishment of four Miscanthus × giganteus genotypes as influenced by N management. Biomass Bioenergy 91:98-107.
Brouder, S.M., and J.J. Volenec. 2017. Future climate change and plant macro-nutrient use efficiency. pp. 357-379. In Plant macro-nutrient use efficiency: Molecular and genomic perspectives. Hossain, M.A., Kamiya, T., Burrit, D.J., Phan Tran, L.-S., Fujiwara, T. (Eds.). Elsevier. ISBN: 9780128113080
Dierking R.M., D.J. Allen, S.M. Cunningham, S.M. Brouder, and J.J. Volenec. 2017. Nitrogen dynamics in above and belowground tissues of two Miscanthus × giganteus genotypes under various N fertilization rates. Front. Plant Sci. DOI: 10.3389/fpls.2017.01618.