Location: Application Technology Research2018 Annual Report
1. Hot water and steam can be used to sanitize plastic nursery pots and trays for weed seed. Seeds of many weeds, most notably bittercress (Cardamine flexuosa) and creeping woodsorrel (Oxalis corniculata), stick to plastic nursery containers and trays and are reintroduced into the production system when that plastic is reused. An ARS scientist in Wooster, Ohio, determined the specific temperatures and exposure times necessary to kill weed seeds on plastic containers and propagation trays using either hot-water or steam. Temperatures of 90 C provided nearly complete control of both species. The results of this work can be used by greenhouse and nursery producers to control weed seeds on between crops, drastically reducing weed populations in propagation and other phases of production where herbicides are limited.
2. The conventional system for identifying plants as silicon (Si) accumulators is flawed. Plants are classified as Si accumulators or low Si accumulators based on foliar Si concentration, and most greenhouse-grown ornamentals are considered low Si-accumulators. However, little knowledge exists on Si distribution within these species. ARS researchers in Toledo, Ohio determined that Si concentration was greater in the leaves than in the roots, stems, or flowers for both an accumulator (sunflower) and non-accumulator (petunia). Additionally, Si concentration increased in both the roots and aerial portions of the accumulator species, but only in the roots of the non-accumulator species. This suggests a difference in Si uptake and regulation between foliar Si accumulator and non-accumulator species, and the results of this work can be used by researchers to further understand how plants take up, store, and utilize Si.
3. Drought stress affects nutrient uptake proteins in plants. Drought stress impacts plant productivity and nutrient concentration in plants, but its impact on nutrient uptake proteins was not well understood. Researchers at the University of Toledo, Toledo, Ohio, in collaboration with ARS researchers, have developed biomarkers for nutrient-uptake proteins in roots. It was determined the decrease in %P was correlated with a decrease in both the concentration and activity of P-uptake proteins, and the decrease in %N was due, in part, to a decrease in the activity of N-uptake proteins. This occurred in both drought-tolerant and drought-sensitive species. Results of this research will be useful to plant breeding efforts focused on improving the tolerance of crops to drought and minimizing yield losses, including adaptations that help roots maintain bulk root protein levels or increase the expression of nutrient uptake proteins.Altland, J.E., Boldt, J.K. 2017. Effect of rice hull mulch on nutrient concentration of fertilized irrigation water. HortScience. 52(9):1288–1292.
Altland, J.E., Jeong, K.Y. 2017. Initial substrate moisture content and storage temperature affects chemical properties of bagged substrates containing controlled release fertilizer at two different temperatures. HortScience. 52(10):1429-1434. doi:10.21273/HORTSCI12216-17.
Boldt, J.K., Locke, J.C., Altland, J.E. 2018. Silicon accumulation and distribution in petunia and sunflower grown in a rice hull-amended substrate. HortScience. 53:698-703. https://doi.org/10.21273/HORTSCI12325-17.
Altland, J.E., Boldt, J.K. 2018. Influence of substrate physical properties on container weed germination. Journal of Environmental Horticulture. 36(1):1-6.
Bista, D.R., Heckathorn, S.A., Jayawardena, D.M., Mishra, S., Boldt, J.K. 2018. Effect of drought on nutrient uptake and the levels of nutrient-uptake proteins in roots of drought-sensitive and –tolerant grasses. Plants. 7(2):28-44. http://doi:10.3390/plants7020028.
Albano, J.P., Altland, J.E., Merhaut, D., Wilson, S., Wilson, C. 2017. Irrigation water acidification to neutralize alkalinity for nursery crop production: Substrate pH, electrical conductivity, nutrient concentrations, and plant nutrition and growth. HortScience. 52(10):1401-1405. doi: 10.21273/hortsci11439-17.
Altland, J.E., Locke, J.C., Boldt, J.K. 2018. Pyrolysis temperature and heating time affect rice hull biochar properties. Acta Horticulturae. 1191:145-152.