Effects of Drought on Nutrient Uptake and the Levels of Nutrient-Uptake Proteins in Roots of Drought-Sensitive and -Tolerant Grasses

Abstract

Climate change will increase drought in many regions of the world. Besides decreasing productivity, drought also decreases the concentration (%) of nitrogen (N) and phosphorous (P) in plants. We investigated if decreases in nutrient status during drought are correlated with decreases in levels of nutrient-uptake proteins in roots, which has not been quantified. Drought-sensitive (Hordeum vulgare, Zea mays) and -tolerant grasses (Andropogon gerardii) were harvested at mid and late drought, when we measured biomass, plant %N and P, root N- and P-uptake rates, and concentrations of major nutrient-uptake proteins in roots (NRT1 for NO3, AMT1 for NH4, and PHT1 for P). Drought reduced %N and P, indicating that it reduced nutrient acquisition more than growth. Decreases in P uptake with drought were correlated with decreases in both concentration and activity of P-uptake proteins, but decreases in N uptake were weakly correlated with levels of N-uptake proteins. Nutrient-uptake proteins per gram root decreased despite increases per gram total protein, because of the larger decreases in total protein per gram. Thus, drought-related decreases in nutrient concentration, especially %P, were likely caused, at least partly, by decreases in the concentration of root nutrient-uptake proteins in both drought-sensitive and -tolerant species.

Optimizing Soil Fertility Management Strategies to Enhance Banana Production in Volcanic Soils of the Northern Highlands, Tanzania

“…Highest foliar nutrient concentrations were attained in the most humid zone of Lyamungo, suggesting that nutrient acquisition in the other two zones was negatively hampered by moisture stress. This supports earlier findings where drought stress reduced the concentration (%) of N by 44-51 and P by 39-48% in barley, corn, and big bluestem [51]. Foliar analyses revealed further that banana plants contained adequate concentrations of N, P, K, Mg, Ca, S, Fe, and Mn, but were deficient in B (in Lyamungo) and Cu and Zn (across the trial sites).…”

Turnover and change in plant species composition in a shielded salt marsh following variation in precipitation and temperature

“…Both salt and drought stress alter the ability of plants to utilize nutrients (Bista et al, 2018;Hu & Schmidhalter, 2005). Nitrogen is a main limiting factor for salt marsh vegetation (Kiehl, Esselink, & Bakker, 1997;van Wijnen & Bakker, 1999) and in agreement with results by Morgan and Adams (2018), total species richness in our study was limited by the availability of nitrogen.…”

“…Where we found NH 4 + levels to increase and NO 2 − / NO 3 − levels to decrease, Palomo et al (2013) found the opposite response in an experimental salt marsh experiencing drought. The increased soil available N and available P might, however, partly be a result of the plants' decreased ability to acquire nutrients during a drought (Bista et al, 2018). Soil salinity levels are known to increase during a drought (Chapple & Dronova, 2017;Forbes & Dunton, 2006), as was also the case in this study, although not significantly (Table 1).…”

“…Further, droughts alter the soil chemistry and result in more saline conditions (Chapple & Dronova, 2017;Forbes & Dunton, 2006;Palomo, Meile, & Joye, 2013). Stressful conditions not only affect the physical environment but both salt and drought stress impact plant ability to utilize nutrients (Bista, Heckathorn, Jayawardena, Mishra, & Boldt, 2018;Hu & Schmidhalter, 2005).…”

“…We expected the species composition to change toward being adapted to drier and more saline condition during the dry year compared to the wet year; and (c) is species turnover linked to environmental dissimilarity? As both salt and drought stress impact the ability of plants to utilize nutrients (Bista et al, 2018;Hu & Schmidhalter, 2005), we expected plants to react differently to the edaphic gradient during wet and dry years.…”