Bista Deepesh R, Heckathorn Scott A, Jayawardena Dileepa M, Mishra Sasmita, Boldt Jennifer K
Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA.
Department of Biology, Kean University, Union, NJ 07083, USA.
Plants (Basel). 2018 Mar 30;7(2):28. doi: 10.3390/plants7020028.
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 (, ) and -tolerant grasses () 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.
气候变化将加剧世界许多地区的干旱。干旱不仅会降低生产力，还会降低植物中氮（N）和磷（P）的浓度（%）。我们研究了干旱期间养分状况的下降是否与根中养分吸收蛋白水平的下降相关，这一点尚未得到量化。在干旱中期和后期收获对干旱敏感的（，）和耐旱的草（），此时我们测量了生物量、植物N和P的百分比、根对N和P的吸收速率以及根中主要养分吸收蛋白的浓度（NO₃的NRT1、NH₄的AMT1和P的PHT1）。干旱降低了N和P的百分比，表明其对养分获取的减少超过了对生长的影响。干旱导致的P吸收减少与P吸收蛋白的浓度和活性下降相关，但N吸收的减少与N吸收蛋白的水平弱相关。尽管每克总蛋白增加，但每克根中的养分吸收蛋白减少，这是因为每克总蛋白下降幅度更大。因此，干旱相关的养分浓度下降，尤其是%P，可能至少部分是由干旱敏感和耐旱物种根中养分吸收蛋白浓度的下降引起的。
