Veatch-Blohm Maren E, Medina Gustavo, Butler Jane
Loyola University Maryland, 4501 N. Charles St., Baltimore, MD, USA.
Heliyon. 2023 Feb 10;9(2):e13632. doi: 10.1016/j.heliyon.2023.e13632. eCollection 2023 Feb.
Root architecture is important in nutrient uptake and avoidance of toxic compounds within the soil. spp. has widespread distribution in disjunct environments that encounter unique stressors starting at germination. Five populations of spp. show local adaptation to Nickel (Ni) but cross-tolerance to variations in Calcium (Ca) concentration within the soil. Differentiation among the populations begins early in development and appears to impact timing of lateral root formation; therefore the purpose of the study was to understand changes in root architecture and root exploration in response to Ca and Ni within the first three weeks of growth. Lateral root formation was first characterized under one concentration of Ca and Ni. Lateral root formation and tap root length were reduced in all five populations in response to Ni compared to Ca, with the least reduction in the three serpentine populations. When the populations were exposed to a gradient (either Ca or Ni) there were differences in population response based on the nature of the gradient. Start side was the greatest determinant of root exploration and lateral root formation under a Ca gradient, while population was the greatest determinant of root exploration and lateral root formation under a Ni gradient. All populations exhibited about the same frequency of root exploration under a Ca gradient, while the serpentine populations exhibited much higher levels of root exploration under a Ni gradient compared to the two non-serpentine populations. Differences among populations in response to Ca and Ni demonstrate the importance of stress responses early in development, particularly in species that have widespread distribution among disparate habitats.
根系结构对于养分吸收以及避免土壤中的有毒化合物至关重要。[物种名称]在不同的环境中广泛分布，这些环境从种子萌发开始就会遇到独特的压力源。[物种名称]的五个种群表现出对镍（Ni）的局部适应性，但对土壤中钙（Ca）浓度的变化具有交叉耐受性。种群间的分化在发育早期就开始了，并且似乎会影响侧根形成的时间；因此，本研究的目的是了解在生长的前三周内，根系结构和根系探索对钙和镍的响应变化。首先在一种钙和镍浓度下对侧根形成进行了特征描述。与钙相比，所有五个种群对镍的响应均表现为侧根形成和主根长度减少，其中三个蛇纹石种群的减少程度最小。当种群暴露于梯度（钙或镍）时，根据梯度的性质，种群响应存在差异。在钙梯度下，起始侧是根系探索和侧根形成的最大决定因素，而在镍梯度下，种群是根系探索和侧根形成的最大决定因素。在钙梯度下，所有种群的根系探索频率大致相同，而与两个非蛇纹石种群相比，蛇纹石种群在镍梯度下表现出更高水平的根系探索。种群对钙和镍的响应差异表明了发育早期应激反应的重要性，特别是在广泛分布于不同栖息地的物种中。
