Wang Weibo, Li Hua, Guénon René, Yang Yuyi, Shu Xiao, Cheng Xiaoli, Zhang Quanfa
CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China.
Front Microbiol. 2021 Jan 18;11:582655. doi: 10.3389/fmicb.2020.582655. eCollection 2020.
Terrestrial cyanobacteria is an ideal species to study the geographical variation of mineral elements of soil cyanobacteria at the species level. Here, we first address the following questions: (1) from where are these mineral elements, (2) are there geographical variations for these mineral elements, and if so, (3) which environmental factors drive the geographical variation of these mineral elements? Second, we tested whether the soil cyanobacterial mineral elements followed the "restrictive element stability hypothesis" of higher plants. Finally, we explored the effect of mineral geographic variation on ecological adaptation of soil cyanobacteria. We collected samples across gradients of climate, soil, and atmospheric wet deposition mineral concentration in mainland China. We measured fifteen minerals, including five macroelements (N, Ca, K, Fe, P), five microelements (Mn, Zn, Cu, Co, Se), and five heavy metals (Pb, Cr, As, Cd, Hg). We found that five elements (P, Cu, Zn, Co, Pb) had significant geographical variation. They increased as the distance from the equator increased and decreased as the distance from the prime meridian increased. Mean annual precipitation and mean annual temperature explained most of the variation. We did not find any significant correlations between the mineral element contents in and the minerals in soil and rainfall, except for P. There was no significant correlation between the variation coefficients of different elements and their actual detected contents and their potential physiological required contents. The statistical results of our experiment did not support the "restrictive element stability hypothesis." We speculated that net accumulation of mineral elements in cyanobacterial cells and extracellular polysaccharides (EPS) might play an important role for terrestrial cyanobacteria in the adaptation to dry and cold conditions.
陆生蓝细菌是在物种水平上研究土壤蓝细菌矿质元素地理变异的理想物种。在此，我们首先解决以下问题：（1）这些矿质元素来自何处，（2）这些矿质元素是否存在地理变异，如果存在，（3）哪些环境因素驱动了这些矿质元素的地理变异？其次，我们测试了土壤蓝细菌矿质元素是否遵循高等植物的“限制元素稳定性假说”。最后，我们探讨了矿质地理变异对土壤蓝细菌生态适应的影响。我们在中国陆地跨越气候、土壤和大气湿沉降矿质浓度梯度采集样本。我们测量了15种矿物质，包括5种大量元素（氮、钙、钾、铁、磷）、5种微量元素（锰、锌、铜、钴、硒）和5种重金属（铅、铬、砷、镉、汞）。我们发现5种元素（磷、铜、锌、钴、铅）存在显著的地理变异。它们随着离赤道距离的增加而增加，随着离本初子午线距离的增加而减少。年均降水量和年均温度解释了大部分变异。除了磷之外，我们没有发现土壤蓝细菌中的矿质元素含量与土壤和降雨中的矿物质之间存在任何显著相关性。不同元素的变异系数与其实际检测含量以及其潜在生理需求含量之间没有显著相关性。我们实验的统计结果不支持“限制元素稳定性假说”。我们推测蓝细菌细胞和胞外多糖（EPS）中矿质元素的净积累可能在陆生蓝细菌适应干旱和寒冷条件中起重要作用。
