Malik Rondy J, Bever James D
Department of Ecology and Evolutionary Biology, Kansas Biological Survey, 2101 Constant Ave, Lawrence, KS 66045, USA.
Plants (Basel). 2021 Nov 16;10(11):2474. doi: 10.3390/plants10112474.
While milkweeds ( spp.) are important for sustaining biodiversity in marginal ecosystems, CO flux may afflict species and cause detriment to native communities. Negative CO-induced effects may be mitigated through mycorrhizal associations. In this study, we sought to determine how mycorrhizae interacts with CO to influence biomass and root morphology. A broad range of species (n = 6) were chosen for this study, including four tap-root species (, , and ) and two fibrous root species ( and ). Collectively, the six species were manipulated under a 2 × 2 full-factorial design that featured two mycorrhizal levels (-/+ mycorrhizae) and two CO levels (ambient and enriched (i.e., 3.5× ambient)). After a duration of 10 months, responses were assessed as whole dry weight (i.e., biomass) and relative transportive root. Relative transportive root is the percent difference in the diameter of highest order root (transportive root) versus that of first-order absorptive roots. Results revealed an asymmetrical response, as mycorrhizae increased biomass by ~12-fold, while enriched CO decreased biomass by about 25%. CO did not impact relative transportive roots, but mycorrhizae increased root organ's response by more than 20%. Interactions with CO and mycorrhizae were observed for both biomass and root morphology (i.e., relative transportive root). A gene associated with CO fixation () revealed that the two fibrous root species formed a phylogenetic clade that was distant from the four tap-root species. The effect of mycorrhizae was most profound in tap-root systems, as mycorrhizae modified the highest order root into tuber-like structures. A strong positive correlation was observed with biomass and relative transportive root. This study elucidates the interplay with roots, mycorrhizae, and CO, while providing a potential pathway for mycorrhizae to ameliorate CO induced effects.
虽然马利筋属植物对于维持边缘生态系统中的生物多样性很重要，但二氧化碳通量可能会影响这些物种并对本地群落造成损害。通过菌根共生关系，二氧化碳诱导的负面影响可能会得到缓解。在本研究中，我们试图确定菌根如何与二氧化碳相互作用以影响生物量和根系形态。本研究选择了广泛的物种（n = 6），包括四种直根物种（[物种名称1]、[物种名称2]、[物种名称3]和[物种名称4]）和两种须根物种（[物种名称5]和[物种名称6]）。总体而言，这六个物种在2×2全因子设计下进行处理，该设计具有两个菌根水平（有/无菌根）和两个二氧化碳水平（环境水平和富集水平（即环境水平的3.5倍））。经过10个月的时间，评估的响应指标为全干重（即生物量）和相对输导根。相对输导根是最高级根（输导根）直径与一级吸收根直径的百分比差异。结果显示出一种不对称的响应，因为菌根使生物量增加了约12倍，而富集的二氧化碳使生物量减少了约25%。二氧化碳没有影响相对输导根，但菌根使根器官的响应增加了20%以上。在生物量和根系形态（即相对输导根）方面都观察到了二氧化碳与菌根的相互作用。一个与二氧化碳固定相关基因（[基因名称]）显示，两种须根物种形成了一个与四种直根物种距离较远的系统发育分支。菌根的影响在直根系中最为显著，因为菌根将最高级根改变为块状结构。观察到生物量与相对输导根之间存在很强的正相关。本研究阐明了根系、菌根和二氧化碳之间的相互作用，同时为菌根改善二氧化碳诱导效应提供了一条潜在途径。
