Tolerant mechanism of Jatropha curcas L. roots to acid rain in soils with different acid-buffering capacities

Abstract

Acid rain remains a global environmental issue that can indirectly impact plant root growth and health by mediating soil acidification. The impact of acid rain on the roots of Jatropha curcas L., however, has not been thoroughly evaluated to date in soils with a range of buffering capacities. We, therefore, explored the ability of J. curcas roots to tolerate acid rain in a range of soil types by exposing samples to simulated acid rain (SAR) (pH2.5, pH3.5, pH4.5, pH5.6) and then examining the impact of such exposure on root morphology, relative growth rate (RGR root ), nutrient absorption, enzymatic activity, and microbial biomass. Yellow-brown soil (YBS) and purple soil (PS) were found to be better able to buffer SAR-mediated acidification, thereby providing superior benefits to J. curcas root growth as compared to red soil (RS) and yellow soil (YS) under these experimental conditions. SAR (pH 4.5) significantly enhanced Ca, K, and Mg absorption by J. curcas roots, thereby improving their growth characteristics, whereas SAR (pH 2.5) impaired K and Mg absorption and thus suppressed root growth. K and Mg absorption characteristics were regulated by changes in plasma membrane H + -ATPase activity under these different SAR treatment conditions. Morphological and growth (RGR root ) adaptations of J. curcas roots to SAR treatment were associated with superoxide dismutase activity levels therein. SAR (pH 4.5) was sufficient to bolster the rhizosphere microbial activity of J. curcas seedlings, and correlation analyses revealed that root growth was regulated by rhizosphere microbial biomass P content under SAR treatment conditions.

Effects of simulated acid rain on rhizosphere microorganisms of invasive Alternanthera philoxeroides and native Alternanthera sessilis

“…When the ecosystem is disturbed by natural or human factors, microbial composition, structure, and function change accordingly (Chu et al, 2016). Most studies show that soil acidification caused by acid rain changes soil physicochemical properties (Mohsen and Elaheh, 2012;Liu et al, 2020), reduces soil nutrients, decreases soil microbial biomass, and adversely affects microbial community structure (Xu et al, 2015;Shu et al, 2021), thereby affecting plant growth and development (El-Tarabily et al, 2007). In some shortterm experimental studies, the activity of soil microbial communities' diversity and richness has a positive response to acid rain (Liu et al, 2017;.…”