Evidence of stress imprinting with population‐level differences in two moss species. Issue 11 (9th May 2019)

• Record Type: Journal Article
• Authors: Liu, Weiqiu; Xu, Jianqu; Fu, Wei; Wang, Xiangyuan; Lei, Chunyi; Chen, Yunfeng
• Is Part Of: Ecology and evolution. Volume 9:Issue 11(2019)
• Page Start: 6329
• Page End: 6341
• Publication Date: 2019-05-09
• Subjects: bryophytes -- desiccation -- osmolytes -- phytohormones -- population differentiation -- stress imprint; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.5205
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Plants are often repeatedly exposed to stresses during their lives and have a mechanism called stress imprinting that provides "memories" of stresses they experience and increases their ability to cope with later stresses. To test hypotheses that primed bryophytes can preserve their stress imprinting after 6 days of recovery and induce higher levels of osmolytes and ROS‐scavenging activities upon later stress exposure, and there exist population‐level differentiation in their desiccation defenses, we transplanted samples of two populations of each of two moss species, Hypnum plumaeforme and Pogonatum cirratum, in a nature reserve in southern China. After 16 months of acclimation, sets of each population were subjected to control, one‐time desiccation stress, duplicated desiccation stress and cross‐stress (low temperature stress followed by desiccation stress) treatments. Levels of oxidant enzymes, osmolytes, and phytohormones in the samples were then determined. The desiccation stress generally led to increases in activities or contents of superoxide dismutase, guaiacol peroxidase, catalase, proline, soluble sugars, soluble proteins, and stress hormones including abscisic acid (ABA), jasmonates (JA), and salicylic acid (SA), with differences between both species and populations. After a 6‐day recovery period, contents of phytohormones (including ABA, JA, SA, and cytokinins) in stressed H. plumaeforme had substantially fallen toward control levels. The duplicated and cross‐stress treatments generally led to further accumulation of proline, soluble sugars, and soluble proteins, with further increases in activities of antioxidant enzymes in some cases. Furthermore, significant differences between allochthonous and native populations were found in contents of malondialdehyde and osmolytes, as well as antioxidant enzyme activities. Our results confirm the hypotheses and highlight the importance of osmolytes in mosses' stress responses. Abstract : Osmolytes and antioxidant enzymes were involved in stress imprinting in mosses. Stresses generally induced significant accumulation of ABA, JA, and SA in the mosses, though there is population differentiation in their stress responses. Responses of IAA and cytokinins to stress differed at both species and population levels, but cis‐zeatin was the most abundant cytokinin consistently.