Legacy effects of historical grazing alter leaf stomatal characteristics in progeny plants

Abstract

Grazing, one of the primary utilization modes of grassland, is the main cause of grassland degradation. Historical overgrazing results in dwarf phenotype and decreased photosynthesis of perennial plants. However, it remains unknown what the mechanism underlying of this legacy effect is, and the role of stomata in the resulting decreased photosynthesis also remains unclear. To address these questions, differences in stomatal density, length and width on both adaxial and abaxial epidermis were compared between overgrazing and ungrazed Leymus chinensis offspring by using rhizome buds cultivated in a greenhouse, and the correlation between photosynthetic capacity and stomatal behavior was also investigated. Our results showed that historical grazing significantly impacted phenotype, photosynthesis and stomatal traits of L. chinensis. The offspring plants taken from overgrazed parents were dwarfed compared to those taken from ungrazed parents, and the photosynthesis and stomatal conductance of plants with a grazing history decreased by 28.6% and 21.3%, respectively. In addition, stomatal density and length on adaxial and abaxial leaf surfaces were significantly increased; however, stomatal width on abaxial leaf surfaces of overgrazed L. chinensis was significantly decreased compared with ungrazed individuals. Moreover, the expression patterns of eight genes related to stomatal regulation were tested: seven were down-regulated (2–18 times) and one was up-regulated (three times). Genes, involved in ABC transporter and receptor-like serine/threonine protein kinase were down-regulated. These results suggest that legacy effects of historical grazing affect the stomatal conductance by decreasing the stomatal width in progeny plants, which thus results in lower photosynthesis. Furthermore, changes of stomatal traits and function were regulated by the inhibition of ABC transporter and serine/threonine protein kinase. These findings are helpful for future exploration of the possible mechanisms underlying the response of grassland plants to long-term overgrazing.

Growth-Defense Trade-Offs Induced by Long-term Overgrazing Could Act as a Stress Memory

“…In addition, ABA regulates the stomatal aperture by changing the volume of guard cells that control gas exchange (Chen et al, 2021 ). Our previous study found that stomatal conductance of overgrazed L. chinensis significantly decreased (Yin et al, 2020 ), which may be related to ABA content changes.…”

Genome‐wide characterization and expression analysis of GATA transcription factors under combination of light wavelengths and drought stress in potato

“…In this study, there was an increase in the expression level under red + drought conditions, especially in the drought‐sensitive cultivar Agria; however, a similar response was not observed in the tolerant cultivar Sante. There are studies available in the literature on cyclin‐P3‐1, and its function is described by stomatal development and activity, as reported in Leymus chinensis (Yin et al, 2020 ). This could suggest the role of cyclin‐P3‐1 and StGATA3 in the drought response in potato, as positive transcriptional induction of each seems to stimulate the response both for sensitive and tolerant cultivars; however, the increase in expression was higher in sensitive cultivar because it experienced severe drought.…”

High grazing pressure accelerates changes in community assembly over time in a long-term grazing experiment in the desert steppe of northern China

“…In northern China, desert steppe is the most arid grassland type (Perrings & Walker 1997), where the environment is severe and heavily impacted by large climate uctuations (Ren et al 2018). Over the previous two decades, desert steppe also experienced major changes in vegetation structure as intense livestock ranching operations arose (Yin et al 2020). Previous research in the desert steppe of northern China found clear evidence for impacts of intensive grazing on community composition, individual species traits such as plant height, leaf area, speci c leaf area, seed mass, and stoichiometry of organisms (Jiangwen 2018;Ye et al 2020), and ecosystem functions such as productivity, plant diversity, and photosynthetic capacity (Wang et al 2011;YuXi.…”