Ethylene‐regulated leaf lifespan explains divergent responses of plant productivity to warming among three hydrologically different growing seasons

Abstract

Leaf senescence is known to be regulated by the plant hormone ethylene, but how leaf lifespan responds to global environmental change and links to ecosystem‐level responses remains largely unexplored. Here we investigated the effects of climate warming and nitrogen addition on plant functional traits, plant hormone ethylene and net primary production in a 13‐year field experiment in a desert steppe. Across the last 3 years of the experiment (2016–2018), plant productivity increased under warming only in 2016, when there was above normal precipitation, but consistently increased with nitrogen addition. Warming enhanced net photosynthesis, leaf nitrogen and ethylene production and reduced leaf lifespan in 2016 (a wet year), but not in 2017 (a drought year); the effect of warming in 2018 (a year with normal precipitation) was opposite to 2016, likely due to the below‐normal precipitation in the mid‐growing season in 2018. Nitrogen addition led to increases in leaf nitrogen, ethylene production and net photosynthesis, and declines in leaf lifespan in 2016 and 2018, but not in 2017. The ethylene‐regulated lifespan was further evidenced by the addition of CoCl2 (an ethylene biosynthesis inhibitor) that reduced ethylene production and prolonged lifespan. Structural equation modeling showed that leaf lifespan had a negative effect on plant productivity, both directly and indirectly via its negative effect on net photosynthesis, across all 3 years. Our results demonstrate the divergent responses of leaf lifespan and, in turn, plant productivity to warming under inter‐annual and intra‐annual precipitation variation, thus linking plant hormone production, functional traits and ecosystem functioning in the face of global environmental change.

Variations in Rainfall Affect the Responses of Foliar Chemical Properties of Cunninghamia lanceolata Seedlings to Soil Warming

“…We found that warming significantly increased foliar δ 15 N (Figure 4), indicating warming increases the fractionation of δ 15 N and exacerbates the loss of lighter 14 N in the soil. Likewise, warming treatments triggered large N losses in desert steppes and subarctic ecosystems (Maranon-Jimenez et al, 2019;Ren et al, 2021). Moreover, δ 15 N fractionation was intensified by lower rainfall, as evidenced by the significant negative correlation between seasonal rainfall and the response ratio of foliar δ 15 N to warming.…”

“…Many other factors, such as rainfall, developmental stage, and resource supply might also affect the response of plant stoichiometry to warming (Han et al, 2011). One-time sampling only provides a "snapshot" of the plant's response to warming, and the details of seasonal and interannual variations in these responses warrant further investigation (Ren et al, 2021).…”

Effects of Exogenous Ethylene and Cobalt Chloride on Root Growth of Chinese Fir Seedlings under Phosphorus-Deficient Conditions

“…Ethephon is a precursor of ethylene synthesis and signal transduction, and it functions as a plant growth regulator. Depending on the environment, ethylene signaling pathways can lead to the inhibition or activation of a series of genes, thereby inducing differential morphological developments in plants [17,18]. In contrast, CoCl 2 promotes the synthesis of auxin and cytokinin and directly inhibits the synthesis of ethylene; therefore, it can reduce the effects of ethylene, and thus, significantly affect plant growth and development as well as the stress resistance physiology [19].…”

Transcriptome Level Analysis of Genes of Exogenous Ethylene Applied under Phosphorus Stress in Chinese Fir

“…Under P stress conditions, low concentrations of CoCl 2 promoted both POD and SOD activities in Chinese fir seedlings [ 17 ]. The application of CoCl 2 in desert grasslands can extend the life span of plant leaves by reducing ethylene content [ 18 ]. Therefore, under Pi deficiency, we used ethephon and CoCl 2 to control the exogenous ethylene content separately to observe its response in the genes.…”