Abstract
Plant senescence is a critical life history process accompanied by chlorophyll degradation and has large implications for nutrient resorption and carbohydrate storage. Although photoperiod governs much of seasonal leaf senescence in many plant species, temperature has also been shown to modulate this process. Therefore, we hypothesized that climate warming would significantly impact the length of the plant growing season and ultimate productivity. To test this assumption, we measured the effects of simulated autumn climate warming paradigms on four native herbaceous species that represent distinct life forms of alpine meadow plants on the Tibetan Plateau. Conditions were simulated in open-top chambers (OTCs) and the effects on the degradation of chlorophyll, nitrogen (N) concentration in leaves and culms, total non-structural carbohydrate (TNC) in roots, growth and phenology were assessed during one year following treatment. The results showed that climate warming in autumn changed the senescence process only for perennials by slowing chlorophyll degradation at the beginning of senescence and accelerating it in the following phases. Warming also increased root TNC storage as a result of higher N concentrations retained in leaves; however, this effect was species dependent and did not alter the growing and flowering phenology in the following seasons. Our results indicated that autumn warming increases carbohydrate accumulation, not only by enhancing activities of photosynthetic enzymes (a mechanism proposed in previous studies), but also by affecting chlorophyll degradation and preferential allocation of resources to different plant compartments. The different responses to warming can be explained by inherently different growth and phenology patterns observed among the studied species. The results implied that warming leads to changes in the competitive balance among life forms, an effect that can subsequently shift vegetation distribution and species composition in communities.
Highlights
Global warming has raised the global mean surface temperature by approximately 0.74uC over the period 1906–2005 and is predicted to further increase it by an additional 1.8–4.0uCduring the 21st century [1]
We found that non-perennial herbs (E. regelii and S. mussotii) ceased their senescence mainly by late-September, while perennials species (E. nutans and D. caeruleum) completed senescence by late-October (Figure 2)
In conclusion, our study has shown that autumn warming in an alpine meadow of the Tibetan Plateau can affect plant senescence processes by slowing chlorophyll degradation
Summary
Global warming has raised the global mean surface temperature by approximately 0.74uC over the period 1906–2005 and is predicted to further increase it by an additional 1.8–4.0uCduring the 21st century [1]. This unprecedented warming has greatly impacted plant growth phenology and function across biomes, and attracted a growing alarm from ecologists [2,3,4,5]. One of the growing concerns of global warming is its potential effects on basic plant processes, such as the degradation of chlorophyll during senescence. The potential effects of climate change on senescence and C usage are poorly understood provides the basis of our investigation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
