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Journal of Arid Land

Article Title

Ecological biomass allocation strategies in plant species with different lifeforms in a cold desert, China

Abstract

Biomass allocation patterns among plant species are related to theiradaptive ecological strategies. Ephemeral, ephemeroid and annual plant life forms represent three typical growth strategies of plants thatgrow in autumn and early spring in the cold deserts of China. These plants play an important role in reducing wind velocity in the desert areas. However, despite numerous studies, the strategies of biomass allocation amongplant species with these three lifeforms remain contentious. In this study, we conducted a preliminary quadrat study during2014–2016 in the southern part of the Gurbantunggut Desert, China, to investigate the allocation patterns of above-ground biomass (AGB) and below-ground biomass (BGB) at the individual level in 17 ephemeral, 3 ephemeroid and 4 annual plant species. Sinceephemeral plants can germinate in autumn, we also compared biomass allocation patterns between plants thatgerminated in autumn 2015 and spring 2016 for 4 common ephemeral species. Thehealthy mature individualplants of each species were sampled and the AGB, BGB, total biomass (TB), leaf mass ratio (LMR) and root/shoot ratio (R/S) were calculatedfor 201 sample quadrats in the study area. We also studiedthe relationshipsbetween AGB and BGB of plants with the three different life forms (ephemeral, ephemeroid and annual).The mean AGB valuesof ephemeral, ephemeroid and annual plants were 0.806,3.759 and 1.546 g/plant, respectively, and the mean BGB values were 0.106, 4.996 and 0.166 g/plant, respectively. The mean R/S value was significantly higher in ephemeroid plants (1.675) than in ephemeral (0.154) and annual (0.147) plants. The mean LMR was the highest in annual plants, followed by ephemeroid plants and ephemeral plants, reflecting the fact that annual plants allocate more biomass to leaves,associated with their longer life span. Biomass of ephemeral plants that germinated in autumn was significantly higher than those of corresponding plants that germinated in spring in terms of AGB, BGB and TB. However, the R/S valuewas similar in plants that germinated in autumn and spring. The slopeof regression relationship between AGB and BGB differed significantly among the three plant life forms. These results support different biomass allocation hypotheses. Specifically, at the individual level, the AGB and BGB partitioning supports the allometric hypothesisforephemeroid and annual plants and the isometric hypothesisfor ephemeral plants.

Keywords

above-ground biomass; below-ground biomass; plant lifeforms; herbaceous species; allometric hypothesis; isometric hypothesis; Gurbantunggut Desert

First Page

729

Last Page

739

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