Variation in resource allocation strategies and environmental driving factors for different life forms of aquatic plants in cold temperate zones

1. Resource allocation, including biomass allocation and nutrient
allocation between different organs in a plant, reflects the trade-off in
partitioning between aboveground and belowground organs and the growth and
adaptation strategies of plants in a changing environment. Although varied
resource allocation patterns among different organs in different
functional groups of terrestrial plants have been found, few studies have
focused on freshwater ecosystems. 2. In this study, to clarify biomass and
nutrient allocation strategies and their responses to environmental
factors, we collected and analysed 2162 samples from 262 aquatic plant
communities (including emergent plants, floating-leaved plants and
submerged plants) in various aquatic habitats in northeastern China. 3.
The results showed that the root/shoot (R/S) ratios of the three aquatic
plant life forms were significantly different, and the trend showed that
the ratio values for the three plant life forms occurred in the following
order: emergent plants > floating-leaved plants > submerged
plants. There were obvious scaling relationships between aboveground
biomass, N (or P or N:P ratios) and belowground biomass, N (or P or N:P
ratios), but their scaling exponents changed among different aquatic plant
life forms. The allocation of biomass and nutrients between different
organ responses to environmental factors was not consistent for the
different life forms of aquatic plants. The partial least squares path
model revealed that plant stoichiometric characteristics are important
direct drivers of biomass production. Climate conditions, water properties
and soil nutrients indirectly affect biomass through effects on plant
stoichiometric characteristics. 4. Synthesis: Our study
demonstrates that global climate change may affect water properties and
soil nutrients, influence plant stoichiometric characteristics and affect
aquatic plant growth, further altering aquatic plant community structure
and biogeochemical cycles.