Belowground advantages in construction cost facilitate a cryptic plant invasion

Area of Science:

• Plant Ecology
• Global Change Biology
• Plant Physiology

Background:

• Plant organ construction cost is a key trait for understanding carbon investment and resource allocation.
• Studies on construction costs have predominantly focused on leaves, neglecting belowground organs like roots and rhizomes.
• Roots and rhizomes are crucial for resource acquisition and plant responses to global change.

Purpose of the Study:

• To compare the construction costs of aboveground and belowground organs between native and introduced lineages of Phragmites australis.
• To investigate the influence of elevated CO2 and nitrogen levels on these construction costs.
• To understand the implications of differing construction costs for plant growth and spread.

Main Methods:

• Cultivating Phragmites australis plants under ambient and elevated CO2 levels, and two soil nitrogen concentrations.
• Measuring the construction costs of leaves, stems, rhizomes, roots, and whole plants.
• Analyzing differences in construction costs between native and introduced lineages across treatments.

Main Results:

• The introduced Phragmites lineage showed a 4.3% lower mean rhizome construction cost than the native lineage across all conditions.
• Whole-plant construction costs were also lower in the introduced lineage, with the largest difference (3.3%) observed under ambient conditions.
• Lower construction costs in the introduced lineage facilitate faster recouping of investment and increased biomass generation.

Conclusions:

• Introduced Phragmites possesses a more advantageous tissue investment strategy, characterized by lower construction costs.
• This strategy has likely facilitated its clonal spread and success, especially under historical global change conditions.
• Future research on plant carbon economy and global change should incorporate construction costs from multiple organ types.