Physical space interacts with clonal fragmentation and nutrient availability to affect the growth of Salvinia natans.

Chao Si,Jing Lin,Fei-Hai Yu,Jian-Feng Zhang,Jin-Song Chen,Yu Jin,Jian Liu

doi:10.1371/journal.pone.0226850

Chao Si, Jing Lin + Show 5 more

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https://doi.org/10.1371/journal.pone.0226850

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Abstract

Physical space, clonal fragmentation and nutrient availability can each affect the growth of clonal plants, but their interactive effect has been little studied. We grew un-fragmented (connected) and fragmented (disconnected) ramet pairs of the floating, clonal plant Salvinia natans in cylindrical containers with different diameters and heights (volumes) filled with solutions of two nutrient levels (high vs. low). To simulate competition environments that are commonly confronted by S. natans, we also added two ramets of another floating plants Spirodela polyrrhiza in each container. Biomass (total biomass, floating biomass and submerged biomass) and number of ramets of S. salvinia were higher in the containers with a larger diameter. Compared to the low nutrient level, the high nutrient level increased number of ramets, and altered submerged to floating mass ratio of S. salvinia. The impacts of physical space on floating mass and number of ramets were stronger under the high than under the low nutrient level. Clonal fragmentation positively affected biomass in the containers with a smaller volume (a smaller height and diameter), but had little impact in the containers with a larger volume (a larger height or diameter). Our results suggest that physical space can interact with nutrients and clonal fragmentation to affect the performance of S. salvinia under competition.

Highlights

Aquatic ecosystems are commonly dominated by clonal plants [1,2,3,4]
The high nutrient level decreased submerged mass in all three levels of physical space, but such an impact was higher in W than in S and T
The high nutrient level decreased the ratio of submerged mass to floating mass, but such an impact was much higher in S and W than in T

Summary

Introduction

Aquatic ecosystems are commonly dominated by clonal plants [1,2,3,4]. Many clonal plants can form a network of ramets interconnected by stolons, rhizomes or horizontally growing roots [5,6,7,8]. Aquatic ecosystems are frequently subjected to disturbances caused by natural events and human activities such as flooding, invertebrate and waterfowl grazing, fishing and transportation [3,9,10,11], which can fragment the previous interconnected clonal network of aquatic plants [10,12,13]. Fragmentation may adversely affect plant growth because transport of resources such as carbohydrates and mineral nutrients between ramets is cut off [14,15,16].

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