Effects of size and moisture of rhizome on initial invasiveness ability of giant reed

Abstract

Studies were conducted under controlled conditions to determine growth and reproductive capabilities of Arundo donax L. (giant reed), a riparian invasive perennial plant that has spread widely. Greenhouse experiments were conducted to determine the influence of rhizome size and moisture content in the early invasiveness ability of giant reed. We tested different sizes of rhizomes: rhizome size of 1 cm, 3 cm, 5 cm and shredded rhizome. (fragments < 1 cm). These rhizomes were observed at 7, 14, 21, 28 and 35 days after planting (DAP). To test the effect of moisture content we used fresh rhizome fragments; rhizomes with moderate dehydration (50%); rhizomes with high dehydration (over 70%) with 48 hours of rehydration and rhizomes with high dehydration (70–90%). The rhizomes monitored for moisture content and biomass increase were between 3 and 5 cm, and were observed 60 DAP. The initial size of rhizomes affected the level of sprouting. Rhizomes with low moisture content (due to dehydration) showed high increase in biomass compared with the rhizomes that had not been treated or had been dehydrated and then rehydrated. Our results indicated that size of rhizomes is related to regrowth and low moisture (dehydration) content can be overcome by this species. This could be linked to high rates of colonization and early establishment ability of this species even after mechanical treatment of rhizomes, in riparian environments.

Keywords:

• Aquatic ecosystems
• Arundo
• greenhouse
• growth
• invasive
• weed
• riparian environment

Acknowledgments

This study is part of a Research, Development & Investigation project developed by the Dirección General del Agua of the Spanish Ministry of Agriculture, Food and the Environment, the Spanish company TRAGSA and INIA (CON10-044). The original manuscript was checked by an experienced English teacher, Charlotte Harvey.