Does water hyacinth (Eichhornia crassipes) compensate for simulated defoliation? Implications for effective biocontrol

作者：Soti Pushpa G; Volin John C^*

来源：Biological Control, 2010, 54(1): 35-40.

DOI：10.1016/j.biocontrol.2010.01.008

• Eichhornia crassipes
• Water hyacinth
• Invasive species
• Simulated herbivory
• Relative growth rate
• Photosynthesis
• Allocation
• Specific leaf area
• Leaf mass ratio
• Compensation
• Neochetina eichhorniae
• Neochetina bruchi

Biocontrol agents of water hyacinth (Eichhornia crassipes), one of the most ubiquitous invasive aquatic species in the world, were introduced in the waterways of Florida, USA, more than 30 years ago but have not been as successful as expected. The high nutrient, high light, warm year-round temperatures and lack of natural predators provide an optimal growth environment for the plant. The current study was designed to test if a compensatory response by the water hyacinth plants to low levels of biomass removal was one of the reasons for the ineffectiveness of biocontrol agents in the successful control of water hyacinth. The plants were exposed to two levels of nutrient (high and low) and three levels (0%, 10% and 80%) of simulated herbivory treatment. The effect of the nutrient and repeated (i.e., chronic) defoliation treatments was determined after 6 weeks. Plants with 10% defoliation did not show any significant difference from control plants in biomass allocation or relative growth rate (RGR) in either nutrient concentration, while 80% defoliation caused a significant decrease in the final RGR under high and low nutrient treatments. High nutrient treatment resulted in higher RGR and allocation to asexual reproduction resulting in higher biomass accumulation compared to the low nutrient treatment, which had higher root growth and allocation to sexual reproduction. Results from this study indicate that water hyacinth can fully compensate for low levels of continuous defoliation regardless of the nutrient concentration, which has implications and important considerations for biocontrol strategies.

• 出版日期2010-7