The legume tree Serianthes nelsonii, the most endangered plant species in the Mariana Islands, is facing persistent threats to its recovery. One of the main challenges is the short lifespan of habitat seedlings and the rapid death of saplings transplanted from conservation nurseries.
To address this issue, the Plant Physiology Laboratory at the University of Guam has taken a proactive approach. They have successfully improved the growth and survival of Serianthes seedlings by strategically placing mirrors beneath deeply shaded seedlings to increase the available ambient light. This groundbreaking research has been published in the August issue of the prestigious journal Agronomy.
“We combined several known facts to develop the protocols,” said author Thomas Marler, retired University of Guam professor. “First, the amount of sunlight that penetrates to the sub-canopy is minimal in Guam’s karst forest communities, and adding available light by installing lamps above Serianthes seedlings can increase longevity. Second, colored plastic mulch has been exploited for decades to reflect sunlight to improve crop production systems.”
The pioneering protocol stemmed from the extensive adoption of black plastic mulch in various crop production systems. Visionary individuals in the 1980s recognized that since growers were already using plastic mulch, experimenting with different colors could lead to more effective management of beneficial plant responses. This led to the development of enhanced production systems for numerous crops, resulting in increased yields and minimized pest damage.
“Our first conception was to mimic these vegetable production protocols by exploiting commercially available plastic-colored mulch products,” Marler said. “Then we realized that costs associated with a reflective product were less limiting for small-scale tree conservation approaches than for large-scale crop production settings.”
The team decided to utilize mirrors as they are the most reflective option available.
Research findings demonstrated that the mirrors reflected over 70% of the incoming ambient light at midday in certain scenarios. This increase in available light energy resulted in significant plant responses, with seedling survival rates rising by over 160% and plant height increasing by more than 170% in one of the experiments.
Conservation practitioners often lack essential information to enhance management strategies for the recovery of endangered tree species.
However, this newly developed protocol is an invaluable addition to the plant conservation toolbox due to its minimal costs and high probability of improving plant performance in various applications. Moreover, the new procedure poses negligible risks of harm to the managed plants, making it a safe and effective approach.
Journal reference:
- Thomas E. Marler. Below-Plant Mirrors Improve Serianthes Seedling Survival and Growth in Shade. Agronomy, 2024; DOI: 10.3390/agronomy14081854