Abstract
With the development of economy, the heavy metal contamination has become an increasingly serious problem, especially the cadmium (Cd) contamination. The emergent plant Nasturtium officinale R. Br. is a Cd-accumulator with low phytoremediation ability. To improve Cd phytoextraction efficiency of N. officinale, the straw from Cd-hyperaccumulator plants Youngia erythrocarpa, Galinsoga parviflora, Siegesbeckia orientalis, and Bidens pilosa was applied to Cd-contaminated soil and N. officinale was then planted; the study assessed the effect of hyperaccumulator straw on the growth and Cd accumulation of N. officinale. The results showed that application of hyperaccumulator species straws increased the biomass and photosynthetic pigment content and reduced the root/shoot ratio of N. officinale. All straw treatments significantly increased Cd content in roots, but significantly decreased Cd content in shoots of N. officinale. Applying hyperaccumulator straw significantly increased the total Cd accumulation in the roots, shoots, and whole plants of N. officinale. Therefore, application of straw from four hyperaccumulator species promoted the growth of N. officinale and improved the phytoextraction efficiency of N. officinale in Cd-contaminated paddy field soil; the straw of Y. erythrocarpa provided the most improvement.
Keywords: Cadmium; Hyperaccumulator straw; Nasturtium officinale; Phytoremediation.
Write only the 1. main points 2. Gaps 3. Difficulty in the studies 4 future research studies base on information given
1. Main points:
- Straw from hyperaccumulator plants can improve the Cd phytoextraction efficiency of Nasturtium officinale in Cd-contaminated soil.
- Application of hyperaccumulator species straw increases biomass and Cd accumulation in roots of N. officinale, while decreasing Cd accumulation in shoots.
- Y. erythrocarpa straw showed the most improvement in Cd phytoextraction efficiency.
2. Gaps:
- The study did not investigate the mechanisms behind the improved Cd phytoextraction efficiency of N. officinale with hyperaccumulator straw application.
- The long-term effects of hyperaccumulator straw application on soil health and plant growth were not examined.
3. Difficulty in the studies:
- It may be challenging to identify the specific factors in hyperaccumulator straw that lead to improved Cd phytoextraction efficiency in N. officinale.
- Conducting long-term field studies to assess the sustainability of hyperaccumulator straw application in Cd-contaminated soils can be complex and require extensive resources.
4. Future research studies:
- Investigate the mechanisms behind the improved Cd phytoextraction efficiency of N. officinale with hyperaccumulator straw application, such as changes in soil microbial communities or nutrient availability.
- Conduct long-term field studies to evaluate the sustainability of hyperaccumulator straw application on soil health and plant growth in Cd-contaminated environments.