Tej Bahadur Darji1, Barsha Adhikari2, Seeta Pathak1, Shristi Neupane2, Lal B Thapa3, Tara Datt Bhatt4, Ramesh Raj Pant2, Gunanand Pant5, Khadka Bahadur Pal6, Kiran Bishwakarma7. 1. Central Department of Botany, Institute of Science and Technology, Tribhuvan University, Kathmandu, Nepal. 2. Central Department of Environmental Science, Institute of Science and Technology, Tribhuvan University, Kathmandu, Nepal. 3. Central Department of Botany, Institute of Science and Technology, Tribhuvan University, Kathmandu, Nepal. lal.thapa@cdbtu.edu.np. 4. Department of Plant Resources, Ministry of Forests and Environment, Government of Nepal, Thapathali, Kathmandu, Nepal. 5. Department of Biology, Kailali Multiple Campus, Tribhuvan University, Dhangadhi, Nepal. 6. Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal. 7. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China.
Abstract
The response of native plants to allelopathic interference of invasive species may differ from species to species. In this study, the phytotoxic effects of Ageratina adenophora were tested on two native shrubs (Osbeckia stellata and Elsholtzia blanda) of Nepal. Both the shrubs were grown in pots under treatments of A. adenophora fresh leaves and root leachates, and litter. Then, the seedling length and biomass were compared among the treatments. The results show that A. adenophora litter has stimulatory effects but the leachates from fresh leaves and root are phytotoxic to the growth and development of native shrubs. Infrared Spectroscopy (IR) analysis confirmed the presence of O-H (Hydroxyl), N-H (Amines), C≡C (Alkynes), and C-H stretching (Aromatic) or C-O-C stretching (Ethers) in the leachates representing harmful allelochemicals. The invaded soil by A. adenophora had low pH and a high amount of organic matter, total nitrogen, phosphorus, and potassium than the uninvaded soil. The results indicate that the native O. stellata and E. blanda are harmed by A. adenophora in nature by leaching of allelochemicals and probably by reducing the soil pH. Overall, this study has provided valuable insights regarding the effects of A. adenophora invasion on native shrubs and revealing the potential mechanism of its invasiveness.
The response of native plants to allelopathic interference of invasive species may differ from species to species. In this study, the phytotoxic effects of Ageratina adenophora were tested on two native shrubs (n class="Species">Osbeckia stellata and Elsholtzia blanda) of Nepal. Both the shrubs were grown in pots under treatments of A. adenophora fresh leaves and root leachates, and litter. Then, the seedling length and biomass were compared among the treatments. The results show that A. adenophora litter has stimulatory effects but the leachates from fresh leaves and root are phytotoxic to the growth and development of native shrubs. Infrared Spectroscopy (IR) analysis confirmed the presence of O-H (Hydroxyl), N-H (Amines), C≡C (Alkynes), and C-H stretching (Aromatic) or C-O-C stretching (Ethers) in the leachates representing harmful allelochemicals. The invaded soil by A. adenophora had low pH and a high amount of organic matter, total nitrogen, phosphorus, and potassium than the uninvaded soil. The results indicate that the native O. stellata and E. blanda are harmed by A. adenophora in nature by leaching of allelochemicals and probably by reducing the soil pH. Overall, this study has provided valuable insights regarding the effects of A. adenophora invasion on native shrubs and revealing the potential mechanism of its invasiveness.