A systematic review of the effects of elevated CO2 concentration on the growth of selected tropical trees
Abstract
The elevated CO2 concentration causes drastic changes in the world's climatic conditions, affecting the growth and development of plants in their natural settings. Hence, scientists have been exploring this field to understand better the current trend of plant responses toward the intervention of elevated CO2, and this systematic review created a generalized body of knowledge. The 27 out of 3,568 articles that passed the final selection process were selected and evaluated following the inclusion or exclusion Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Population-Intervention-Comparison-Outcome (PICO) model was used to create Boolean search strings for the ScienceDirect and Scopus databases to find these included articles and Google Scholar for manual searching. These articles were downloaded as BibTeX and organized on Mendeley (version 1.19.8). The QGIS (version 3.16.15) was used to create the world map, and RStudio (version 4.2.2) was also used to visualize the descriptive statistics. The results showed that India (9 articles) has the highest number of reviewed articles, followed by the Republic of Panama and Brazil (4 articles each), Malaysia (3 articles), China and England (2 articles each), and Portugal, Australia, and Borneo (1 article each). Twenty-four articles had a controlled methodological approach, while three had an observational approach. The reviewed articles revealed that the elevated CO2 affected the biomass (aboveground, belowground, dry, and total plant biomass) production, morphological (leaf characteristics, root characteristics, number of branches, stomatal characteristics, plant height, and stem diameter), and physiological (photosynthetic rates, transpiration rates, water use efficiency, stomatal conductance, intercellular CO2 concentration, chlorophyll content, and biochemical activity) response of the tropical trees. Hence, it is justified that there are tropical tree species that can and cannot survive the worsening climate change.
