Original Research ARTICLE
Significance of Photosynthetic Characters in the Evolution of Asian Gnetum (Gnetales)
- 1Chinese Academy of Forestry, China
- 2Hunan Academy of Forestry, China
- 3Hunan Cili Forest Ecosystem State Research Station, P.R. China
- 4School of Life Sciences, Sun Yat-sen University, China
- 5Fujian Agriculture and Forestry University, China
- 6Department of Genetic Ecology, Institute of Botany, Academy of Sciences of the Czech Republic, Czechia
Gnetum is rich in bioactive compounds such as flavonoids and stilbenoids, which have been considered as important materials for traditional medicines and healthy food. Previous studies reveal that Gnetum has lower photosynthetic capacities than those of other seed plants. An explicit examination, however, is required since the investigated earlier samples were restricted to low numbers of species from narrow taxonomic and geographic ranges. Therefore, we conducted a study to investigate photosynthetic characteristics and composition of chloroplast genomes of five Chinese Gnetum species. We studied both Gnetum and co-occurring woody angiosperms in wild and also seedlings from different species of Gnetum in greenhouse. Our results showed that the five species of Chinese Gnetum had considerably lower levels of photosynthesis, including net photosynthetic rate, transpiration rate, intercellular CO2 concentration, stomatal conductance, than those of other seed plant representatives. These results are congruent with the results of the previous studies. Interrelated analyses revealed that low photosynthetic capacities may be an intrinsic property of Gnetum, indicating a unique evolutionary history and specific ecological adaptations in this ancient genus. In addition, through comparisons of plastid genomes among Gnetum and the representatives of other seed plants, we found that 17 coding genes were absent in this genus. This finding suggests that the lack of multiple functional genes in plastid genomes could lead to low photosynthetic rates we observed in different species of the genus. The present investigation of photosynthesis in both ecophysiological and genomic terms can provide a new perspective onevolutionary history of the Gnetales and tropical biomes in general. Our results can thus benefit the future research on breeding and cultivation of Gnetum and improve understanding of evolutionary ecology of tropical flora.
Keywords: Photosynthesis, plastid genomes, phylogeny, seed plants evolution, Gymnosperms
Received: 05 Sep 2018;
Accepted: 10 Jan 2019.
Edited by:Badri Padhukasahasram, Illumina (United States), United States
Reviewed by:Rosa A. Scherson, Universidad de Chile, Chile
Alejandra Vázquez-Lobo, Universidad Autónoma del Estado de Morelos, Mexico
Copyright: © 2019 Nan, chen, Liu, li, Bartish, tian, chen, du, jiang and Shi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Deng Nan, Chinese Academy of Forestry, Beijing, China, firstname.lastname@example.org