Most cited article - PubMed ID 30413987
Effects of polyploidization on the contents of photosynthetic pigments are largely population-specific
Melissa officinalis L., a well-known herb with diverse industrial and ethnopharmacological properties. Although, there has been a significant lack in the breeding attempts of this invaluable herb. This study aimed to enhance the agronomical traits of M. officinalis through in vitro polyploidization. Nodal segments were micropropagated and subjected to oryzalin treatment at concentrations of 20, 40, and 60 mM for 24 and 48 hours. Flow cytometry, chromosome counting, and stomatal characteristics were employed to confirm the ploidy level of the surviving plants. The survival rate of the treated explants decreased exponentially with increasing oryzalin concentration and duration. The highest polyploid induction rate (8%) was achieved with 40 mM oryzalin treatment for 24 hours. The induced tetraploid plants exhibited vigorous growth, characterized by longer shoots, larger leaves, and a higher leaf count. Chlorophyll content and fluorescence parameters elucidated disparities in photosynthetic performance between diploid and tetraploid genotypes. Tetraploid plants demonstrated a 75% increase in average essential oil yield, attributed to the significantly larger size of peltate trichomes. Analysis of essential oil composition in diploid and tetraploid plants indicated the presence of three major components: geranial, neral, and citronellal. While citronellal remained consistent, geranial and neral increased by 11.06% and 9.49%, respectively, in the tetraploid population. This effective methodology, utilizing oryzalin as an anti-mitotic agent for polyploid induction in M. officinalis, resulted in a polyploid genotype with superior morpho-physiological traits. The polyploid lemon balm generated through this method has the potential to meet commercial demands and contribute significantly to the improvement of lemon balm cultivation.
- Keywords
- Melissa officinalis, chromosome doubling, crop improvement, essential oil, oryzalin, polyploid induction, polyploidization,
- Publication type
- Journal Article MeSH
Epigenetic regulation of gene expression is expected to be an important mechanism behind phenotypic plasticity. Whether epigenetic regulation affects species ecophysiological adaptations to changing climate remains largely unexplored. We compared ecophysiological traits between individuals treated with 5-azaC, assumed to lead to DNA demethylation, with control individuals of a clonal grass originating from and grown under different climates, simulating different directions and magnitudes of climate change. We linked the ecophysiological data to proxies of fitness. Main effects of plant origin and cultivating conditions predicted variation in plant traits, but 5-azaC did not. Effects of 5-azaC interacted with conditions of cultivation and plant origin. The direction of the 5-azaC effects suggests that DNA methylation does not reflect species long-term adaptations to climate of origin and species likely epigenetically adjusted to the conditions experienced during experiment set-up. Ecophysiology translated to proxies of fitness, but the intensity and direction of the relationships were context dependent and affected by 5-azaC. The study suggests that effects of DNA methylation depend on conditions of plant origin and current climate. Direction of 5-azaC effects suggests limited role of epigenetic modifications in long-term adaptation of plants. It rather facilitates fast adaptations to temporal fluctuations of the environment.
- MeSH
- Azacitidine pharmacology MeSH
- Epigenesis, Genetic * MeSH
- Climate Change MeSH
- Humans MeSH
- DNA Methylation * MeSH
- Genes, Plant MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Azacitidine MeSH
Knowledge of the relationship between environmental conditions and species traits is an important prerequisite for understanding determinants of community composition and predicting species response to novel climatic conditions. Despite increasing number of studies on this topic, our knowledge on importance of genetic differentiation, plasticity and their interactions along larger sets of species is still limited especially for traits related to plant ecophysiology. We studied variation in traits related to growth, leaf chemistry, contents of photosynthetic pigments and activity of antioxidative enzymes, stomata morphology and photosynthetic activity across eight Impatiens species growing along altitudinal gradients in Himalayas cultivated in three different temperature regimes and explored effects of among species phylogenetic relationships on the results. Original and target climatic conditions determine trait values in our system. The traits are either highly plastic (e.g., APX, CAT, plant size, neoxanthin, β-carotene, chlorophyll a/b, DEPSC) or are highly differentiated among populations (stomata density, lutein production). Many traits show strong among population differentiation in degree of plasticity and direction in response to environmental changes. Most traits indicate that the species will profit from the expected warming. This suggests that different processes determine the values of the different traits and separating the importance of genetic differentiation and plasticity is crucial for our ability to predict species response to future climate changes. The results also indicate that evolution of the traits is not phylogenetically constrained but including phylogenetic information into the analysis may improve our understanding of the trait-environment relationships as was apparent from the analysis of SLA.
