Two basic ecological relationships, herbivory and competition, distinctively influence terrestrial ecosystem characteristics, such as plant cover, species richness and species composition. We conducted a cage experiment under natural conditions in an aquatic ecosystem to test the impacts of two treatments combined in a factorial manner: (i) a pulse treatment - removal of dominant competitors among primary producers (macroalgae Chara sp. and Vaucheria sp.), and (ii) a press treatment - preventing herbivore (fish, crayfish) access to caged plots. The plots were sampled once before the treatments were established and four more times within two years. Both treatments had a significantly positive impact on macrophyte cover and species richness and changed the macrophyte species composition. The effect of the macroalgae removal was immediate with the highest species richness occurrence during the first post-treatment monitoring, but the positive effect vanished with time. In contrast, preventing herbivore access had a gradual but long-lasting effect and reached a more steady-state over time. Two of the most common species showed contrasting responses, the palatable Potamogeton pectinatus was most supported by caging, while the distasteful Myriophyllum spicatum preferred open plots. Our findings may be applicable during the revitalisation of aquatic ecosystems that aims to increase macrophyte biodiversity.

• MeSH
• Biodiversity * MeSH
• Herbivory physiology   MeSH
• Chara physiology   MeSH
• Plant Dispersal * MeSH
• Lakes MeSH
• Potamogetonaceae physiology   MeSH
• Environmental Restoration and Remediation MeSH
• Fishes physiology   MeSH
• Astacoidea physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Land plants evolved from charophytic algae, among which Charophyceae possess the most complex body plans. We present the genome of Chara braunii; comparison of the genome to those of land plants identified evolutionary novelties for plant terrestrialization and land plant heritage genes. C. braunii employs unique xylan synthases for cell wall biosynthesis, a phragmoplast (cell separation) mechanism similar to that of land plants, and many phytohormones. C. braunii plastids are controlled via land-plant-like retrograde signaling, and transcriptional regulation is more elaborate than in other algae. The morphological complexity of this organism may result from expanded gene families, with three cases of particular note: genes effecting tolerance to reactive oxygen species (ROS), LysM receptor-like kinases, and transcription factors (TFs). Transcriptomic analysis of sexual reproductive structures reveals intricate control by TFs, activity of the ROS gene network, and the ancestral use of plant-like storage and stress protection proteins in the zygote.

• MeSH
• Biological Evolution MeSH
• Cell Wall metabolism   MeSH
• Chara genetics   growth & development   MeSH
• Genome, Plant * MeSH
• Gene Regulatory Networks MeSH
• Pentosyltransferases genetics   MeSH
• Protein Serine-Threonine Kinases genetics   metabolism   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Plant Growth Regulators metabolism   MeSH
• Plant Proteins genetics   metabolism   MeSH
• Transcription Factors genetics   metabolism   MeSH
• Transcriptome MeSH
• Embryophyta genetics   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Melatonin was found in the fresh water characeae Chara australis. The concentrations (~4 μg/g of tissue) were similar in photosynthesizing cells, independent of their position on the plant and rhizoids (roots) without chloroplasts. Exogenous melatonin, added at 10 μM to the artificial pond water, increased quantum yield of photochemistry of photosystem II by 34%. The increased efficiency appears to be due to the amount of open reaction centers of photosystem II, rather than increased efficiency of each reaction center. More open reaction centers reflect better functionality of all photosynthetic transport chain constituents. We suggest that melatonin protection against reactive oxygen species covers not only chlorophyll, but also photosynthetic proteins in general.

• MeSH
• Antioxidants metabolism   pharmacology   MeSH
• Chara drug effects   metabolism   MeSH
• Characeae MeSH
• Chlorophyll metabolism   MeSH
• Chloroplasts MeSH
• Photosynthesis * drug effects   MeSH
• Photosystem II Protein Complex metabolism   MeSH
• Melatonin metabolism   pharmacology   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Light-Harvesting Protein Complexes metabolism   MeSH
• Electron Transport * drug effects   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH