Identification of the unique molecular framework of heterophylly in the amphibious plant Callitriche palustris L.

Heterophylly is the development of different leaf forms in a single plant depending on the environmental conditions. It is often observed in amphibious aquatic plants that can grow under both aerial and submerged conditions. Although heterophylly is well recognized in aquatic plants, the associated developmental mechanisms and the molecular basis remain unclear. To clarify these underlying developmental and molecular mechanisms, we analyzed heterophyllous leaf formation in an aquatic plant, Callitriche palustris. Morphological analyses revealed extensive cell elongation and the rearrangement of cortical microtubules in the elongated submerged leaves of C. palustris. Our observations also suggested that gibberellin, ethylene, and abscisic acid all regulate the formation of submerged leaves. However, the perturbation of one or more of the hormones was insufficient to induce the formation of submerged leaves under aerial conditions. Finally, we analyzed gene expression changes during aerial and submerged leaf development and narrowed down the candidate genes controlling heterophylly via transcriptomic comparisons, including a comparison with a closely related terrestrial species. We discovered that the molecular mechanism regulating heterophylly in C. palustris is associated with hormonal changes and diverse transcription factor gene expression profiles, suggesting differences from the corresponding mechanisms in previously investigated amphibious plants.

Composition and Larvicidal Activity of the Oil of Dizygostemon riparius (Plantaginaceae), a New Aromatic Species Occurring in Maranhão, Brazil.

Dizygostemon riparius (Plantaginaceae) is a new aromatic herbaceous species occurring in Maranhão State, Brazil. It is used as flavorings to remove domestic animal parasites and preventing mosquitoes. GC and GC/MS were used to analyze its essential oil, and a larvicidal bioassay was performed against Aedes albopictus larvae, a vector of arboviruses in Brazil. endo-Fenchyl acetate, endo-fenchol, (E)-caryophyllene, and caryophyllene oxide were the oil's primary constituents, totalizing 88.0 %. The two morphotypes of D. riparius, with purple and white flowers, did not present a significant difference in the oils' composition. From a chemotaxonomic point of view, D. riparius oil showed some similarities with other oils of Plantaginaceae, suggesting (E)-caryophyllene and caryophyllene oxide as possible chemical markers. The oil larvicidal action displayed the lowest and highest mortality percentage at 50 mg/L (2.0 %) and 600 mg/L (88.0 %). The fenchyl acetate and fenchol standards showed a lower and higher mortality percentage at a concentration of 300 mg/L (42.0 % and 26.0 %) and 900 mg/L (96.0 % and 98.0 %), respectively. The present study results with the D. riparius oil point to a new bioproduct with significant larvicidal activity.

Host Plant Suitability in a Specialist Herbivore, Euphydryas anicia (Nymphalidae): Preference, Performance and Sequestration.

The checkerspot butterfly, Euphydryas anicia (Nymphalidae), specializes on plants containing iridoid glycosides and has the ability to sequester these compounds from its host plants. This study investigated larval preference, performance, and sequestration of iridoid glycosides in a population of E. anicia at Crescent Meadows, Colorado, USA. Although previous studies showed that other populations in Colorado use the host plant, Castilleja integra (Orobanchaceae), we found no evidence for E. anicia ovipositing or feeding on C. integra at Crescent Meadows. Though C. integra and another host plant, Penstemon glaber (Plantaginaceae), occur at Crescent Meadows, the primary host plant used was P. glaber. To determine why C. integra was not being used at the Crescent Meadows site, we first examined the host plant preference of naïve larvae between P. glaber and C. integra. Then we assessed the growth and survivorship of larvae reared on each plant species. Finally, we quantified the iridoid glycoside concentrations of the two plant species and diapausing caterpillars reared on each host plant. Our results showed that E. anicia larvae prefer P. glaber. Also, larvae survive and grow better when reared on P. glaber than on C. integra. Castilleja integra was found to contain two primary iridoid glycosides, macfadienoside and catalpol, and larvae reared on this plant sequestered both compounds; whereas P. glaber contained only catalpol and larvae reared on this species sequestered catalpol. Thus, although larvae are able to use C. integra in the laboratory, the drivers behind the lack of use at the Crescent Meadows site remain unclear.

In vitro and in vivo wound healing activities of Globularia arabica leaf methanolic extract in diabetic rats.

AIM: This study assessed the effects of topical application of the plant Globularia arabica extract on the diabetic rate of wound closure. METHODS: The effect of methanol extracts of G. arabica leaf extract on pro-inflammatory and anti-inflammatory cytokines, as well as the rate of wound contraction, hydroxyproline, and collagen content, was examined using an excision model of wound repair in male rats. RESULTS: The healing pattern was also highly related to using 10% plant extract and significantly, (p-values <0.025) increased wound contraction and increased hydroxyproline and collagen expression in both non-diabetic and diabetic rats, demonstrating that G. arabica extract possesses potent wound healing capacity. During the early wound healing phase, IL-6 levels were found to be upregulated by G. arabica treatment. Increased wound contraction augmented hydroxyproline and collagen content, supporting the early wound healing exhibited by G. arabica. One of the ways for speeding wound healing may be the induction of cytokine production. The result of our study shows that the fibroblast cell line treated with 20 µg/ml methanolic extract of G. arabica significantly (p-values <0.035) increases the cell migration that indicated the high wound healing activity. CONCLUSION: Results suggest that G. arabica may be useful in the topical management of wound healing.

Root exudate composition of grass and forb species in natural grasslands.

Plants exude a diverse cocktail of metabolites into the soil as response to exogenous and endogenous factors. So far, root exudates have mainly been studied under artificial conditions due to methodological difficulties. In this study, each five perennial grass and forb species were investigated for polar and semi-polar metabolites in exudates under field conditions. Metabolite collection and untargeted profiling approaches combined with a novel classification method allowed the designation of 182 metabolites. The composition of exuded polar metabolites depended mainly on the local environment, especially soil conditions, whereas the pattern of semi-polar metabolites was primarily affected by the species identity. The profiles of both polar and semi-polar metabolites differed between growth forms, with grass species being generally more similar to each other and more responsive to the abiotic environment than forb species. This study demonstrated the feasibility of investigating exudates under field conditions and to identify the driving factors of exudate composition.