Breaking the Dormancy of Snake's Head Fritillary (Fritillaria meleagris L.) In Vitro Bulbs-Part 1: Effect of GA3, GA Inhibitors and Temperature on Fresh Weight, Sprouting and Sugar Content

Modeling of the Potential Geographical Distribution of Three Fritillaria Species Under Climate Change

Fritillaria species, a well-known Chinese traditional medicine for more than 2,000 years, have become rare resources due to excessive harvesting. In order to balance the economical requirement and ecological protection of Fritillaria species, it is necessary to determine (1) the important environmental variables that were responsible for the spatial distribution, (2) distribution change in response to climate change in the future, (3) ecological niche overlap between various Fritillaria species, and (4) the correlation between spatial distribution and phylogenies as well. In this study, the areas with potential ecological suitability for Fritillaria cirrhosa, Fritillaria unibracteata, and Fritillaria przewalskii were predicted using MaxEnt based on the current occurrence records and bioclimatic variables. The result indicated that precipitation and elevation were the most important environmental variables for the three species. Moreover, the current suitable habitats of F. cirrhosa, F. unibracteata, and F. przewalskii encompassed 681,951, 481,607, and 349,199 km2, respectively. Under the scenario of the highest concentration of greenhouse gas emission (SSP585), the whole suitable habitats of F. cirrhosa and F. przewalskii reach the maximum from 2021 to 2100, while those of F. unibracteata reach the maximum from 2021 to 2100 under the scenario of moderate emission (SSP370) from 2021 to 2100. The MaxEnt data were also used to predict the ecological niche overlap, and thus high overlap occurring among three Fritillaria species was observed. The niche overlap of three Fritillaria species was related to the phylogenetic analysis despite the non-significance (P > 0.05), indicating that spatial distribution was one of the factors that contributed to the speciation diversification. Additionally, we predicted species-specific habitats to decrease habitat competition. Overall, the information obtained in this study provided new insight into the potential distribution and ecological niche of three species for the conservation and management in the future.

Plant Growth Regulators Application Enhance Tolerance to Salinity and Benefit the Halophyte Plantago coronopus in Saline Agriculture

Climate change, soil salinisation and desertification, intensive agriculture and the poor quality of irrigation water all create serious problems for the agriculture that supplies the world with food. Halophyte cultivation could constitute an alternative to glycophytic cultures and help resolve these issues. Plantago coronopus can be used in biosaline agriculture as it tolerates salt concentrations of 100 mM NaCl. To increase the salt tolerance of this plant, plant growth regulators such as polyamine spermidine, salicylic acid, gibberellins, cytokinins, and auxins were added in a hydroponic culture before the irrigation of NaCl (200 mM). In 45-day-old plants, dry weight, water content, osmolyte (sorbitol), antioxidants (phenols, flavonoids), polyamines (putrescine, spermidine, spermine (free, bound, and conjugated forms)) and ethylene were determined. In non-saline conditions, all plant regulators improved growth while in plants treated with salt, spermidine application was the most effective in improving growth, osmolyte accumulation (43%) and an increase of antioxidants (24%) in P. coronopus. The pretreatments that increase the sorbitol content, endogenous amines (bound spermine fraction), phenols and flavonoids may be the most effective in protecting to P. coronopus against stress and, therefore, could contribute to improving the tolerance to salinity and increase nutritional quality of P. coronopus.

Bulb Dormancy In Vitro-Fritillaria meleagris: Initiation, Release and Physiological Parameters

In ornamental geophytes, conventional vegetative propagation is not economically feasible due to very slow development and ineffective methods. It can take several years until a new plant is formed and commercial profitability is achieved. Therefore, micropropagation techniques have been developed to increase the multiplication rate and thus shorten the multiplication and regeneration period. The majority of these techniques rely on the formation of new bulbs and their sprouting. Dormancy is one of the main limiting factors to speed up multiplication in vitro. Bulbous species have a period of bulb dormancy which enables them to survive unfavorable natural conditions. Bulbs grown in vitro also exhibit dormancy, which has to be overcome in order to allow sprouting of bulbs in the next vegetation period. During the period of dormancy, numerous physiological processes occur, many of which have not been elucidated yet. Understanding the process of dormancy will allow us to speed up and improve breeding of geophytes and thereby achieve economic profitability, which is very important for horticulture. This review focuses on recent findings in the area of bulb dormancy initiation and release in fritillaries, with particular emphasis on the effect of plant growth regulators and low-temperature pretreatment on dormancy release in relation to induction of antioxidative enzymes' activity in vitro.

Breaking the Dormancy of Snake's Head Fritillary (Fritillaria meleagris L.) In Vitro Bulbs-Part 2: Effect of GA3 Soaking and Chilling on Sugar Status in Sprouted Bulbs

The bulb is the main propagation organ of snake’s head fritillary (Fritillaria meleagris L.), a horticulturally attractive and rare geophyte plant species. In this study, we investigated the effect of soaking bulbs in GA₃ solution (1, 2, and 3 mg L⁻¹) combined with low-temperature treatment (7 °C) on breaking the dormancy of in vitro bulbs. Sugar status (total soluble sugars, glucose, and fructose content) was analyzed in different parts of the sprouted bulbs. The results showed that the soluble sugar concentration was highest in bulbs soaked in GA₃. The main sugar in fritillary bulbs was glucose, while fructose content was much lower. Glucose concentration dramatically increased after bulb chilling (7 °C), and its accumulation was predominantly detected in the lower sprout portion during the first weeks of sprouting. Sugar concentration was significantly lower in nonchilled bulbs, which indicates the importance of low temperature in bulb development and sprouting.