An experimental assessment of competitive interactions between sexual and apomictic fern gametophytes using Easy Leaf Area.

Premise: Few studies have explored competition in fern gametophyte populations. One limiting factor is the tedious measurement of gametophyte size as a proxy for biomass in these small plants. Here, an alternative approach of estimating the number of green pixels from photos was employed to measure the competitive interactions among apomictic and sexual Dryopteris gametophytes. Methods: We cultivated the gametophytes of two apomictic (diploid and triploid) and one sexual (tetraploid) Dryopteris species in monocultures and in two-species mixtures in the ratios 1 : 1 and 1 : 3. The total gametophyte cover of each population originating from 20 spores was assessed using Easy Leaf Area. Assessments were performed weekly between weeks 4 and 10 of cultivation. Additionally, during week 5, the cover of each species in each mixture was estimated separately. Results: We identified a positive correlation between gametophyte size and ploidy level as well as sexual reproduction. The performance of the tested species in mixtures was dependent on the competitor species identity, indicating the importance of competition between gametophytes. Discussion: The methods outlined can be used for a rapid assessment of fern gametophyte cover in large gametophyte populations. Ploidy level and reproduction type seem to play a major role in the competitive abilities of fern gametophytes, but more research is needed on this topic.

Intralaboratory comparison of analytical methods for quantification of major phytocannabinoids.

This study compares alternative approaches for analyzing phytocannabinoids in different plant materials. Three chromatographic analytical methods (ultra-high-performance liquid chromatography with tandem mass spectrometric detection and gas chromatography with mass spectrometric and flame ionization detection) were evaluated regarding selectivity, sensitivity, analytical accuracy, and precision. The performance of the methods was compared and all three methods were demonstrated to be appropriate tools for analyzing phytocannabinoids in cannabis. Gas chromatography coupled with mass spectrometric detection showed slightly better accuracy in determining phytocannabinoid acids, which are often difficult to quantify owing to their limited stability. Aspects of sample preparation, such as material homogenization and extraction, were also considered. A single ultrasonic-assisted ethanolic extraction of dried and powdered plant samples of cannabis was shown to be exhaustive for extracting the samples prior to analysis.