Seed Cryopreservation, Germination, and Micropropagation of Eastern Turkeybeard, Xerophyllum asphodeloides (L.) Nutt.: A Threatened Species from the Southeastern United States

Cryopreservation of bioflavonoid-rich plant sources and bioflavonoid-microcapsules: emerging technologies for preserving bioactivity and enhancing nutraceutical applications

Bioflavonoids are natural polyphenolic secondary metabolites that are medicinal. These compounds possess antitumor, cardioprotective, anti-inflammatory, antimicrobial, antiviral, and anti-psoriasis properties to mention a few. Plant species that contain bioflavonoids should be preserved as such. Also, the bioactivity of the bioflavonoids as neutraceutical compounds is compromised following extraction due to their sensitivity to environmental factors like light, pH, and temperature. In other words, the bioflavonoids' shelf-life is affected. Scientists noticed that bioflavonoids have low solubility properties, poor absorption, and low bioavailability following consumption. Researchers came up with methods to encapsulate bioflavonoids in order to circumvent the challenges above and also to mask the unpleasant order these chemicals may have. Besides, scientists cryopreserve plant species that contain bioflavonoids. In this review, we discuss cryopreservation and bioflavonoid microencapsulation focusing mainly on vitrification, slow freezing, and freeze-drying microencapsulation techniques. In addition, we highlight bioflavonoid extraction techniques, medicinal properties, challenges, and future perspectives of cryopreservation and microencapsulation of bioflavonoids. Regardless of the uniqueness of cryopreservation and microencapsulation as methods to preserve bioflavonoid sources and bioflavonoids' bioactivity, there are challenges reported. Freeze-drying technology is costly. Cryoprotectants damage the integrity of plant cells, to say the least. Researchers are working very hard to overcome these challenges. Encapsulating bioflavonoids via coaxial electrospray and then cryopreserving the micro/nanocapsules produced can be very interesting.

Seed Longevity-The Evolution of Knowledge and a Conceptual Framework

The lifespan or longevity of a seed is the time period over which it can remain viable. Seed longevity is a complex trait and varies greatly between species and even seed lots of the same species. Our scientific understanding of seed longevity has advanced from anecdotal 'Thumb Rules,' to empirically based models, biophysical explanations for why those models sometimes work or fail, and to the profound realisation that seeds are the model of the underexplored realm of biology when water is so limited that the cytoplasm solidifies. The environmental variables of moisture and temperature are essential factors that define survival or death, as well as the timescale to measure lifespan. There is an increasing understanding of how these factors induce cytoplasmic solidification and affect glassy properties. Cytoplasmic solidification slows down, but does not stop, the chemical reactions involved in ageing. Continued degradation of proteins, lipids and nucleic acids damage cell constituents and reduce the seed's metabolic capacity, eventually impairing the ability to germinate. This review captures the evolution of knowledge on seed longevity over the past five decades in relation to seed ageing mechanisms, technology development, including tools to predict seed storage behaviour and non-invasive techniques for seed longevity assessment. It is concluded that seed storage biology is a complex science covering seed physiology, biophysics, biochemistry and multi-omic technologies, and simultaneous knowledge advancement in these areas is necessary to improve seed storage efficacy for crops and wild species biodiversity conservation.

Seed Maturity and Its In Vitro Initiation of Chilean Endemic Geophyte Alstroemeriapelegrina L

Alstroemeria pelegrina (A. pelegrina), a Chilean endemic, is considered vulnerable as its natural habitat is currently threatened. The decline in the reproductive capacity of the species due to anthropogenic impacts and climate change has made it imperative to address the problem by developing large-scale propagation methods. The objective of this study was to establish protocols for breaking the dormancy and in vitro germination of A. pelegrina seeds to speed up the germination and seedling production processes. The research began with morphological observations of the reproductive process, followed by in vitro sowing. The results showed that the seeds reached full maturity in 51 days, and physiological maturity in 41 days, at which point the seeds could be harvested for in vitro germination. The mechanical scarification pretreatment improves the in vitro germination rate to 96% and the germination time to 7 days, showing that the species is characterized by physical seed dormancy. On the other hand, if the seed coat incisions are deeper than 0.5 mm, 30% of the potential plants are lost due to embryo damage. The study provides scientific evidence for the feasibility of large-scale in vitro propagation of the species and establishes an efficient method of seedling production.

Plant Cryopreservation: A Look at the Present and the Future

Cryopreservation is known as an applied aspect of cryobiology or the study of life at low temperatures [...].