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Worldwide, oak species are threatened with extinction due to habitat loss, pathogens, and changing fire regimes. Ex situ conservation through tissue culture may protect the remaining genetic diversity of Quercus dumosa, or the coastal sage scrub oak, from further loss. We designed three basal salt formulations based on the mineral composition of shoot tips and first leaves from mature Q. dumosa and explored carbohydrate source, stress-mitigating compounds, and plant growth regulator concentrations to develop a method of cultivating many Q. dumosa culture lines in vitro. All three novel basal salt formulations led to decreased necrosis compared with commercial basal salt formulas WPM, MS, and DKW. Substitution of 30 g L−1 sucrose with glucose and adding 250 mg L−1 ascorbic acid, 5.2 mg L−1 SNP sodium nitroprusside, and 103 mg L−1 y-aminobutyric acid improved culture health overall. In an experiment involving 115 culture lines, 0.66 mg L−1 6-benzylaminopurine produced the highest average shoots per explant, but 0.33 mg L−1 produced the greatest proportion of shoots 2 cm or greater. Incubation for 24 h in 20 mg L−1 indole-3-butyric acid led to the most rooting. These methods show promise for the ex situ conservation of many genotypes of endangered Q. dumosa. [ABSTRACT FROM AUTHOR]

Palms have high ecological and economical importance in tropical and subtropical regions around the world. Preserving genetic resources of palms is hampered by poor understanding of the complex seed physiology, which differs in desiccation tolerance and germination requirements depending on species and ecoregion. This study investigates Butia catarinensis embryo water content threshold, in vitro germination using gibberellin 3 (GA3) (0 and 8µM) and cryopreservation methods (cooling rate and cryoprotectant solution) for propagation and ex situ preservation of an endemic Arecaceae from Brazil. We use light and electronic microscopy to study the effect of desiccation and low temperatures in embryos cells. B. catarinensis embryos exhibit physiological and cytological traits from both, desiccations tolerant (small vacuoles, lipid and protein reserves) and sensitive (many mitochondria and endoplasmic reticulum) palms seeds. Embryos excised from mature seeds lacked differentiated cells, especially above the cotyledonary axis, but showed 90% of germination on MS medium containing 8µM of GA3, suggesting that B. catarinensis seeds exhibit morphophysiological dormancy. Embryos from mature fruits were quite moist (1.42 gH2O•gDW− 1). Extreme embryo dehydration to 0.13gH2O•gDW− 1 caused ultrastructural deformation, but did not reduce the capacity of the embryo to germinate (83%) upon rehydration. As a step toward cryobanking, embryo response to immersion in liquid nitrogen (LN) were 77% normal seedlings post-thawing and in vitro cultivation. B. catarinensis embryos are rudimentary, desiccation tolerant and can be stored in LN and revived using cryobiotechnology strategies. This can be effective at protecting genetic diversity of threatened species as B. catarinensis from anthropogenic threats.Key message: Butia catarinensis embryos are rudimentary, desiccation tolerant and can be stored at liquid nitrogen temperatures and revived using cryobiotechnology strategies. [ABSTRACT FROM AUTHOR]

Recognizing that most clinicians do not work in MLPs to readily address these climate vulnerabilities for their patients, 2 Florida groups - the Florida Clinicians for Climate Action (FCCA) and the Florida Medical-Legal Partnerships Network came together to identify how to share best practices. While much work remains to be done on this issue, clinicians with their legal partners can serve as effective communicators, raising public awareness of climate health concerns, and giving voice to the concerns of their impacted patients while highlighting policy changes that can be pursued. [Extracted from the article]

Gene banks have a critical role in preserving genetic diversity for many conservation uses. A key challenge in this task is maintaining both the genetic integrity and the viability of a collection during regeneration and long-term storage. In this study we examine the interacting effects of sampling and viability decline from seed aging on genetic diversity. To do this, we developed a model that simulates sampling during regeneration of individual genotypes using two commonly used but contrasting regeneration protocols. Critically, the model simulates a realistic nonlinear decline in viability across time, and the combined effects of sampling and mortality were evaluated for their effect on allelic diversity. In addition, the model was used to contrast the kinetics of allelic richness among rounds of regeneration in accessions with different heterozygosity levels (e.g., cultivars vs. wild) and different breeding systems (outcrossing vs. inbred). Results underscore a significant interaction between regeneration timing and regeneration size. Regeneration procedures should consider viability kinetics and intra-accession diversity to best manage genetic erosion. These changes highlight the trade-off faced by curators between the logistics of increasing regeneration sampling size and improving the technical procedures for seed storage and monitoring. doi: 10.2135/cropsci2010.04.0236