Orchid seeds are not always short lived in a conventional seed bank!

BACKGROUND AND AIMS: Orchid seeds are reputed to be short lived in dry, cold storage conditions, potentially limiting the use of conventional seed banks for long-term ex situ conservation. This work explores whether Cattleya seeds are long lived or not during conventional storage (predried to ~12 % relative humidity, then stored at -18 °C). METHODS: We explored the possible interaction of factors influencing seed lifespan in eight species of the genus Cattleya using physiological (germination and vigour), biochemical (gas chromatography), biophysical (differential scanning calorimetry) and morphometric methods. Seeds were desiccated to ~3 % moisture content and stored at -18 °C for more than a decade, and seed quality was measured via three in vitro germination techniques. Tetrazolium staining was also used to monitor seed viability during storage. The morphometric and germination data were subjected to ANOVA and cluster analysis, and seed lifespan was subjected to probit analysis. KEY RESULTS: Seeds of all Cattleya species were found to be desiccation tolerant, with predicted storage lifespans (P50y) of ~30 years for six species and much longer for two species. Cluster analysis showed that the three species with the longest-lived seeds had smaller (9-11 %) airspaces around the embryo. The post-storage germination method impacted the quality assessment; seeds equilibrated at room temperature for 24 h or in 10 % sucrose solution had improved germination, particularly for the seeds with the smallest embryos. Chromatography revealed that the seeds of all eight species were rich in linoleic acid, and differential scanning calorimetry identified a peak that might be auxiliary to selecting long-lived seeds. CONCLUSIONS: These findings show that not all orchids produce seeds that are short lived, and our trait analyses might help to strengthen prediction of seed longevity in diverse orchid species.

Behind the forest restoration scene: a socio-economic, technical-scientific and political snapshot in Amazonas, Brazil / Por trás do cenário da restauração florestal: um panorama socioeconômico, técnico-científico e político no Amazonas, Brasil

Conservation of the Amazon rainforest is a global concern and is supported by the Brazilian government's ratification of the Bonn Challenge and Paris Agreement and the introduction of national regulations on vegetation protection and restoration. Amazonas is the largest and least deforested of the states occupied by the Brazilian Amazon (< 3%). We carried out a survey on the current state and growth potential of seed and seedling production in Amazonas state, pointing out constraints where future investment can promote the achievement of large-scale restoration commitments. We visited the 35 officially registered seed producers or nurseries working with native seeds and interviewed their owners or managers using open and closed questions. Enterprises were mainly privately-owned family businesses with small production (10,001 - 100,000 seedlings per year) and concentrated in the metropolitan area of the state capital Manaus. We uncovered a further 54 non-officially registered nurseries. Annual production (2018) was almost four tons of seeds and nearly ten million seedlings. According to the owners, production could be increased five to seven times with existing infrastructure. Production is focused foremost on species for food production (48% seeds, 74% seedlings), while ecological restoration only makes up 35% of seed and 8% of seedling use. Major bottlenecks cited by the producers were low demand for native tree species, high transportation costs and excessive bureaucracy. To achieve large-scale restoration, we recommend enforcement of national policies for vegetation protection and restoration, and a restructuring of the seed and seedling sector with a bottom-up approach.(AU)

A conservação da Amazônia é uma preocupação global, apoiada pela ratificação do Bonn Challenge e do Acordo de Paris pelo governo brasileiro e pelas regulamentações nacionais de proteção e restauração da vegetação. O Amazonas é o maior e menos desmatado estado da Amazônia brasileira (<3%). Realizamos um levantamento do estado atual e potencial da produção de sementes e mudas no Amazonas, indicando os principais obstáculos e gargalos onde investimentos futuros podem ajudar a alcançar o compromisso da restauração ecológica em larga escala. Visitamos os 35 produtores de sementes ou mudas de espécies nativas oficialmente registrados, e entrevistamos seus proprietários ou responsáveis técnicos, utilizando um questionário com perguntas abertas e fechadas. Os empreendimentos eram predominantemente privados, familiares, com pequena produção (10.001 - 100.000 mudas por ano) e concentrados na região metropolitana de Manaus. Detectamos outros 54 viveiros não oficialmente registrados. A produção anual (2018) foi de quase quatro toneladas de sementes e quase dez milhões de mudas. Segundo os proprietários, esta produção poderia aumentar de cinco a sete vezes com a infraestrutura existente. A produção foi focada principalmente em espécies para produção alimentar (48% sementes, 74% mudas), enquanto apenas 35% de sementes e 8% de mudas foram destinadas para restauração ecológica. Os principais gargalos citados pelos produtores foram baixa demanda por espécies nativas, alto custo de transporte e excessiva burocracia. Para alcançar restauração em larga escala, recomendamos o cumprimento de políticas de proteção e restauração da vegetação e uma reestruturação do setor de sementes e mudas em uma abordagem ascendente (bottom-up).(AU)

Storage of orchid pollinia with varying lipid thermal fingerprints.

Orchid pollinia have the potential to make a valuable contribution to current techniques of germplasm storage and assisted reproduction, yet information regarding their preservation and their ability to remain viable over time is currently limited. Dactylorhiza fuchsii and Disa uniflora were used as models for investigating potential techniques for storing orchid pollinia. Initially, freshly harvested pollinia of Dact. fuchsii were incubated at 25 °C and 100% RH (relative humidity) for up to 7 days and germinated in vitro. For pollinia from both species, moisture sorption isotherms were constructed and thermal fingerprints generated using differential scanning calorimetry (DSC). Pollinia were stored at three temperatures (5, - 18 and - 196 °C) after equilibration at four different RHs (5, 33, 50 and 75%) and germinated. The isotherms and DSC results varied between species. Compared with D. uniflora, pollinia of Dact. fuchsii consistently equilibrated at higher moisture content (MC) for each RH, had less detectable lipids by DSC and had shorter lifespans, remaining viable after 3-4 months only at - 20 and - 196 °C and at low RH (5 and 33%). Both species' pollinia stored well at - 20 °C and - 196 °C, although there was some evidence of a small loss of viability under cryopreservation. In conclusion, pollen of these two species can be stored successfully for at least 3-4 months, and to maximize the pre-storage quality, it is recommended that fresh pollen is collected from flowers just prior to anthesis.

Rainfall, not soil temperature, will limit the seed germination of dry forest species with climate change.

Drylands are predicted to become more arid and saline due to increasing global temperature and drought. Although species from the Caatinga, a Brazilian tropical dry forest, are tolerant to these conditions, the capacity for germination to withstand extreme soil temperature and water deficit associated with climate change remains to be quantified. We aimed to evaluate how germination will be affected under future climate change scenarios of limited water and increased temperature. Seeds of three species were germinated at different temperatures and osmotic potentials. Thermal time and hydrotime model parameters were established and thresholds for germination calculated. Germination performance in 2055 was predicted, by combining temperature and osmotic/salt stress thresholds, considering soil temperature and moisture following rainfall events. The most pessimistic climate scenario predicts an increase of 3.9 °C in soil temperature and 30% decrease in rainfall. Under this scenario, soil temperature is never lower than the minimum and seldomly higher than maximum temperature thresholds for germination. As long as the soil moisture (0.139 cm3 cm3) requirements are met, germination can be achieved in 1 day. According to the base water potential and soil characteristics, the minimum weekly rainfall for germination is estimated to be 17.5 mm. Currently, the required minimum rainfall occurs in 14 weeks of the year but will be reduced to 4 weeks by 2055. This may not be sufficient for seedling recruitment of some species in the natural environment. Thus, in future climate scenarios, rainfall rather than temperature will be extremely limiting for seed germination.