Major factors affecting in vitro immature embryo rescue efficiencies from Prunus persica or P. armeniaca accessions, have been identified along with improving its economic feasibility. Three culture media, based on Woody Plant Medium (WPM) have been used depending on the embryo size. Embryos less than 5-mm-long were cultured in WPM supplemented with 1 mM BAP and 1 mM GA3, while embryos bigger than 5-mm-long were cultured in hormone-free medium, with or without vermiculite. Environmental in vitro culture conditions consisted of three phases, a (I) stratification at 4 C during a 3 to 5-month-long period in the dark, followed by (II) growth of germinated embryos at 14 C for 4-week-long period, with 12h light a day, which favors plantlet development, and finally (III) growth at 24 C, with 16h light a day, until the plantlets were moved to the greenhouse for acclimatization. Germination of smaller embryos, at the end of the phase I, ranged from 82.2% to 22.1%, for apricot and flat peaches, respectively, whereas for bigger embryos the germination varied from 97.4% to 53.2% for the same type of fruits. Embryo germination for peaches and nectarines ranged from 40.1% to 30.3% for smaller embryos, and from 91.9% to 64.0% for bigger embryos. Endo- and exophytic contamination, affecting from 7.4% to 52.9% of cultured embryos depending on the fruit type and conservation conditions, and the capacity to acclimate to soil conditions, ranging from 50.4% to 93.2%, were the two most important factors influencing protocol’s efficiency and economic feasibility. Considering the overall efficiencies, expressed as hardened plants transferred to field plots over clean uncontaminated embryo, values ranged from 55.8% for nectarines, 54.0% for peaches, 45.6% for apricot, and 23.3% for flat fruits. Addition of vermiculite to the culture medium significantly improved plantlet development, avoiding subculture to fresh medium when an extension of the phase III was required before acclimatization. Compared to laboratory glassware, use of food glass containers with air-permeable sealing film, along with vermiculite-containing medium significantly reduced costs, when handling the large number of embryos required for breeding programs.

The goal of this short communication is to analyze a published discussion that states that long-term residing at a thermoneutral indoor temperature condition hinders human thermal acclimation capacities. According to current research, human thermal acclimation and acclimatization capacities can be easily gained through repeated heat and cold exposures mixed with physical activity over a period of days (often 3–21 days). Furthermore, heat and cold adaptations are not permanent, and heat acclimation would progressively fade away if frequent heat exposures (associated with physical work/exercise) were discontinued. People who have been heat acclimatized for a long period and live in tropical places may progressively lose their physiological and perceptual benefits when they shift to temperate zones. On the other hand, the decay of cold acclimation and cold acclimatization has not been well examined, demanding future research on this area. To summarize, there is no evidence to support the claim that extended exposure to thermoneutral conditions impairs human acclimatization abilities.

Peatlands in Indonesia are one of the world's largest carbon sinks, helping to regulate greenhouse gas emissions and global climate change. Lophostemon suaveolens is a plant found in Papua's endemic peat ecosystem that grows well in wet areas with low fertility. It is geographically dispersed and has the potential for peatland re-habilitation. We present an efficient and reproducible protocol for in vitro multiplication of plantlets using nodal segments and shoot apices collected from plantlets. The Murashige and Skoog (MS) medium was sup-plemented with single and double kinds of PGRs (BAP and NAA). The concentration used in this study is based on the best findings of earlier preliminary research on single PGR treatment (0.5 ml/l BAP and 0.1 ml/l NAA) for the initiation stage. After 3 months of in vitro axillary shoot initiation, elongated shoots from plant-lets were separated from the clumps and multiplied. Until 6 months incubation, the potential multiplication of axillary shoots was determined by counting the number of nodule multiplication coefficients (NMC), shoot length, root length, and number of leaves (6 successive subculture). The highest average per plantlet of NMC (8.4 0.13) was observed in MS medium with a combination of 0.5 ml/l BAP and 0.1 ml/l NAA (double PGRs), with the longest shoots (5.91 0.17 cm), the longest root length (8.83 0.69 cm), and the most leaves (32 0.69). They were cultured in a pH 5 environment with a light photoperiod (40 mol/m2/s intensity) for 16 hours. When BAP and NAA were used together after acclimatization, seedling survival was highest. This is the first report of L. suaveolens in vitro multiplication, and the protocol could be used to propagate this peatland species on a large scale.

Traditional asexual propagation of hops limits its phytosanitary quality and the concomitant plant availability. This scenario worsens with the global climate change. In this study we develop protocols for in vitro propagation of Humulus lupulus var. mapuche. Two explant types were evaluated: shoot tips, from field material collected in Río Negro province (Argentina), and nodal segments, from vitroplants. Different growth regulator, such as 6-Benzylaminopurine, gibberellic acid, indole-3-butyric acid and indole-3-acetic acid, was used to induce desired morphogenic responses. Additionally, the impact of abscisic acid application on acclimatization was assessed, and resulted in robust growth and reduced plant stress symptoms during ex vitro adaptation. Also, the study develops a protocol for synthetic seeds production, with storage at 4°C to enhance conservation and plant material transport, ensuring a constant supply of female plants. This comprehensive approach addresses current producer demands and emerging climate challenges. The findings highlight the fundamental role of in vitro multiplication of hops in improving plant material availability and quality, with significant implications for the brewing industry and related sectors.

Research in seaweed cultivation technologies aims to increase production and reduce costs, leading to more efficient and sustainable processes. In this study, we analyzed the outdoor production of Ulva compressa cultured in summertime at different stocking densities of 0.6, 0.8 and 1.0 kg Fresh weight (FW) m-2 in a raceway photobioreactor with 30 m2 surface (3000L) and its relation to pho-tosynthetic activity. Under the experimental conditions of high temperature (> 28-30 oC) and pH > 9 in culture water, higher seaweed density resulted in lower specific growth rate. The biomass pro-duction has been related to photosynthetic activity by using in vivo chlorophyll a fluorescence. Dynamic photoinhibition was observed at noon, which was less severe in cultures with higher algal densities. However, photosynthesis recovered in the afternoon. Seaweeds that were acclimatized for a week to the conditions of 1.0 kg FW m-2 stocking density showed an increase in biomass growth and absence of photoinhibition compared to non-acclimatized thalli. In conclusion, by using high densities (1.0 kg FW m-2), U. compressa presented the highest growth rate in a mid-scale raceway photobioreactor under stressed conditions related to the increase of photosynthetic capacity.