Citronella mucronata (C. mucronata), a tree species endemic to Chile, has become threatened in its natural habitat and is currently listed as vulnerable. Tree population parameters have deteriorated due to indiscriminate logging and other anthropogenic activities, warranting research on mass propagation as a means of recovery. This study, unprecedented for this native species, has developed a successful method for its micropropagation. The objective was to establish a protocol for in vitro propagation of C. mucronata to produce large quantities of high-quality seedlings in an accelerated plant acquisition process. The best results were achieved by growing explants on Murashige and Skoog (MS) basal culture medium supplemented with 4.44 μM 6-benzylaminopurine (BAP) and 14.76 μM indole-3-butyric acid (IBA). Explant survival rate was 78 %, the average shoot length reached 3.2 cm, the number of lateral shoots was 3.9, and rooting rate was 60%. Furthermore, stimulation with red and blue light in a 1:2 ratio, supplemented with 14.76 μM IBA, improved the rooting rate to 93%. The survival rate of rooted explants reached 100% in the acclimatization stage when using peat and perlite substrate (1:1 v/v).

Peumus boldus Mol (P. boldus), a Chilean endemic tree species occurring in sclerophyllous or evergreen forests, has historically played a significant role in indigenous ancestral medicine. Recently, P. boldus has garnered renewed attention, spurred by the growing interest in its leaves and bark. These parts contain a wealth of bioactive agents, including alkaloids, flavonoids, essential oils, and potent antioxidant properties attributed to their high phenolic compound content. However, the species’ regeneration within its native habitat has been hindered by a confluence of factors such as climate change, agricultural activities, and shifts in land use. Coupled with the seeds’ low germination rate and protracted emergence period, the necessity to develop large-scale propagation methods to bolster P. boldus population numbers has become increasingly evident. Furthermore, the widespread use of P. boldus for medicinal purposes renders it vulnerable to overexploitation, thereby underscoring the need for a comprehensive mass propagation protocol to support conservation efforts. Thus, the main objective of this study was to formulate an in vitro protocol for mass regeneration of P. boldus. The explants excised from nodal sections demonstrated an average survival rate of 74%, while the application of 6-benzylaminopurine (4.44 μM) yielded an average shoot length of 5.9 cm. In vitro shoot rooting achieved a success rate of 80% using perlite supplemented with indole-3-butyric acid (9.84 μM). During the acclimation phase, in vitro rooted plants displayed a remarkable 100% survival rate at the 30-day mark after being transplanted into a substrate consisting of perlite and peat in a (1:1 v/v) ratio.

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.

The Chilean rhizomatous geophyte Alstroemeria pelegrina (A. pelegrina), a species endemic to the Coquimbo (31°45′ S) and Valparaíso (33°12′ S) regions, is currently classified as vulnerable and experiencing population decline due to loss of habitat. This heightened threat underscores the need to develop effective mass propagation techniques to support its conservation efforts. Consequently, the present study aimed to establish an optimized in vitro propagation protocol tailored specifically for A. pelegrina to facilitate its large-scale propagation and promote the preservation of this vulnerable geophyte. In our experiment, explants obtained from in vitro germination were used. These explants were then cultured on a Murashige and Skoog (MS) medium solidified with agar (6 g L⁻¹) and supplemented with 2.22 μM 6-Benzylaminopurine (BAP) and 30 g L⁻¹ sucrose. The results indicated an average of 4.6 new shoots produced per initial explant. The implementation of light-emitting diode (LED) illumination with a red:blue ratio of 3:1 and 2.22 μM BAP resulted in an average shoot length of 6.2 cm. For rhizome induction, the addition of either 5.37 μM 1-naphthaleneacetic acid (NAA) or 5.37 μM indole-3-butyric acid (IBA) resulted in average rhizome lengths of 1.9 cm and 1.7 cm, respectively, with fresh weights of the vitroplants ranging from 2.9 g to 3.1 g, and rooting percentages between 100% and 96%, respectively. Notably, the survival rate of rooted plants obtained through in vitro propagation was 90% after a 4-week acclimatization period in a cold greenhouse, indicating the efficacy of the developed protocol for mass propagation and conservation efforts of this vulnerable geophyte species.

In vitro propagation of avocado faces several limitations. To optimize the establishment phase, we evaluated three plant material types: etiolated shoots, 30-day covered field shoots, and uncovered field shoots, collected at two time points. Biochemical and anatomical analyses were conducted to understand material performance during establishment. Across both collection times, etiolated shoots exhibited minimal oxidation, enhanced bud sprouting, reduced malondialdehyde (MDA) and reactive oxygen species (ROS) levels, increased peroxidase (POD) activity, and improved xylem development, consistently outperforming field-derived materials. Using etiolated shoots, we optimized disinfection and in vitro multiplication protocols. Pre-disinfection with 3 mL L⁻¹ Phyton 27^® and 2% sodium hypochlorite yielded the highest survival rates. In multiplication experiments, varying concentrations of 6-benzylaminopurine (BAP) and meta-topolin (MT), supplemented with gibberellic acid (GA₃), did not significantly affect growth variation. However, 8.88 µM BAP with 0.29 µM GA₃ resulted in the greatest number of sprouted buds.

Peumus boldus Mol. (boldo) is a Chilean endemic tree species, characteristic of the region’s sclerophyllous forests. Increasing demand for its leaves and bark, valued for their antioxidant properties, has contributed to declining populations of this species in its natural habitat. This decline is further exacerbated by low natural germination rates and anthropogenic pressures. To support conservation efforts, efficient mass propagation protocols are needed. This study pioneered the use of temporary immersion systems (TIS) for the in vitro propagation of boldo, successfully developing a novel mass propagation protocol. To optimize the in vitro propagation of boldo shoots using the temporary immersion system (TIS), various immersion durations were tested. While a 3 min immersion resulted in a high proliferation rate (10.8), it also induced shoot vitrification, a detrimental physiological disorder. However, reducing the immersion duration to 2 min successfully prevented vitrification while still achieving a satisfactory multiplication rate of 7.2. The shoots reached an average length of 6.1 to 6.4 cm with 6-benzylaminopurine (4.44 μM). Ex vitro rooting was achieved in 75.4% of shoots treated with 1476 μM indole-3-butyric acid (IBA) across all tested substrates. The plantlets subsequently acclimatized with a survival rate between 77.1% and 83.3%.