Exposure of Calophyllum antillanum seeds to liquid nitrogen delays seedling emergence and decreases leaf anthraquinones.

BACKGROUND: Trees within the Calophyllum genus are multi-use trees that produce valuable wood, phytochemicals with a range of biological activities, and seed oil as a source of biodiesel. As a consequence of climate change, there is a need to develop strategies to preserve valuable plant genetic resources. Cryopreservation represents the most suitable option for the long-term storage of germplasm with minimal space and maintenance requirements. OBJECTIVE: To determine appropriate methods to cryopreserve seeds of Calophyllum antillanum and maintain secondary compound production. MATERIALS AND METHODS: Seeds at a moisture content of 6% were used to evaluate two treatments: seeds immersed in liquid nitrogen and control seeds. Biosynthetic pathway efficiency was assessed post-cryo by determining anthraquinone contents in roots, stems and leaves following 30 and 75 d of seedling growth. RESULTS: The results indicated that exposure to liquid nitrogen delayed germination and seedling emergence for a period of up to 45 d after seed sowing. By 60 d of cultivation, no significant differences in plant growth were observed for cryostored and control seeds. The levels of anthraquinones, which were also measured in seeds and seedlings, were lower in plants regenerated from cryostored seeds following 30 d of growth, but there were no differences in roots and stems by 75 d of growth. Furthermore, the difference in leaf anthraquinone levels for cryopreserved and control seeds at 75 d was much smaller than at 30 d. CONCLUSION: The low initial anthraquinone levels in emerging seedlings correlated with the initial slow growth of cryopreserved seeds.

Cryopreservation of seeds of the highly valued tropical timber species Swietenia mahagoni.

BACKGROUND: Swietenia mahagoni wood is one of the most valuable in world trade and, as a result, natural populations have been decimated due to unsustainable harvesting. The decline in natural population levels is being exacerbated by climate change. In order to ensure the preservation of valuable genotypes, there is an urgent need to develop strategies to conserve the genetic diversity present within this species. At present, cryopreservation is the most viable option for the long-term storage of plant germplasm, particularly for long-lived species which are challenging to maintain in the field. OBJECTIVE: To cryopreserve intact seeds of S. mahagoni, with the dual goal of retaining the biosynthetic capacity of plants, which is critical since this species is highly valued for medicinal purposes. MATERIALS AND METHODS: Seeds at a moisture content of 6% were immersed in liquid nitrogen (LN) before warming and recovery. Plantlet establishment and growth were assessed over a period of 70 days and anthraquinone synthesis was determined in roots, stems and leaves. RESULTS: The results showed an initial lag in the germination rate of cryopreserved seeds compared with control seeds; however, this difference disappeared over time. The lag in seedling emergence observed in cryostored seeds was also evident in the plant characteristics measured following 30 days of culture when all plant parameters measured were significantly higher in plants produced from control than cryostored seeds. However, after 70 days of growth, these differences were no longer apparent. Anthraquinone levels were also initially lower (at 30 days) in plants regenerated from cryopreserved seeds than those from control seeds, however, this difference was substantially reduced by 70 days thereby indicating the ability of these plants to accumulate secondary metabolites, albeit at a reduced rate, during the early stages of development. CONCLUSION: In S. mahagoni, the delay in anthraquinone production in plants regenerated from cryostored seeds during the early stages of development may have occurred as a consequence of the preferential allocation of resources towards the initiation of recovery processes in response to the stresses imposed by cryopreservation. Once the stresses were overcome and plant growth resumed, resources could be directed to secondary processes such as anthraquinone synthesis. doi.org/10.54680/fr22610110412.

Sterols, triterpenes and biflavonoids of Viburnum jucundum and cytotoxic activity of ursolic acid.

The triterpenes ursolic acid (1), 27-p-Z-coumaroyloxyursolic acid (2), 27-p-E-coumaroyloxyursolic acid, alpha-amyrine-3-palmitate and lupeol-3-palmitate were isolated through a bioactivity-guided fractionation from the acetonic extract of the aerial parts of Viburnum jucundum Morton in addition to amentoflavone, an epimeric mixture at C-2 of 2,3-dihydroamentoflavone, beta-sitosterol and beta-sitosteryl glucopyranoside. Ursolic acid (1) was the only constituent that exhibited cytotoxic activity toward three human cancer cell lines in culture. This is the first phytochemical and cytotoxic analysis performed to this plant species.

[The rural population. Dispersion and needs]. / La poblacion rural. Dispersion y carencias.

PIP: Significant changes have occurred in recent decades in the dynamics and distribution of the Mexican population. The average annual growth rate declined from 3.4% in the 1960s to 2.3% in the 1980s, and the population has become predominantly urban. Intense urbanization began in the 1940s, but in 1960 some 67% of the population still lived in rural areas. Although urbanization and the pace of urban development decelerated beginning in 1960, the urban growth rate continued to exceed that of the total population. The proportion of the rural population living in places with fewer than 2500 inhabitants has remained nearly constant. In 1960, 74% of the rural population lived in 88,000 places with under 2500 inhabitants. In 1990, 67% of the rural population lived in 154,000 localities of fewer than 2500 people. Between 1960 and 1990, 98% of places considered rural continued to have fewer than 2500 inhabitants. Such places are characterized by severe deficiencies in employment, infrastructure, housing, educational services, and health. The proportion of the total Mexican population living in places of fewer than 2500 people was 49% in 1960, 41% in 1970, 34% in 1980, and 27% in 1990. In 1990, Oaxaca, Chiapas, Hidalgo, and Zacatecas had the highest proportions of their total populations in places of under 2500, with proportions ranging from 54% to 60%. Between 1960 and 1990, the rural population increased by 11 million and the urban by 35 million. The proportion of rural dwellers in localities with 2500 to 14,999 inhabitants increased more rapidly than did that in localities of under 2500.^ieng