Resumo

MANZO RODRIGUEZ, Sinai Mariana et al. Viability and germination of seeds of four endangered species of cacti. Caldasia [online]. 2022, vol.44, n.2, pp.209-220.  Epub 23-Maio-2024. ISSN 0366-5232.  https://doi.org/10.15446/caldasia.v44n2.86192.

There are few studies about methods of evaluating the viability and germination of cacti seeds, key information to plan their conservation and preservation in their habitat or their survival for long periods under unfavorable environmental or storage conditions. In the present study, the viability of the seeds of the threatened Mexican species Echinocactus platyacanthus, Ferocactus pilosus, Lophophora wil-liamsii, and Echinocactus grusonii, was explored with 2,3,5-triphenyl tetrazolium chloride (TZ) as well as their germination efficiency, in vitro and ex vitro. Seeds stored at room temperature for three years were used; viability was assessed with different concentrations of TZ. Germination rate and germination speed index (GSI) in the four species of cacti was assessed with different substrates. The viability of the seeds of E. platyacanthus was 87.5 % with 0.1 % tetrazolium chloride. The 98 % of germination percentage was obtained for F. pilosus without scarification and in organic forest soil-tezontle soil; the IVG was of 4.03 seeds per day. E. grusonii scarified using sulfuric acid by 1 min show better germination (100 %) in the mixture of organic forest soil-tezontle soil and sand; both show a GSI of 8.3 and 8.1 seeds per day, respectively. There was a positive relationship between the tetrazolium viability test and the germination test. The topological staining patterns for each species were obtained and, in addition, reproduction methods were established, which may help in the conservation efforts of these endangered species.

Palavras-chave : tetrazolium chloride; GSI; germination speed index; seed vigor.

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