Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Carlos De la Cuadra x
Clear All Modify Search
Restricted access

Carlos De la Cuadra, Alexis K. Vidal and Leví M. Mansur

Zephyra compacta is a geophyte plant endemic to Chile with the potential to be used as an ornamental crop. Its natural habitat is the coastal plains of the Atacama Desert, with a climate described as coastal desert with abundant cloudiness. This work analyzes the germination of Z. compacta seeds at 10, 15, 20, and 25 °C. Seeds were collected in 2011 and stored for 2 years and 4 months at 5 °C, until sowing. A mathematical model was used for germination analysis, p = A{1 − exp[−k(tt 0)]}, where p is the germination percentage at a certain time t, A is the final germination percentage, t 0 is the estimated time of germination of the first seed, and k is the measure of the spread of the time to germination. Furthermore, the rate of germination of the median seed to germinate (1/t A/2) was included. The germination curves showed a coefficient of determination (R 2) between 0.86 and 0.99. The results show that temperature range for germination is from 10 to 20 °C, where A is over 90%. In this range, other evaluated parameters (t 0, k, and 1/t A/2) show no significant difference, with the exception of k at 15 °C. At this temperature, germination is obtained in a shorter period of time and could be considered as the optimal temperature within the range. Finally, 25 °C is a supraoptimal temperature, where the value of A decreased to 30%.

Restricted access

Carlos De la Cuadra, Alexis K. Vidal, Patricia Peñaloza, Leví Mansur and Carlos Huenchuleo

Zephyra elegans is a geophyte endemic to Chile that has horticultural value as a cut flower. Its natural habitat is a coastal desert climate with abundant cloud cover, little and variable precipitation, and mean monthly temperatures between 10 and 20 °C. It is hypothesized that the temperature requirements for germination of Z. elegans seeds are similar to those of Zephyra compacta, which shares the same habitat. As it is a species from a desert climate, it can be expected that its seeds remain viable during long periods of storage. The seeds used in this study were harvested in different years from plants grown from cultivated corms of Z. elegans. The germination test temperatures were 10, 15, 20, and 25 °C, and the dry storage times at room temperature (20 ± 5 °C) were 4, 16, 28, and 40 months. The temperature requirements for germination of Z. elegans seeds are similar to those of Z. compacta, which has been studied earlier, i.e., the temperature range for achieving high germination percentages is 10 to 20 °C, whereas 25 °C can be considered supraoptimal. After-ripening of the seeds occurred during dry storage, as shown by increased germination when tested at a supraoptimal temperature. The seeds had high viability after 40 months of dry storage at room temperature.

Free access

Carlos De la Cuadra, Alexis K. Vidal, Susana Lefimil and Leví Mansur

Leucocoryne is a Chilean endemic genus from the Amaryllidaceae family. It is an emerging crop with some registered varieties, currently oriented to a niche ornamental market. In the present work, seed germination in Leucocoryne dimorphopetala, Leucocoryne coquimbensis, Leucocoryne purpurea, Leucocoryne aff. vittata, Leucocoryne aff. violacescens, and Leucocoryne ixioides for seeds stored for 4 months and in L. purpurea, Leucocoryne vittata, L. aff. vittata, and L. ixioides for seeds stored for up to 16 months was analyzed at 10, 15, 20, or 25 °C. Germination data were analyzed by the previously developed time-germination model p = A{1 − exp[−k(tt 0)]}. Each germination curve had a coefficient of determination (R 2) higher than 0.89, except when there was lack of germination. Results show that higher germination was better achieved at lower (10 or 15 °C) rather than at the higher temperatures (20 or 25 °C). When comparing germination results at temperatures of 10 and 15 with results at 20 °C, germination decreased by at least 30% and became near zero at 25 °C in seed stored for 4 months. Similarly when seeds were stored for 16 months, germination decreased by ≈20% at 20 °C, and again was near zero for germination at 25 °C. These germination habits of Leucocoryne are interpreted as an adaptive strategy to its natural habitats. In addition, L. dimorphopetala presents a type of dormancy and other species (L. purpurea, L. ixioides, and L. aff. vittata) may be sensitive to after-ripening changes during storage.