PS 10-124 - Morphological description and germination of a rare cactus seed

Monday, August 8, 2011
Exhibit Hall 3, Austin Convention Center
Sylvia Patricia Ruiz-González1, Jordan Goluvob2, María del Carmen Mandujano Sánchez1 and Mariana Rojas-Aréchiga3, (1)Ecología de la Biodiversidad, Instituto de Ecología, UNAM, Mexico city, Mexico, (2)El hombre y su ambiente, UAM-X, Mexicoo city, Mexico, (3)Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico

The status of endangered species relies on a basic framework of information that can be used to evaluate their conservation status and propose management plans, for instance, the early stages of the life cycle (i.e germination). Echinomastus unguispinus is a globose cactus distributed in the northern states of the Chihuahuan Desert, Mexico. It is considered an endangered species by the Mexican Red List and there is currently no basic ecological information that can be used to assess its conservation status. In this study, we describe the morphology and germination of Echinomastus unguispinus’ seeds.We collected a sample of fruits and the number of seeds per fruit were counted. One hundred and fifty seeds were photographed under estethoscope microscope and then measured (length and width) with the software Vision Works and weighed individually in an analytical balance. We sowed ten seeds in each Petri dish with 1% bacteriological agar and put them inside a germination chamber at 25ºC under two conditions: white light and darkness. We made fifty replicates. Germinated seeds were counted every other day during 45 days and finally we obtained the final germination percentage.


We got an average of 58.26 seeds per fruits, their weight is 1.43 g, and they are 1.69 mm long and 1.45 mm wide. Under white light they germinated 76% and showed no germination under darkness, but when these seeds were exposed to light we got a 42% germination. These results suggest that this species needs light to germinate and when they are in the dark they enter into a secondary or induced dormancy state. Overall, germination percentage is high, but it is lower in comparison with other globose cacti. Seed size is similar to that reported for photoblastic cacti seeds. Conservation programs that aim to introduce plants can be easily settled based on our germination results.

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