Estudio comparativo de germinación de semillas de totora provenientes de tres lagos norte-andinos de Ecuador / Comparative study of germination of totora seeds from three north-andean lakes of Ecuador

La “totora” (Schoenoplectus californicus - Cyperaceae) es una especie acuatica que se distribuye desde el sur de los Estados Unidos de America hasta el norte de Argentina. Posee importancia ecologica, ya que elimina nutrientes y sirve como alimento y refugio de fauna silvestre asociada a los lagos. Tambien tiene importancia economica porque a partir de sus tallos fibrosos se elaboran artesanias que son el sustento economico de numerosas familias. No existen informes de plantas obtenidas a partir de semillas, por lo que toda la produccion de totora se basa en especimenes reproducidos de forma vegetativa. En este sentido, se informa que las poblaciones presentes en los lagos altoandinos del norte del Ecuador, son hibridas entre S. californicus var. californicus y S. californicus var. totora, que producen semillas no viables. En este estudio se realizaron  ensayos de germinacion y para ello se utilizaron semillas procedentes de tres lagos de la provincia de Imbabura (Yahuarcocha, Cuicocha e Imbacocha), distribuidas en seis tratamientos con tres repeticiones (100 semillas por unidad experimental). Las semillas se sometieron a procedimientos pregerminativos quimicos, termico y mecanico (escarificacion con arena silice). Las semillas fueron hidratadas con agua destilada o con agua procedente del respectivo lago. Se midio porcentaje de germinacion, dias a la germinacion de la primera y ultima semilla, y duracion del periodo germinativo. Solo la escarificacion con arena silice provoco la germinacion de las semillas. La germinacion fue de 69%, 28% y 55% para las semillas provenientes de Yahuarcocha, Cuicocha e Imbacocha, respectivamente. Requirieron entre 26 y 53 dias de hidratacion para germinar. No se detectaron diferencias en las variables analizadas, en relacion a las fuentes de agua usadas, pero si se obtuvieron resultados diferentes al emplear semillas de diversas procedencias. Las pruebas de imbibicion confirmaron que las semillas de totora presentan latencia fisica y latencia fisiologica. La latencia fisica se evidencia por la impermeabilidad de la testa. La latencia fisiologica, es observo en semillas escarificadas que, pese que el agua ingreso a la semilla, tuvieron baja tasa de germinacion. Las semillas procedentes de los tres lagos son viables si se aplica la escarificacion, por lo que es poco probable que se trate de poblaciones hibridas sin capacidad germinativa. Abstract The "totora" (Schoenoplectus californicus - Cyperaceae), aquatic species that is distributed from the south of the United States of America to the north of Argentina. These plants have ecological importance since they eliminate the nutrients of the lakes and serve as food and refuge for the wild fauna associated with the lakes, also they have economic importance since with their stems crafts are made. This constitutes economic sustenance of numerous families. There are no reports of plants obtained from seeds, so all totora production is based on specimens reproduced in a vegetative way. The literature considers that the populations present in the high Andean lakes of northern Ecuador, are hybrids between S. californicus var. californicus and S. californicus var. totora, which produce non-viable seeds. In the germination trials seeds from three lakes of the province of Imbabura (Yahuarcocha, Cuicocha and Imbacocha) were used, distributed in six treatments with three repetitions (100 seeds per experimental unit), which were subjected to pregerminative treatments chemical, thermal and mechanical (scarification with silica sand). The seeds were hydrated with distilled water or with water from the respective lake. Germination percentage was measured, days to the germination of the first and last seeds, duration of the germination period. Only the scarification with extra fine sand caused germination of the seeds. The percentages of germination were 69, 28 and 55 for the seeds from Yahuarcocha, Cuicocha and Imbacocha, respectively, and required between 26 and 53 days of hydration to germinate. No statistical differences were detected between the water sources in the evaluated characters, but different results were obtained when using seeds from different origins. The imbibition tests confirmed that the totora seeds present physical latency and physiological latency. The physical latency caused by the impermeability of the testa; the physiological latency is evidenced in scarified seeds that, despite the fact that the water entered the seed, had a low germination rate. It is concluded that the seeds from the three lakes are viable if the scarification is applied, so it is unlikely that they are hybrid populations without germinative capacity.