Walck, Jeffrey , Cofer, M. Shea , Hidayati, Siti .
Germination ecology of bulbils from the exotic vine Dioscorea oppositifolia (Dioscoreaceae).
REQUIREMENTS for dormancy break and germination were determined for bulbils of Chinese yam (Dioscorea oppositifolia) from middle Tennessee. Bulbils collected in September 2005 germinated to 0-7% at 15/6, 20/10, 25/15, 30/15, and 35/20oC in light or darkness during 20 weeks of incubation. In contrast, bulbils cold stratified at 5oC for 18 weeks in light or darkness germinated to 0 and 71-99% in light or darkness during 2 weeks of incubation at 15/6 and 20/10-35/20oC, respectively. Of the bulbils that germinated, number of roots per bulbil increased from a maximum of 1 (nonstratified) to 10 (stratified) and only stratified bulbils produced shoots. No germinated bulbils were present in bags when exhumed from soil between November 2005 and February 2006 but 50% of the bulbils exhumed in March 2006 had roots. Bulbils sown on the soil surface in flats during September 2005 began to germinate between 6 and 12 March 2006. During the 2-week period prior to germination, mean maximum and minimum air temperatures were 18 and 8oC, respectively. Approximately 95 and 43% of the bulbils collected in February 2006 from the ground and vines, respectively, were viable. Bulbils collected from the ground or vines germinated to 0-3% at 15/6oC and 15-94% at 20/10-35/20oC in light or darkness during 2 weeks of incubation. In addition, shoots emerged from 18-62% of bulbils obtained from the ground and incubated at 25/15-35/20oC and from 0-12% of bulbils from vines. Our results show that bulbils are dormant at maturity and require cold stratification to break dormancy. In contrast, statements in the gray literature suggest that they are non-dormant and can germinate soon after they are formed.
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1 - Middle Tennessee State University, Department of Biology, Murfreesboro, Tennesee, 37132
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 31st, 2006
Time: 3:45 PM