Background and Aims: Diptychocarpus strictus is an annual ephemeral in the cold desert of northwest China that produces heteromorphic fruits and seeds. The primary aims of this study were to characterize the morphology and anatomy of fruits and seeds of this species and compare the role of fruit and seed hetermorphism in dispersal and germination. Methods: Shape, size, mass and dispersal of siliques and seeds and the thickness of the mucilage layer on seeds were measured, and the anatomy of siliques and seeds, the role of seed mucilage in water absorption/dehydration, germination and adherence of seeds to soil particles, the role of pericarp of lower siliques in seed dormancy and seed after-ripening and germination phenology were studied using standard procedures. Key Results: Plants produce dehiscent upper siliques with a thin pericarp containing seeds with large wings and a thick mucilage layer and indehiscent lower siliques with a thick pericarp containing nearly wingless seeds with a thin mucilage layer. The dispersal ability of seeds from the upper siliques was much greater than that of intact lower siliques. Mucilage increased the amount of water absorbed by seeds and decreased the rate of dehydration. Seeds with a thick mucilage layer adhered to soil particles much better than those with a thin mucilage layer or those from which mucilage had been removed. Fresh seeds were physiologically dormant and after-ripened during summer. Non-dormant seeds germinated to high percentages in light and in darkness. Germination of seeds from upper siliques is delayed until spring primarily by drought in summer and autumn, whereas the thick, indehiscent pericarp prevents germination for >1 year of seeds retained in lower siliques. Conclusions: The life cycle of D. strictus is morphologically and physiologically adapted to the cold desert environment in time and space via a combination of characters associated with fruit and seed heteromorphism.
|Number of pages||16|
|Journal||Annals of Botany|
|State||Published - Jun 2010|
Bibliographical noteFunding Information:
This work was supported in part by the Projects on the Research and Development of High Technology of Xinjiang Uygur Autonomous Region (200810102), the Open Projects of Xinjiang Key Laboratory of Grassland Resources and Ecology (XJDX0209-2008-01), China, and the Construction of Scientific and Technological Platforms Project from the Chinese Ministry of Science and Technology (2005DKA21006 and 2005DKA21403).
- Cold desert annual ephemeral
- Fruit and seed heteromorphism
- Non-deep physiological dormancy
- Seed dispersal
- Seed germination
ASJC Scopus subject areas
- Plant Science