Nutlet dimorphism in individual flowers of two cold desert annual Lappula species (Boraginaceae): Implications for escape by offspring in time and space

W. B. Ma, X. J. Zhao, D. Y. Tan, C. C. Baskin, J. M. Baskin, J. H. Xue

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Most studies on seed heteromorphism have been done on species that produce one diaspore per flower. In Lappula duplicicarpa and L. semiglabra, the four nutlets per flower are dimorphic. We determined the ratio of nutlets with long (LN) and short (SN) glochids (stiff bristles) produced by individual flowers and compared their morphology, anatomy, dispersal, and germination characteristics. Nutlet morph ratios in all flowers in infructescences of field-grown plants were recorded, and morphology, anatomy, dispersal ability, and germination of LN and SN compared. The LN/SN ratio in different flowers varied; the proportion of LN in a single flower increased from base to top of infructescence. In both species, LN had greater mass and was more easily detached and dispersed than SN. LN of both species had higher overall germination percentages and rates than SN. The proportion of SN and LN produced at different positions in the infructescence changed through time. Thus, SN are produced first and then LN, resulting in an investment in long-distance dispersal after the safe sites of mother plants potentially are filled.

Original languageEnglish
Pages (from-to)361-374
Number of pages14
JournalPlant Ecology
Volume209
Issue number2
DOIs
StatePublished - 2010

Bibliographical note

Funding Information:
Acknowledgments We thank Juanjuan Lu for her help with early data collection and Xiaojun Cheng, Juanjuan Lu, and Aibo Wang for comments on the manuscript. This study was supported in part by the Projects on the Grant Research Projects of Xinjiang Uygur Autonomous Region (200731138-1), the Research and Development of High Technology of Xinjiang Uygur Autonomous Region (200810102), and the Open Projects of Xinjiang Key Laboratory of Grassland Resources and Ecology (XJDX0209-2008-01), China.

Keywords

  • Boraginaceae
  • Dimorphic nutlets
  • Germination characteristics
  • Lappula
  • Nutlet dispersal
  • Optimal germination fraction

ASJC Scopus subject areas

  • Ecology
  • Plant Science

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