Correlation of pectin methylesterase activity in root caps of pea with root border cell separation

Martha B. Stephenson, Martha C. Hawes

Research output: Contribution to journalArticlepeer-review

73 Scopus citations


We tested predictions of the hypothesis that pectin methylesterase in the root cap plays a role in cell wall solubilization leading to separation of root border cells from the root tip. Root cap pectin methylesterase activity was detected only in species that release large numbers of border cells daily. In pea (Pisum sativum) root caps, enzyme activity is correlated with border cell separation during development: 6-fold more activity occurs during border cell separation than after cell separation is complete. Higher levels of enzyme activity are restored by experimental induction of border cell separation. A corresponding increase in transcription of a gene encoding root cap pectin methylesterase precedes the increase in enzyme activity. A dramatic increase in the level of soluble, deesterified pectin in the root tip also is correlated with pectin methylesterase activity during border cell development. This increase in acidic, de-esterified pectin during development occurs in parallel with a decrease in cell wall/apoplastic pH of cells in the periphery of the root cap.

Original languageEnglish (US)
Pages (from-to)739-745
Number of pages7
JournalPlant physiology
Issue number2
StatePublished - Oct 1994

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science


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