Heat-induced electrical signals affect cytoplasmic and apoplastic pH as well as photosynthesis during propagation through the maize leaf

Thorsten E.E. Grams, Silke Lautner, Hubert H. Felle, Rainer Matyssek, Jörg Fromm

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

Combining measurements of electric potential and pH with such of chlorophyll fluorescence and leaf gas exchange showed heat stimulation to evoke an electrical signal (propagation speed: 3-5 mm s-1) that travelled through the leaf while reducing the net CO2 uptake rate and the photochemical quantum yield of both photosystems (PS). Two-dimensional imaging analysis of the chlorophyll fluorescence signal of PS II revealed that the yield reduction spread basipetally via the veins through the leaf at a speed of 1.6 ± 0.3 mm s-1 while the propagation speed in the intervein region was c. 50 times slower. Propagation of the signal through the veins was confirmed because PS I, which is present in the bundle sheath cells around the leaf vessels, was affected first. Hence, spreading of the signal along the veins represents a path with higher travelling speed than within the intervein region of the leaf lamina. Upon the electrical signal, cytoplasmic pH decreased transiently from 7.0 to 6.4, while apoplastic pH increased transiently from 4.5 to 5.2. Moreover, photochemical quantum yield of isolated chloroplasts was strongly affected by pH changes in the surrounding medium, indicating a putative direct influence of electrical signalling via changes of cytosolic pH on leaf photosynthesis.

Original languageEnglish
Pages (from-to)319-326
Number of pages8
JournalPlant Cell and Environment
Volume32
Issue number4
DOIs
StatePublished - Apr 2009

Keywords

  • Chlorophyll fluorescence imaging
  • Electron quantum yield
  • Gas exchange
  • Zea mays

Fingerprint

Dive into the research topics of 'Heat-induced electrical signals affect cytoplasmic and apoplastic pH as well as photosynthesis during propagation through the maize leaf'. Together they form a unique fingerprint.

Cite this