Root-shoot communication in tomato plants: Cytokinin as a signal molecule modulating leaf photosynthetic activity

Noga Glanz-Idan, Petr Tarkowski, Veronika Turečková, Shmuel Wolf*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Photosynthetic activity is affected by exogenous and endogenous inputs, including source-sink balance. Reducing the source to sink ratio by partial defoliation or heavy shading resulted in significant elevation of the photosynthetic rate in the remaining leaf of tomato plants within 3 d. The remaining leaf turned deep green, and its area increased by almost 3-fold within 7 d. Analyses of photosynthetic activity established up-regulation due to increased carbon fixation activity in the remaining leaf, rather than due to altered water balance. Moreover, senescence of the remaining leaf was significantly inhibited. As expected, carbohydrate concentration was lower in the remaining leaf than in the control leaves; however, expression of genes involved in sucrose export was significantly lower. These results suggest that the accumulated fixed carbohydrates were primarily devoted to increasing the size of the remaining leaf. Detailed analyses of the cytokinin content indicated that partial defoliation alters cytokinin biosynthesis in the roots, resulting in a higher concentration of trans-zeatin riboside, the major xylem-translocated molecule, and a higher concentration of total cytokinin in the remaining leaf. Together, our findings suggest that trans-zeatin riboside acts as a signal molecule that traffics from the root to the remaining leaf to alter gene expression and elevate photosynthetic activity.

Original languageAmerican English
Pages (from-to)247-257
Number of pages11
JournalJournal of Experimental Botany
Issue number1
StatePublished - 1 Jan 2020

Bibliographical note

Publisher Copyright:
© 2019 The Author(s). Published by Oxford University Press on behalf of the Society for Experimental Biology.


  • Cytokinin
  • Solanum lycopersicum
  • leaf development
  • photosynthesis
  • source-sink relationship
  • tomato
  • xylem


Dive into the research topics of 'Root-shoot communication in tomato plants: Cytokinin as a signal molecule modulating leaf photosynthetic activity'. Together they form a unique fingerprint.

Cite this