Degli Agosti, R.

Favre, P.

Franck, T.

Greppin, Hubert

Jouve, L.

Kayali, S.

Decapitation of Arabidopsis floral stem suppresses elongation and any associated rate oscillation. This growth inhibition also appeared after application on intact plants of IAA transport inhibitors such as NPA. A subsequent IAA paste application on the cut surface restored growth and circadian oscillations in extension rate. These results indicate that the upper zone of the inflorescence has a major influence on floral stem extension rate and give a particular importance to auxin. Furthermore, measurement of endogenous contents of IAA and IAA-aspartate conjugate displayed that they were subjected to a circadian rhythm during Arabidopsis floral stem growth. All together, these data point out IAA as an essential factor in circadian growth rhythm regulation of Arabidopsis floral stem.

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