We investigated the role of auxin on stem elongation in pea (Pisum sativum L.) grown for 10 d in continuous darkness or under low-irradiance blue, red, far red and white light. The third internode of treated seedlings was peeled and the tissues (epidermis and cortex+central cylinder) were separately analyzed for the concentration of free and conjugated indole-3-acetic acid (IAA). Under red, far red and white light internode elongation was linearly related with the free IAA content of all internode tissues, suggesting that phytochrome-dependent inhibition of stem growth may be mediated by a decrease of free IAA levels in pea seedlings. The correlation between IAA and internode elongation, however, did not hold for blue light-grown seedlings. The hypothesis that the growth response under low-irradiance blue light might be correlated with the lack of phytochrome B signalling and changes in gibberellin metabolism is discussed in view of current knowledge on hormonal control of stem growth.

The involvement of indole-3-acetic acid in the control of stem elongation in dark- and lightgrown pea (Pisum sativum) seedlings

SORCE, CARLO
;
PICCIARELLI, PIERO;LERCARI, BARTOLOMEO;CECCARELLI, NELLO
2008

Abstract

We investigated the role of auxin on stem elongation in pea (Pisum sativum L.) grown for 10 d in continuous darkness or under low-irradiance blue, red, far red and white light. The third internode of treated seedlings was peeled and the tissues (epidermis and cortex+central cylinder) were separately analyzed for the concentration of free and conjugated indole-3-acetic acid (IAA). Under red, far red and white light internode elongation was linearly related with the free IAA content of all internode tissues, suggesting that phytochrome-dependent inhibition of stem growth may be mediated by a decrease of free IAA levels in pea seedlings. The correlation between IAA and internode elongation, however, did not hold for blue light-grown seedlings. The hypothesis that the growth response under low-irradiance blue light might be correlated with the lack of phytochrome B signalling and changes in gibberellin metabolism is discussed in view of current knowledge on hormonal control of stem growth.
Sorce, Carlo; Picciarelli, Piero; Calistri, G; Lercari, Bartolomeo; Ceccarelli, Nello
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/201336
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