NO flowering.

The complex control of flowering time ensures that plants flower in conditions favourable for reproductive success. A recent study adds another dimension to this established complexity by revealing that nitric oxide (NO) represses flowering in Arabidopsis. The analysis of recently identified mutants that either overproduce or are compromised in endogenous NO production has identified NO-sensitive features of the circuitry of flowering time control: NO acts to repress the amplification of gene expression dependent on the circadian clock and promotes the accumulation of mRNA encoding a key repressor of flowering, FLC. (c) 2005 Wiley Periodicals, Inc.