Evidence of stress induced flowering in bamboo and comments on probable biochemical and molecular factors

Bamboo is used as a multi-purpose, non-timber plant worldwide. The variation in flowering time across bamboo species and prolonged interval between vegetative and reproductive phases has attracted researchers over the decade to understand the ecological, physiological, and molecular reasons behind this. Typical flowering pathway genes related to photoperiod, vernalization, and hormonal regulation have been identified in the sequenced bamboo genome Phyllostachys edulis and many of them are transcriptionally active in other bamboo species such as Bambusa tulda. However, growing evidences suggest that stress such as drought may act as an important 'cue' to determine the flowering time in bamboo species. Here we provide evidence that indeed, an abundance of ABA, which is the marker hormone for drought response, is higher in young leaf from flowering culm (YLF) than a leaf from non-flowering culm (YLN). We also have observed that fire and pruning can induce flowering in Bambusa tulda, B. balcooa, Dendrocalamus hookeri and Melocanna baccifera. Finally, we discuss on the putative role of stress-induced flowering pathway genes in bamboo. Taken together, the finding of this study will aid in the sustainable management of bamboo resources in India and elsewhere.