Growth and Development of higher plants

In a third approach, activity of known flowering time genes will be analysed at floral transition in SAM and RAM of Arabidopsis WT plants. A detailed time course of changes will be established, using the induction of flowering by a single LD. A crucial question is to know how long-distance signals which, at first glance, may be hypothesised to follow the ‘source-to-sink’ route in phloem have different effects in SAM and RAM. To facilitate these studies, antibodies will be raised for FT analyses (the protein will be produced in Arabidopsis transgenics designed for root secretion of recombinant proteins; this system is already set up in the laboratory of P2). Arrival of FT in the SAM and the RAM will be studied by imunolocalisation (collaboration with EU1). The expression of other genes that are known to be activated (or repressed) in the SAM at floral transition will be analysed in the RAM by RT-PCR and/or in situ hybridization. Distribution of aquaporins will also be studied in collaboration with P4B since turgor of the SAM clearly increases at floral transition and it is still unknown whether water uptake by the roots changes at the same time.