Senescence-induced ectopic expression of the A. tumefaciens ipt gene in wheat delays leaf senescence, increases cytokinin content, nitrate influx, and nitrate reductase activity, but does not affect grain yield.

The manipulation of cytokinin levels by senescence-regulated expression of the Agrobacterium tumefaciens ipt gene through its control by the Arabidopsis SAG12 (senescence-associated gene 12) promoter is an efficient tool for the prolongation of leaf photosynthetic activity which potentially can affect plant productivity. In the present study, the efficiency of this approach was tested on wheat (Triticum aestivum L.)-a monocarpic plant characterized by a fast switch from vegetative to reproductive growth, and rapid translocation of metabolites from leaves to developing grains after anthesis.

Comparison of cytokinin-binding proteins from wheat and oat grains.

Cytokinin-binding proteins (CBPs) isolated from mature grains of oat (Avena sativa L.) and wheat (Triticum aestivum L.) by acid precipitation, ion-exchange and affinity chromatography had similar characteristics, although they differed somewhat in apparent molecular weight of the native protein as determined by gel filtration (109 and 133 kDa, respectively) and subunit size as estimated by SDS-polyacrylamide gel electrophoresis (47 and 55 kDa, respectively).