[Effects of phosphorus application rate on distribution of C assimilates and spike formation in different til-lers of wheat with supplementary irrigation].

To clarify the appropriate rate of phosphorus application and physiological mechanism for promoting wheat tillering and efficient utilization of phosphorus fertilizer with supplementary irrigation, we used 'Jimai 22' wheat variety as the test material, to set up three phosphorus application treatments, including low (90 kg PO·hm, P), medium (135 kg PO·hm, P), and high (180 kg PO·hm, P) application rates, with no phosphorus application as the control (P). We increased the relative soil water content of each treatment at join-ting stage and anthesis stage to 70%, and measured the area of tiller node, the content of endogenous hormones, the number of tillers in each tiller position, photosynthetic parameters, the distribution of C assimilates in each stem and tiller, as well as the grain yield and partial productivity of phosphate fertilizer. The results showed that compared with P and P treatments, P significantly increased the area of tiller node and the trans-zeatin (tZ), the photosynthetic parameters of the uppermost expanded leaves of the main stem, the total tillers per plant, and the distribution of C assimilates in each tiller.