The effect of lodging on ¹⁴C‐assimilate distribution after anthesis in <i>Lolium perenne</i>, CV. S24, grown for seed

Abstract

Abstract Field experiments in 1981 and 1981 examined assimilate distribution in lodged and non‐lodged plots of perennial ryegrass ( Lolium perenne) , cv. S24, grown for seed. Lodging was prevented either mechanically (1982 only) or chemically, by application of paclobutrazol (PP333) at 2 0 kg a.i. ha ‐1 . For each treatment, main‐tiller ears, stems and leaves and subtending vegetative tillers were fed with 14 CO 2 at 24 and 17 days after anthesis in 1981 and 1982, respectively, and the pattern of 14 C‐assimilate export from each fed part was determined. Prevention of lodging increased assimilate movement to the ear from the flag leaf, although movement from main‐tiller leaves was primarily downwards to vegetative tillers. Assimilate movement to the stem was also increased because the cessation of stem elongation was delayed, especially where lodging was prevented by PP333. Both increases were at the expense of the tillers, although their number was not reduced in non‐lodged plots. Possible reasons for these changes in assimilate distribution are discussed.