Annals of Botany 81: 287-294, 1998
© 1998 Annals of Botany Company
Uptake and Partitioning of Nitrogen by Maize Infected withStriga hermonthica
Department of Soil Science, The University of Reading, P.O. Box 233, Whiteknights, Reading, RG6 6DW Department of Agricultural Botany, The University of Reading, 2 Earley Gate, Reading, RG6 6AU
May 12, 1997 ; August 7, 1997 . October 13, 1997 .
The uptake and partitioning of nitrogen (N) by maize infected with the parasitic angiosperm,Striga hermonthicawas investigated in sand culture in a glasshouse. The purpose was to determine the effect ofStrigaon N uptake and partitioning in maize. Maize was grown at 22, 66 and 133 mg N per plant and sampled five times. There was no significantStrigaxN interaction in any measured response. Leaf dry matter ofStriga-infected maize, averaged over all N treatments, was 92% that of uninfected maize at the four-leaf stage but by the 18-leaf stage it had decreased to 58%. Similarly, stem dry matter of infected maize which was 91% that of uninfected maize at the four-leaf stage was only 42% at the 18-leaf stage. Root dry matter was similar for infected and uninfected maize. N concentration in the leaf, stem and root declined asymptotically from the first to the last sampling date for both infected and uninfected maize. The asymptotic value of N concentration inStriga-infected maize was 16% greater in the leaf, 55% in the stem, and 21% in the root than in uninfected maize. The concentration of N inStrigawas higher than in maize at the 16- and 18-leaf stages. Uptake of N was similar for infected and uninfected plants at the four–eight leaf stage but at the eight–12 leaf stage, N uptake by infected maize was 52% that of uninfected maize. However, the proportion of total plant nitrogen partitioned to the root was greater (P<0.001) forStriga-infected maize. These results showed that the extent to whichS. hermonthicareduced maize growth and N uptake, but increased the proportion of N partitioned to the roots, did not depend on the rate of N fertilizer applied.Copyright 1998 Annals of Botany Company
Maize; nitrogen; partitioning;Striga hermonthica; uptake.