Regrowth dynamics of Calamagrostis epigejos after defoliation as affected by nitrogen availability
2007
Gloser, V.,Masarykova Univ., Brno (Czech Republic). Ustav Experimentalni Biologie | Kosvancova, M.,Masarykova Univ., Brno (Czech Republic). Ustav Experimentalni Biologie | Gloser, J.,Masarykova Univ., Brno (Czech Republic). Ustav Experimentalni Biologie
Young plants of a rhizomatous grass Calamagrostis epigejos were grown from seed in nutrient solutions containing nitrogen in concentrations 0.1, 1.0, and 10 mM. After six weeks of cultivation the plants were defoliated. Changes in growth and content of storage compounds were measured in the course of regrowth under highly reduced N availability. Plants grown at high N supply before defoliation had higher amounts of all types of N storage compounds (nitrates, free amino acids, soluble proteins), which was beneficial for their regrowth rate, in spite of a lower concentration of storage saccharides. Amino acids and soluble proteins from roots and stubble bases were the most important sources of storage compounds for the regrowth of the shoot. Faster growth of plants with higher N concentration was mediated by greater leaf area expansion and greater number of leaves. In plants with low concentrations of N compounds the number of green leaves decreased after defoliation significantly. Our results suggest that internal N reserves can support regrowth of plants after defoliation even under fluctuating external N availability. Faster regrowth of C. epigejos with more reserves was mediated mainly by changes in plant morphogenesis.
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