Improvement of Oil Rape Hardening and Frost Tolerance

We studied the chemical composition of autumnal rosette leaves of winter rape hybrid Kasimir in stands of different density and its influence on plant wintering. The average duration of winter wheat growth in autumn was 95.7 days. For this period, rape accumulated 24.7% of dry weight in rosette leaves and 29.7% of dry weight in a terminal bud, whereas the sum of active temperatures was 857.3 °C . The content of dry matter, protein, and sulfur increased with increased crop density. In contrast, the total content of sugars, lipids, potassium, and phosphorus decreased. Tight correlations were observed between crop density and total sugar content (r = −0.877) and between crop density and the N/K ratio (r = 0.920) in the terminal bud. Rape overwintering depended directly on the total level of sugars in the leaves of autumnal rosette (r = 0.684) and in the terminal bud (r = 0.720) and on the lipid content in leaves (r = 0.623) and terminal bud (r = 0.832). The winter rape hybrid overwintered best in stands of low density (21–40 plants/m²) (r = –0.900). Changes in the protein composition in tissues of developing inflorescence and root collar (the appearance of novel proteins, dehydrins in particular, and disappearance of some other proteins) under the influence of auxin-like compounds TA-12 and TA-14 are one of the principal biochemical characteristics of oilseed rape cold hardening.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 4, 2005, pp. 532–539.Original Russian Text Copyright © 2005 by Velicka, Rimkeviciene, Novickiene, Anisimoviene, Brazauskiene.