Rapacz M, Tokarz K, Janowiak F
Agricultural University of Kraków, Faculty of Agriculture, Department of Plant Physiology, Podl&z.shtsls;uzna 3, 30-239, Kraków, Poland
Plant Sci. 2001 Jul;161(2):221-230. doi: 10.1016/s0168-9452(00)00341-1.
The aim of the present investigation was to determine if the loss of frost resistance observed in spring-type oilseed rape during winter may be the effect of the tendency to start elongation growth during the prolonged low-temperature stay. Interactions between elongation growth rate, properties of photosynthetic apparatus and frost resistance were studied under these conditions in spring and winter cultivars of oilseed rape. Both spring and winter cultivars of oilseed rape reached the maximal frost resistance after 6 weeks at +5 degrees C. Photosynthetic apparatus of both cultivars acclimated to functioning in cold. The resistance of winter type plants remained unchanged at the end of the experiment (10 weeks) whereas spring-type plants lost the maximal resistance in subsequent weeks. It was preceded in the 7th week of low-temperature stay by acceleration of elongation growth without an increase in dry matter accumulation. A gradual loss of photosynthetic activity was also observed during this period. It was manifested as a decrease in antenna trapping efficiency, photochemical and non-photochemical fluorescence quenching and actual quantum yield of PSII without affecting apparent quantum yield of PSII. At the 70th day of the experiment, a decrease in CO(2) exchange and dry matter accumulation were even observed. The possible relationships between growth rate and functioning of photosynthetic apparatus are discussed.
本研究的目的是确定春季型油菜在冬季观察到的抗冻性丧失是否可能是在长时间低温停留期间开始伸长生长趋势的结果。在这些条件下，研究了油菜春季和冬季品种的伸长生长速率、光合器官特性与抗冻性之间的相互作用。油菜的春季和冬季品种在5摄氏度下6周后均达到最大抗冻性。两个品种的光合器官都适应了在寒冷环境中的功能。冬季型植物的抗性在实验结束时（10周）保持不变，而春季型植物在随后几周失去了最大抗性。在低温停留的第7周，伸长生长加速，但干物质积累没有增加，随后出现了这种情况。在此期间还观察到光合活性逐渐丧失。这表现为天线捕获效率、光化学和非光化学荧光猝灭以及PSII的实际量子产率降低，而不影响PSII的表观量子产率。在实验的第70天，甚至观察到CO₂交换和干物质积累减少。讨论了生长速率与光合器官功能之间的可能关系。
