Ontogenetic changes of potato plants during acclimation to elevated carbon dioxide.
Ontogenetic changes of potato plants during acclimation to elevated carbon dioxide.
复制标题
马铃薯植株在适应二氧化碳浓度升高过程中的个体发生变化。
DOI：
10.1093/jexbot/51.suppl_1.429
复制
发表时间：
2000
影响因子：
6.9
通讯作者：
D. Heineke
中科院分区：
文献类型：
--
作者：
F. Kauder;Frank Ludewig;D. Heineke
转基因马铃薯（Solanum tuberosum cv.）并与野生型植物进行了反义抑制叶绿体三磷酸酯转运子的比较。植物在环境（400亩巴）或升高（1000亩巴）二氧化碳的环境中生长。7周后，野生型和转基因植株在两种CO2浓度下的CO2同化速率相同，但两种株系的块茎产量在高CO2条件下均提高了约30%。一种解释是，植物只有在特定的生长阶段才会对二氧化碳的升高做出反应。因此，分析了野生型植物在第2周至第7周之间的生长情况。相对生长速率和CO2同化仅在第2周和第3周受到刺激。在此期间，CO2浓度升高的叶片碳水化合物含量低于环境CO2生长的叶片。在高CO2环境下生长的植株，CO2同化速率在5周后开始下降，碳水化合物的积累在7周后开始。由此得出结论，马铃薯植株对高CO2的适应是加速发育的结果，而不是碳水化合物积累导致光合作用下调的结果。为了详细分析2周后刺激生长的原因，测定了野生型植株和转基因植株磷酸化中间体的含量。二氧化碳同化的刺激伴随着磷酸化中间体含量的变化，导致磷酸二羟丙酮的量增加，这是一种从叶绿体输出到细胞质的代谢物。野生型植物和三磷酸易位反义植物在高CO2环境下的二羟丙酮磷酸含量均高于环境CO2，而转基因植物在高CO2环境下的二羟丙酮磷酸含量未见增加。这些植物不能进一步增加二羟丙酮磷酸以应对增加的二氧化碳供应。从这些磷酸化中间体在野生型和转基因植物中的变化可以得出结论，淀粉和蔗糖的合成途径只有在中等碳通量速率下才能相互替代。
Transgenic potato plants (Solanum tuberosum cv. Desirée) with an antisense repression of the chloroplastic triosephosphate translocator were compared with wild-type plants. Plants were grown in chambers with either an atmosphere with ambient (400 mu bar) or elevated (1000 mu bar) CO2. After 7 weeks, the rate of CO2 assimilation between wild-type and transgenic plants in both CO2 concentrations was identical, but the tuber yield of both plant lines was increased by about 30%, when grown in elevated CO2. One explanation is that plants respond to the elevated CO2 only at a certain growth stage. Therefore, growth of wild-type plants was analysed between the second and the seventh week. Relative growth rate and CO2 assimilation were stimulated in elevated CO2 only in the second and the third weeks. During this period, the carbohydrate content of leaves grown with elevated CO2 was lower than that of leaves grown with ambient CO2. In plants grown in elevated CO2, the rate of CO2 assimilation started to decline after 5 weeks, and accumulation of carbohydrates began after 7 weeks. From this observation it was concluded that acclimation of potato plants to elevated CO2 is the result of accelerated development rather than of carbohydrate accumulation causing down-regulation of photosynthesis. For a detailed analysis for the cause of the stimulation of growth after 2 weeks, the contents of phosphorylated intermediates of wild-type plants and transgenics were measured. Stimulation of CO2 assimilation was accompanied by changes in the contents of phosphorylated intermediates, resulting in an increase in the amount of dihydroxyacetone phosphate, the metabolite which is exported from the chloroplast into the cytosol. An increase of dihydroxyacetone phosphate was found in wild-type plants in elevated CO2 when compared with ambient CO2 and in triosephosphate translocator antisense plants in ambient CO2, but not in the transgenic plants when grown in elevated CO2. These plants were not able to increase dihydroxyacetone phosphate further to cope with the increased CO2 supply. From these changes in phosphorylated intermediates in wild-type and transgenic plants it was concluded that starch and sucrose synthesis pathways can replace each other only at moderate carbon flux rates.