Münzbergová Zuzana
Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic.
Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic.
Ann Bot. 2017 Aug 1;120(2):329-339. doi: 10.1093/aob/mcx070.
Understanding the direct consequences of polyploidization is necessary for assessing the evolutionary significance of this mode of speciation. Previous studies have not studied the degree of between-population variation that occurs due to these effects. Although it is assumed that the effects of the substances that create synthetic polyploids disappear in second-generation synthetic polyploids, this has not been tested.
The direct consequences of polyploidization were assessed and separated from the effects of subsequent evolution in Vicia cracca , a naturally occurring species with diploid and autotetraploid cytotypes. Synthetic tetraploids were created from diploids of four mixed-ploidy populations. Performance of natural diploids and tetraploids was compared with that of synthetic tetraploids. Diploid offspring of the synthetic tetraploid mothers were also included in the comparison. In this way, the effects of colchicine application in the maternal generation on offspring performance could be compared independently of the effects of polyploidization.
The sizes of seeds and stomata were primarily affected by cytotype, while plant performance differed between natural and synthetic polyploids. Most performance traits were also determined by colchicine application to the mothers, and most of these results were largely population specific.
Because the consequences of colchicine application are still apparent in the second generation of the plants, at least the third-generation polyploids should be considered in future comparisons. The specificities of the colchicine-treated plants may also be caused by strong selection pressures during the creation of synthetic polyploids. This could be tested by comparing the initial sizes of plants that survived the colchicine treatments with those of plants that did not. High variation between populations also suggests that different polyploids follow different evolutionary trajectories, and this should be considered when studying the effects of polyploidization.
了解多倍体化的直接后果对于评估这种物种形成模式的进化意义至关重要。以往的研究尚未探讨因这些效应而产生的种群间变异程度。虽然假定创造人工合成多倍体的物质的效应在第二代人工合成多倍体中会消失，但这一点尚未得到验证。
在广布野豌豆（Vicia cracca）中评估多倍体化的直接后果，并将其与后续进化的效应区分开来，广布野豌豆是一种具有二倍体和同源四倍体细胞型的天然物种。从四个混合倍性种群的二倍体中创造出人工合成四倍体。将天然二倍体和四倍体的表现与人工合成四倍体的表现进行比较。人工合成四倍体母本的二倍体后代也纳入比较。通过这种方式，可以独立于多倍体化的效应，比较母代使用秋水仙素对后代表现的影响。
种子和气孔的大小主要受细胞型影响，而天然多倍体和人工合成多倍体的植株表现有所不同。大多数表现性状也由对母本使用秋水仙素决定，并且这些结果大多在很大程度上具有种群特异性。
由于秋水仙素处理的后果在植物的第二代中仍然明显，因此在未来的比较中至少应考虑第三代多倍体。秋水仙素处理植物的特异性也可能是由人工合成多倍体形成过程中的强烈选择压力导致的。这可以通过比较在秋水仙素处理中存活的植株与未存活植株的初始大小来验证。种群间的高度变异还表明不同的多倍体遵循不同的进化轨迹，在研究多倍体化的效应时应考虑这一点。
