Fecundity and offspring ploidy in matings among diploid, triploid and tetraploid Chamerion angustifolium (Onagraceae):: consequences for tetraploid establishment
Fecundity and offspring ploidy in matings among diploid, triploid and tetraploid Chamerion angustifolium (Onagraceae):: consequences for tetraploid establishment
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DOI：
10.1046/j.1365-2540.2001.00955.x
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发表时间：
2001-11-01
期刊：
影响因子：
3.8
通讯作者：
Husband, BC
中科院分区：
文献类型：
--
作者：
Burton, TL;Husband, BC
多倍体进化的模型表明，四倍体更有可能建立在二倍体种群时，他们形成反复通过unreduced（n =2n）配子的工会。为了解释Chamerion angustifolium种群中二倍体和四倍体的共存，将二倍体、三倍体和四倍体植物以所有可能的组合进行杂交，并使用流式细胞术测量繁殖力和倍性或所得后代。结合以前的细胞型适合度的数据，这些数据被用于模拟研究未减数配子对四倍体进化的影响。每个果实的种子集在2x x 2x杂交中最高（69%），在4x x 4x、2x x 4x和3x x 4x杂交中居中（范围，11-35%），并且在3x x 2x和3x x 3x杂交中最低（范围，1-10%）。2x x 2x杂交后代为二倍体（94%）或三倍体（6%），3x x 2x杂交后代为二倍体（17.5%）、三倍体（56%）或四倍体（26.5%），所有其他杂交后代（4x x 4x、3x x 4x、2x x 4x）为三倍体（53%）和四倍体（44%），表明有些配子未减数，特别是在三倍体中。来自三个不同杂交的42%的后代的DNA含量大于四倍体。基于这些结果的计算机模拟表明，C.沙枣可以促进二倍体或四倍体的共存，但由于三倍体适合度不高，不足以克服四倍体少数的劣势。
Models of polyploid evolution indicate that tetraploids are more likely to establish within diploid populations when they are formed recurrently through the union of unreduced (n =2n) gametes. To account for the coexistence of diploids and tetraploids in populations of Chamerion angustifolium, diploid, triploid and tetraploid plants were crossed in all possible combinations and fecundity and ploidy using flow cytometry or the resulting progeny were measured. Combined with previous data on cytotype Fitness, these data were used in a simulation to examine the impact of unreduced gametes on tetraploid evolution. Seed set per fruit was highest in 2x x 2x crosses (69%), intermediate in 4x x 4x, 2x x 4x and 3x x 4x crosses (range, 11-35%) and lowest in 3x x 2x and 3x x 3x crosses (range, 1-10%). Offspring were diploid (94%) or triploid (6%) in 2x x 2x crosses, diploid (17.5%), triploid (56%) or tetraploid (26.5%) in 3x x 2x crosses, and triploid (53%) and tetraploid (44%) in all others (4x x 4x, 3x x 4x, 2x x 4x), indicating that some gametes are unreduced, particularly in triploids. Forty-two percent of offspring, from three different crosses, had DNA contents greater than tetraploids. Computer simulations based on these results showed that unreduced gamete formation via triploids in C. angustifolium can promote the coexistence or diploids and tetraploids, but, due to law triploid fitness, is insufficient to overcome tetraploid minority disadvantage.