Seedling survival and seed size: a synthesis of the literature
Seedling survival and seed size: a synthesis of the literature
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DOI：
10.1111/j.0022-0477.2004.00884.x
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发表时间：
2004-06-01
影响因子：
5.5
通讯作者：
Westoby, M
中科院分区：
文献类型：
--
作者：
Moles, AT;Westoby, M
1.长期以来，大种子物种在建立过程中比小种子物种具有更高的存活率。在这里，我们通过汇编已发表的关于出苗、幼苗建立和树苗建立的存活数据来评估这种优势的大小。我们发现，在从土壤中或土壤上有活力的种子到新出现的幼苗的过渡过程中，种子质量与存活率之间没有关系（P = 0.47，n = 33）.综合的数据，从实验研究的优势，大种子的物种建立在特定的危害（如阴影，干旱或草食动物）证实，幼苗的大种子的物种比小种子的物种在大多数情况下表现更好。然而，这种优势的大小不足以抵消更多的种子产生的小种子物种m（-2）的树冠轮廓年（-1.4。自然条件下的种群田间研究数据的合成也表明，大种子的物种有较高的存活率，通过早期幼苗建立比小种子的物种（P = 0.006，n = 112种）。然而，如果死亡率在一段时间内保持不变，这种优势的大小只足以抵消林冠轮廓年（-1）小种子物种m（-2）产生的更多种子。一个种子大10倍的物种在种子生产过程中恢复小种子物种所获得的优势所需的时间从数据集中最小种子物种的8.8周到最大种子物种的4.2年不等。因此，虽然在幼苗形成期间，大种子物种确实比小种子物种具有生存优势，但现有证据表明，这种优势也必须在生命周期的其他阶段积累。一种可能性是，小种子物种的较大种子产量（林冠轮廓年（-1）的m（-2））部分被较大的林冠和大种子物种较长的生殖寿命所抵消。
1. Large-seeded species have long been known to have higher survivorship during establishment than small-seeded species. Here, we assessed the size of this advantage by compiling published data on survival through seedling emergence, seedling establishment and sapling establishment.2. We found no relationship between seed mass and survival through the transition from viable seed in or on the soil to newly emerged seedlings (P = 0.47, n = 33 species).3. Synthesis of data from experimental studies on the advantages of large-seeded species establishing under particular hazards (such as shade, drought or herbivory) confirmed that seedlings of large-seeded species perform better than those of small-seeded species in most situations. However, the magnitude of this advantage was not sufficient to counterbalance the greater number of seeds produced by small-seeded species m(-2) of canopy outline year(-1).4. Synthesis of data from field studies of populations under natural conditions also showed that large-seeded species have higher survival through early seedling establishment than small-seeded species (P = 0.006, n = 112 species). However, the magnitude of this advantage would only be sufficient to counterbalance the greater number of seeds produced by small-seeded species m(-2) of canopy outline year(-1) if mortality continued at the same rate for some time.5. The time required for a species with 10-fold larger seeds to recoup the advantage gained by a smaller-seeded species during seed production ranged from 8.8 weeks for the smallest seeded species in the data set, up to an implausible 4.2 years for the largest-seeded species. Thus, while large-seeded species do have a survival advantage over small-seeded species during seedling establishment, the available evidence suggests that advantages must also accrue during other stages in the life cycle. One possibility is that the greater seed production of small-seeded species (m(-2) of canopy outline year(-1)) is partly offset by larger canopies and longer reproductive life spans in large-seeded species.