Seed-mass effects in four Mediterranean Quercus species (Fagaceae) growing in contrasting light environments
Seed-mass effects in four Mediterranean Quercus species (Fagaceae) growing in contrasting light environments
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DOI：
10.3732/ajb.94.11.1795
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发表时间：
2007-11-01
影响因子：
3
通讯作者：
Poorter, Lourens
中科院分区：
文献类型：
--
作者：
Quero, Jose Luis;Villar, Rafael;Poorter, Lourens
已经提出了三个假设来解释种子质量和幼苗性能之间的函数关系：储备效应（较大的种子在发芽后保留较大比例的储备），代谢效应（较大种子的幼苗具有较慢的相对生长速率）和幼苗大小效应（较大的种子产生较大的幼苗）。我们测试了这些假设，在不同的光照条件下（3，27，和100%的可用辐射）生长的四个地中海栎属物种。我们发现了三个假设中两个的证据，但四个物种中没有一个同时符合所有三个假设。在所有物种中均未发现储备效应，在3种物种中发现了代谢效应。ilex、冬青Q. pyrenaica和Q. suber），以及所有物种的幼苗大小效应。光照条件显著影响种子大小与幼苗性状的关系。对于Q.冬青和Q. canariensis在3种光照条件下均表现出幼苗大小效应，但Q. suber和Q. pyrenaica。在所有物种中，种子质量和幼苗质量之间的相关性增加，减少在光，表明幼苗生长在低光下更多地依赖于他们的种子储备。因果模型整合了这三个假设，表明较大的种子一般产生较大的幼苗。
Three hypotheses have been proposed to explain the functional relationship between seed mass and seedling performance: the reserve effect (larger seeds retain a larger proportion of reserves after germinating), the metabolic effect (seedlings from larger seeds have slower relative growth rates), and the seedling-size effect (larger seeds produce larger seedlings). We tested these hypotheses by growing four Mediterranean Quercus species under different light conditions (3, 27, and 100% of available radiation). We found evidence for two of the three hypotheses, but none of the four species complied with all three hypotheses at the same time. The reserve effect was not found in any species, the metabolic effect was found in three species (Q. ilex, Q. pyrenaica, and Q. suber), and the seedling-size effect in all species. Light availability significantly affected the relationships between seed size and seedling traits. For Q. ilex and Q. canariensis, a seedling-size effect was found under all three light conditions, but only under the lowest light (3%) for Q. suber and Q. pyrenaica. In all species, the correlation between seed mass and seedling mass increased with a decrease in light, suggesting that seedlings growing in low light depend more upon their seed reserves. A causal model integrates the three hypotheses, suggesting that larger seeds generally produced larger seedlings.