Phenotypic plasticity and biomass allocation pattern in three Dryopteris (Dryopteridaceae) species on an experimental light-availability gradient
Phenotypic plasticity and biomass allocation pattern in three Dryopteris (Dryopteridaceae) species on an experimental light-availability gradient
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DOI：
10.1007/s11258-006-9250-0
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发表时间：
2007-09
期刊：
影响因子：
1.7
通讯作者：
K. Rünk;K. Zobel
中科院分区：
文献类型：
--
作者：
K. Rünk;K. Zobel
我们感兴趣的是，是否有对比的区域分布格局的三个同源，经常共存的蕨类植物（鳞毛蕨carthusiana，D。D. expansa）可以用不同的生物量分配策略和不同的表型对光的可塑性来解释。已知这些蕨类植物的形态和栖息地偏好非常相似，但在爱沙尼亚，它们的出现频率差异很大--鳞毛蕨常见，D。expandsagrows在分散的地方，和D.很少见。我们在不同光照水平（100%，50%，25%和10%的全日照）下种植的物种在一个实验花园，比较他们的autecological遮荫反应。一个生长季后，植物总生物量积累的种间差异明显。carthusiana>D. expansa>D.在幼孢子体阶段，后者可能处于竞争劣势。expansa最不耐荫，光照不足50%时生物量急剧下降; dilatata是最耐阴性的，在所有照明水平下生长相似。在相对生物量分配格局中，物种间最显著的差异是根茎中储存的生物量的相对份额。在D. carthusiana和D.扩展这个份额几乎是恒定的，并且与照明条件无关。D.在遮荫条件下，鳞毛蕨分配给根茎的生物量很少，但在50%光照条件下，鳞毛蕨的生物量增加了2倍以上。在根茎质量、地上部生物量比、柄长和比叶面积4个性状上，其个体发育对光的可塑性程度均显著高于D。expansa和D.虽然实验中物种的一般表现（生物量生产）与自然界中观察到的一致，但可塑性估计的结果有些令人惊讶-很难解释物种的低劣表现（D.（2）具有高度的形态可塑性。也许，该物种是罕见的，因为某些气候限制，或因为它目前正在扩大其分布，并在入侵爱沙尼亚林下群落的阶段。
We were interested in whether the contrasting regional distribution patterns of three congeneric, frequently co-occurring fern species (Dryopteris carthusiana, D. dilatataandD. expansa)could be explained by differential biomass allocation strategies and different phenotypic plasticities to light availability. The morphology and habitat preference of these ferns are known to be very similar, but in Estonia, their frequencies of occurrence differ sharply––Dryopteris carthusianais common,D. expansagrows in scattered localities, andD. dilatatais rare. We grew the species under different levels of illumination (100, 50, 25 and 10% of full daylight) in an experimental garden to compare their autecological responses to shading. After one growing season there were clear interspecific differences in total plant biomass accumulation––D. carthusiana>D. expansa>D. dilatata––indicating the possible competitive inferiority of the latter at the young sporophyte stage.D. expansawas the least shade-tolerant, with biomass decreasing sharply under less than 50% illumination;D. dilatatawas the most shade-tolerant, with similar growth at all illumination levels. In relative biomass allocation patterns, the most notable differences among species were in the relative shares of biomass stored in rhizomes. InD. carthusianaandD. expansathis share was nearly constant and independent of the illumination conditions.D. dilatataallocated very little biomass into rhizome in deep shade, but was able to increase this share more than twofold in 50% light.Dryopteris dilatatawas clearly shown to be morphologically the most plastic of the three. In four traits––rhizome mass, frond:below-ground biomass ratio, stipe length and specific leaf area––its degree of ontogenetic plasticity to light was significantly higher than that ofD. expansaandD. carthusiana.While the general performance (biomass production) of species in the experiment coincided with that observed in nature, the results of plasticity estimation were somewhat surprising––it is difficult to explain the inferior performance of a species (D. dilatata) through high morphological plasticity. Probably, the species is rare either because of certain climatic restrictions, or because it is presently expanding its distribution and is in the phase of invading Estonian understory communities.