Sexual vs. vegetative reproduction in relation to forest dynamics in the understorey shrub, Hydrangea paniculata (Saxifragaceae)
Sexual vs. vegetative reproduction in relation to forest dynamics in the understorey shrub, Hydrangea paniculata (Saxifragaceae)
复制标题
DOI：
10.1023/b:vege.0000019027.88318.54
复制
发表时间：
2004-01-01
期刊：
影响因子：
1.7
通讯作者：
Seiwa, K
中科院分区：
文献类型：
--
作者：
Kanno, H;Seiwa, K
在森林林下，灌木通常是无性繁殖而不是有性繁殖，但这两种繁殖方式的相对贡献可能会随着环境条件的时间变化而变化。例如，在一个实施例中，光，森林底质），与森林动态密切相关。为了评估无性系林下灌木圆锥绣球（Hydrangea paniculata）繁殖模式的偶然变化，开花，幼苗建立，营养繁殖，生殖大小和年龄）进行了调查，在四个不同的发展阶段（早期的差距，EG;后期的差距，LG;建设，BU;成熟，MA）在日本山毛榉林。开花的个人只发生在EG和LG，并观察到在EG和LG比BU和MA，主要是因为冠层间隙提供了足够的光开花和合适的基板（倒下的树木和暴露的矿物土壤）幼苗建立的幼苗数量要多得多。开花个体起源于在林隙形成之前一直在荫蔽的林下植物。与有性繁殖相反，无性系破碎化程度随林分发育而增加，其顺序为LG、EG、BU、MA。这是因为，在后期阶段的森林动态（BU和MA），大的个人，其中一些以前花在间隙阶段，分层的森林地面上，随后产生了大量的克隆片段的分离被埋的分支从主茎已经腐烂。这导致了大量的克隆片段起源于一个单一的母株。这些结果表明，该虫的生殖方式与其繁殖方式有关。paniculata是强烈的影响，在环境条件的变化方面的动态冠层树木。从种子的间隙阶段，尽管他们的时间很短，繁殖提供了新的基因在既定的人口，而营养繁殖通过碎片在封闭的冠层阶段，提高人口的稳定性，直到下一个干扰。
In the forest understorey, shrubs usually reproduce vegetatively rather than sexually, but the relative contribution of these two reproductive modes may vary with temporal changes in environmental conditions ( e. g., light, substrates of forest floor) that are closely related to forest dynamics. To evaluate the occasional changes in reproductive modes of the clonal understorey shrub Hydrangea paniculata, the reproductive characteristics (i.e., flowering, seedling establishment, vegetative propagation, reproductive size and age) were investigated in four different developmental stages in a Japanese beech forest ( early gap, EG; late gap, LG; building, BU; mature, MA). Flowering individuals occurred only in EG and LG, and a much greater number of seedlings was observed in both EG and LG than in BU and MA, mainly because canopy gaps provided sufficient light for flowering and suitable substrates ( fallen trees and exposed mineral-soil) for seedling establishment. The flowering individuals originated from plants that had persisted in the shaded understorey until gap formation. In contrast to sexual reproduction, clonal fragmentation increased with forest development in the order LG, EG, BU, MA. This is because, in later stages of forest dynamics ( BU and MA), large individuals, some of which had previously flowered in gap stages, were layered on the forest floor and subsequently produced a substantial number of clonal fragments by separation of the buried branches from the main stems which had decayed. This resulted in a large number of clonal fragments originating from a single mother plant. These results suggest that the reproductive modes of H. paniculata is strongly influenced by the changes in environmental conditions with respect to the dynamics of canopy trees. Reproduction from seed in gap stages, despite their short period, provide new genets in established populations, whereas vegetative propagation via fragmentation in closed-canopy stages enhance the stability of the population until the next disturbance.