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101.
Marie-Eve Bellavance 《Aquatic Botany》2010,93(2):129-134
Over the last decades, the abundance of common reed has significantly increased in freshwater wetlands of eastern North America, and stands of this species are now commonly alternating with stands of cattails. Since these species share many characteristics, the contact zone between common reed and cattail stands may witness strong interspecific interactions. We surveyed stand dynamics in roadside ditches and freshwater marshes at these contact zones over three years, and we examined the morphological plasticity in response to neighbors. Results indicate that common reed is clearly gaining ground over time, while cattails stands are retreating. We also found annual variability in the spatial dynamics, suggesting that other factors, such as the effect of weather conditions on water level, may affect population processes. Interspecific interactions had a detrimental effect on both common reed and cattail biomass. However, common reed showed morphological plasticity in shoot height, number of nodes, and internodes length, while cattails did not. Our observations suggest that common reed has a net competitive advantage over cattails in roadside ditches and freshwater marshes. 相似文献
102.
Qing-Song Shao Qiao-Sheng Guo Yan-Ming Deng Hai-Peng Guo 《Biochemical Systematics and Ecology》2010,38(6):1160-1169
The diversity and genetic relationship among 29 populations of Chrysanthemum morifolium, one of Chrysanthemum indicum and one of Chrysanthemum nankingense from China were analyzed using morphological traits and molecular markers. Twenty morphological traits were scored as well as 182 ISSR marker-fragments, as amplified by 22 primers [the percentage of polymorphic bands (PPB): 81.87%], and 243 SRAP marker-fragments as generated by 26 primer pairs (PPB: 75.72%). Mantel’s test indicated significant correlation (r = 0.624) of morphological trait and SRAP. By contrast, the morphological trait showed low correlation with ISSR (r = 0.246). Cluster analysis showed groupings of the accessions according to all four methods correlated well with their geographic region of origin, and most populations from the south of China were classified into one cluster and most populations from the north of China were classified into another cluster. Finally, an appropriate strategy for conserving the C. morifolium germplasm was proposed. 相似文献
103.
香菇单孢杂交子代群体灰色关联度和ISSR分析 总被引:3,自引:0,他引:3
以香菇Lentinula edodes栽培菌株秋6和K95-1为亲本,通过单孢菌株配对杂交获得21个杂交子,观察杂交子及亲本菌丝体生长情况,进行栽培出菇试验。采用灰色关联度分析法,对9个正常出菇的杂交子从8个性状方面进行综合评价,结果表明,杂交子QK-8和QK-15关联度仅次于亲本秋6,农艺性状和子实体性状表现最好。采用ISSR技术对21个杂交子及亲本进行DNA多态性聚类分析,单孢杂交后代遗传分化十分明显,归于同一类群的杂交子在菌丝生长、子实体形态和农艺性状等方面常表现相似,ISSR分析能为优良杂交子初步筛选提供重要参考。 相似文献
104.
美洲黑杨×小叶杨杂种多倍体诱导研究 总被引:1,自引:0,他引:1
用不同浓度秋水仙素处理美洲黑杨(Populus deltoides)与小叶杨(Populus simonii)杂种后代以诱导产生多倍体,并采用流式细胞术(FCM)对初选的多倍体材料进行DNA含量分析.结果表明:小于0.1%秋水仙素浓度处理对诱导多倍体无作用;0.3%及其以上浓度处理对诱导产生多倍体效果较好,但随处理浓度增加秋水仙素对杨树的毒害作用增大, 0.5%浓度处理可使顶芽死亡率高达71.43%,且在顶芽死亡的植株中未发现多倍体单株.应用气孔性状对388株扦插苗进行多倍体初选后,采用流式细胞术对初选的5株拟多倍体进行DNA含量分析,鉴定到2株四倍体材料.获得的四倍体材料与二倍体植株在株高和叶绿素含量上差异显著,但在SOD和POD活性上无显著性差异. 相似文献
105.
Spatial and temporal heterogeneity in the environment is a common feature affecting many natural populations. For example,
both the resource levels and optimal habitat choices of individuals likely change over time. One way for organisms to cope
with environmental variation is to display adaptive plasticity in traits such as behavior and morphology. Since trait plasticity
is hypothesized to be a prerequisite for character divergence, studies of mechanisms behind such plasticity are warranted.
In this study, we looked at the interaction of two potentially important environmental variables on behavioral and morphological
plasticity in Eurasian perch (Perca fluviatilis L.). More specifically, the plastic responses in activity and morphology of perch exposed to different resource levels and
simulated habitat types were studied in an aquarium experiment. The resource level experienced had a large influence on plasticity
in both activity and morphology. Behavioral adaptations have been thought to mediate morphological transitions, and we suggest
that the morphological response to the resource level was mediated by differences in activity and growth rates. The habitat
type also affected morphological plasticity but to a lesser extent, and there was no effect on activity from habitat type.
Based on these results, we suggest that it is essential to include several environmental factors acting in concert when studying
mechanisms behind trait plasticity. We also propose that variation in resource levels might play a key role in fostering trait
plasticity in at least fish populations, while other environmental variables such as divergent habitat complexities and prey
types might be less influential. Dynamics in resource levels and optimal habitat choices might thus be important factors influencing
character divergence in natural populations. 相似文献
106.
华南沿海地区西部入海水系中间黄颡鱼的形态变异及地理分化 总被引:2,自引:0,他引:2
为探讨不同水系中间黄颡鱼(Pelteobagrus intermedius)的形态差异及地理分化问题,采用形态学方法, 测量12个水系中间黄颡鱼150尾样本的18个形态性状,进行主成分分析.其结果显示,前3个主成分累积贡献率为58.918%,并可将这12个水系的群体分为3簇.华南沿海地区西部诸独立入海小水系中的中间黄颡鱼群体与海南岛群体之间的相似性大于与西江干流群体的相似性.防城港地区3条直接入海的小水系的群体在形态特征上已发生了一定程度的分化,其分化主要表现在吻、眼和尾的变异. 相似文献
107.
The response of clonal growth and ramet morphology to water depth (from 60 to 260 cm) and sediment type (sand versus organic
clay) was investigated for the stoloniferous submersed macrophyte Vallisneria natans in an outdoor pond experiment. Results showed that water depth significantly affected clonal growth of V. natans in terms of clone weight, number of ramets, number of generations, clonal radius and stolon length. V. natans showed an optimal clonal growth at water depths of 110–160 cm, but at greater depths clonal growth was severely retarded.
A high allometric effect was exhibited in ramet morphology. Along the sequentially produced ramet generations, ramet weight
and plant height decreased while stolon length and the root:leaf weight ratio increased. When using ramet generations as covariate,
sediment type rather than water depth more strongly affected the ramet characteristics. For plants grown in clay, ramet weight,
ramet height and stolon length were greater, and plants exhibited lower root:leaf weight ratio. These data suggest that water
depth and sediment type have differential effects on clonal growth of V. natans: Water depth appears primarily to affect numerical increase in ramets and spatial spread, whereas sediment type mainly affects
biomass accumulation and biomass allocation.
Handling editor: S. M. Thomaz 相似文献
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