Dynamics of distribution and performance of ramets constructing genets: a demographic�Cgenetic study in a clonal plant, Convallaria keiskei

Background and Aims

In clonal plants producing vegetative offspring, performance at the genet level as well as at the ramet level should be investigated in order to understand the entire picture of the population dynamics and the life history characteristics. In this study, demography, including reproduction and survival, the growth patterns and the spatial distributions of ramets within genets of the clonal herb Convallaria keiskei were explored.

Methods

Vegetative growth, flowering and survival of shoots whose genets were identified using microsatellite markers were monitored in four study plots for 3 years (2003–2005). The size structures of ramets in genets and their temporal shifts were then analysed. Their spatial distributions were also examined.

Key Results

During the census, 274 and 149 ramets were mapped in two 1 × 2 m plots, and 83 and 94 ramets in two 2 × 2 m quadrats. Thirty-eight genotypes were identified from 580 samples. Each plot included 5–18 genets, and most ramets belonged to the predominant genet(s) in each plot. Shoots foliated yearly for several years, but flowering ramets did not have an inflorescence the next year. A considerable number of new clonal offspring persistently appeared, forming a bell-shaped curve of the size structure of ramets in each genet. Comparing the structures modelled by the normal distributions suggested variation among ramets belonging to a single genet and variation among genets. Furthermore, spatial analyses revealed clumped and distant distributions of ramet pairs in a genet, in which the distant patterns corresponded to the linearly elongating clonal growth pattern of this species.

Conclusion

Characteristics of ramet performances such as flowering and recruitment of clonal offspring, in addition to growth, played a large part in the regulation of genet dynamics and distribution, which were different among the studied genets. These might be characteristics particularly relevant to clonal life histories.Key words: Clonal plant, Convallaria keiskei, demography, genet, genetic identification, growth pattern, life history, ramet, spatial distribution     

Do rhizome severing and shoot defoliation affect clonal growth of Leymus chinensis at ramet population level?

Leymus chinensis (Trin.) Tzvel. is a perennial species of Gramineae, usually subject to defoliation from grazing and mowing. We examined whether shoot defoliation and rhizome severing affected rhizome and ramet growth, and vegetative bud outgrowth of L. chinensis ramet populations. We also tested the hypothesis that clonal growth of the ramets subject to defoliation would benefit from clonal integration between interconnected ramets besides from possible compensatory growth. To 48 experimental plots, we applied six treatments resulting from interactions between two rhizome connection states (unsevered/severed) and three defoliation regimes (non-defoliated, mildly-defoliated and heavily-defoliated). Defoliation affected rhizome growth and bud outgrowth, but had little effect on shoot growth. Mild and heavy defoliation exerted similar effects on rhizome growth. Only heavy defoliation significantly reduced bud outgrowth while mild defoliation did not. The fact that shoot growth did not change after defoliation and that the bud numbers remained unchanged after mild defoliation suggest that the compensatory response enable the species to tolerate grazing to some extent. Neither rhizome severing nor the interaction of rhizome severing and defoliation had effect on any tested variables. Lack of the effect of rhizome severing falsified the first half of our hypothesis, that is, clonal integration was unimportant in our experiment. The probable reasons were suspected to be the short duration of the experiment and/or the buffer effect of carbohydrate reserves in rhizomes for shoot growth and bud production in time of defoliation.     

短穗兔耳草基株大小对其克隆生长特征的影响

对采自青藏高原5个不同海拔高度上的短穗兔儿草基株干重与匍匐茎数量、单位长度匍匐茎干重和无性系分株干重之间的相关性,以及匍匐茎与无性系分株总干重与基株干重的比值进行了分析.结果表明,除人为干扰比较严重的生境外,基株大小与匍匐茎数量、单位长度匍匐茎干重之间存在极显著的正线形相关(P<0.01),基株大小对分株的影响可能与匍匐茎数量有关;匍匐茎与分株总干重与基株干重的比值在海拔最高和最低两个样地中最大.短穗兔儿草基株干重对克隆生长有明显的影响,但在不同海拔高度影响作用的大小和方式表现出一定的差异.     

Influences of the genetic neighborhood on ramet reproductive success in a clonal desert cactus

Clonal structure in clonal plants can affect sexual reproduction. Individual ramets can decrease reproduction if their neighbors are ramets of the same genet due to inbreeding depression or self-incompatibility. We assessed ramet reproductive success in the partial self-incompatible Ferocactus robustus (Cactaceae) as a function of floral display size in focal ramets and floral display size and clonal structure of their reproductive neighborhoods. Ramets were labeled, sized in number of stems, mapped and genetically identified through RAPD markers in one population. A pollen dispersal area of 15-m radius was established for each ramet to determine the clonal diversity in the neighborhoods. Flower production and fruit set were counted on a monthly basis during one reproductive season as a surrogate of ramet fitness. We expected a decrease in individual ramet reproductive success as a function of the number of reproductive ramets of the same genet in the neighborhood. A total of 272 sampled ramets revealed 116 multilocus genotypes, showing high clonal diversity in the population (G/N = 0.43, D = 0.98). Clonal diversity of neighborhoods ranged from 0.06 to 1 and fruit set varied from 0 to 76.9%. Individual ramet reproductive success was influenced by (1) mate availability, (2) floral display size of a genet within the reproductive neighborhood, and (3) the proportion of distinguishable genotypes. Floral display size of genets and ramets coupled with the genetic diversity within the reproductive neighborhood determines the low sexual reproduction in F. robustus.     

Clonal segmentation – The development of physiological independence within stolons of Glechoma hederacea L. (Lamiaceae)

The youngest parts of clonal plants benefit from substantial physiological support from older parts, but the extent to which this physiological dependence persists through time is poorly understood. The development of autonomy among connected subunits was therefore analysed in the clonal species Glechoma hederacea. The stolons of a series of clonal fragments with differing numbers of primary ramets were severed at a fixed point relative to the four oldest primary ramets. The subsequent growth of both parts of the severed fragments was compared with that of a series of intact fragments.The growth of apical stolon portions that included five or more rooted primary ramets at the time of severing was unaffected by severing. Apical portions with three or fewer rooted ramets at the time of severing produced fewer new primary ramets than equivalent parts of intact fragments, while apical portions with four or fewer rooted ramets produced less above-ground mass than equivalent apical portions of intact clonal fragments. Basal portions of clonal fragments severed when there were one or two rooted ramets in the apical portion produced more secondary ramet mass than equivalent parts of intact fragments. The gain in mass of secondary ramets in the basal portions of severed fragments matched the reduction in mass of secondary ramets in the apical portions. However, severing caused an overall loss of mass when apical portions had three or fewer rooted ramets at the time of severing, because the mass of primary ramets in basal portions did not increase following severing. Severing had little impact on the allometry of the apical portions. The relationship between mass in secondary ramets and mass in primary ramets was similar in the apical portions of severed and intact clonal fragments. None of the severing treatments increased the total mass of secondary ramets, suggesting that apical dominance in this species only affects branches very close to the apex.These observations, combined with existing knowledge of vascular architecture in G. hederacea, demonstrate that, whether or not physical connections persist between ramets, growing stolons rapidly develop into physiologically autonomous segments. This may be a characteristic of species that exploit disturbed, spatially heterogeneous habitats through rapid multiplication of ramets connected by long, aerial runners or stolons.     

克隆整合有助于狗牙根抵御水淹

尽管国内外开展了大量的克隆整合对克隆植物抵御逆境能力影响的研究, 但整合对植物抵御水淹能力的影响研究仍比较缺乏。该文从克隆整合的角度探讨多年生草本植物狗牙根(Cynodon dactylon)对水淹胁迫的响应。试验模拟了先端分株(相对年幼的分株)分别处于0、5和15 cm三种水淹胁迫环境, 并在每个水淹梯度下实施先端分株与基端分株(相对年长的分株)之间匍匐茎连接或切断处理, 调查水淹一个月后基端分株和先端分株以及整个克隆片段在形态和生理上的表现。研究发现: 切断匍匐茎连接显著降低了狗牙根先端分株的生长, 表现在生物量下降、匍匐茎长度减短和分株数减少等方面; 水淹显著抑制了先端分株的生长, 但对基端分株的生长并未造成显著影响; 在5 cm水淹处理下, 匍匐茎保持连接时, 先端分株和整个克隆片段的生长显著增加; 连接或切断处理在不同水淹梯度下对匍匐茎平均节间长没有显著影响, 对先端分株或基端分株在光化学转化效率上也未表现显著性差异。结果表明: 克隆整合效应促进了狗牙根在水淹胁迫下分株的生长, 并有助于整个克隆片段抵御水淹胁迫。     

Relative costs and benefits of clonal integration of Zoysia japonica under various N:P ratios

Clonal plants adaptively respond to abiotic stress, but to date little is known about under what circumstanses clonal integration is beneficial, or costly. To study the costs and benefits of clonal integration on clonal growth, we cultivated Zoysia japonica under three ratios of N:P (N:P ≈ 7, 14:1 and 21:1), and four types of stolon severing treatments (connected stolon CS, light severing LS, moderate severing MS, serious severing SS). The results showed that Z. japonica performed best at a low ratio of N:P (N:P ≈ 7:1). When the stolons were connected (CS), the growth of primary A‐ramets, multiple‐nodes and stolons benefited from clonal integration; however, the growth of primary B‐ramets on the primary stolons, A and B ramets was significantly reduced (p < 0.05). In the moderate stolon severing treatment MS_7:1 (N:P ≈ 7:1), clonal integration appeared more cost effective than in all other treatments. On the whole, with increasing stolon severing intensity, the cost of clonal integration increased and the clonal growth of Z. japonica declined significantly. The pattern of biomass allocation may be useful for Z. japonica to adapt to the various environments, and clonal integration plays a significant role under adverse environmental conditions.     

Partial mechanical stimulation facilitates the growth of the rhizomatous plant Leymus secalinus: modulation by clonal integration

Background and Aims

Mechanical stimulation (MS) often induces plants to undergo thigmomorphogenesis and to synthesize an array of signalling substances. In clonal plants, connected ramets often share resources and hormones. However, little is known about whether and how clonal integration influences the ability of clonal plants to withstand MS. We hypothesized that the effects of MS may be modulated by clonal integration.

Methods

We conducted an experiment in which ramet pairs of Leymus secalinus were subjected to three treatments: (1) connected ramet pairs under a homogeneous condition [i.e. the proximal (relatively old) and distal (relatively young) ramets were not mechanically stressed]; (2) connected ramet pairs under a heterogeneous condition (i.e. the proximal ramet was mechanically stressed but the distal ramet was not); and (3) disconnected ramet pairs under the same condition as in treatment 2. At the end of the experiment, we harvested all plants and determined their biomass and allocation.

Key Results

Clonal integration had no significant influence on measured traits of distal L. secalinus ramets without MS. However, under MS, plants with distal ramets that were connected to a mother ramet produced more total plant biomass, below-ground biomass, ramets and total rhizome length than those that were not connected. Partial MS exerted local effects on stimulated ramets and remote effects on connected unstimulated ramets. Partial MS increased total biomass, root/shoot ratio, number of ramets and total rhizome length of stimulated proximal ramets, and increased total biomass, root weight ratio, number of ramets and total rhizome length of connected unstimulated ramets due to clonal integration.

Conclusions

These findings suggest that thigmomorphogenesis may protect plants from the stresses caused by high winds or trampling and that thigmomorphogenesis can be strongly modulated by the degree of clonal integration.     

Clonal plant allocation to daughter ramets is a simple function of parent size across species and nutrient levels

The evolution of clonal growth is a widespread phenomenon among plant species, characterized by the production of genetically identical clonal fragments (ramets) via rhizomes or stolons that form an interconnected clonal organism (genet). Clonal plant species are known to differ in their investment into ramet production, and exhibit considerable variation in ramet morphology both within and among species. While patterns of resource allocation are thought to be linked to a number of plant characteristics, many analyses are limited by uncertainty in how clonal plants determine the morphology and resources allocated to new ramets. In this study, we attempted to discern what aspects of parent ramets best predicted resource allocation to new daughter ramets, and the relationship between resource allocation and daughter ramet rhizome morphology. We grew two sedge species, Schoenoplectus tabernaemontani and Eleocharis elliptica, in a greenhouse under two levels of fertilizer addition. By harvesting daughter ramets that had initiated stem production, yet remained aphotosynthetic, we were able to isolate parental investment into non-independent daughter ramets at a point where daughter ramet spacer length became fixed. Our results indicate that parent ramets allocated a non-linear proportion of parent rhizome biomass to the production of daughter ramets. Moreover, this relationship was unaffected by environmental nutrient availability. Daughter ramet biomass, in turn, was strongly correlated with daughter ramet spacer length. These observations shed light on key processes governing clonal growth in plants, and their potential application in unifying allocational and morphological perspectives to explore the fitness implications of variability in clonal growth.     

Differential effects of clonal integration on performance in the stoloniferous herb Duchesnea indica, as growing at two sites with different altitude

Clonal integration may be adaptive and enhance the genet performance of clonal plants. Degree of clonal integration may differ between different environments . Here, a container experiment was used to determine how clonal integration affected the performance of the stoloniferous herb Duchesnea indica at two sites with different altitude along the transitional zone between the Qinghai-Tibet plateau and the Sichuan basin of Southwest China. In the experiment, the stolon between partially shaded two ramets experienced severing and intact treatments.We predicted that clonal integration would increase performance of whole clonal fragments and their shaded clonal parts at both sites. In both arctic and alpine environments, clonal plants may form highly integrated plant units (group of ramets).We predicted again that the reduction due to stolon severing in performance of whole clonal fragments and their shaded clonal parts would be greater at the site with high altitude than one with low altitude. The results indicated that the benefit for the shaded clonal parts and whole clonal fragments due to clonal integration was only observed at the site with high altitude. The results suggest that the performance of Duchesnea indica tends to be more responsive to the stolon severing at the site with high altitude than one with low altitude and support the second prediction. In addition, the effects of conditions of the sites and clonal integration on local morphological traits of ramets may be adaptive, five morphological traits of ramet-level (length of petiole, mean stolon internode length, specific petiole weight, specific stolon internode weight and specific leaf area) were investigated. Altogether, the results suggest that clonal integration might help D. indica plants to successfully inhabit the high-altitude habitat of the Qinghai-Tibet plateau of Southwest China, providing new evidences for the notion that clonal integration is an adaptive trait in stressful environments.     

Clonal integration supports the expansion from terrestrial to aquatic environments of the amphibious stoloniferous herb Alternanthera philoxeroides

Effects of clonal integration on land plants have been extensively studied, but little is known about the role in amphibious plants that expand from terrestrial to aquatic conditions. We simulated expansion from terrestrial to aquatic habitats in the amphibious stoloniferous alien invasive alligator weed ( Alternanthera philoxeroides ) by growing basal ramets of clonal fragments in soils connected (allowing integration) or disconnected (preventing integration) to the apical ramets of the same fragments submerged in water to a depth of 0, 5, 10 or 15 cm. Clonal integration significantly increased growth and clonal reproduction of the apical ramets, but decreased both of these characteristics in basal ramets. Consequently, integration did not affect the performance of whole clonal fragments. We propose that alligator weed possesses a double-edged mechanism during population expansion: apical ramets in aquatic habitats can increase growth through connected basal parts in terrestrial habitats; however, once stolon connections with apical ramets are lost by external disturbance, the basal ramets in terrestrial habitats increase stolon and ramet production for rapid spreading. This may contribute greatly to the invasiveness of alligator weed and also make it very adaptable to habitats with heavy disturbance and/or highly heterogeneous resource supply.     

Reproductive demography of ramets and genets in a rhizomatous clonal plant <Emphasis Type="Italic">Convallaria keiskei</Emphasis>

Clonal growth occurring below the ground makes it difficult to identify individuals and demonstrate the demographic features of a focal plant species. In this study, genotypically identified ramets of a rhizomatous clonal herb, Convallaria keiskei Miq., were monitored for their growth, survival, and reproduction from 2003 to 2006. After the monitoring period, their subterranean organs were excavated to explore the underground connections of established ramets and the direction of clonal growth. We then combined data on the fate of the monitored ramets with the information of rhizome connections, clarifying reproductive demography at both the ramet and genet levels. Although each ramet initiated both sexual reproduction (via flowering) and clonal growth, clonal growth tended to precede sexual reproduction. In a surveyed genet, 51.0% of ramets produced flowers and 29.6% generated clonal offspring during the study period. Consequently, we clarified the reproductive demography of C. keiskei: clonal growth tended to precede flowering in a ramet, and a genet can keep reproducing every season at the genet level, despite a ramet not having inflorescence every year.     

资源异质性环境中三种匍匐茎草本植物克隆内资源共享和分株功能特化

研究了3种来自中国北方林下、草地和碱化草甸匍匐茎型克隆草本植物绢毛匍匐委陵菜 (Potentilla reptans L. var. sericophylla Franch.)、鹅绒委陵菜 (P. anserina L.) 和金戴戴 (Halerpestes ruthenica (Jacq.) Qvcz.) 对由高光照低养分斑块和低光照高养分斑块组成的资源交互斑块性生境的适应性对策.当生长于高光照低养分条件下分株 (HL分株) 与生长于低光照高养分条件下分株 (LH分株) 之间的匍匐茎连接时, 3种克隆植物HL分株、LH分株以及整个分株对系统 (HL分株 + LH分株) 的生物量均得到显著提高.同时, LH分株根冠比显著增加, 而HL分株根冠比显著下降.这表明, 当互连分株置于由低光照高养分斑块和高光照低养分斑块组成的异质性环境中时, 3种植物克隆分株均发生了环境诱导的功能特化.克隆内资源共享以及克隆内不同分株的功能特化有利于整个分株系统对局部丰富资源的获取, 从而能够缓解资源交互斑块性生境对克隆植物的不利影响.     

Clonal integration and its ecological significance in Hedysarum laeve,a rhizomatous shrub in Mu Us Sandland

Hedysarum laeve, a rhizomatous clonal half-shrub, commonly dominates in inland dunes in semiarid areas of northern China. This species propagates vegetatively by the extension of horizontal rhizomes resulting in programmed reiteration of apical and/or axillary meristems. In this study, (14)C labeling and experimental defoliation were employed to test the photosynthate translocation within the interconnected parent-daughter ramet pairs. A proportion of (14)C-photosynthates was transported from the parent ramet into the daughter ramet, the roots of the daughter ramet, and the rhizome; these three components showed more than 70% sink activity after 24-h translocation. On the other hand, the basipetal translocation (from daughter ramet into parent ramet) was relatively small with sink activity of less than 5%, but sink activity of the rhizome exceeded 10%. Defoliation had an influence on the photosynthate translocation between parent and daughter ramets. The intact parent ramets significantly increased their (14)C-photosynthate translocation into defoliated daughter ramets when compared to intact daughter ramets. The daughter ramets transported significantly more (14)C-photosynthates to the defoliated parent ramets than to the intact parent ramets. A portion of (14)C-photosynthates was transported into the rhizome from both parent and daughter ramets, indicating that the rhizome is supported by both ramets for photosynthates. The clonal integration between ramets of the species through rhizome connection may confer benefit both to the ramets and the genet in adverse environments.     

两种践踏胁迫下克隆整合对入侵植物空心莲子草生长的影响

研究了两种践踏胁迫下克隆整合对入侵植物空心莲子草生长的影响.结果表明:(1)切断分株间的匍匐茎连接,会降低先端分株的生物量、分株数、总匍匐茎长度和总叶片数,但会显著增强基端分株的生物量.(2)对先端分株的践踏胁迫会显著降低先端分株叶片的叶绿素相对含量,对基端分株的践踏胁迫会显著降低基端分株的生物量和总匍匐茎长度.(3)对于基端分株的分株数、总匍匐茎长度和总叶片数来说,当进行基端分株践踏胁迫时,匍匐茎连接对其影响不大,而当进行先端分株践踏胁迫时,则明显对其不利.(4)对于整个克隆片段,践踏胁迫的差异和匍匐茎是否切断对其生长没有显著影响.     

Clonal integration and its ecological significance in Hedysarum laeve, a rhizomatous shrub in Mu Us Sandland

Hedysarum laeve, a rhizomatous clonal half-shrub, commonly dominates in inland dunes in semiarid areas of northern China. This species propagates vegetatively by the extension of horizontal rhizomes resulting in programmed reiteration of apical and/or axillary meristems. In this study, ¹⁴C labeling and experimental defoliation were employed to test the photosynthate translocation within the interconnected parent–daughter ramet pairs. A proportion of ¹⁴C-photosynthates was transported from the parent ramet into the daughter ramet, the roots of the daughter ramet, and the rhizome; these three components showed more than 70% sink activity after 24-h translocation. On the other hand, the basipetal translocation (from daughter ramet into parent ramet) was relatively small with sink activity of less than 5%, but sink activity of the rhizome exceeded 10%. Defoliation had an influence on the photosynthate translocation between parent and daughter ramets. The intact parent ramets significantly increased their ¹⁴C-photosynthate translocation into defoliated daughter ramets when compared to intact daughter ramets. The daughter ramets transported significantly more ¹⁴C-photosynthates to the defoliated parent ramets than to the intact parent ramets. A portion of ¹⁴C-photosynthates was transported into the rhizome from both parent and daughter ramets, indicating that the rhizome is supported by both ramets for photosynthates. The clonal integration between ramets of the species through rhizome connection may confer benefit both to the ramets and the genet in adverse environments. Received: April 12, 2001 / Accepted: November 26, 2001     

资源异质性环境中三种匍匐茎草本植物克隆内资源共享和分株功能特化(英文)

研究了 3种来自中国北方林下、草地和碱化草甸匍匐茎型克隆草本植物绢毛匍匐委陵菜 (PotentillareptansL .var.sericophyllaFranch .)、鹅绒委陵菜 (P .anserinaL .)和金戴戴 (Halerpestesruthenica (Jacq .)Qvcz .)对由高光照低养分斑块和低光照高养分斑块组成的资源交互斑块性生境的适应性对策。当生长于高光照低养分条件下分株(HL分株 )与生长于低光照高养分条件下分株 (LH分株 )之间的匍匐茎连接时 ,3种克隆植物HL分株、LH分株以及整个分株对系统 (HL分株 LH分株 )的生物量均得到显著提高。同时 ,LH分株根冠比显著增加 ,而HL分株根冠比显著下降。这表明 ,当互连分株置于由低光照高养分斑块和高光照低养分斑块组成的异质性环境中时 ,3种植物克隆分株均发生了环境诱导的功能特化。克隆内资源共享以及克隆内不同分株的功能特化有利于整个分株系统对局部丰富资源的获取 ,从而能够缓解资源交互斑块性生境对克隆植物的不利影响     

匍匐茎草本绢毛匍匐委陵菜对局部遮荫的克隆可塑性

采自林窗和林内生境的绢毛匍匐委陵菜 (PotentillareptansL .var.sericophyllaFranch)“分株对”(即由一匍匐茎节间相连着的两个分株 ,其一为“目标分株” ,另一为“相连分株”)在一户外实验中经历了全不遮荫、全部遮荫和局部遮荫处理。该植物的基株生物量、匍匐茎总长度、分株数、匍匐茎比节间重、叶柄长、比叶柄重在遮荫条件下较小。匍匐茎节间长度没有对遮荫处理发生反应。在局部遮荫处理 ,遮荫斑块的分株的叶柄长度由于连着未遮荫斑块中分株而变得更长。这种克隆整合对克隆形态可塑性的修饰作用只在林窗生境来源的实验植物中观察到。其他克隆生长和克隆形态特征的可塑性在不同生境来源的实验植物间没有差异。     

Clonal Plasticity in Response to Partial Neutral Shading in the Stoloniferous Herb Potentilla reptans var. sericophylla

Ramet-pairs of Potentilla reptans L. var.sericophylla Franch from forest gap and forest understory were subjected to unshading, shading and partial shading treatments in a pot experiment. The genet biomass, total length of stolons, number of ramets, specific stolon weight, petiole length and specific petiole weight of the plant species under the shaded condition were smaller than those under the unshaded condition. The stolon internode length did not respond to the various treatments. In the plants from the forest gap, the petiloes of ramet grown in the shaded patch were longer as connected to plant part in the unshaded patch than as connected to plant part under the same shaded condition. Such modification of local response of ramet petiole to shading due to physiological integration was not observed in the plants from the understory. There was no effect of connection to ramets in shaded patches on the local response of the rest ramet characters to the partial unshading.     

CLONAL INTEGRATION: NUTRIENT SHARING BETWEEN SISTER RAMETS OF SOLIDAGO ALTISSIMA (COMPOSITAE)

To test whether sharing of resources occurs among connected ramets of the tall goldenrod, Solidago altissima, we examined the extent of clonal integration for nutrients. In a greenhouse experiment, two-ramet clones were grown in a triad of connected pots so that nutrients could be supplied to either sister ramet or to their old rhizome (mother rhizome). Mother rhizomes and their associated roots shared nutrients with daughter ramets; however, any nutrient sharing that occurred between sister ramets was too little to significantly affect their growth. In addition, sister ramets not only competed for nutrients through parental connections, but larger ramets inhibited the growth of smaller ramets. We suggest that, for tall goldenrod, a clonal growth strategy in which nutrients are not shared among sister ramets may increase genet fitness by reducing the rhizome production of ramets in poor-nutrient microsites. Consequently, the genet would produce relatively fewer ramets in unfertile areas and make better use of heterogeneous nutrient resources.