Growth Of Ramets Research Articles

Clonal integration facilitates the expansion of Hydrocotyle vulgaris from a limited space to a larger area

AbstractClonal integration is an important ecological advantage of clonal plants. To ask whether clonal integration can help invasive plants escape space limitations, we tested the hypothesis that it can promote the growth of apical ramets when their connected basal ramets grow in limited space. We conducted a greenhouse experiment on the common perennial herb Hydrocotyle vulgaris. Clonal fragments consisting of pairs of connected ramets grew with basal ramets in three different sizes of pots (small, medium, and large) and apical ramets in large pots, and the connection between ramets was either severed or left intact. Pot size significantly affected the growth of basal ramets such that the biomass, number of leaves and flowers, and stolon length were in general greater in medium pots than in large and small pots when stolons were intact and were greater in medium and large pots than in small pots when stolons were severed. Furthermore, pot size interacted with severance to affect the performance of H. vulgaris. When the basal ramets grew in small pots, the intact stolon resulted in a significant promotion of apical ramet growth, but such positive effect was not found when the basal ramets grew in medium and large pots. Our results suggest that H. vulgaris is able to promote the growth of apical ramets to occupy the surrounding areas through clonal integration when the space where basal ramets grow is limited.

Changes induced by parental neighboring touch in the clonal plant Glechoma longituba depend on the light environment.

Touch by neighboring plants is a common but overlooked environmental variable for plants, especially in dense vegetation. In addition, shade is inevitable for understory plants. The growth performance of clonal plant to the interaction between thigmomorphogenesis and shade response, and their impact on light adaptability is still unknown. At the present study, parental ramets of Glechoma longituba were exposed to two conditions (neighboring touch and shade), and their offspring ramets were in ambient or shaded environment. The phenotype and growth of parental and offspring ramets were analyzed. The results showed that neighboring touch of parental ramets regulated the performance of offspring ramets, while the effect depended on the light environment. The parental neighboring touch occurring in ambient environment suppressed the expansion of leaf organ, showed as a shorter petiole and smaller leaf area. Moreover, G. longituba exhibited both shade avoidance and shade tolerance characters to shaded environment, such as increased leaf area ratio and leaf mass ratio, longer specific petiole length and specific stolon length. It was notable that these characters of shade response could be promoted by parental neighboring touch to some extent. Additionally, parental light environment plays an important role in offspring growth, parent with ambient light always had well-grown offspring whatever the light condition of offspring, but the growth of offspring whose parent in shaded environment was inhibited. Finally, for the offspring with shaded environment, the touch between parental ramets in shade environment showed a disadvantage on their growth, but the influence of the touch between parental ramets in ambient environment was slight. Overall, the interaction of parental neighboring touch and shade environment complicate the growth of understory plants, the performance of plants is the integrated effect of both. These findings are conducive to an in-depth understanding of the environmental adaptation of plants.

Clonal integration reduced sexual reproduction of Leymus chinensis clones in heterogeneous environments regardless of stress/disturbance intensities

Clonal integration can benefit the performance and fitness of clonal plants in heterogeneous environments. Although trade-offs of sexual and asexual reproduction are key life-history strategies to assess the plant fitness and adaptive abilities, the effects of clonal integration on these is less studied. In this study, a pot experiment was conducted to test how reproductive strategies were affected by clonal integration of clonal plant species Leymus chinensis growing in heterogeneous saline-alkali soils. The results showed that clonal integration had no significant effect on total biomass of whole clone of L. chinensis. The total biomass of younger ramets was higher (+32.8%, P < 0.001) under integration condition, while at the cost of the older ramets (-21.7%, P < 0.001). Moreover, the ratio of ear biomass to clonal growth organs (CGO) biomass was slightly reduced by 31.7% (P = 0.09). For younger ramets, clonal integration enhances biomass allocation towards CGO, while reducing allocation towards ear growth, and the ratio of ear/CGO biomass was significantly reduced by 39.1% (P < 0.01). Results indicated that clonal integration reduced the ratio of ear to clonal growth organ biomass of whole clone, and more biomass was allocated to younger ramets for spatial expansion. Clonal integration influenced reproductive strategies of L. chinensis, while its impact is not depended on nutrient levels or defoliation interference. The study emphasized the significance of clonal integration in promoting the growth of offspring ramets and, consequently, enhancing their abilities to expand rapidly. It could enhance the spatial expansion of L. chinensis on a site scale and provide high potential for restoration of patchy degraded grassland where it is dominant.

The oldest known clones of Salix herbacea growing in the Northern Apennines, Italy are at least 2000 years old.

Dominant in many ecosystems around the world, clonal plants can reach considerable ages and sizes. Due to their modular growth patterns, individual clonal plants (genets) can consist of many subunits (ramets). Since single ramets do not reflect the actual age of genets, the ratio between genet size (radius) and longitudinal annual growth rate (LAGR) of living ramets is often used to approximate the age of clonal plants. However, information on how the LAGR changes along ramets and how LAGR variability may affect age estimates of genets is still limited. We assessed the variability of LAGR based on wood-section position along the ramets and on the duration of the growing season on three genetically distinct genets of Salix herbacea growing in the Northern Apennines (Italy). We compared genet ages estimated by dividing genet radius by the LAGRs of its ramets. LAGR increased significantly from the stem apex to the root collar; indicating that ramet growth rate decreased with time. Furthermore, a difference of ca. 2 weeks in the onset of the growing period did not impact LAGR. Considering the high LAGR variability, we estimated that the three genets started to grow between ~2100 and ~7000 years ago, which makes them the oldest known clones of S. herbacea even considering the most conservative age estimate. Our findings indicate that analyzing ramets at the root collar provides an integrative measurement of their overall LAGR, which is crucial for estimating the age of genets.

Effects of clonal integration and nutrient availability on the growth of Glechoma longituba under heterogenous light conditions.

Clonal integration of connected ramets within clones is an important ecological advantage. In this study, we tested the hypothesis that the effects of clonal integration on performance of donor and recipient ramets when one resource is heterogeneous can be influenced by the availability of another resource of donor ramets. We conducted a greenhouse experiment on the widespread, perennial herb Glechoma longituba. Clonal fragments consisting of pairs of connected ramets were grown for seven weeks. The younger, apical ramets were exposed under 30% or 100% light condition and the older, basal ramets were treated with three levels of nutrients. The connections between ramets were either severed or left intact. 30% light condition negatively affected the growth of apical ramets, basal ramets and the whole fragments. Clonal integration significantly increased the growth of apical ramets, but decreased the growth of the basal ramets. Medium and high level nutrient availability of basal ramets significantly increased the growth of apical ramets, basal ramets and the whole fragments. At the high nutrient level, the reduction in growth of basal ramets from clonal integration was decreased, but the growth responses of apical ramets and the whole fragments to clonal integration were not influenced by nutrient availability. The results suggested that clonal integration was benefit to the growth of apical ramets of Glechoma longituba but at the cost of reducing the growth of basal ramets. Although the high nutrient level could reduce the cost that clonal integration brought to the unshaded basal ramets, but could not increase the benefit that clonal integration brought to the shaded apical ramets and whole fragment.

Clonal integration can promote the growth and spread of Alternanthera philoxeroides in cadmium-contaminated environments

Clonal plants are able to support the growth of their ramets in stressful environments via clonal integration between the ramets. However, it remains unclear whether the developmental status of stressed ramets affects the role of clonal integration. Here, we explored the effects of clonal integration at both the ramet level and the whole clonal fragment level when the apical ramets (younger) and basal ramets (older) were subjected to different concentrations of cadmium contamination. We grew pairs of ramets of Alternanthera philoxeroides, which were connected or disconnected by stolon between them. The apical and basal ramets were either uncontaminated or individually subjected to Cd contamination at concentrations of 5 mg kg−1 and 50 mg kg−1, respectively. Our results showed that clonal integration significantly promoted the growth of apical ramets subjected to Cd contamination. More importantly, under high Cd treatment, clonal integration also had a significant positive effect on the fitness of the whole clonal fragments. However, clonal integration did not affect plant growth when basal ramets were subjected to Cd contamination. Our study reveals the influence of the developmental status of stressed ramets on the role of clonal integration in heterogeneous heavy metal stress environments, suggesting that clonal integration may facilitate the spread of A. philoxeroides in Cd-contaminated habitats.

The Plant Invader Alternanthera philoxeroides Benefits from Clonal Integration More than Its Native Co-Genus in Response to Patch Contrast.

Different connected parts of clonal plants often grow in different patches and the resource contrast between patches has an important effect on the material transfer between the connected ramets. However, it is unclear whether the effect of clonal integration differs between the invasive clonal plant and the related native species in response to patch contrast. To explore this, we grew the clonal fragment pairs of plant invader Alternanthera philoxeroides and its co-genus native species A. sessilis under high contrast, low contrast, and no contrast (control) nutrient patch environments, respectively, and with stolon connections either severed or kept intact. The results showed that, at the ramet level, clonal integration (stolon connection) significantly improved the growth of apical ramets of both species, and such positive effects were significantly greater in A. philoxeroides than in A. sessilis. Moreover, clonal integration greatly increased the chlorophyll content index of apical ramets and the growth of basal ramets in A. philoxeroides but not in A. sessilis under low and high contrast. At the whole fragment level, the benefits of clonal integration increased with increasing patch contrast, and such a positive effect was more pronounced in A. philoxeroides than in A. sessilis. This study demonstrated that A. philoxeroides possesses a stronger ability of clonal integration than A. sessilis, especially in patchy environments with a higher degree of heterogeneity, suggesting that clonal integration may give some invasive clonal plants a competitive advantage over native species, thus facilitating their invasion in patchy habitats.

Effect of Rhizome Severing on Survival and Growth of Rhizomatous Herb Phragmites communis Is Regulated by Sand Burial Depth.

Rhizome fragmentation and sand burial are common phenomena in rhizomatous clonal plants. These traits serve as an adaptive strategy for survival in stressful environments. Thus far, some studies have been carried out on the effects of rhizome fragmentation and sand burial, but how the interaction between rhizome fragmentation and sand burial affects the growth and reproduction of rhizomatous clonal plants is unclear. We investigated the effect of the burial depth and rhizome fragment size on the survival and growth of the rhizomatous herb Phragmites communis using 288 clonal fragments (6 burial depths × 8 clonal fragment sizes × 6 replicates) in a field rhizome severing experiment. The ramet survival of the rhizomatous species significantly increased with the sand burial depth and clonal fragment size (p < 0.01), and the effects of the clonal fragment size on ramet survival depended on the sand burial depth. Sand burial enhanced both the vertical and horizontal biomass (p < 0.05), while the clonal fragment size affected the vertical biomass rather than the horizontal biomass. Sand burial facilitated the vertical growth of ramets (p < 0.05) while the number of newly produced ramets firstly increased and then decreased with the increasing clonal fragment size, and the maximal value appeared in four clonal fragments under a heavy sand burial depth. There is an interaction between the burial depth and rhizome fragment size in the growth of rhizome herbaceous plants. The population growth increases in the increase of sand burial depth, and reaches the maximum under severe sand burial and moderate rhizome fragmentation.

Unequal nitrogen translocation pattern caused by clonal integration between connected ramets ensures necessary nitrogen supply for young Moso bamboo growth

The rapid growth of young Moso bamboo ( Phyllostachys edulis ), a giant woody clonal plant, depends on consistent nutrient supply through clonal integration. However, the effects of clonal integration on nutrient translocation and allocation in Moso bamboo remain unclear. We established an in situ study model unit consisting of a young bamboo ramet, a mature bamboo ramet, and an interconnected rhizome to study nitrogen (N) translocation and allocation using the 15 N isotope labeling method. The results showed 15 N translocation was bidirectional between interconnected Moso bamboo ramets; however, more 15 N was translocated from the mature to the young ramet than vice versa in winter. The N translocation rate within the donor ramet was faster when the young was donor ramet, and N translocation rate from the donor to the recipient ramet was faster when young bamboo was the recipient ramet. Demand-driven source-sink relationships between connected ramets determined the net flow direction and speed of N translocation. Therefore, an “unequal N translocation pattern between the young and connected mature ramets” was proposed, in which N was preferentially translocated from the mature to the young ramet to meet its growth demand in winter. Our findings provide new insights into the underlying mechanism of Moso bamboo growth and N clonal integration network in Moso bamboo forests and could serve as a guide for precision fertilization in forest management. • N translocation was bidirectional with net flow from the mature to the young ramet. • N translocation within the ramet was faster when the young was donor or recipient ramet. • Demand-driven source-sink relationships determined net N flow direction and speed. • Unequal N translocation between young and mature ramets ensures young ramet growth.

Heterogeneous Nitrogen Supply With High Frequency and Ramet Damage Increases the Benefits of Clonal Integration in Invasive Hydrocotyle vulgaris.

Nitrogen (N) deposition significantly affects the growth and the function of invasive clonal plants. However, the effects of heterogeneous N supply with different frequencies on the growth and the potential contribution of clonal integration in invasion plants are still unclear, especially in the complex environment considering ramet damage. To address this question, apical and basal ramets of the clonal invader Hydrocotyle vulgaris were connected or disconnected, N was added to the basal ramets with a high frequency, a low frequency, or no supply, and the total N quantity was the same for the different frequency. Furthermore, 8 aphids were placed on the apical ramets, and 30% of each leaf was cut off to cause damage. The connection between ramets significantly increased the biomass, total carbon (C), and total N of the basal and apical ramets. Higher frequency N supply significantly increased the biomass, total C, and total N of the basal ramets and the entire clonal fragment biomass. The damage had no significant effect on the growth of basal and apical ramets. Especially, under the high N frequency and ramet damage condition, the connection between ramets more significantly increased the biomass, total C, and total N of the apical ramets and the entire clonal fragment biomass. In addition, the uptake rates of 15 and 15 in H. vulgaris had no significant difference, and N supply increased the uptake rates of 15 and 15 of the basal ramets. Our results suggest that both higher frequency N supply and clonal integration are beneficial to the growth of H. vulgaris. Moreover, the heterogeneous N supply with high frequency and ramet damage increases the benefits of clonal integration in H. vulgaris. These findings improve our understanding of the response of clonal invader H. vulgaris to nitrogen deposition and ramet damage.

Contrasting effects of plant-soil feedbacks on growth and morphology of physically-connected daughter and mother ramets in two clonal plants

Contrasting effects of plant-soil feedbacks on growth and morphology of physically-connected daughter and mother ramets in two clonal plants

Effects of sand burial in integrated clonal systems of the invasive Carpobrotus edulis

ABSTRACT Sand burial represents one of the most common stresses for plant performance in coastal sand dunes. Clonal plants inhabiting sand dunes frequently experience situations in which the sand can bury part of the clone while other modules remain unburied. Here we present a field experiment in a coastal sand dune testing the effect of sand burial in the clonal Carpobrotus edulis. In the experiment, apical ramets were either or not subjected to burial in sand to a depth of 90% ramet height, and connected basal ramets were not subjected to sand burial. Sand burial significantly reduced survival and growth of apical ramets. Interestingly, we found a non-local plastic response in basal ramets that was dependent on the conditions experienced by their apical ramets. Thus, when apical ramets remained unburied a developmentally programmed division of labour was found. In this situation, basal ramets specialized in the acquisition of soil-based resources while apical ramets specialized in aboveground expansion. On the contrary, when apical ramets were subjected to sand burial, basal ramets increased the production of photosynthetic structures. This response could alleviate the light stress suffered by the buried apical ramets. We demonstrate that burial stress suffered by apical ramets of C. edulis triggered a compensatory response in their connected unburied ramets. This result highlights the importance of considering modular plasticity to understand plant responses to sand burial stress.

Response of Chinese sea buckthorn clonal growth and photosynthetic physiological mechanisms toward a soil moisture gradient

Studies have reported on the regulation of clonal growth in Chinese sea buckthorn in response to environmental resource availability, but these studies have been limited to external mechanisms. In this report, we controlled irrigation to generate a soil moisture gradient in order to examine the photosynthetic physiological mechanisms regulating clonal growth in this species. The results indicated that as irrigation intensity increased, the soil water content increased vertically and tissue water content first increased and then decreased. Furthermore, Rubisco activase (RCA) and Mg-chelatase H subunit (CHLH) gene expression levels, photosynthetic capacity (net photosynthetic rate, transpiration rate, chlorophyll content, and stomatal conductance), and clonal growth (ramet growth, clonal proliferation, clonal propagation) all showed a quadratic parabolic change (i.e., first increasing and then decreasing). In addition, gene expression levels and tissue water content, photosynthetic capacity and gene expression levels, and clonal growth and photosynthetic capacity were all significantly positively correlated. When irrigation intensity (soil water content) is exceedingly low or high, the tissue water content is also low, RCA and CHLH gene expression levels are low, photosynthetic capacity is weak, clonal growth ability is inhibited, and clonal growth layout tends toward the “guerrilla type.” This type manifests as fewer and smaller clonal daughter ramets that are sparsely distributed with reduced clonal organ extension ability and branching intensity. When irrigation intensity (soil water content) is moderate, the tissue water content, gene expression levels, and photosynthetic capacity is high, clonal growth ability is completely uninhibited, and the clonal growth layout tends toward the “aggregated type.” This type is associated with numerous large clonal daughter ramets that are densely distributed with high clonal organ extension ability and branching intensity. Therefore, as irrigation intensity continuously changes from inordinately low to moderate to exceedingly high, Chinese sea buckthorn regulates clonal growth by photosynthetic capacity through photosynthetic gene expression. This results in a clonal growth layout continuum of “guerrilla-aggregated-guerrilla” that depends on irrigation intensity.

Opposing effects of plant growth regulators via clonal integration on apical and basal performance in alligator weed

AbstractInvasive plants are a major threat to biodiversity and may adversely affect food security. Clonal integration enables the sharing of resources between connected ramets and can enhance plant performance in many invasive species. However, few studies have examined the role of clonal integration when weeds are exposed to plant growth regulators (PGRs). PGRs are used extensively in agriculture and may affect nearby weeds through soil leaching, erosion and runoff. Our aim was to investigate the effects of clonal integration on growth in a noxious weed, Alternanthera philoxeroides (alligator weed), in response to two PGRs frequently used in agriculture, gibberellins (GAs) and paclobutrazol (PAC). Ramets of A. philoxeroides were propagated in the greenhouse, and treated with PGRs. PGRs were applied to the older ramets (i.e. ‘basal’ part), with half of the plants having the stems between the apical (younger) and basal parts left connected, while the remaining plants had the stems between the two parts severed. Following the growing period, plants were measured for growth traits. We found that GA and PAC had contrasting effects on plant growth. GA significantly promoted above-ground growth of the apical ramets via clonal integration. Alternatively, PAC inhibited above-ground growth in the basal and apical parts, and enhanced below-ground growth of the basal and apical ramets through clonal integration. Our results highlight how clonal integration can promote growth in A. philoxeroides following the application of PGRs, which is likely an important mechanism for this species to invade new environments.

Ecological niches of an introduced species Typha laxmannii and native Typha species in Austria

We studied fruit morphology, germination and growth of juvenile plants and clonal ramets of the non-native species Typha laxmannii and the two common native species Typha angustifolia and Typha latifolia in Lower Austria by means of morphological measurements, germination tests in an environmental test chamber and garden experiments with different water and nutrient levels. The ecological niche of T. laxmannii was close to the niches of the native species T. latifolia and T. angustifolia. All species were light-dependent and quick germinating under suitable conditions. Fruit morphology of T. laxmannii was very similar to that of T. angustifolia, but viability and germination of T. laxmannii were comparable to that of T. latifolia. All three species were profiting from higher water and nutrient levels in the experiments. Only minor advantages or disadvantages of T. laxmannii compared to the native species were detected, hence a direct replacement of them is not expectable. Additional factors like the availability of diaspores in the study area of the Tullnerfeld and Danube valley could be more crucial for the present distribution of T. laxmannii than differences in ecological niches of species themselves.

Effect of rhizome exposure to contrasting abiotic conditions on the performance of the invasive macrophyte Hedychium coronarium J. Koenig (Zingiberaceae)

Although invasive species are often better competitors than native species, broad environmental tolerance may also drive invasion success. Tolerance to abiotic heterogeneity in riparian ecosystems tends to favour the establishment of alien clonal species, as well as their dispersion by vegetative fragments. Hedychium coronarium J. Koenig is a rhizomatous emergent macrophyte native to Asia and has invaded Neotropical riparian ecosystems. We assessed the effect of H. coronarium rhizome exposure to distinct abiotic conditions on ramet growth. We exposed rhizomes to different desiccation periods (1–90 days), temperatures (15, 25 and 35 °C), and light regimes (0, 12, 16 h) and then assessed the effect of each of these variables on subsequent clonal growth (aboveground biomass production per plant and per ramet, and number and height of ramets) under ambient conditions. While no rhizome survived desiccation periods longer than 30 days, ramet growth among surviving rhizomes was not affected by the period of desiccation. Biomass production per rhizome, ramet biomass, and ramet height were significantly lower at 35 °C than at 25 °C. Constant darkness increased rhizome survival, but decreased ramet growth. Although rhizome exposure to extremes of each abiotic variable may hinder the invasion success of H. coronarium, the subsequent aboveground biomass production of surviving rhizomes did not decrease strongly in response to any treatment. This resilience may contribute to successful establishment of H. coronarium after dispersal through rhizome fragments and to varying abiotic conditions.

Support from mother ramets declines with increasing independence of daughter ramets in submerged clonal Vallisneria natans

Many aquatic plants are characterized by clonal growth through which the mother ramet can support offspring ramets by providing resources. The capacities of exploring space, sampling environment and overcoming establishment risks for offspring ramets could be enhanced with the resource support of the mother plant, which may change over time. This study aimed to investigate whether there is a change of clonal integration between mother ramets and offspring ramets in the submerged macrophyte Vallisneria natans with growth time. The stolons between mother ramets and daughter ramets were severed or intact at different growth times (7th day, 17th day, or 27th day after planting). The anatomical structure of the stolons and the morphological, biomass and nitrogen traits of the plants were measured. The results showed that the anatomical structure of the stolon changed significantly over time. The growth and clonal reproduction of daughter ramets were markedly improved by clonal integration on the 14th day but not on the 24th day or 34th day. In addition, there was no significant cost to support daughter ramets in terms of the total biomass of mother ramets. Our results highlight that the growth and clonal reproduction of daughter ramets of V. natans relies on mother ramets in the early stage and support from mother ramets declines with increasing independence of daughter ramets.

Effect of photoperiod and gibberellic acid (GA3) on flowering and fruiting of strawberry- A review

The use of plant growth regulators is exceptionally common practice in present day cultivation. They give a few benefits rearranging and improving fruit production. In commercial production of strawberry, the most development controller utilized and researched is GA3 for the most part altering the beneficial characteristics of plants. Such as increasing fruit weight, plant height, early flowering, petiole length, fruit set, leaf area, yield and improve quality of fruit and also help in stem elongation and cell division. Photoperiodism plays an essential role in flower initiation. The photoperiod promoted plant growth, but also enhanced runner growth, runner formation and ramet growth. It could encourage a stronger runner plant to multiply. The light irradiation during the nursery season accelerated the harvest due to the ongoing flowering.

With a little help from my friends: physiological integration facilitates invasion of wetland grass Elymus athericus into flooded soils

Tidal wetlands worldwide are undergoing rapid invasions by tall‐growing clonal grasses. Prominent examples are invasions by species of the genera Spartina, Phragmites and Elymus. The responsible physiological and ecological drivers of these invasions are poorly understood. Physiological integration (PI) is a key trait of clonal plants, which enables the exchange of resources among ramets. We investigated PI in Elymus athericus, which has been rapidly spreading from high‐marsh into low‐marsh environments of European salt marshes during the last decades. We applied a nitrogen stable‐isotope approach to trace nutrient translocation between ramets in a factorial mesocosm experiment. The experiment was set up to mimic an invasion pattern commonly found in tidal wetlands, i.e. from high‐elevated and rarely flooded into low‐elevated and frequently flooded microenvironments. We tested for intraspecific variability in PI by including two genotypes of Elymus that naturally occur at different elevations within the tidal frame, a high‐marsh (HM) and a low‐marsh (LM) genotype. PI strongly increased offspring ramet aboveground and belowground biomass by 62 and 81%, respectively. Offspring ramets under drained conditions had 95% greater belowground biomass than those under flooded conditions. LM genotype offspring ramets produced 27% more aboveground biomass than HM genotypes. Offspring ramets were clearly more enriched in 15N under flooded versus drained conditions; however, this positive effect of flooding on δ15N was only significant in the LM genotype. Our findings demonstrate the importance of PI for the growth of Elymus offspring ramets and thereby for the species' capacity for fast vegetative spread. We show that offspring ramets under stressful flooded conditions are more dependent on nutrient supply from parent ramets than those under drained conditions. Our data furthermore suggest a higher degree of adaptation to flooding via PI in the LM versus HM genotype. In conclusion, we highlight the importance of assessing PI and intraspecific trait variability to understand invasion processes within ecosystems.

A meta‐analysis of effects of physiological integration in clonal plants under homogeneous vs. heterogeneous environments

Abstract Clonal plants play key roles in maintaining community productivity and stability in many ecosystems. Connected individuals (ramets) of clonal plants can translocate and share, for example, photosynthates, water and nutrients, and such physiological integration may affect performance of clonal plants both in heterogeneous and homogeneous environments. However, we still lack a general understanding of whether or how physiological integration in clonal plants differs across homogeneous versus heterogeneous environments. We compiled data from 198 peer‐reviewed scientific studies conducted in 19 countries with 108 clonal plant species from 35 families, and carried out a meta‐analysis of effects of physiological integration on 16 traits related to plant growth, morphology, physiology or allocation. Our analyses evaluated these relationships in (A) heterogeneous environments where at least one resource essential for plant growth (e.g. light, soil water and mineral nutrients) or non‐resource factor (e.g. grazing, trampling and burial) is spatially non‐uniformly distributed and (B) homogeneous environments where all these factors are spatially uniformly distributed. Physiological integration increased growth of whole clones in both homogeneous and heterogeneous environments due to its highly significant contribution to growth of recipient ramets. Integration did not affect growth of donor ramets in heterogeneous environments, but decreased it in homogeneous environments. Integration affected physiological traits of donor ramets in neither homogeneous nor heterogeneous environments. It did not affect any physiological traits of recipient ramets in homogeneous environments, but increased most of them in heterogeneous environments. For donor ramets, integration increased height by 53% and internode length by 37% in heterogeneous environments, but had no effect in homogeneous environments. For recipient ramets, integration increased height by 73% in homogeneous environments and by 115% in heterogeneous environments, and increased internode length by 35% only under heterogeneous environments. In heterogeneous environments, integration increased biomass allocation to roots of donor ramets under high water/nutrient conditions and decreased it under high light. Physiological integration plays a strong role in clonal plant physiology, morphology and growth, especially for recipient ramets in heterogeneous environments. Therefore, physiological integration may have contributed to the widespread of clonal plants in nature and their dominance in many ecosystems. It may also play important roles in invasion success of alien clonal plants and in maintaining functions and stability of ecosystems where clonal plants are abundant. A free Plain Language Summary can be found within the Supporting Information of this article.