scholarly journals Root and shoot competition lead to contrasting competitive outcomes under water stress: A Meta-analysis

2019 ◽  
Author(s):  
Alicia J. Foxx ◽  
Florian Fort
Keyword(s):  
Water Availability ◽  
Plant Competition ◽  
Root Competition ◽  
Environmental Constraints ◽  
Plant Interactions ◽  
Growth Responses ◽  
Knowledge Gaps ◽  
Plant Parts ◽  
Shoot Competition ◽  
Competitive Outcomes

AbstractBackgroundCompetition is a critical process that shapes plant communities and interacts with environmental constraints. Though important to natural communities and agricultural systems, there are surprising knowledge gaps related to mechanisms that belie those processes: the contribution of different plant parts on competitive outcomes and the effect of environmental constraints on these contributions.ObjectiveStudies that partition competition into root-only and shoot-only interactions assess whether plant parts impose different competitive intensities using physical partitions and serve as an important way to fill knowledge gaps. Given predicted drought escalation due to climate change, we focused meta-analytic techniques on the effects of water supply and competitive outcomes.MethodsWe searched Web of Science for peer-reviewed studies and found 2042 results. From which six suitable studies with 92 effect sizes on 10 species were identified to test these effects.ResultsWater availability and competition treatment (root-only, shoot-only, and full plant competition) significantly interact to affect plant growth responses (p < 0.0001). Root-only and full plant competition are more intense in low water availability conditions than shoot-only competition. Shoot-only competition in high-water availability was the most intense showing the opposite pattern. These results also show that the intensity of full competition is similar to root-only competition and that low-water availability intensifies root competition while weakening shoot competition.ConclusionsThese results emphasize the importance of root competition and these patterns of competition may shift in a changing climate, creating further urgency for further filling knowledge gaps to address issues of drought on plant interactions and communities.

A study of root and shoot interactions between cereals and peas in mixtures

1993 ◽  
Vol 120 (1) ◽  
pp. 13-24 ◽  
Author(s):  
M. P. Tofinga ◽  
R. Paolini ◽  
R. W. Snaydon
Keyword(s):  
Relative Yield ◽  
Root Competition ◽  
Total Biomass ◽  
N Content ◽  
Total N ◽  
Resource Complementarity ◽  
Relative Yield Total ◽  
Shoot Competition ◽  
Competitive Abilities ◽  
Different Sources

SUMMARYWheat, barley and two morphologically contrasting cultivars of peas (leafy and semi-leafless) were grown in pure stands, at standard agricultural densities, and in additive mixtures of cereals with peas. The stands were grown in boxes in the field, and partitions were used to separate the effects of root and shoot interactions. The cereals and peas were either planted at the same time, or one species was planted 10 days before the other. The origin of the N present in each species was determined by applying N fertilizer labelled with 15N.Both cultivars of peas had greater shoot and root competitive abilities than wheat or barley, probably because of their larger seed size; leafy peas had greater shoot and root competitive abilities than semi-leafless peas. Sowing peas after cereals reduced their competitive ability.The relative yield total (RYT) of cereal-pea mixtures, based on total biomass, averaged 1·6 when only the root systems interacted, and 1·4 when only the shoot systems interacted, but did not differ significantly from 10 when both root and shoot systems interacted. RYT values were greater when peas were grown with wheat, rather than with barley, and when peas were sown at the same time as the cereals.Shoot competition from peas increased the N% of cereals, but substantially reduced their total N content, because biomass yield was reduced. Shoot competition from cereals had no effect on the N% of peas, and only slightly reduced their total N content. Shoot competition between cereals and peas had no significant effect upon the proportion of N derived from various sources by either cereals or peas.Root competition from peas significantly reduced both the N% and total N content of cereals. Root competition from cereals had little effect on the N% of peas, but significantly reduced their total N content and increased the proportion of N derived from rhizobial fixation from 76 to 94%. Since cereals and peas largely used different sources of N, resource complementarity for N was probably an important component of intercropping advantage, when the roots of cereals and peas shared soil resources.

Does root competition asymmetry increase with water availability?

2009 ◽  
Vol 2 (3) ◽  
pp. 255-264 ◽  
Author(s):  
Boris Rewald ◽  
Christoph Leuschner
Keyword(s):  
Water Availability ◽  
Root Competition

Studies of grain production in Sorghum bicolor (L. Moench). IV.* Some effects of increasing and decreasing photosynthesis at different stages of the plant's development on the storage capacity of the inflorescence

1975 ◽  
Vol 26 (1) ◽  
pp. 25 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson
Keyword(s):  
Storage Capacity ◽  
Developmental Stages ◽  
Light Transmission ◽  
Plant Competition ◽  
Grain Filling ◽  
Floral Initiation ◽  
Grain Production ◽  
Grain Number ◽  
Plant Parts ◽  
Sorghum Bicolor L

Sorghum plants (cv. RS610) grown in field stands at two population densities were manipulated to increase the supply of assimilates (by removing neighbouring plants) at one of three developmental stages—10-15 days after floral initiation, 1 week prior to three-quarters anthesis, and 1 week after three-quarters anthesis. Post-initiation exposure increased the number of grains per inflorescence 1.8-fold and 3.5-fold in medium and high density populations respectively, but had relatively less effect on grain size. Higher grain number resulted largely from more grains per secondary branch in the lower part of the inflorescence. Neither of the post-heading exposure treatments influenced grain number, but the higher supply of assimilates resulted in larger grains at both densities. Differences at one density only between yield characteristics of plants exposed at the two times provide evidence of inter-plant competition for assimilates to the extent that the potential size of the grain may be affected. Shading (10% light transmission) of plants grown in a glasshouse, whether for 1 week at anthesis or during grain filling, reduced grain yield at maturity by the same amount as the immediate reduction at the end of the shading period. The experiment was unable to demonstrate changes in the potential size of grains resulting from the loss of assimilates at anthesis. There was substantial compensation for the loss by translocation from other plant parts. *Part III, Aust. J. Agric. Res., 26: 11 (1975).

scholarly journals Are Commonly Measured Functional Traits Involved in Tropical Tree Responses to Climate?

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fabien Wagner ◽  
Vivien Rossi ◽  
Christopher Baraloto ◽  
Damien Bonal ◽  
Clément Stahl ◽  
...  
Keyword(s):  
Functional Traits ◽  
Tree Growth ◽  
Water Availability ◽  
Growth Response ◽  
Climate Models ◽  
Growth Strategy ◽  
Limiting Factor ◽  
Maximum Height ◽  
Growth Strategies ◽  
Growth Responses

Climate models predict significant rainfall reduction in Amazonia, reducing water availability for trees. We present how functional traits modulate the tree growth response to climate. We used data from 3 years of bimestrial growth measurements for 204 trees of 53 species in the forest of Paracou, French Guiana. We integrated climate variables from an eddy covariance tower and functional trait values describing life history, leaf, and stem economics. Our results indicated that the measured functional traits are to some extent linked to the response of trees to climate but they are poor predictors of the tree climate-induced growth variation. Tree growth was affected by water availability for most of the species with different species growth strategies in drought conditions. These strategies were linked to some functional traits, especially maximum height and wood density. These results suggest that (i) trees seem adapted to the dry season at Paracou but they show different growth responses to drought, (ii) drought response is linked to growth strategy and is partly explained by functional traits, and (iii) the limited part of the variation of tree growth explained by functional traits may be a strong limiting factor for the prediction of tree growth response to climate.

Long-term trends in growth of Pinus palustris and Pinus elliottii along a hydrological gradient in central Florida

2001 ◽  
Vol 31 (10) ◽  
pp. 1661-1670 ◽  
Author(s):  
Tammy E Foster ◽  
J Renee Brooks
Keyword(s):  
Water Table ◽  
Water Availability ◽  
River Flow ◽  
Basal Area ◽  
Pinus Palustris ◽  
Pinus Elliottii ◽  
Drought Severity ◽  
Growth Responses ◽  
Shallow Water Table ◽  
Hydrologic Gradient

Forest species composition in Florida is sensitive to changes in hydrology that accompany small shifts in elevation. In this study, we use dendrochronological techniques to determine how the growth of Pinus elliottii var. elliottii Engelm. (slash pine) and Pinus palustris Mill. (longleaf pine) along a hydrologic gradient from mesic flatwoods to xeric sandhills responds to fluctuations in climate (temperature, precipitation, river flow, and Palmer drought severity index). Interspecies and intraspecies comparisons of growth responses were made between a xeric P. palustris plot, a transition zone plot containing both species, and a mesic P. elliottii plot. Growth of P. elliottii individuals was negatively correlated with increased water availability on sites with a shallow water table (<1 m) but positively correlated on sites with a deeper water table. The basal area increment (BAI) of P. elliottii individuals on the drier site was 41% lower than the BAI of individuals on the wetter site. In contrast, the growth response of P. palustris, which only grows in the dryer sites, was similar along the hydrologic gradient, with growth being positively related to water availability and only a 16% lower BAI on the driest site.

GROWTH RESPONSES OF SCOTS PINE (PINACEAE) TO ARTIFICIAL AND SAWFLY (HYMENOPTERA: DIPRIONIDAE) DEFOLIATION

1999 ◽  
Vol 131 (4) ◽  
pp. 455-463 ◽  
Author(s):  
Päivi Lyytikäinen-Saarenmaa
Keyword(s):  
Scots Pine ◽  
First Year ◽  
Growth Responses ◽  
Early Season ◽  
Late Season ◽  
Plant Parts ◽  
Biomass Loss ◽  
Growth Loss ◽  
Growth Differences ◽  
The Impact

AbstractThe influence of defoliation type (artificial versus natural), timing (early versus late), and intensity (25%, 50%, and 75% of needle mass removed) on leader growth of Scots pine, Pinus sylvestris (Linnaeus), was assessed for 2 years after treatment on an even-aged stand located in southeastern Finland. Trees were defoliated simultaneously, either artificially with a pair of scissors or naturally with larvae of Neodiprion sertifer (Geoffroy) and Diprion pini (Linnaeus) for the early- and late-season treatments, respectively. After 1 year, early-season artificial defoliation generally caused greater growth reduction than natural defoliation. Late-season defoliation yielded opposite results. Trees defoliated artificially in early-season treatments were significantly shorter than control trees irrespective of defoliation intensity, whereas those defoliated late in the season did not differ from controls, except at the highest intensity. Trees defoliated by sawflies, either early or late in the season, were significantly shorter than control trees only at the highest defoliation intensity. The pattern of growth loss in the second year appeared similar to that in the first year. The impact of defoliation was either prolonged neutral or negative, as no compensatory responses on height growth in Scots pine were observed. Timing of the treatment in relation to completion of leader growth, differences in defoliation types, alteration of the photosynthetic capacity due to biomass loss, and the functional role of plant parts defoliated may explain the results observed.

Growth of skeleton weed (Chondrilla juncea L.) as affected by growth of subterranean clover (Trifolium subterraneum L.) and infection by Puccinea chondrillina Bubak and Syd

1975 ◽  
Vol 26 (6) ◽  
pp. 975 ◽  
Author(s):  
RH Groves ◽  
JD Williams
Keyword(s):  
Leaf Area ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Root Competition ◽  
Leaf Number ◽  
Root Weight ◽  
Large Reduction ◽  
Plant Parts ◽  
Chondrilla Juncea

Growth of skeleton weed (Chondrilla juncea, form A) and subterranean clover (Trifolium subterraneum) was studied in a glasshouse experiment in which the species were grown alone or together and the resultant effects of shoot and root competition assessed. The leaf number and weight of plant parts of C. juncea were reduced by competition vith subterranean clover, especially when shoots of the two species were competing. The leaf area of C. juncea was reduced, especially when roots of the two species were growing together. Puccinia chondrillina on C. juncea rosettes reduced leaf number, leaf area, and weight of plant parts. Subterranean clover grown with C. juncea infected with P. chondrillina further reduced the size and weight of the weed. The large reduction in leaf area and root weight of C. juncea (form A) plants in the presence of both subterranean clover and P. chondrillina suggests that growth of this form of C. juncea in Australia will be greatly reduced in pastures containing these species. In the long term, densities of this form may possibly be so lowered that a significant level of control will be reached in a cereal cropping-pasture system.

Growth responses of ponderosa pine to long-term exposure to ozone, wet and dry acidic deposition, and drought

1993 ◽  
Vol 23 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Patrick J. Temple ◽  
George H. Riechers ◽  
Paul R. Miller ◽  
Robert W. Lennox
Keyword(s):  
Soil Water ◽  
Sierra Nevada ◽  
Water Availability ◽  
Ponderosa Pine ◽  
Dry Deposition ◽  
Acidic Deposition ◽  
Ambient Air ◽  
Soil Water Availability ◽  
Growth Responses

A 3-year field study of the cumulative effects of ozone (O3), wet and dry acidic deposition, and soil water availability was conducted on ponderosa pine (Pinusponderosa Laws.) in the Sierra Nevada of California from 1988 to 1990. Thirty-six 2-year-old potted seedlings were placed in each of 30 chambers and exposed from May through October to three levels of O3 (charcoal-filtered (CF), nonfiltered (NF), and NF plus 1.5 times ambient O3 (NF150)); three levels of acidity in simulated rain (pH 3.5, 4.4, 5.3); two levels of dry deposition (60 or 90% filtration), and two levels of soil water availability (well watered (WW) or drought stressed (DS)). An additional six plots served as ambient air (AA) controls. One-third (432) of the trees were harvested at the end of each exposure season. Low soil water availability was the only stress factor to significantly affect growth following the first exposure season. After the second season, O3 significantly reduced foliar biomass in WW–NF150 trees, but DS seedlings did not respond to O3. After 3 years of exposure, WW–NF150 trees averaged 70% loss of 1988 needles and 48% loss of 1989 foliage. Ozone-injured seedlings compensated for these losses by increased growth of current-year needles and stems and also increased growth of fine feeder roots. Radial stem growth and coarse-root growth were significantly reduced in O3-injured trees. DS trees in NF150 chambers averaged half the needle loss of WW trees and showed no reduction in radial growth in response to O3. Rain pH and dry deposition had no direct effects on growth of ponderosa pine. These cumulative responses to interacting stresses indicate the importance of multifactorial, long-term studies to evaluate forest tree responses to atmospheric deposition.

scholarly journals The Critical Importance of Old World Fruit Bats for Healthy Ecosystems and Economies

2021 ◽  
Vol 9 ◽  
Author(s):  
Sheema Abdul Aziz ◽  
Kim R. McConkey ◽  
Krizler Tanalgo ◽  
Tuanjit Sritongchuay ◽  
Mary-Ruth Low ◽  
...  
Keyword(s):  
Plant Species ◽  
Research Priorities ◽  
Fruit Bats ◽  
Plant Interactions ◽  
Conservation Action ◽  
Old World ◽  
Plant Parts ◽  
Foraging Movement ◽  
The Many ◽  
Anthropogenic Threats

Despite extensive documentation of the ecological and economic importance of Old World fruit bats (Chiroptera: Pteropodidae) and the many threats they face from humans, negative attitudes towards pteropodids have persisted, fuelled by perceptions of bats as being pests and undesirable neighbours. Such long-term negativity towards bats is now further exacerbated by more recent disease-related concerns, particularly associated with the current COVID-19 pandemic. There remains an urgent need to investigate and highlight the positive and beneficial aspects of bats across the Old World. While previous reviews have summarised these extensively, numerous new studies conducted over the last 36 years have provided further valuable data and insights which warrant an updated review. Here we synthesise research on pteropodid-plant interactions, comprising diet, ecological roles, and ecosystem services, conducted during 1985-2020. We uncovered a total of 311 studies covering 75 out of the known 201 pteropodid species (37%), conducted in 47 countries. The majority of studies documented diet (52% of all studies; 67 pteropodid species), followed by foraging movement (49%; 50 pteropodid species), with fewer studies directly investigating the roles played by pteropodids in seed dispersal (24%; 41 pteropodid species), pollination (14%; 19 pteropodid species), and conflict with fruit growers (12%; 11 pteropodid species). Pteropodids were recorded feeding on 1072 plant species from 493 genera and 148 families, with fruits comprising the majority of plant parts consumed, followed by flowers/nectar/pollen, leaves, and other miscellaneous parts. Sixteen pteropodid species have been confirmed to act as pollinators for a total of 21 plant species, and 29 pteropodid species have been confirmed to act as seed dispersers for a total of 311 plant species. Anthropogenic threats disrupting bat-plant interactions in the Old World include hunting, direct persecution, habitat loss/disturbance, invasive species, and climate change, leading to ecosystem-level repercussions. We identify notable research gaps and important research priorities to support conservation action for pteropodids.

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