The Role of Expert and Hypertext Systems in Modeling Root-Shoot Interactions and Carbon Allocation

Author(s):  
H. Michael Rauscher
Keyword(s):  
2016 ◽  
Vol 43 (2) ◽  
pp. 105 ◽  
Author(s):  
Lu Wang ◽  
Yong-Ling Ruan

Roots and shoots are distantly located but functionally interdependent. The growth and development of these two organ systems compete for energy and nutrient resource, and yet, they keep a dynamic balance with each other for growth and development. The success of such a relationship depends on efficient root-shoot communication. Aside from the well-known signalling processes mediated by hormones such as auxin and cytokinin, sugars have recently been shown to act as a rapid signal to co-ordinate root and shoot development in response to endogenous and exogenous clues, in parallel to their function as carbon and energy resources for biomass production. New findings from studies on vascular fluids have provided molecular insights into the role of sugars in long-distance communications between shoot and root. In this review, we discussed phloem- and xylem- translocation of sugars and the impacts of sugar allocation and signalling on balancing root–shoot development. Also, we have taken the shoot–root carbon–nitrogen allocation as an example to illustrate the communication between the two organs through multi-layer root–shoot–root signalling circuits, comprising sugar, nitrogen, cytokinin, auxin and vascular small peptide signals.


2018 ◽  
Vol 115 (31) ◽  
pp. E7361-E7368 ◽  
Author(s):  
Bernardo García-Carreras ◽  
Sofía Sal ◽  
Daniel Padfield ◽  
Dimitrios-Georgios Kontopoulos ◽  
Elvire Bestion ◽  
...  

Relating the temperature dependence of photosynthetic biomass production to underlying metabolic rates in autotrophs is crucial for predicting the effects of climatic temperature fluctuations on the carbon balance of ecosystems. We present a mathematical model that links thermal performance curves (TPCs) of photosynthesis, respiration, and carbon allocation efficiency to the exponential growth rate of a population of photosynthetic autotroph cells. Using experiments with the green alga, Chlorella vulgaris, we apply the model to show that the temperature dependence of carbon allocation efficiency is key to understanding responses of growth rates to warming at both ecological and longer-term evolutionary timescales. Finally, we assemble a dataset of multiple terrestrial and aquatic autotroph species to show that the effects of temperature-dependent carbon allocation efficiency on potential growth rate TPCs are expected to be consistent across taxa. In particular, both the thermal sensitivity and the optimal temperature of growth rates are expected to change significantly due to temperature dependence of carbon allocation efficiency alone. Our study provides a foundation for understanding how the temperature dependence of carbon allocation determines how population growth rates respond to temperature.


2008 ◽  
Vol 72 (1) ◽  
pp. 85-89 ◽  
Author(s):  
J. R. Leake ◽  
A. L. Duran ◽  
K. E. Hardy ◽  
I. Johnson ◽  
D. J. Beerling ◽  
...  

AbstractBiological weathering is a function of biotic energy expenditure. Growth and metabolism of organisms generates acids and chelators, selectively absorbs nutrient ions, and applies turgor pressure and other physical forces which, in concert, chemically and physically alter minerals. In unsaturated soil environments, plant roots normally form symbiotic mycorrhizal associations with fungi. The plants provide photosynthate-carbohydrate-energy to the fungi in return for nutrients absorbed from the soil and released from minerals. In ectomycorrhiza, one of the two major types of mycorrhiza of trees, roots are sheathed in fungus, and 15—30% of the net photosynthate of the plants passes through these fungi into the soil and virtually all of the water and nutrients taken up by the plants are supplied through the fungi. Here we show that ectomycorrhizal fungi actively forage for minerals and act as biosensors that discriminate between different grain sizes (53—90 μm, 500—1000 μm) and different minerals (apatite, biotite, quartz) to favour grains with a high surface-area to volume ratio and minerals with the highest P content. Growth and carbon allocation of the fungi is preferentially directed to intensively interact with these selected minerals to maximize resource foraging.


1983 ◽  
Vol 61 (3) ◽  
pp. 1005-1014 ◽  
Author(s):  
T. V. St. John ◽  
D. C. Coleman

The effects of vesicular–arbuscular mycorrhizae (VAM) and ectomycorrhizae (ECM) on plant ecology are considered, with emphasis on four areas. The first of these is mycotrophy in wild plants. We suggest that many natives have lower nutrient demands than crop plants and may therefore be less responsive to mycorrhizal infection. Pot experiments must be interpreted with caution because their outcome is strongly influenced by such factors as soil type and pot size. The second topic is the role of mycorrhizae in competition. Mycorrhizae have been shown to figure in plant–plant competition for limited resources. Several lines of indirect evidence suggest that mycorrhizae are involved in allelopathic interactions between plants. Mycorrhizae could aid in competition between plants and microorganisms. Mycorrhizal roots are sometimes found in humus layers of the forest floor. It has been postulated that mycorrhizal fungi influence the decomposition of plant detritus. The most important role of mycorrhizal roots in the organic layer may be, in many cases, a close physical association with the most nutrient-rich microsites of the heterogeneous soil volume. The ability to allocate absorbing tissue to localized organic matter zones has been documented for roots of forest trees and for hyphae of VAM fungi. The advantageous physical placement may result in greater nutrient acquisition for the plant than would occur if root and hyphal distribution were random. Third, the occurrence of mycorrhizae in natural communities has not frequently been documented in ways that show the abundance of infection in the whole community. Future surveys in natural ecosystems should include a measure of the relative abundance of the major plant species in the community. The final topic is carbon allocation to the symbiosis. We suggest that estimates for VAM from a few percent to ~50% of gross photosynthesis can be reconciled to some extent by considering the dynamic processes of root and mycelial turnover.


2017 ◽  
Vol 174 (3) ◽  
pp. 1863-1880 ◽  
Author(s):  
Tuomas Huokko ◽  
Dorota Muth-Pawlak ◽  
Natalia Battchikova ◽  
Yagut Allahverdiyeva ◽  
Eva-Mari Aro

2011 ◽  
Vol 41 (4) ◽  
pp. 773-781 ◽  
Author(s):  
L.J. Haavik ◽  
D.W. Stahle ◽  
F.M. Stephen

Extreme climate events are frequently important factors associated with episodes of forest decline. A recent oak decline event and concurrent outbreak of a native wood-boring beetle, the red oak borer ( Enaphalodes rufulus (Haldeman)), occurred throughout Arkansas Ozark and Ouachita Mountains. To investigate the role of drought and stand maturity on northern red oak ( Quercus rubra L.) decline, we analyzed tree-ring growth patterns and their relationships to climate from 815 live and 161 recently dead Q. rubra. While younger Q. rubra exhibited faster growth rates and stronger climate relationships than older Q. rubra, some individuals within all stands that originated >60 years ago were susceptible to growth decline or mortality. A significant growth interaction occurred among the three age classes identified where currently healthy Q. rubra were initially growing at slower decadal rates than currently declining or recently dead Q. rubra and later transitioned to higher growth rates than the others. These differences appear to be related to carbon allocation patterns towards rapid aboveground and (or) belowground growth early in development that led to later decline and (or) mortality. Decline in growth and weakening tree growth – climate relationships appeared to be initiated by an unusually severe and sustained drought in the early 1950s.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mika T. Tarkka ◽  
Thorsten E. E. Grams ◽  
Oguzhan Angay ◽  
Florence Kurth ◽  
Hazel R. Maboreke ◽  
...  

AbstractEndogenous rhythmic growth (ERG) is displayed by many tropical and some major temperate tree species and characterized by alternating root and shoot flushes (RF and SF). These flushes occur parallel to changes in biomass partitioning and in allocation of recently assimilated carbon and nitrogen. To address how biotic interactions interplay with ERG, we cross-compared the RF/SF shifts in oak microcuttings in the presence of pathogens, consumers and a mycorrhiza helper bacterium, without and with an ectomycorrhizal fungus (EMF), and present a synthesis of the observations. The typical increase in carbon allocation to sink leaves during SF did not occur in the presence of root or leaf pathogens, and the increase in nitrogen allocation to lateral roots during RF did not occur with the pathogens. The RF/SF shifts in resource allocation were mostly restored upon additional interaction with the EMF. Its presence led to increased resource allocation to principal roots during RF, also when the oaks were inoculated additionally with other interactors. The interactors affected the alternating, rhythmic growth and resource allocation shifts between shoots and roots. The restoring role of the EMF on RF/SF changes in parallel to the corresponding enhanced carbon and nitrogen allocation to sink tissues suggests that the EMF is supporting plants in maintaining the ERG.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2680
Author(s):  
Youfu Zhang ◽  
Tuo Chen ◽  
Hanbo Yun ◽  
Chunyan Chen ◽  
Yongzhi Liu

Understanding carbon allocation in plants is essential for explaining their growth strategies during environmental adaptation. However, the role of mobile carbon in plant growth and its response to habitat conditions is still disputed. In degraded meadow (alpine sandy grassland) and non-degraded meadow (typical alpine meadow and swamp meadow) on the Qinghai–Tibetan Plateau, we measured the monthly averages of above-ground biomass (AGB) and below-ground biomass (BGB) of the investigated species in each meadow and the average concentration of non-structural carbohydrates (NSCs), an indicator of carbon storage. Below-ground organs had higher concentrations and showed more seasonal variation in NSCs than above-ground organs. BGB had a positive correlation with below-ground NSCs levels. However, AGB had no clear relationship with above-ground NSCs levels. Plants in sandy grasslands had higher total NSC, soluble sugars, fructose, and sucrose concentrations and lower starch concentrations in below-ground organs than plants in alpine or swamp meadows. Overall, NSCs storage, particularly soluble sugars, is a major process underlying the pattern of below-ground growth, but not above-ground growth, in the meadow ecosystem of the Qinghai–Tibetan Plateau, and degraded meadow strengthens this process. These results suggest that the extent of carbon storage in non-photosynthetic organs of alpine herbs impacts their growth and habitat adaptation.


2015 ◽  
Vol 112 (23) ◽  
pp. 7213-7218 ◽  
Author(s):  
Caroline E. Farrior ◽  
Ignacio Rodriguez-Iturbe ◽  
Ray Dybzinski ◽  
Simon A. Levin ◽  
Stephen W. Pacala

Increasing atmospheric CO2 concentrations and changing rainfall regimes are creating novel environments for plant communities around the world. The resulting changes in plant productivity and allocation among tissues will have significant impacts on forest carbon storage and the global carbon cycle, yet these effects may depend on mechanisms not included in global models. Here we focus on the role of individual-level competition for water and light in forest carbon allocation and storage across rainfall regimes. We find that the complexity of plant responses to rainfall regimes in experiments can be explained by individual-based competition for water and light within a continuously varying soil moisture environment. Further, we find that elevated CO2 leads to large amplifications of carbon storage when it alleviates competition for water by incentivizing competitive plants to divert carbon from short-lived fine roots to long-lived woody biomass. Overall, we find that plant dependence on rainfall regimes and plant responses to added CO2 are complex, but understandable. The insights developed here will serve as an important foundation as we work to predict the responses of plants to the full, multidimensional reality of climate change, which involves not only changes in rainfall and CO2 but also changes in temperature, nutrient availability, and disturbance rates, among others.


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