High Heterogeneity of Root Carbon Allocation Affects Root Turnover Rate and Production of Bothriochloa ischaemum Under Drought Stress

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.

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Enhanced root carbon allocation through organic farming is restricted to topsoils

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.143551 ◽

2021 ◽

Vol 755 ◽

pp. 143551

Author(s):

Juliane Hirte ◽

Florian Walder ◽

Julia Hess ◽

Lucie Büchi ◽

Tino Colombi ◽

...

Keyword(s):

Organic Farming ◽

Carbon Allocation ◽

Root Carbon

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A deeper look at the relationship between root carbon pools and the vertical distribution of the soil carbon pool

10.5194/soil-2017-5 ◽

2017 ◽

Author(s):

Ranae Dietzel ◽

Matt Liebman ◽

Sotirios Archontoulis

Keyword(s):

Soil Carbon ◽

Plant Root ◽

Substantial Contribution ◽

Root Turnover ◽

Soil Organic C ◽

Organic C ◽

Native Prairie ◽

Perennial Plant ◽

Root Carbon ◽

The Relationship

Abstract. Plant root material makes a substantial contribution to the soil organic carbon (C) pool, but this contribution is disproportionate below 20 cm, where 30 % of root mass and 50 % of soil organic C is found. Root carbon inputs changed drastically when native perennial plant systems were shifted to cultivated annual plant systems. We used the reconstruction of a native prairie and a continuous maize field to examine both the relationship between root carbon and soil carbon and the fundamental rooting system differences between the vegetation under which the soils developed versus the vegetation under which the soils continue to change. In all treatments we found that root C : N ratios increased with depth, which may help explain why an unexpectedly large proportion of soil organic C is found below 20 cm. Measured root C : N ratios and turnover times along with modeled root turnover dynamics showed that in moving from prairie to maize, a large, structural-tissue dominated root C pool with slow turnover, concentrated at shallow depths was replaced by a small, non-structural-tissue dominated root C pool with fast turnover evenly distributed in the soil profile. These differences in rooting systems suggest that while prairie roots contribute more C to the soil than maize at shallow depths, maize may contribute more C to the soil than prairies at deeper depths.

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Summer drought stress: differential effects on cane anatomy and non-structural carbohydrate content in overwintering Cabernet Sauvignon and Syrah vines

BIO Web of Conferences ◽

10.1051/bioconf/20191303007 ◽

2019 ◽

Vol 13 ◽

pp. 03007 ◽

Cited By ~ 2

Author(s):

Rachele Falchi ◽

Elisa Petrussa ◽

Marco Zancani ◽

Valentino Casolo ◽

Paola Beraldo ◽

...

Keyword(s):

Water Stress ◽

Drought Stress ◽

Biochemical Characterization ◽

Carbon Allocation ◽

Starch Accumulation ◽

Cabernet Sauvignon ◽

Severe Drought ◽

Summer Drought ◽

Long Term Effects ◽

Experimental Conditions

Grapevines store non-structural carbohydrates (NSC) during late summer to sustain plant development at the onset of the following spring’s growth. Starch is the main stored carbohydrate, found in the wood-ray parenchyma of roots and canes. Although the relationship between hydraulic and plant photosynthetic performance is well-recognized, little research has been done on the long-term effects of drought in grapevines adopting different strategies to cope with water stress (i.e. isohydric and anisohydric). We performed our study by exposing two different grape cultivars (Syrah and Cabernet Sauvignon) to a short but severe drought stress, at two stages of the growing season (July and September). No marked differences in the physiological and hydraulic responses of the two varieties were found, probably due to our experimental conditions. However, anatomical and biochemical characterization of overwintering canes pointed out several interesting outcomes. We found a significant and parallel increase of starch and medullar ray number in both cultivars exposed to early water stress. We hypothesize that stressed vines limited their carbon allocation to growth, while shifting it to starch accumulation, with a most evident effect in the period of intense photosynthetic activity. We also speculate that a different aptitude to osmotic adjustment may underlay variation in starch increase and the specific involvement of bark NSC in the two cultivars.

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A dynamic simulation of loblolly pine (Pinustaeda L.) seedling establishment based upon carbon and water balances

Canadian Journal of Forest Research ◽

10.1139/x88-130 ◽

1988 ◽

Vol 18 (7) ◽

pp. 833-850 ◽

Cited By ~ 4

Author(s):

John I. Blake ◽

Gerrit Hoogenboom

Keyword(s):

Drought Stress ◽

Water Potential ◽

Loblolly Pine ◽

Carbon Allocation ◽

Weather Data ◽

Soluble Carbohydrate ◽

Plant Water ◽

Short Term ◽

Evaporative Demand ◽

Plant Water Potential

A generalized simulation model, ROOTSIMU, which utilizes dynamic carbon and water balance algorithms, was modified to simulate loblolly pine (Pinustaeda L.) seedling growth and water uptake for a 100-day transplant period. The modifications included an allowance for time-dependent changes in photosynthesis and carbon allocation. Heat sums were used to control the initiation of growth. Additional compartments were added to separate the physiological functions of suberized and nonsuberized roots and secondary woody tissues. Values used to initialize the model were largely derived from the published literature. The predicted results of a simulation run using 1985 and 1986 weather data are reported. Changes in simulated plant water potential were closely related to periods of rainfall or high evaporative demand. Midday values were occasionally less than −7 MPa when evaporative demand was high. Simulated responses to the 1986 drought indicated that initial soil water potentials at planting affected survival at values of less than −0.064 MPa in a sandy soil. Simulated growth was very sensitive to the photosynthetic rate, less sensitive to initial soluble carbohydrate concentration, and insensitive to instantaneous carbon allocation in relation to drought stress. The predicted increase in total root length for 1985 corresponded to the responses reported in several controlled environmental studies, but these were generally higher than those reported under field conditions. The results suggest that the carbon balance algorithm represents potential root growth within the constraints imposed by the model assumptions. The extreme diurnal fluctuations in plant water potential indicate that one or more important components of the plant system used to regulate short-term drought stress are not represented. Both stem tissue capacitance and the hydraulic conductance of mycorrhizal mycelia at low soil moisture contents may be important in controlling short-term water deficits. Further advances in the application of similar models depend upon an evaluation of these variables and a better theoretical and experimental determination of the effects of the geometry of the transplanted root system.

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Growth, Morphological, and Physiological Responses to Drought Stress in Bothriochloa ischaemum

Frontiers in Plant Science ◽

10.3389/fpls.2017.00230 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 4

Author(s):

Ying Liu ◽

Peng Li ◽

Guo Ce Xu ◽

Lie Xiao ◽

Zong Ping Ren ◽

...

Keyword(s):

Drought Stress ◽

Physiological Responses ◽

Bothriochloa Ischaemum

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Root trait responses to drought depend on plant functional group

10.1101/801951 ◽

2019 ◽

Cited By ~ 1

Author(s):

Y.M. Lozano ◽

C.A. Aguilar-Trigueros ◽

I.C. Flaig ◽

M.C. Rillig

Keyword(s):

Functional Groups ◽

Morphological Traits ◽

Functional Group ◽

Carbon Allocation ◽

Root Traits ◽

Root Trait ◽

Plant Responses ◽

Plant Functional Group ◽

Tissue Density ◽

Root Carbon

ABSTRACTDrought can strongly modify plant diversity and ecosystem processes. As droughts are expected to intensify in the future, it is important to better understand plant responses to drought. We expect that roots traits constitute an overlooked but powerful predictor of plant responses as roots are in direct contact with the soil environment, taking up nutrients and water.Here, we determine which root traits are sensitive to drought, the magnitude of that response, whether their predictive power and relationships with shoot biomass are affected by drought and whether all these responses depend on plant functional group. To do so, we conducted a glasshouse experiment with 24 plant species grown in pots (10 replicates per species), which represent three different functional groups: grasses, herbs and legumes. All replicates were well watered during the first month and then half of the replicates were kept under drought (30 % water holding capacity (WHC)) with the other half serving as control (kept at 70% WHC). After two months of the treatment, leaf and root traits were measured.Leaf traits had a strong but more uniform response to drought compared to root traits. Root trait response was variable and differed by plant functional group. Most grasses had increased root diameter, specific root surface area (SRSA) while decreased root tissue density (RTD) with drought. Production of thicker roots with a low tissue density could allow grasses to achieve greater nutrient and water acquisition through mycotrophy and would be linked to an increase in the reserve of non-structural carbohydrates needed for osmoregulation. Herbs had decreased SRSA and specific root length (SRL) while increase root carbon allocation. Reduction of root elongation or sacrifice of fine roots would be compensated by an increase in root carbon allocation, which allow herbs to improve water uptake. Legumes did not alter root morphological traits but promote an early flowering in order to scape drought.Our results identify changes in root morphological traits as mechanisms to likely face drought, a response that is species-specific and differed among functional groups.

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