Related Experiment Video
Updated: Oct 1, 2025
09:38
Collection and Analysis of Arabidopsis Phloem Exudates Using the EDTA-facilitated Method
Published on: October 23, 2013
24.8K
Coordination Between Phloem Loading and Structure Maintains Carbon Transport Under Drought
Ryan C Stanfield1, Megan K Bartlett1
1Department of Viticulture and Enology, University of California, Davis, Davis, CA, United States.
Frontiers in Plant Science
|March 7, 2022
Summary
Regulating sugar loading in the phloem using sucrose transporter proteins is crucial for plant drought tolerance. This mechanism helps maintain carbon transport and phloem function under water stress, vital for crop resilience.
Area of Science:
- Plant Physiology
- Ecology
- Biophysics
Background:
- Phloem transport is vital for whole-plant drought tolerance, but underlying traits remain unclear.
- Active phloem loading via sucrose transporter proteins is used by many angiosperms, including crops.
- Plants can adjust transporter levels to regulate phloem loading under stress.
Purpose of the Study:
- To investigate how phloem loading regulation impacts sucrose export under varying water status.
- To quantify the combined effects of transporter kinetics, phloem anatomy, and water status on phloem transport.
- To test the hypothesis that regulated phloem loading enhances drought tolerance in active-loading species.
Main Methods:
- Developed an integrated xylem-phloem-stomatal model.
- Parameterized the model with literature data on phloem resistance and transporter kinetics.
- Simulated loading regulation by linking loading rates to phloem pressure to prevent viscosity issues.
Main Results:
- Unregulated loading led to unrealistic phloem pressures due to viscosity, even in well-watered conditions.
- Pressure-regulated loading maintained realistic phloem pressures and improved sucrose export under drought.
- Regulation allowed for efficient transport in both wet and dry conditions, preventing viscosity buildup.
Conclusions:
- Feedback between phloem pressure and loading is critical for carbon transport in active-loading species, especially during drought.
- Transporter kinetics must be coordinated with phloem architecture and plant water status for optimal function.
- This study provides a framework for understanding phloem ecophysiology and engineering drought-resilient crops.
Related Concept Videos
02:02Phloem and Sugar Transport
38.2K
Like many living organisms, plants have tissues that specialize in specific plant functions. For example, shoots are well adapted to rapid growth, while roots are structured to acquire resources efficiently. However, sugar production is primarily restricted to the photosynthetic cells that reside in the leaves of angiosperm plants. Sugar and other resources are transported from photosynthetic tissues to other specialized tissues by a process called translocation.
38.2K
02:03Xylem and Transpiration-driven Transport of Resources
24.8K
The xylem of vascular plants distributes water and dissolved minerals that are taken up by the roots to the rest of the plant. The cells that transport xylem sap are dead upon maturity, and the movement of xylem sap is a passive process.
24.8K
02:41Responses to Drought and Flooding
11.2K
Water plays a significant role in the life cycle of plants. However, insufficient or excess of water can be detrimental and pose a serious threat to plants.
11.2K
01:27C4 Pathway and CAM
46.5K
Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy.
C4 Pathway
The C4 pathway is used by plants such as...
C4 Pathway
The C4 pathway is used by plants such as...
46.5K
02:12Short-distance Transport of Resources
16.6K
Short-distance transport refers to transport that occurs over a distance of just 2-3 cells, crossing the plasma membrane in the process. Small uncharged molecules, such as oxygen, carbon dioxide, and water, can diffuse across the plasma membrane on their own. In contrast, ions and larger molecules require the assistance of transport proteins due to their charge or size. Transport across membranes also occurs within individual cells, playing a variety of essential roles for the plant as a whole.
16.6K
02:04Regulation of Transpiration by Stomata
29.3K
During photosynthesis, plants acquire the necessary carbon dioxide and release the produced oxygen back into the atmosphere. Openings in the epidermis of plant leaves is the site of this exchange of gasses. A single opening is called a stoma—derived from the Greek word for “mouth.” Stomata open and close in response to a variety of environmental cues.
29.3K