Related Experiment Video
Updated: May 5, 2026
11:27
A Flexible Low Cost Hydroponic System for Assessing Plant Responses to Small Molecules in Sterile Conditions
Published on: August 25, 2018
10.7K
Sugar uptake into Allium cepa leaf tissue: an integrated approach
C Wilson1, J W Oross, W J Lucas
1Department of Botany, University of California, 95616, Davis, CA, USA.
Planta
|November 20, 2013
Summary
This study investigated sugar uptake in Allium cepa leaves using enzymatic and mechanical methods. All leaf tissues absorb sugar, indicating leaf disc uptake doesn't solely represent phloem loading.
Area of Science:
- Plant Physiology
- Plant Anatomy
- Biochemistry
Background:
- Understanding sugar uptake mechanisms in plant leaves is crucial for plant physiology.
- The contribution of different leaf tissues to overall sugar absorption requires detailed investigation.
Purpose of the Study:
- To determine the role of various Allium cepa leaf tissues in total sugar uptake.
- To analyze the anatomy and ultrastructure of Allium cepa leaves and assess tissue integrity after manipulation.
- To investigate the impact of anoxia on sugar uptake and adenine nucleotide levels.
Main Methods:
- Enzymatic (pectolyase) and mechanical manipulation of Allium cepa leaves.
- Light and transmission-electron microscopy for tissue analysis.
- Kinetic analysis of sucrose and fructose uptake in leaf discs and isolated tissues.
- High-performance liquid chromatography (HPLC) for adenine nucleotide quantification.
Main Results:
- Chloroplasts in bundle-sheath cells of Allium cepa leaves were found to contain starch.
- All investigated leaf tissues demonstrated sugar uptake, exhibiting linear plus saturable kinetics, except for fructose in inner parenchyma and bundle-sheath cells (linear only).
- Anoxia inhibited both linear and saturable components of sucrose influx, accompanied by a general loss of adenine nucleotides.
Conclusions:
- The study concludes that all tissues within the Allium cepa leaf actively retrieve exogenous sugars.
- Observed sugar uptake kinetics in leaf discs do not exclusively represent phloem loading.
- The presence of starch in bundle-sheath cell chloroplasts suggests a role in carbohydrate metabolism and translocation.
Related Concept Videos
02:16Light Acquisition
8.0K
In order to produce glucose, plants need to capture sufficient light energy. Many modern plants have evolved leaves specialized for light acquisition. Leaves can be only millimeters in width or tens of meters wide, depending on the environment. Due to competition for sunlight, evolution has driven the evolution of increasingly larger leaves and taller plants, to avoid shading by their neighbors with contaminant elaboration of root architecture and mechanisms to transport water and nutrients.
8.0K
02:35Key Elements for Plant Nutrition
18.0K
Like all living organisms, plants require organic and inorganic nutrients to survive, reproduce, grow and maintain homeostasis. To identify nutrients that are essential for plant functioning, researchers have leveraged a technique called hydroponics. In hydroponic culture systems, plants are grown—without soil—in water-based solutions containing nutrients. At least 17 nutrients have been identified as essential elements required by plants. Plants acquire these elements from the...
18.0K
02:02Phloem and Sugar Transport
28.8K
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.
28.8K