The Hidden Half

Date Palm

Phoenix dactylifera, commonly known as date palm, is well known for its sweet fruit. This flowering plant is in the palm family Arecaceae. Date palm trees grow 20m tall and have large leaves that can reach lengths of up to six metres. The date fruit form at the top of the tree similar to that of coconut palm.

These trees are adapted to arid conditions, commonly growing in areas with very long hot summers with low rainfall. It is likely that date palms originated in Iraq and have been cultivated since ancient times. 

Image showing the root structure of a date palm after 9 months of growth.

The ancient Egyptians used the fruit to make wine whilst the palm trees were popular garden plants for the Romans.

These images show that the roots of this young date plant branch horizontally, not at a sloping angle like most species. They also have a high degree of branching that create a very dense root system.

3D Root Architecture

This timelapse video shows the growth and development of a date palm grown within a soil column over a period of 9 months, from its initial germination, early establishment in the soil through to branching and development of water storage roots.

Root Anatomy

This image (left) shows a cross-section taken from the middle of the primary root of a date palm. The image was collected using a destructive technique called root sectioning and imaged at high magnification using a confocal microscope.

The confocal microscope using different wavelength of light that causes fluorescence of different materials in the cells walls of the root. As the technique give information on the anatomy of the root, it has been termed ‘Root Anatomics’. 

The root section reveals the central area known as the stele containing cells responsible for water and nutrient transport. The small red dots in the stele represent xylem vessels that transport water and nutrients.  The bright green dots in the stele are phloem which transport sugars and nutrients. 

Outside the stele the next cell layer is called the endodermis. Between each endodermal cell exists the casparian strip (see thin red lines) which forms a barrier to water and nutrients, forcing them into endodermal cells. 

The next outer layers are termed cortex. 

Image showing the root anatomy of a date palm root.Image showing cell anatomy of date palm stele.

The date palm cortex contains air spaces termed aerenchyma and sclerenchyma fibres which contain lignin and act as structural support.  The outermost layer termed the epidermis appears heavily modified based on its strong red fluorescence, presumably to reduce water loss.

The Hidden Half

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University of Nottingham
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