Dictionary > Protophloem

Protophloem

Definition
noun, plural: protophloems
The first phloem to develop from the procambium
Supplement
The phloem is a vascular tissue that is responsible for transporting photosynthates to different parts of a vascular plant through a process called translocation. The phloem may be primary or secondary. A primary phloem is the type of phloem that is produced by the procambium during the primary growth (vertical growth) whereas a secondary phloem is one that is produced by the vascular cambium during the secondary growth (lateral growth).
The primary phloem is comprised of the protophloem and the metaphloem. The protophloem is the first phloem that develops from the procambium. The protophloem develops first but is more sensitive to stretch or mechanical stress thus often does not develop fully compared to the metaphloem that attains full development when the plant reaches maturity, or when the internodes stopped from elongating.
Although they look similar, the protophloem can be seen near the exterior whereas the metaphloem is located adjacent to the metaxylem. The protophloem can be further differentiated from the metaphloem in terms of cellular components and morphology. In protophloem, the sieve elements are relatively thin-walled, narrow, elongated, and short-lived compared with those of the metaphloem. The companion cells may or may not be present in protophloem.
Word origin: Greek prôtos (“first”) + phloem
See also:


You will also like...

genes controlling growth and development
Control of Growth & Development

Control of Growth & Development tutorials look at how the genetic makeup determines the biological processes on a da..

Neural Control Mechanisms
Neural Control Mechanisms

Neurons generate electric signals that they pass along to the other neurons or target tissues. In this tutorial, you wil..

Human Nervous System
The Human Nervous System

The nervous system is essentially a biological information highway. This tutorial gives an overview of the nervous syste..

Oligodendrocyte and Schwann cell
The Central Nervous System

Myelin sheath is essential for a faster conductivity of signals. Know more about this feature of some neurons in the Cen..

green leaf - close up view
Leaves

Leaves are the major photosynthetic organ of a plant. Apart from that, they are also crucial to water movement. In this ..

human respiratory system
Respiration

The human respiratory system is an efficient system of inspiring and expiring respiratory gases. This tutorial provides ..

Related Articles...

No related articles found

See all Related Topics