noun
- the first-formed phloem tissue in a plant, consisting of narrow sieve tubes that develop during primary growth
Usage: botanical
Examples
- The protophloem forms before the metaphloem during stem development.
- Botanists can identify protophloem by its characteristic narrow sieve tubes.
- In young plant stems, protophloem appears near the outer edge of vascular bundles.
- The protophloem becomes crushed as the stem continues to grow and expand.
- Students examined cross-sections to distinguish between protophloem and metaphloem.
- Primary phloem consists of both protophloem and metaphloem tissues.