Primary phloem
1. . Derived from procambium of apical meristem.
2. . District protophloem and metaphloem elements.3 Sieve tubes long and narrow.
3. Less or no development of phloem parenchyma.
4. Phloem fibres on the outer part.
Secondary phloem
1. . Derived from vascular cambium.
2. . No clear demarcation between protophloems and metaphloems.
3. Sieve tubes short and wide.
4. .Well developed and abundant phloem parenchyma.
5. . Phloem fibers among the phloem parenchyma.
Vascular cambium
Leaves are designed to last only a short time so a secondary xylem and phloem supply is not needed. These chemicals offer a strong support system that is not needed in the leaves, just the trees.
3 rings of xylem and 1 of phloem
The cambium is a layer of cells in plants that is responsible for lateral growth, producing new xylem and phloem cells. It plays a key role in secondary growth, increasing the width of stems and roots.
Most of the plant's new xylem and phloem are produced in the vascular cambium, which is a thin layer of meristematic cells located between the xylem and phloem in the stem and root. This region is responsible for secondary growth in plants, leading to the production of new xylem towards the inside and new phloem towards the outside.
The precambium is a layer of meristematic tissue found between the primary xylem and phloem in vascular plants. It is responsible for the production of secondary vascular tissue in the form of secondary xylem (wood) and secondary phloem.
Secondary xylem
The vascular cambium, a layer of cells between the xylem and phloem tissues in the stem, is responsible for producing secondary growth in plants. This results in the thickening of the stem and roots as new layers of xylem and phloem are added.
Vascular cambium
Leaves are designed to last only a short time so a secondary xylem and phloem supply is not needed. These chemicals offer a strong support system that is not needed in the leaves, just the trees.
The cambium is a layer of actively dividing cells located between the xylem and phloem in vascular plants, mainly in the stems and roots. Its primary function is to produce new cells for secondary growth, resulting in the thickening of the plant body.
It is located in the vascular bundles between the primary xylem (wood) and primary phloem (bast) tissues.
3 rings of xylem and 1 of phloem
There is structural difference between xylem and phloem. This is because their function is also different. Had there been no difference in structure, how these could have performed different function?
The primary growth in vascular plants takes place with the differentiation of vascular tissue from parenchymatous cells and the secondary growth takes place when the intra-vascular and inter vascular cambium adds to the secondary phloem and secondary xylem.
the cells of phloem are the only ones with cytoplasm
Xylem is part of the vascular tissue of plants, and the xylem and phloem together are grouped together as the stele (latin for 'pillar'). Xylem tissue is encased in lignin, the substance that creates the strength of wood, causing the protoplasm (living part of the cell) to die, and therefore be dead tissue; phloem is living tissue.