difference between primary xylem and secondary xylem
primary phloem ans secondary phloem
Answers
Answer:
xylem is transport water, food, mineral and phloem is transport other things
Answer:
When plants photosynthesize, they convert sunlight into energy, and the phloem is what brings the nutrients downward to the roots. Primary phloem forms in primary growth regions at the tips of stems and roots, and secondary phloem is what arises from the vascular cambium.
Meristem Modification
Trees have what are known as meristems, which are groups of plain cells that essentially have no function yet. When growth occurs, these meristems suddenly start changing. The cells turn into specific tissues that form the tree’s vascular system. Just as veins and arteries transport blood and oxygen in humans, the vascular system in a tree transports nutrients and water to different parts of the tree.
Primary Growth
Primary growth happens at apical meristems. These are meristem regions found at the tips of stems and roots, and in buds as well. Primary growth leads to the tree growing taller and the roots extending. It’s a lengthening growth that makes portions of the tree longer. As the sections grow, new meristems form at the tips so that in each growing season, the tree can continue to get taller and taller, until it reaches its maximum height. Primary growth occurs first in the growing season and contains xylem and phloem.
Secondary Growth
Secondary growth, however, is a lateral, widening growth. Secondary growth is what makes trees wider over time, and it begins after the primary growth is over. The main meristem in action here is the vascular cambium, which usually divides into three layers. The central layer remains vascular cambium, the outer layer becomes phloem and the inner layer becomes xylem.
Feeding the Tree
Phloem transports nutrients downward from the leaves. When plants photosynthesize, they convert sunlight into energy, and the phloem is what brings the nutrients downward to the roots. Primary phloem forms in primary growth regions at the tips of stems and roots, and secondary phloem is what arises from the vascular cambium. Because the phloem acts as a conduit, it has to cover the entire trunk and the branches. It needs to form during both growth stages so that there are no areas of the trunk that have no phloem.
Drink Up
Xylem brings water up from the roots into the rest of the tree. Like phloem, primary xylem forms in primary growth, and secondary xylem forms in secondary growth. As the growing season continues, the secondary xylem expands to the point where the secondary phloem can’t stay intact anymore. The secondary phloem is crushed and compacted, though nothing happens to the xylem except that it stops growing. When the growing season starts up again the next year, the vascular cambium forms new layers of secondary phloem and xylem. These layers of xylem form the tree rings used in dating wood.