Plant Anatomy
-
Upload
delhi-university -
Category
Science
-
view
23 -
download
0
Transcript of Plant Anatomy
![Page 1: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/1.jpg)
SECONDARY GROWTH IN ROOTS
BY PRANJAL DHAKA
2042
![Page 2: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/2.jpg)
CONTENT
• Why we need secondary growth?
• Anatomy of dicot roots.
• Process of secondary growth.
![Page 3: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/3.jpg)
Why need it?
• It increases the ability of plants to absorb water and facilitates transport of water and minerals in bulk quantities.
• Helps in mechanical support and anchoring when the tree grows big.
![Page 4: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/4.jpg)
ANATOMY OF DICOT ROOT• Epiblema: Consists of the
outermost epidermal layer with root hair arising from it.
• Cortex: Thin layer of parenchymatous layer. Main function is storage.
• Endodermis: Barrel shaped, rich in Starch and have radial and tangential thickenings called casparian bands due to lignin depositions.
![Page 5: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/5.jpg)
ANATOMY OF DICOT ROOT
• Pericycle: Made up of thin walled parenchyma cells. It gives rise to cork cambium, part of vascular cambium and all lateral roots.
• Vascular Strands: They are alternate bands of xylem and phloem. Protoxylem towards the periphery and metaxylem towards the center.
• Pith: Not very prominent. Bundle of parenchymatous tissue.
![Page 6: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/6.jpg)
PROCESS OF SECONDARY GROWTH
![Page 7: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/7.jpg)
THE CAMBIAL RING
• It is wavy in the beginning unlike in dicot stems.
• The cambial ring is completely secondary in origin.
![Page 8: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/8.jpg)
SECONDARY VASCULAR TISSUE
![Page 9: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/9.jpg)
FUNCTIONS OF SECONDARY XYLEM
• principle water-conducting tissue
• combination of vessels and tracheids
• primary xylem derived from procambium
• secondary xylem formed by vascular cambium
• wood made of accumulated secondary xylem
![Page 10: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/10.jpg)
FUNCTIONS OF SECONDARY PHLOEM
• principle food-conducting tissue in vascular plants, located toward the outer part of roots and stems
• carried out through sieve cells and sieve-tube members
• some sieve areas (pores) have larger pores called sieve plates
• each sieve-tube member associated with companion cell
![Page 11: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/11.jpg)
EXTRA-STELAR SECONDARY GROWTH
• Roots can also form the exact kind of periderm by the process of seconary growth.
• The cork cambium cuts off the phelloderm inside of it, composed of living parenchymatous tissue.
• It cuts off phellem (cork) on the outside of it.
![Page 12: Plant Anatomy](https://reader034.fdocuments.us/reader034/viewer/2022042701/55c3ce74bb61eb86318b45df/html5/thumbnails/12.jpg)
THANK YOU