A Full Detail Of "CONIFERALES" Plant "PINUS & THUJA" And Their Morphological , Anatomical Characters.

1. ANATOMY OF CONIFERALS
Presented by,
Kavan Chaudhari & Nidhi Parekh
MSc ,Sem-3
Paper No - 301,Botany
M.N.College, Visnagar

2.  CONTENTS
 Introduction
 Pinus
 Anatomy Of Pinus
 Thuja
 Anatomy Of Thuja
 Comparative Anatomical Account Of Pinus & Thuja

3.  Introduction
 What Is Coniferals Plant?
• It is a type of gymnosperm plant. It grows in cool or subtropical climates and
bears angular or cone-shaped fruits. The reproduction of these trees takes
place through this cone. The leaves of such trees are long rod shaped. Such
plants are called coniferals plants
E.X:-
• Pinus
• Thuja
• Firs

4.  Pinus
Classification:
• Division: Gymnosperms
• Class: Coniferopsida
• Order: Coniferals
• Family: pinaceae
• Genus: Pinus

5.  Anatomy Of Pinus
 Leaf:
o It is circular in outline in Pinus monophylla, semicircular in P. sylvestris and
triangular in P. longifolia, P. roxburghii, etc.
o Outermost layer is epidermis, which consists of thick-walled cells. It is covered
by a very strong cuticle. Many sunken stomata are present on the epidermis.
o Below the epidermis are present a few layers of thick-walled sclerenchymatous
hypodermis.
o In between the hypodermis and endodermis is present the mesophyll tissue.
o Few resin canals are present in the mesophyll.
o Endodermis is single-layered with barrel-shaped cells and clear casparian strips.
.

6. o Pericycle is multilayered and consists of mainly parenchymatous cells and
some sclerenchymatous cells forming T-shaped girder, which separates two
vascular bundles. Transfusion tissue consists of tracheidial cells.vascular
bundles are present in the centre. Xylem lies towards the angular side and the
phloem towards the convex side of the needle.

7.  Stem:
o The internal structure of shoots of pinus is largely similar to that of
dicotyledonous plants.
o The secondary growth are present in pinus.
o The secondary xylem and phloem are present in stem at secondary
growth
o Stem is differentiated internally into epidermis, cortex, vascular tissue
and central pith.
 Epidermis:
o The surface is covered by an epidermis. It consists of a single layer of cells.
Outer walls of these cells are highly cutinized. Below the epidermis is a
hypodermis which is formed of layers of lignified cells.

8.  Cortex:
o The cortex is formed of parenchymatous cells. Cortex has a large number of
resin canals.Each resin canal is surrounded by a layer of resin secreting
glandular epithelial cells.
 Pith:
o It occupies the center of the stem.
o The vascular bundles are conjoint, collateral and open.
o They form a ring around the pith.
o In each vascular bundle the xylem is towards the inner side and phloem
towards the outerside.
o A narrow strip of cambium is present between xylem and phloem.
Pericycle is present outer to the ring of vascular bundles.

9. o A single layered thin walled endodermis is present outside the
pericycle

10.  Secondary Growth in Stem:
o The secondary growth in pinus stem takes place in exactly the same
way as in a dicotyledonous stem.
o Secondary growth takes place by the activity of cambium ring. There
are distinct annual growth rings in the wood.

11.  Root:
o Two types of root are found in pinus.
1: Young Root
2: Old Root
 Young Root:
o Outermost layer of the circular roots is thick-walled epiblema withmany
root hair.
o Epiblema is followed by many layers of parenchymatous cortex.
o Inner to the cortex is present a layer of endodermis and many layersof
pericycle.
o Vascular bundles are radially arranged and diarch to tetrarch withexarch
protoxylem.

12. o Protoxylem is bifurcated (Y-shaped) towards the periphery, and
inbetween each bifurcation is present a resin cannal.
o Phloem is present alternate to the protoxylem.
o Pith is poorly-developed or absent.

13.  Old Root:
o On the outer side are present a few layers of cork, formed by the
meristematic activity of the cork cambium.
o Cork cambium cuts secondary cortex towards inner side.

14. o Many resin canals and stone cells are present in the secondary cortex, the
cells of which are separated with the intercellular spaces.
o Below the phloem patches develop cambium, which cuts secondary phloem
towards outer side and secondary xylem towards inner side.
o Crushed primary phloem is present outside the secondary phloem.
o Many uniseriate medullary rays are present in the secondary xylem

15.  Thuja
Classification:
• Division: Gymnosperms
• Class: Coniferopsida
• Order: Coniferals
• Family: Cupressaceae
• Genus: Thuja

16. Anatomy Of Thuja
 Leaf:
o The internal structure of Thuja leaf as seen in its cross section reveals its xerophytic nature
and can be differentiated into epidermis, hypodermis, mesophyll and vascular cylinder
regions.
o The epidermis is single layered with sunken stomata.
o The epidermal cells are thick walled and strongly cutinized.
o A single layered hypodermis with strongly lignified cells is present below the epidermis.The
mesophyll is differentiated into palisade and spongy parenchyma, though this
differentiation is not very sharp.
o Resin canals are present in the region of spongy parenchyma.
o In the centre of the lamina is present a single collateral vascular bundle having protoxylem
facing the ventral side and phloem on the dorsal side.

18. Stem:
o Two types of stem are found in thuja
1: Young Stem
2: Old Stem
 Young Stem :
o A transverse section of the young stem shows well developed epidermis covered with
cuticle.
o A very wide cortex which contains photosynthetic tissue towards the outer side while,
the cells of inner cortex are loose.
o Vascular bundles are arranged in a ring.
o In between vascular bundles medullary rays are present.
o Vascular bundles are conjoint, collateral, endrach and open.
o Pith is small while medullary rays are broad.
o Resin canals are present in the cortex only.

19. o Xylem consists of tracheids only.
o The protoxylem shows annular or spiral thickening.
o Phloem lacks companion cells.
o The wood consists of tracheids only, which shows pitted thickening.
o The pits are uniseriate and confinedonly to the radial wall.
o The medullary rays are uniseriate varying from 2-5 cells in their vertical
extent and are never associated with resin canal.
 Old Stem:

20. o Root system similar as pinus .
o Secondary growth are present in root.
o Primary growth are present in root so it's known as young root.
o Outermost layer of the circular roots is thick- walled epiblema with many root hair.
o Epiblema is followed by many layers of parenchymatous cortex.
o Inner to the cortex is present a layer of endodermis and many layers of pericycle.
o Vascular bundles are radially arranged and diarch to tetrarch with exarch protoxylem.
o Secondary xylem and phloem are present in root.
Root:

21. Comparative Anatomical Account Of Pinus &
Thuja
Pinus
• Scaly & needle like leaves.
• Vessel elements are
absent in xylem(leaf).
• Secondary growth well
developed.
• Resin canal well
developed.
• Sunken stomata are well
developed.
Thuja
• Large & composed leaves.
• Vessel elements are
absent in xylem(leaf).
• Primary type of
Secondary growth.
• Primary type of resin
canal present.
• Sunken stomata present.

22. • Reference:
• Botany For Degree Students, Gymnosperms, (1990), Vol. V, P. C. Vashishta,
S. Chand And Company Ltd., Ram Nagar, New Delhi-110 055.
• A Text Book of Botany, (2016-17), (Fifth edition), Prof. V. Singh, P. C.
Pandey D. K. Jain, Rastogi Publications, Gangotri Shivaji Road, Meerut,
250002.
• Yourlibrary.com
• www.biologydiscussion.com