Phylum Coniferophyta And Phylum Gnetophyta

Question 1

Members of Coniferophyta are

Answer 1

Branching, woody plants with mostly long shoots and short shoots

Question 2

Secondary xylem or wood of Coniferophyta is made of

Answer 2

Made of tracheids, rays and resin canals

Question 3

Leaves and reproductive structure of Coniferophyta

Answer 3

-spirally arranged or opposite
-needle like or scale like

-unisexual cones: female cones (megastrobili) usually consist of a main axis with bract scales, each subtending or fused with an ovuliferous scale bearing 2 ovules

Question 4

Where are conifers found

Answer 4

Boreal forests

Question 5

Phylum Coniferophyta
Class Coniferopsida
Order Coniferales
Family Pinaceae
Pinus sp. (Pine trees)

Types of leaves

Answer 5

2 kinds

-photosynthetic needles (in groups of 2,3 or 5)

-non photosynthetic scale leaves (grow on long shoots and at the base of short shoots

Question 6

Shoots of Pines

Answer 6

Short lateral branches on which needle leaves arise are called short shoots

Normal twigs and branches are long shoots

Question 7

Needle leaves of Pinus sp. exhibit striking ______ attributes

Answer 7

Xerophytic

-heavy cutinized epidermis
-hypodermal cells
-sunken stomata
-Strands (trabeculae) of chlorenchyma cells extend from the hypodermics to the vascular region.
-one or two vascular bundles are embedded in transfusion tissue

Question 8

Young stems of Pinus are ____and _____

Answer 8

Green

Photosynthetic

Question 9

The vascular cambium of Pinus becomes active before

Answer 9

Primary differentiation has been completed

Cambium adds many new cells that mature into secondary xylem internally and into secondary phloem externally.

Question 10

Xylem of Pinus

Answer 10

-very homogeneous (composed mostly of tracheids)
-narrow medullary rays of parenchyma extend radially through the xylem
-well marked concentric circles of secondary xylem (annual rings)

Question 11

Growth rings based on environment

Answer 11

-cold and dry makes for narrow or even absent rings

-wide in favourable weather

-sometimes a growing season is interrupted by a period of stress: frost, insect attack, drought, fire: leads to two growth rings (false ring)

Question 12

Phellogen

Answer 12

Cork cambium

-arises in the outer most layer of the cortex
-meristematic activity of the phellogen cells result in the production of Phellem (cork cells) on the outer margin of the cambium and phelloderm (cork parenchyma or secondary cortex) on the inner margin of the cork cambium

Question 13

Root of Pinus

Answer 13

-protostelic taproot
-narrow pericycle
-prominent endodermis
-extensive cortex
-root hairs on epidermis
-limited root hair zone

Question 14

Do Pinus roots undergo secondary growth?

Answer 14

Yes, like stems

Become woody

However root system is shallow

Question 15

Free nuclear stage in Pinus lifecycle

Answer 15

Indicates a point in time (~13 months) after pollination. Where the Megagametophyte has undergone a large number of nuclear divisions and formed ~2000 cells.

Have not developed cell walls yet and therefore are “free” nuclei

Question 16

Phylum Coniferophyta
Class Coniferopsida
Order Coniferales
Family Cupressaceae

-leaves

Answer 16

-whirled leaves or decussate (arranged in 4 rows at right angles to each other)
-leaves are scale like or needle like in juvenile plants

Question 17

Phylum Coniferophyta
Class Coniferopsida
Order Coniferales
Family Cupressaceae
Juniperus sp.

-common name
-colour
-function
-monoecious or dioecious
-megastrobili

Answer 17

-Juniper
-produced fragrant reddish tinted wood
-used to line closets and chests

-dioecious mainly

-fleshy and resemble berries; these berries are used to give gin it’s distinctive odour and fragrance

Question 18

Phylum Coniferophyta
Class Coniferopsida
Order Coniferales
Family Cupressaceae
Thuja sp.

-common name
-uses
-wood specialty

Answer 18

-White Cedar
-fragrant, fine-grained wood which is desired for closets and saunas
-not strong, but is particularly rot resistant and so it’s good for lawn furniture.

Question 19

Phylum Coniferophyta
Class Coniferopsida
Order Taxales

-monoecious or dioecious
-ovules

Answer 19

-dioecious
-ovules occur singly at the spices of short branches
-Each ovule is enclosed in a fleshy aril

Question 20

Phylum Coniferophyta
Class Coniferopsida
Order Taxales
Family Taxaceae
Taxus sp.

-common name
-plant type
-megastrobili

Answer 20

-Yew/ ground hemlock
-evergreen with dense, fir-like foliage.
-red, fleshy berries that open at the apex, revealing the single poisonous purple seed.

Question 21

Phylum Gnetophyta

3 orders

Answer 21

-Ephedrales
-Gnetales
-Welschiales

Question 22

Phylum Gnetophyta
-vessels

Answer 22

-primitive vessels in secondary xylem

Question 23

Phylum Gnetophyta
Order Ephedrales

-environment
-type of plant
-leaves
-branches
-strobili

Answer 23

-xerophytic plant in warm-temperature latitudes
-shrub ( up to 2 m)
-reduced to little-bract-like organs that function once early in development, however they are megaphylls.
-chief photosynthetic organ
-mega and micro strobili are compound structures, in which the sporogenous organs are appendicular (tip of branch) and not cauline.

Question 24

Sporophyll of Ephedra

Answer 24

Surrounds integument of ovule suggesting the development of a primitive carpel.