L15 - Anomalous Secondary growth

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Fascicular Cambium comes from

residual Procambium

Interfascicular Cambium is formed by

de-differentiation of cortical parenchyma cells

A complete ring of vascular cambium around the stem leads to a _________________ in the stem

a cylinder of secondary growth in the stem

What two things are common in normal secondary growth

1. The secondary xylem and phloem form complete rings
2. The cambium separates the secondary xylem from secondary phloem

abnormal secondary phloem

Causes of anomalous secondary growth (5)

1) The ACTIVITY of cambium is abnormal, despite normal appearance
2) The SHAPE of cambium is abnormal, despite normal fxn
3) Formation of secondary tissues by the accessory cambium
4) Formation of INTER-XYLARY phloem (AKA included phloem)
5) Formation of INTRA-XYLARY phloem

Wedge Parenchyma is an example of

normal cambium is normal, but abnormal activity

describe wedge parenchyma

The interfascicular sections of the cambium contribute wide rays or
spokes of parenchyma cells

Wedge Parenchyma or connective tissues

Green Arrow - Fascicular Cambium
Orange Bracket - Crushed Primary Phloem
Pink Arrow - Phloem Fiver
Red Arrow - Cambium Ray
Blue Arrow - Metaxylem
Yellow Arrow - Secondary Phloem

Liana are an example of

Normal cambium with abnormal activity

describe Liana cambium
why are they abnormal in activity

The cambium makes more phloem than xylem
Results in VARIENT PHLOEM WEDGES

Varient phloem wedges in liana are caused by

Leaves and axillary buds

Fewer leaves in Liana, _______- wedges

fewer wedges

Bauhinia is an example of

Normal cambium, abnormal activity

Bauhinia have an abnormal shape due to

stem shape

After secondary growth, what happens to Bauhinia

inner cylinder stays same, but the cambium ONLY makes outer xylem in 2 rings with many gelatinous fibers

Bauhinia gelatinous fibers do what

offer flexibility for the wood

what happens here with secondary growth

Outer xylem has gelatinous fiber

Secondary growth through unequal or asymmetrical cambial activity
( Asymmetric stems ) result from the activity of ___________ starting with a regular, ________ stem, and later becoming ___________ stem

of a single cambium
Round stem
an asymmetrical stem

Secondary growth through unequal or asymmetrical cambial activity is an example of

Normal cambium, abnormal activity

What does the cambium do in plants

The cambium is a layer of plant cells responsible for growth, particularly secondary growth, which increases the plant's girth by producing new wood (xylem) and inner bark (phloem)

Liana VASCULAR BUNDLES are an example of

abnormal cambium, normal activity

What makes Liana cambium abnormal

Certain parts of the vascular cylender seoerate out, but cambium differentiation continues until each forms its own cambium

What do the multiple bundles of a Liana do

helps offer support for the woody vine

Bougainvillea is another climbing vine,
It makes ________ by making __________

it makes secondary tissue by making accessory cambium

What are accessory cambium

Accessory cambium refers to a type of secondary meristematic tissue that forms after the primary vascular cambium and results in anomalous secondary growth, thickening the stem in unusual ways

Accessory Cambium and crushed Phloem arches are an example of

abnormal cambium, normal activity

Whats this

crushed phloem rings frm accessory cambium

Whats this

Liana cambium bundles

In Bougainvillea secondary growth, how are the crushed phloem made

Patches of accessory cambium form, each having its own vascular bundles, which each has its own ‘secondary growth’, resulting in smaller patches of crushed phloem arches

whats this

crushed phloem arches caused by accessory cambium rings

What is the difference of accessory cambium rings and arches

HELP - ADD (rewatch)

Thunbergia is an example of

formation of inter-xylary phloem

explain the formation of inter-xylary phloem

Vascular cambium makes secondary phloem instead of xylem, but goes back to making the xylem later on

whats this

Inter-Xylary Phloem

what does Inter-Xylary Phloem do // what is it like

it is a mixture of hard and soft cells intertwined, offering support and flexibility

Intra-xylary Phloem is most common in _________

Monocots

We learned that monocots often have closed collateral bundles.
Does this mean that MONOCOTs NEVER undergo secondary growth

FALSE
Most do not, but exceptions exist

Explain intra-xylary phloem formation

the cambial derives outside the atactostele

atactostele is in center outside, there is further cambial activity known as monocot cambium

(look for blurry ring)

monocot cambium makes bundles unlike the standard
P surrounds X

what is monocot cambium

cambium formed outside atactstele

Atactostele on the RIGHT
INTRA Xy phloem on the LEFT

intra xylary phloem

Describe secondary growth in dracena

intra-xylary phloem

Describe the formation secondary growth of palms

do not have growth rings
→ instead have overlapping leaf bases creating pseudobark 
→ pseudobark is highly sclerified 
→ palms lack a lt of secondary tissue

Have secondary growth like this because everything occurs close to SAM, and the primary thickening meristem thickens the base early allowing it to just grow up and be wide at the start

T/F everything occurs close to SAM in palm

True

what is PTM

Primary thickening meristem

a plant meristem responsible for the primary thickening (radial growth) of a stem, primarily found in monocots like Palms

Describe this image

This is the formation of secondary growth in palms

How do Palms thicken

Via primary thickening meristem

_________ make up most of the root mass of woody
perennials.

Secondary tissues

(In roots) The ______ continues to __________, with the
normal tissue differentiation, producing root hair and lateral
roots.
This is critical for root absorptive function

RAM
make primary root tissues

In secondary root growth
support for the secondary body made above ground
comes from __________ produced by the __________, the _________, and the _________

secondary tissues
lateral meristems, vascular cambium, and cork cambium

The underground root systems of trees are as extensive as the
aerial plant body. The provide the ________ for the
aboveground weight keeping the tree stable

support

What does the pericycle make / do

lateral roots
cork cambium
vascular cambium
root branching

is this an example of normal secondary growth

Yes

Explain carrot secondary growth

Tiny vascular cambium, small 2 X, lts of 2 P

Explain storage secondary growth in Beets

successive cambium each with 2 X/P and spaced out with parenchyma

Explain sweet potato secondary growth

cambium with 2 Xylem and Phloem
rings of anmylus cambium each with secondary X / P and tertiary cambium within

Green → vascular cambium

white → tertiary vascular cambia

Which of the shoots is showing normal secondary growth

D

NO

ALL OF THE ABOVE

which of these roots is showing normal secondary growth

A

accessory cambium can be ______ or ______

arches or rings

accessory cambium can appear like asymmetric _________

steps

intraxylary phloem is made in _______ arrangements

files to thicken

do cordylene and palms have primary thickening meristems

Yes

help

sweet potato