Lecture 4: How Plants Communicate Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Intra-plant communication: Root-to-Shoot Signaling

A

Works via the cohesion-tension theory (transportation of water via the xylem)

Transpiration in the leaves led to water being drawn in roots
-Transportation +photosynthesis are closely interconnected (stomata opening and closing)
-When there is high transpiration there is high water availability in the roots (plant can control their water-use efficiency)

In a drought: low transpiration due to low water availability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Transpiration

A

When water is taken up from the soil, up the root system, through the plant, and then evaporated from the leaf surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Role of roots when sensing water availability

A

Roots can senses soil water availability through endogenous signals and control stomata with it.
1.) Abscisic acid (ABA): hormone that controls stomatal opening and closing

2.) When there is water stress: ABA increases in roots and moves to leaves (Root-to-shoot).
-ABA pools stored in leaves becomes available, and when reaching a threshold, stomata closes

-Water potential in leaves determine stomatal resistance: the more negative the leaf water potential, the higher the stomatal resistance and ABA content in the leaf

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Role of ABA

A
  1. ABA binds to receptor at guard cell membrane
  2. Stimulates opening of calcium channels in guard cells
  3. Ca2+ enters the cell, acting as a second messenger
  4. Calcium binds to receptor, activating anion channels: anions leave the cell, causing polarization
  5. Due to polarization, K+ leaves cell, depolarisation occurs
  6. Exit of ions reduces turgor pressure in guard cell: stomatal closure
  7. Stoma opens again when: ABA concentrations reduce and turgor pressure returns.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Inter-plant communication: Competitive interactions

A

-Shape vegetation composition and control biodiversity
-Need to be able to rapidly detect neighbours and respond:
–Defensive strategies: avoidance of competitive interactions
–Offensive strategies: inhibition of competitor’s performance

-Need to be capable of self-recognition (identity+kin) to avoid accidentally fighting themselves or plants of the same species.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Self-recognition

A

1.) Identity recognition in root growth:
-Plants can alter their root growth and sense the presence of other roots
-Can change direction, grow more/less

2.) Kin recognition: ability to distinguish between genetically related and unrelated individuals
-Kin: sibling plants from same mother plant
-Cooperation with kin can save resources: e.g increasing self-shading to avoid shading of other kin plants, competing with non-kin instead.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Shade avoidance

A

Competition for light can induce changes in plants to avoid being shaded
-Shaded plant canopy exhibits low red to far-red ratios
-Causes an increased growth of stems and/or petioles
-Redirection of leaf growth vertically and/or horizontally
-Plants want to reach better red to far-red ratio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Inter-specific communication: Volatile Organic Compounds (VOCs)

A

Play a crucial role for different plant functions:
-Plant reproduction (attraction of pollinators)
-Plant defines
-Plant communication
-Interaction with environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Inter-specific communication: Communication with pollinators (goals)

A

To produce a lot of offspring, plant requires:
-Maximum reproductive fitness
-Maximum pollen dispersal
-Avoid stigma’s clogging
-Avoid wasting energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Insects as pollen distributors

A

-short+quick stay on flower
-moves fast between individuals
-stays within one plant species
-doesn’t consume too much

Plants compete for attention of pollinators (evolution of flower traits according to pollen vectors)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pollen vectors

A

-Color
-Shape
-Scent
-Reward

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Communication+symbiosis

A

1.) Bacteria (rhizobium): nitrogen-fixing organisms that are ‘bound’ to root nodules
-Bacteria attracted by flavonoids which induce nod genes in Rhizobium
-synthesis of nod factors: encourages rhizobium to colonise plant’s root hair
-symbiotic relationship: bacteria feeds on sugar+plant relies on nitrogen-fixed by bacteria

2.) Fungi: mycorrhizae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Plants vs Pathogens

A

-Requires hormones+VOCs to fight off microorganisms (Can be abiotic or biotic stress)

-Plants have direct and indirect defence:
–Direct: Fight off herbivorous insects
–Indirect: signal other plants about danger

-Plant’s ‘immune system’: Systematic Acquired Resistance (SAR)
–response to an attack by bacteria+fungi+viruses
–Provides parts of the plants with long-lasting protection against pathogens
-Involved molecules: salicylic acid+jasmonic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly