By

Fahad ShafiqPhD Scholar / Research Associate

Department of Botany,GC University Faisalabad, Pakistan

How do Plants Sense Gravity?

Cell Level

Root Level

Stem Level

Answer

Motion of a Falling or Sedimenting Body.

Mechanisms of Gravity Sensing

Amyloplasts

Statoliths

Statocytes

Hypotheses

Starch-Statolith Hypothesis

Tensegrity Model

Gravity Sensing in Columella Cells

Gravity sensing in Arabidopsis

Dynamics of Amyloplasts and AFs in Wild Type and fiz1/+ Endodermal Cells.

Linear actin cable and amyloplast. The arrow indicates an amyloplast that has moved a long distance along a linear actin cable.

Otoliths in Fishes

Why these experiments are required?

Space Colonization

International Space Station

Antioxidant Rich Food for astronauts

BLSS

Technical Limitations

Difficult to achieve gravity levels

Atmospheric conditions

Maintenance of experimental conditions

International Space Station

Vegetable Production Units

How does the gravity environment shape/alter the way plants grow and reproduce?

Directs Root & Stem Growth

Requires Gravity Perception

Gravity Studies involves

Micro gravity

Hyper-gravity

Effects on Secondary Metabolism

Increased isoflavonoids in soy bean 6-day exposure to micro gravity.

β -carotene, neoxanthin, violaxanthin, and lutein in aquatic plant Ceratophyllum (9-d)

75 % more glucosinolate in Brassicarappa.

EVIDENCES OF ALTERED SECONDARY METABOLISM

Increased disease susceptibility in wheat

soybean seedlings

Incomplete reproductive cycles

Altered gaseous exchange

Reduced seed size

Hormonal Imbalance

Reduced cytokinin due to altered fluid dynamics.

Increased effects of auxin in rice.

Altered secondary metabolism

Mechanical Stress Effects

Micro gravity

Wood formation

Secondary xylem

Lignin formation

Hyper Gravity

Shoot length

Upright growth

Cell wall extensibility

Microgravity and Hyper-gravity Effects on Secondary Metabolism in

Plants and Liquid Cultures.

Conclusions

Micro gravity

Increased secondary compound accumulation,

Decreased PAL activity

Decreased Lignin production.

Hyper gravity

Reduced secondary compound accumulation,

Increased PAL activity

Increased Lignin production

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