mechanism of seed germination inhibitor, signaling pathway of pl

1. POLYPHENOLIC
COMPOUNDS AS SEED
GERMINATION INHIBITOR
NAME: SOUVIK MUKHERJEE
REG NO: 16mphyto01
COURSE: M. Pharm (Pharmacognosy and phytochemistry)
CENTRE FOR PHARMACEUTICAL SCIENCES AND NATURAL PRODUCTS
CENTRAL UNIVERSITY OF PUNJAB

2. CONTENT
1. WHAT IS SEED
2. STRUCTURE OF SEED
3. WHAT IS SEED GERMINATION
4. PROCESS OF SEED GERMINATION
5. STAGES OF SEED GERMINATION
6. GERMINATION INHIBITOR
7. POLYPHENOLIC COMPOUNDS AS SEED GERMINATION INHIBITOR
8. COUMARIN AND COUMARIN DERIVATIVES AS SEED GERMINATION INHIBITOR
9. FLAVONOID AS SEED GERMINATION INHIBITOR
10.CONCLUSION
11. REFFERENCES

3. WHAT IS SEED
• A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of
the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm
plants (Eira MTS Caldas& LS 2000) .
Figure1: Dormant seed(Pumpkin) Baskin J.M., Baskin C.C. (2004) Figure2: Germinate seed(Raddish) Baskin J.M., Baskin C.C. (2004)

4. STRUCTURE OF SEED
Figure (3) : structure of seed (Parolin, P., Ferreira, L.V., Junk, W.J. 2003)

5. WHAT IS SEED GERMINATION
• Being crucial for next-generation plant growth, is a prerequisite
event for crop yield. (Bewley & Black, 2012).
• Two kinds of seed germination occur.
1. Epigeal Germination
2.Hypogeal Germination
• .
Figure(4) : Germinated pumpkin seed
www.helpfulgardener.com

6. Cont.…
Figure(5): Epigeal germination and Hypogeal germination (Parolin,
P., Ferreira, L.V., Junk, W.J. 2003)

7. STAGES OF SEED GERMINATION
• PREGERMINATION: (a) Rehydration
(b)RNA and protein synthesis stimulated
(c)Increase respiration
• GERMINATION: (a) Rupture of seed coat
(b) Emergence of seedling
• POST GERMINATION: (a) Controlled growth of root and shoot
(b) Controlled transport of materials from
storage proteins

8. PROCESS OF SEED GERMINATION
1. Imbibition
- water uptake, softens inner tissues
- causes swelling and seed coat rupture
- more water uptake
2.Gibberelic Acid
- Plant hormone
- Dissolved & distributed by water
- Arrives at aleurone cells
- Activates certain genes
3. Amylase accelerates hydrolysis of starch
4. Transcription Transportation Translation 
amylase
5. Hydrated starch moves to the cotyledon
and radicle to initiate growth
Figure(6) : Process of seed germination
(Raven, Peter H.; Ray F. Evert; Susan E.
Eichhorn 2005).

9. GERMINATION INHIBITORS
• Substances are capable of inhibiting germination Compounds which prevent
germination without killing the seeds.
• Compounds such as cyanide dinitrophenol, azide, fluoride, hydroxylamine, and
others which are germination inhibitor (Bais, Park, Weir, Callaway, & Vivanco,
2004).
• Many poly phenolic compounds have been found to inhibit germination by
(a) Water uptake inhibition
(b) Inhibit the ROS scavenging
(c) specific gene inhibition

10. ADVANTAGES OF SEED
GERMINATION INHIBITION
(A) Seed germination inhibition is also necessary for inducing dormancy.
(B) seed to get dispersed over long distances through unfavorable environment.
(C) It follows storage of seeds for later use by animals and mans.
(D) Seeds can remain alive in the soil for several years.
(E) Provide a continuous source of new plants. (Raven, Peter H.; Ray F. Evert; Susan
E. Eichhorn 2005).

11. INTRODUCTION OF POLYPHENOLIC
COMPOUNDS
• More than one phenolic group attached to one or more benzene rings (Klepacka et al.,
2011).
• They are usually found as esters or glycosides rather than as free compounds (Cheynier,
2005).
• Example vanillic acid, cholrogenic acid, gallic acid, sorgelone, juglone, coumarin and
coumarin derivatives.

12. POLYPHENOLIC COMPOUNDS AS SEED GERMINATION INHIBITOR
• poly phenolic compounds have been found to inhibit germination.
• These have a widespread occurrence and distribution in plants and fruits.
• phenolic compounds that have shown lesser activity include salicylic, (a) gallic,
(b) ferulic, (c) caffeic, (d) vanillic, (e) protocatechuic, (f) chlorogenic, (g) p-
oxybenzoic, and (h) paracoumaric acids.
• Some example of polyphenolic compound which are also inhibited the seed
germination(Bewley & Black, 1994).

13. CONT….

14. LOCATION OF POLYPHENOLIC COMPOUNDS IN SEED
Figure (7): Location of Polyphenolic compounds in seed (Drynan, J.W.; Clifford, M.N.; Obuchowicz, J.; Kuhnert, N. 2010)

15. COUMARIN AND COUMARIN DERIVATIVES AS SEED
GERMINATION INHIBITOR
• Coumarin and coumarins derivatives are large class of polyphenolic compound
• Widely distributed on the leaf, seed surface, and pollen wall.
• Coumarin is a strong inhibitor of seed germination.
• Coumarin is found in several plants, including Tonka beans, lavender, licorice,
strawberries, apricots, cherries, cinnamon, and sweet grass (V; Odhav, B 2013).
Figure(7): sweet grass
www.nyrnaturalnews.com

16. CONT…..
• Coumarin and coumarin derivatives are the seed germination inhibitors, such as 6-
Methyl coumarin, 5,7 dimethoxy coumarin, 7- hydroxyl coumarin, 4- methyl
umbelliferone, 4- hydroxy 3-nitro coumarin , Dihydrocoumarin(Moreland &
Novitzky, 1987).

17. MECHANISM ACTION OF COUMARIN AND COUMARIN
DERIVATIVES
Figure(8) : Mechanism of action of coumarin

18. INTRODUCTION OF FLAVONOIDS
• Flavonoids or bioflavonoids from the Latin word flavus meaning yellow, their color in nature
• Are a class of plant and fungus secondary metabolites.
• Chemically, flavonoids have the general structure of a 15-carbon skeleton.
• Found in the seed of both mono-cots and dicots, the seed embryo, and the pericarp, and
aleurone layer (Holdsworth, Bentsink, & Soppe, 2008).
• Flavonoid is found in several plants such as Aghandha , Apmarg, Khetki etc.
Figure(9): Apmarg pharmaveda.com

19. CONT…
• The major types of flavonoids in seeds are flavonols, anthocyanins,
phlobaphenes, isoflavones, and proanthocyanidins(Harborne & Williams, 2000).
Figure : Proanthocyanidins

20. MECHANISM ACTION OF PROANTHOCYANIDINS
Figure(10): Mechanism action of proanthocyanidins as seed germination inhibitor

21. MECHANISM ACTION OF OTHER POLYPHENOLIC
COMPOUNDS AS SEED GERMINATION INHIBITOR
(B) Cholorogenic acid
• MOA: Inhibition of ion uptake system(Schopfer & Plachy, 1984)
• STRUCTURE:

22. CONT…
(C) Ferulic acid
• MOA: Hindering energy transfer and ion transport(Carnachan & Harris,
2000).
• STRUCTURE:
(D) JUGLONE
• MOA: Inhibition of radicle elongation(Debeaujon & Koornneef, 2000)
• STRUCTURE

23. CONCLUSION
• If germination is inhibited we can see promotion of
dormancy.
• Some of polyphenolic compounds which inhibit germination
are (1)coumarin and coumarin derivatives which inhibit
water uptake system.(2) Flavonoid and flavonoid derivatives
which increase abscissic acid pathway.
• polyphenolic compounds are also produced anti microbial
activity in seed and color of the seed coat.

24. REFFERENCES
• Eira, M. T., & Caldas, L. S. (2000). Seed dormancy and germination as concurrent
processes.
• Revista Brasileira de Fisiologia Vegetal, 12(Edicao Especial), 85-104. Baskin, J. M.,
& Baskin, C. C. (2004). A classification system for seed dormancy. Seed science
research, 14(01), 1-16.
• Albertos, P., Romero-Puertas, M. C., Tatematsu, K., Mateos, I., Sánchez-Vicente,
I., Nambara, E., & Lorenzo, O. (2015). S-nitrosylation triggers ABI5 degradation to
promote seed germination and seedling growth. Nature communications, 6.
• Ali-Rachedi, S., Bouinot, D., Wagner, M. H., Bonnet, M., Sotta, B., Grappin, P., &
Jullien, M. (2004). Changes in endogenous abscisic acid levels during dormancy
release and maintenance of mature seeds: studies with the Cape Verde Islands
ecotype, the dormant model of Arabidopsis thaliana. Planta, 219(3), 479-488.
• Nonogaki, H. (2012). Seed Biology Updates–Highlights and New Discoveries in
Seed Dormancy and Germination Research. Frontiers in Plant Science, 8.

25. CONT….
• Chiba, Y., Shimizu, T., Miyakawa, S., Kanno, Y., Koshiba, T., Kamiya, Y.,
& Seo, M. (2015). Identification of Arabidopsis thaliana NRT1/PTR
FAMILY (NPF) proteins capable of transporting plant hormones.
Journal of plant research, 128(4), 679-686.
• Venugopala, K. N., Rashmi, V., & Odhav, B. (2013). Review on natural
coumarin lead compounds for their pharmacological activity. BioMed
Research International, 2013.