Dear Maorun Fu

All about signals and pathways , interference , cell-cell talks and communications= For  the role of various hormone signals in plant innate immune signal transduction go to http://www.springer.com/us/book/9789401792844

The plant hormone ethylene affects a wide range of physiological processes in horticultural crops, including abscission, senescence and ripening, chlorophyll loss, softening, physiological disorders, sprouting, isocoumarin synthesis, lignification, discoloration (browning), decay, and stimulation of defense systems (Saltveit 1999). Depending on the desired use of the produce, these effects can be positive or negative.

 1-MCP belongs to a class of compounds known as cyclopropenes. The discovery that cyclopropenes inhibit ethylene perception by competitively binding to ethylene receptors represented a major breakthrough in controlling ethylene responses of horticultural products (Blankenship and Dole 2003).

As for  onion  = https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135958/  mentioned = Onion (Allium cepa) is regarded as a nonclimacteric vegetable. In onions, however, ethylene can suppress sprouting while the ethylene-binding inhibitor 1-methylcyclopropene (1-MCP) can also suppress sprout growth; yet, it is unknown how ethylene and 1-MCP elicit the same response

Pls. find the attached files

http://www.sciencedirect.com/science/article/pii/S0925521413001439

http://www.sciencedirect.com/science/article/pii/S0925521406003255

https://www.ncbi.nlm.nih.gov/pubmed/16968096

http://www.sciencedirect.com/science/article/pii/S0308814607003433

http://www.actahort.org/books/945/945_39.htm

https://en.wikipedia.org/wiki/1-Methylcyclopropene

Hoping this will be helpful

Regards

Prof. Houda Kawas

Dear Maorun Fu

ethylene remains dual physiological effect. it can both repress or promote potato germination while using in different concentrations.

on the other hand  its not logical to compare onion with potato, due to potato is botanically stem and onion is an aggregation of leaves, so its expected to respond differently to PGRs. 

on the other hand due to dual effect of ethylene, maybe various concentration of ethylene affect onion sprouting, that should be examined. maybe threshold of PGRs for potato varies onion threshold

moreover, different PGRs follow different signal transaction pathways that should to be considered.

Good Luck. 

It  is well known that natural plant hormones have a wide range of physiological activities  which are influenced  by a number of factors ,  on e of such factors, is the type of plant tissue. we have found that ethylene stimulate leaf abscission,yet it stimulated rooting of the same plant,two contrasting physiological effects. so , ethylene is known to inhibit potato sprouting, but have no effect  on onion which completely different from potato tubers in terms of structure and the nature of growth after dormancy.although,MCP  is known as an inhibitor of ethylene biosynthesis or action,but this apply for  the role of ethylene in fruit ripening, for example. under natural conditions, ethylene has no role to play in sprout growth, but when applied in high concentration,it causes sprout inhibition due  its effect on cell division. furthermore, it is  known , that different tissues have different optimal con centration of plant hormones.

Thanks for your attention and professional reply. Recently, I designed a new experiment for potato sprouting inhibition by 1-MCP, and we found the same role as ethylene in inhibiting sprouting, whereas the concentration was was high. Additon details can be obtained vis my email [email protected].

You most welcome

Houda