15288
To accommodate these observations , we propose that in aqueous media at neutral to slightly alkaline pH about 3 % of the ethephon is converted ( t1 / 2 = 9 . 9 h at pH 7 . 0 ) into a cyclic oxaphosphetane which is the actual BChE inhibitor forming the 2 - hydroxyethylphosphonate adduct on BChE at Ser198 while about 97 % of the ethephon breaks down to ethylene ( t1 / 2 = 11 - 48 h at pH 7 . 0 ) which is responsible for plant growth regulation .
 Chemical: ethephon; Chemical: cyclic oxaphosphetane; Chemical: 2 - hydroxyethylphosphonate; Chemical: Ser198; Chemical: ethephon; Chemical: ethylene
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: ethephon; Chemical: cyclic oxaphosphetane; Chemical: 2 - hydroxyethylphosphonate; Chemical: Ser198; Chemical: ethephon; Chemical: ethylene