Ethylene and flooding stress in plants - ScienceDirect
Ethylene biosynthesis and signaling in rice - ScienceDirect
Etephon (ethylene precursor) has a dual role in tuberization. It promotes already formed tubers by inhibiting stolon growth. Differently though it inhibits the formation of new tubers. Why this makes sense -Tubers may be a strategy for a plant to last through the parts of the year like the winter when conditions or adverse for the species. Theu ethylene being an indicator of difficulty procuring adequate oxygen from the environment, should promote th plant going into dormancy through building up of its tuber. New tubers or stolons are probably more vulnerable to adverse conditons having a great surface area per weight ratio. Thus the plant wisely concentrates on those tubers it already has rather than trying to branch out and create new ones.
Ethylene biosynthesis and signaling in rice
Phosphinothricin is a broad spectrum herbicide and is effective against broad-leafed weeds. It acts as a competitive inhibitor
of the enzyme glutamine synthase which results in the inhibition of the enzyme glutamine synthase and accumulation of ammonia and finally the death of the plant. The disturbace in the glutamine synthesis also inhibits the photosynthetic activity.
The enzyme phosphinothricin acetyl transferase ( which was first observed in Streptomyces sp in natural detoxifying mechanism against phosphinothricin) acetylates phosphinothricin, and thus inactivates the herbicide. The gene encoding for phosphinothricin acetyl transferase (bar gene) was introduced in transgenic maize and oil seed rape to provide resistance against phosphinothricin.