Promotion of flower formation by atrazine and diuron in seedlings of Asparagus.

Flower formation in 25-d-old seedling of Asparagus officinalis L was increased by soaking the seeds for 12 d in solutions of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) or diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea), two herbicides known to affect electron flow of photosystem II, from approx. 4% in controls to 37% in treatments with 400 μM of atrazine or about 100 μM diuron. Both herbicides inhibited plant growth, but treatment of seeds with other growth inhibitors (absicic acid, (2-chloroethyl)trimethylammonium chloride, polyethylene glycol) did not affect flower formation although inhibiting seed germination and plant growth. The increase of flower formation by the two herbicides permits identification of the sex of Asparagus plants at an early developmental stage.