Effect of acidified water on the tracheary elements of the first maize (Zea mays L.) internode and conditions determining elongation of this internode

Conditions for the formation of a long first internode (mesocotyl shoot) of maize (Zea mays L.) formed in a relatively short period of time were analyzed. If an inert substrate was used, the growth of such a shoot is mainly determined by the uptake of water. Effect was examined of acidified water (a substitute for acid rain) on morphology and anatomy of first internodes and of roots of young seedlings produced by deeply sown maize grains in an inert substrate under conditions mentioned above. Light microscopical investigations of transverse sections of first intemodes and roots revealed more tracheary elements mainly consisting of a greater number of tracheids, in the mesocotyl of those seedlings cultivated with acidified water. The effect was more distinct if a combination of sulphuric and nitric acid was applied and less distinct if nitric acid, sulphuric acid or hydrochloric acid were applied. Radial endodermis cell walls (cross walls were not measured) in the mesocotyl were up to twice as thick in plants treated with acidified water than in plants of the control with tap water. Possible water stress symptoms caused by the supplied acidified water are discussed.