Effects of Variation in Nutrient Solution on Growth of Sunflower Plant

Publisher Website
Google Scholar
Abstract
Sand cultures were used to compare in the growth of the sunflower solution IR2S4 of the Livingston triangle (osmotic pressure 1 atmos.) with dilutions of this soln. and with the solns. of other investigators. 6 solns. were compared. When this soln. was diluted to 1/2 or 1/4 conc. the plants were smaller, probably because of too low a conc. of nutrient salts. However, when the conc. of this soln. was reduced to about 0.9 atmos. osmotic pressure by lowering its Ca(NO3)2 content, the plants were larger. The plants grown in a soln. of Hoagland and Arnon (osmotic pressure about 0.7 atmos.) were the largest of the 6 series. The conc. of this soln. seemed to be about optimal. Its low phosphate content in proportion to the nitrate and its low Mg content in proportion to the Ca probably also contributed to its superiority. The pH of the drip from the pots of this soln. was higher than that of any other soln., 3/4 of the detns. being alkaline. All of its N was supplied as nitrate and its phosphate content was low. The pH of the drip of a soln. of Shive and Robbins, which contained a little (NH4)2SO4, was lower and fluctuated less than any other soln. However, its conc. (osmotic pressure 0.5 atmos.) was too low for optimal growth of the sunflower. The conc. of IR2S4 was evidently too high and it contained too much Mg and phosphate for the best growth of the sunflower.