Effect of boron on elongation of tomato root tips

Abstract

B deficiency was studied by measuring elongation rates of root tips of intact plants grown in solution culture. External and internal symptoms of B deficiency were detected within 24 hours after B was withheld from the nutrient solution. External symptoms appeared as early as 6 hours following B withdrawal and consisted of the cessation of root elongation and the development of a brown color in the root tip. Internal symptoms were evident behind the root meristem. B supplied to 1 portion of a split root system did not support elongation of tips on the other portion that did not receive B. Excised tips grown in sterile culture did not show the same striking inhibition of root elongation exhibited by tips of intact plants. B deficiency symptoms of roots of intact plants are not relieved by supplying sugars to the roots. Root elongation of intact plants supplied with adequate B was significantly correlated directly with solar radiation and inversely with plant height. When B was withheld elongation was significantly and negatively correlated with solar radiation.