Ribonucleic Acid Content, Boron Deficiency Symptoms, and Elongation of Tomato Root Tips

Abstract

Tomato plants (Lycopersicum esculentum var. Rutgers) were grown in nutrient solution cultures with adequate B (0.1 mg/liter) until treatments were started. Treatments consisted of placing plants in fresh nutrient solutions containing adequate B or in solutions from which B was withheld. At selected time intervals after initiating treatments root elongation measurements were obtained and tips (3 mm) were analyzed for nucleic acid (RNA and DNA). Elongation of root tips ceased before a decrease in RNA content occurred. The RNA content of root tips decreased soon after (24-48 hours) B was withheld from the nutrient solution. Failure of root tips to elongate in the presence of B and the appearance of typical B deficiency symptoms occurred concurrently as the RNA content of the tips decreased. The DNA content of the tips did not change significantly during the experimental period.