Nutritional and Visual Diagnosis in Broccoli (Brassica oleracea var. italica L.) Plants: Disorders in Physiological Activity, Nutritional Efficiency and Metabolism of Carbohydrates

Abstract

Information on the nutritional status of plants enables adequate fertilisation management. Thus, the aim of this study was to evaluate how nutritional disorders alter the biological, nutritional and biochemical mechanisms of broccoli (Brassica oleracea var. italica L.) plants grown under greenhouse conditions. A complete nutrient solution and omissions of macronutrients were tested in a completely randomised design with four replicates. Broccoli plants grown with the omission of N and Ca were the first of show deficiency symptoms and the greatest reduction in the net photosynthetic rate and stomatal conductance, with evidently impaired plant growth and biomass. Omissions of macronutrients affected carbohydrate partitioning, and the content of soluble sugars significantly decreased by more 60% in response to Mg omission. With K omission, the contents of soluble sugars and starch increased in broccoli leaves by 40% and 60%, respectively. K transport increased in plants grown without Ca. S translocation decreased with the absence of any macronutrient in the nutrient solution. Deficiencies in the nutrients N, K, and Ca cause the most critical early damage in the photosynthetic apparatus and in the nutritional balance of broccoli plants, so attention should be given to replenishing these nutrients in plantations.