Micronutrients

Abstract

Barley plants were grown in a controlled greenhouse, in plastic pots (25 plants/pot) containing 25 g of soil and 475 g of quartz sand. Twelve soils were tested, with each repeated 5 times. Daily, 50 ml of standard nutritive solution containing no Cu were added to every pot. Plants were harvested at approximately the same phenological stage, when showing different degrees of Cu deficiency. Dry weight and P, K, Mg, Cu, Fe, Mn, Zn and B contents were determined separately for shoots and roots. Using the 60 data of every parameter measured, multiple linear correlation analysis and the determination coefficients (R) were obtained, and the contribution of each variable was calculated and expressed as percent.

In roots, Cu deficiency was the cause of variation (percent in parenthesis) of the following parameters, considered as primary actions; K (17%) and Fe (8%), positively; Mn (21%), negatively. In shoots, the primary actions were on K (23%) and Ca (9%), both positively. The variations in the other parameters were considered as being secondary actions, influenced by the above related primary actions of Cu deficiency.

Key words:

• Copper deficiency
• nutrient interactions
• multiple linear correlations
• barley