A new statistical approach for the interpretation of nutrient interrelations in dwarf bean plants grown under Fe deficiency

Abstract

Dwarf bean plants were grown in a controlled greenhouse on 25 g of soil and 475 g of quartz sand. Twelve different soils were tested (x replications). Daily 50 ml of a standard nutrient solution containing no Fe was added to each pot. Plants were harvested at approximately the same phenological stage. All of them were showing different degreees of Fe deficiency. Dry weight and N, P, K, Ca, Mg, Cu, Fe, Mn, Zn and B contents were determined separately for shoots and roots.

Using the data for every parameter measured, multiple linear correlation analysis and determination coefficients (R²) were obtained. A statistical method was elaborated in order to select the variables most effective to explain the variation of every dependent variable; then, the contribution of every selected variable was calculated and expressed as percent. In roots Fe deficiency was the cause of variation of the following parameters considered as primary actions: Cu (54%) and Ca (9%) contents, positively; and Mn (12%) content and dry weight (455), negatively. In shoots the primary actions were on Zn (31%), K (6%), P (5%) contents and dry wt. (20%), all of them positively. The variations in the rest of parameters were considered as being secondary, influenced by the above related primary actions of Fe deficiency.

Key words:

• Bean
• iron deficiency
• nutrient interactions
• multiple linear correlations