Effects of Boron Applications on the Physiology and Yield of Lettuce

Aim: The present study was conducted to determine the effects of boron applications on vegetative development, antioxidant activity and mineral composition of lettuce.

Study Design: In the greenhouse, treatments arranged according to a completely randomized block design, with four replications.

Methodology: Funnly F1 lettuce cultivar was used as the plant material and Etidot-67 (21% B) fertilizer was use as the boron source. Five different boron doses (0, 50, 100, 200 and 400 gr da-1) were applied and changes in lettuce plants were observed. Effects of different boron doses on root weights, head weights, water soluble dry matter (WSDM) contents, titratable acidity (TA), pH, vitamin C, leaf N, P, K and B concentrations were investigated. Besides, leaf ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) contents were also investigated.

Results: Root and marketable plant weights decreased with increasing boron doses. Boron treatments did not show significant effects on plant chlorophyll contents and biochemical characteristics. Leaf B concentrations increased with increasing B doses. Compared to control treatments, significant increases were observed in enzyme activities with boron treatments. APX, CAT, POD activities at the highest boron dose were respectively measured as 6.53, 527 and 0.387. Current results revealed that a boron dose of over 200 gr da-1 created stress conditions in lettuce plants.

Conclusion: Fertilizers should be selected and applied by taking boron sensitivity or resistance levels of plants into consideration.