Effects of Cytokinin and Auxin on Plant Development and Vascular Tissues in Lens culinaris

Abstract

Cytokinins and auxins were studied in Lens culinaris before; however, there was lack of information about their effects on vascular tissues and their relation with plant development. In this study, intact lentil seedlings were treated with different doses of BAP (1 mg/L) and NAA (0.3, 0.6, 0.9, 1.2 mg/L) with periodic intervals of 7, 14, 21, 28, and 35 days under in vitro conditions. The behaviors of plant height, number of shoots per plant, and rooting were investigated to find if their regeneration behavior is related with the developmental behavior of phloem and xylem thickness and stem radius. In most instances, seven-day culture conditions in all plant growth regulators (PGRs) doses demonstrated the best results. BAP and NAA treatments with high doses on prolonged days of culture caused unhealthy growing on plant development and vascular tissues. While phloem region thickness was the highest in control group, xylem region was found to have the highest thickness in 1 mg/L BAP treatment used singly. Moreover, high doses of BAP and NAA caused deformity and shrinking in phloem and xylem regions that also lead to shrinking in stem radius. These results reveal negative effects of BAP and NAA treatments on prolonged days of culture and conclude that the time period of treatment must be optimized precisely to avoid damages to vascular and other tissues and promote desirable growth and development of tissues.