Polyamine-mediated growth and physiological changes in Borago officinalis

Abstract

Polyamines play an important role in regulating plant growth, as well as in physiological and metabolic processes related to crop performance. This study aimed to evaluate the effects of polyamine use on early growth, yield, and quality traits of Borago officinalis L. A factorial layout was performed using a randomized complete block design, considering two factors: seed priming and foliar spraying. Seed priming included one control (dry seeds) and priming with distilled water, putrescine, spermine, and spermidine. Foliar spraying included one control (no spraying) and spraying at the four-leaf stage, at 50 % of the flower bud formation and 50 % of flowering. Seed priming with spermidine and spermine, combined with foliar spraying at 50 % of the flower bud stage, increased chlorophyll contents. The highest carotenoid contents were observed in plants grown from spermidine-primed seeds and sprayed with putrescine at 50 % of the flower bud stage. The highest mucilage percentages and yield performance were obtained for the spermidine and spermine priming, followed by putrescine spraying at 50 % of the flower bud and flowering stages. The saponin content was high in plants from spermidine-primed seeds sprayed at 50 % of the flower bud stage. The use of polyamines increased the essential oil content and yield, in addition to change the relative proportions of palmitic, oleic, and gamma-linolenic fatty acids, in comparison to the control.

KEYWORDS: European borage, photosynthetic pigments, essential oil.