Supplemental UV‐B induced changes in leaf morphology, physiology and secondary metabolites of an Indian aromatic plantCymbopogon citratus(D.C.) Staph under natural field conditions

Abstract

Cymbopogon citratus (D.C.) Staph, an aromatic perennial herb, is known to have great potential as a medicinal plant. In our study, we investigated in realistic field conditions the effect of supplemental ultraviolet-B (sUV-B) at two levels (+1.8 and +3.6 kJ m −2 d −1 above ambient) on various growth, physiological and biochemical characteristics of C. citratus. A higher dose of sUV-B produced a 17.6% reduction in biomass while at a lower dose the characteristics remained unaffected. The sUV-B imparted its negative effects to chlorophyll contents while an increment was noticed for carotenoids and phenolic compounds. No significant change in the rate of photosynthesis was noticed. The SEM observation revealed dense waxy deposition on the adaxial surface of exposed leaves at a lower dose of sUV-B to increase epidermal transmittance. This study clearly indicated the beneficial effect of sUV-B on volatile oils production in C. citratus plants grown under a low dose of sUV-B.

The effects of different UV‐B radiation intensities on morphological and biochemical characteristics in Ocimum basilicum L.

“…In various studies, UV-B radiation has been shown to increase, 27 decrease 9,22 or have no effect on chlorophyll content. 28 In this study the levels of photosynthetic pigments in flowering basil plants were significantly reduced under UV-B treatment (Figs 1A and 1B).…”

“…Numerous studies have been conducted into the effects of enhanced UV radiation on plant growth, physiology and secondary metabolites . One of the mechanisms that plants possess to help them adapt to enhanced UV‐B radiation is the ability to increase the production of secondary metabolites in leaf tissues .…”

Biochemical traits and proteomic changes in postharvest flowers of medicinal chrysanthemum exposed to enhanced UV-B radiation

“…However, some interesting results about UV-B-beneficial effects on secondary metabolism processes in medicinal plants have been found in recent years [5][6][7][8][9][10][11][12]. Most of medically active ingredients in medicinal plants are secondary metabolites.…”

“…Most of medically active ingredients in medicinal plants are secondary metabolites. In the experiment performed by Kumari and Agrawal, a higher dose of UV-B radiation (elevated 3.6 kJ m À2 d À1 above ambient) produced a 17.6% reduction in biomass and increased phenolic compounds concentrations [5]. Germ et al reported that enhanced UV-B radiation increased flavonoid and tannin content in the leaves of St. John's wort (Hypericum perforatum L.) [7].…”

The Effects of UV‐B Radiation Intensity on Biochemical Parameters and Active Ingredients in Flowers of Qi Chrysanthemum and Huai Chrysanthemum

“…In general, enhanced UV-B radiation can indeed negatively affect growth, physiology and productivity of plants (1)(2)(3)(4)(5)(6). In recent years, however, some interesting results about UV-B-beneficial effects on secondary metabolic processes in medicinal plants have been found (7,8).…”