Photon flux density and light quality induce changes in growth, stomatal development, photosynthesis and transpiration of Withania Somnifera (L.) Dunal. plantlets

Abstract

The aim of the study was to establish whether the quantity and the quality of light affect growth and development of Withania somnifera plantlets. We have studied growth and histophysiological parameters [stomatal characteristics, chloroplastic pigments concentrations, photosynthesis, and transpiration (E)] of W. somnifera plantlets regenerated under various light intensities, or monochromatic light or under a mixture of two colors of light in tissue culture conditions. Plantlets grown under a photon flux density (PFD) of 30 mmol m -2 s -1 showed greater growth and development than those raised under other PFDs. Chlorophylls and carotenoids, numbers of stomata, rate of photosynthesis (P N ) and transpiration (E), stomatal conductance (g s ), and water use efficiency (WUE) increased with increasing the PFD up to 60 mmol m -2 s -1 . Light quality also affected plantlets growth and physiology. Highest growth was observed under fluorescent and in a mixture of blue and red light. Very few stomata were developed in any of the monochromatic light but under fluorescent or under a mixture of two colors stomatal numbers increased. Similarly, g s , E, P N, and WUE were also higher under fluorescent light and under a mixture of red and blue light. Regressional analysis showed a linear relationship between P N (r 2 = 70) and g s and between E (r 2 = 0.95) and g s . In conclusion, both the quality and the quantity of light affect growth of plantlets, development of stomata and physiological responses differently depending on the intensity and the wavelength of light.

The impact of red and blue light-emitting diode illumination on radish physiological indices

“…Thus the response of radish growth and biomass partitioning was linked to patterns of non-structural carbohydrate distribution between plant organs. As it is known, the sufficient doses of photosynthetically active radiation are crucial for the formation of assimilates and thus the accumulation of biomass [9,22]. But spectral composition of light controls formative processes and may initiate developmental processes during plant growth [2,23].…”

“…These lamps vary in terms of spectral quality, which can result in differences in plant growth and morphology [6]. Recently most studies are based on solid-state light-emitting diodes (LEDs) lighting [7] as a potential light source for successful growth [8] and to determine if the requirements for plant photosynthesis and photomorphogenesis are met [9,10].…”

“…According to literature data [9], plants can complete a life cycle under red LEDs alone, but supplementing red light with blue light promotes dry matter production in several plant species [2,10], including radish [1]. The trend of higher biomass production and photosynthetic capacity due to blue and red light combinations was observed in many papers [2,9,10]. The effect of light quantity on plant development and physiological indices is also important.…”

The Effect of Different Doses of Blue Light on the Biometric Traits and Photosynthesis of Dill Plants

“…Net photosynthetic rate and dry weight According to literature data, plants can have a full life cycle only under red light, but the addition of blue light increases photosynthetic production in some plants (Lee et al, 2007;Wang et al 2015). It is so because cryptochromes (CRYs) and phototropins are specifically sensitive to blue light and phytochromes are specifically sensitive to red light (Whitelam and Halliday, 2007).…”

The effect of radiation of LED modules on the growth of dill (Anethum graveolens L.)

“…40 (± 5) plants. They were grown in pots with a capacity of 280 cm 3 and a cultivation area of 49 cm 2 . The plants were watered on capillary mats every other day.…”