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DOI: DOI: http://dx.doi.org/10.21088/ijb.2394.1391.4217.10

Abstract

Among the various naturally occurring abiotic factors regulating plant development, light (radiations) plays an important role in photosynthesis, photoperiodism and photomorphogenesis. The present investigations aimed to study the effects of different colour of light on seed germination, hypocotyl growth, mobilization efficiency (ME), vigor index (VI), biomass production and content of photosynthetic pigments (Chl a, Chl b and Carotenoids) in Vigna unguiculata (L.) Walp. cv. Kanchan, an important annual herbaceous food legume crop. Germination rate was found comparatively high in natural light with 95% germination at 84 hours. Individually, red light showed maximum % germination (98) at 84 hours while, green light showed almost no germination even after 96 hours. Blue light and yellow light caused significant reduction in % germination to 71 and 56, respectively, at 84 hours. The seedlings grown under different lights showed variation in biomass production (fresh weight of root and shoot). Root and shoot growth were highest in red light and the order of biomass production was red > yellow > natural > blue > green. ME and VI of cowpea seedlings revealed maximum (610.41 and 4.41, respectively) in red and minimum in yellow light (163.38 and 1.49, respectively). Both, ME and VI could not be determined under green light due to absence of well-marked hypocotyl. The data on photosynthetic pigments indicates synthesis of photosynthetic pigments highly dependent on light quality. Highest content of chlorophyll a, chlorophyll b and carotenoids were observed in red, yellow and natural light, respectively. The findings indicate possibility for using light quality for manipulation of germination and seedling health of crop plants in general and V. unguiculata in particular.

Keywords: Visible Light Wavelengths; Germination; Photosynthetic Pigments; Seedling Vigour; Vigna Unguiculata. 

Corresponding Author : Nand Lal, Head, Department of Life Sciences, Dean, Faculty of Life Sciences, Member, Executive Council & Former Pro-Vice Chancellor, C.S.J.M. University, Kanpur-208024, India.