Intraspecific variations in growth, yield and photosynthesis of sorghum varieties to ambient UV (280–400nm) radiation

• Published in: Plant science (Limerick) Vol. 196; pp. 85 - 92
• Main Authors: Kataria, Sunita, Guruprasad, K.N.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01-11-2012; Elsevier
• Subjects: Adaptation, Physiological - radiation effects; Agronomy. Soil science and plant productions; Biological and medical sciences; Biomass; biomass production; chlorophyll; Chlorophyll - metabolism; Cumulative stress response index; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; harvest index; Intraspecific variation; leaves; photosynthesis; Photosynthesis - radiation effects; Plant Leaves - growth & development; Plant Leaves - metabolism; Plant Leaves - physiology; Sorghum - classification; Sorghum - growth & development; Sorghum - physiology; Sorghum bicolor; Species Specificity; stress response; ultraviolet radiation; Ultraviolet Rays; UV radiation; vegetative growth; Yield; UV radiation; UV; Intraspecific variation; Chl; UAS; CSRI; Yield; Biomass; Cumulative stress response index; SLW; Monocotyledones; Growth; Plant biology; Sorghum; Stress; Ultraviolet radiation; Gramineae; Angiospermae; Herbaceous plant; Spermatophyta; Intraspecific comparison; Photosynthesis; Cultivar
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2012.07.011

► Field study conducted for intraspecific variations in UV-A/B sensitivity of sorghum. ► Cumulative stress response index of sorghum varieties calculated after exclusion of UV-A/B. ► Significant intraspecific variations exist in magnitude of solar UV induced changes. ► Exclusion of solar UV positively regulated all growth/yield parameters in sorghum. ► Absence of ambient UV enhanced photosynthesis consequentially improved yield of sorghum.
A field study was conducted to investigate the impact of ambient solar UV on the various growth, physiological and yield parameters of four sorghum (Sorghum bicolor L.) varieties—Indore-12, Indore-26, CSV-23 and Indore-27 by excluding either UV-B (<315nm) or UV-A/B (<400nm) components of solar spectrum. Exclusion of UV significantly enhanced plant height, area and specific leaf weight of flag leaf, biomass accumulation, yield parameters and harvest index in all the sorghum varieties. Chlorophyll b was significantly enhanced and chlorophyll a increased to a lesser extent, UV-B absorbing substances and chlorophyll a/b ratio were significantly decreased by the exclusion of solar UV. The enhancement in the vegetative growth and yield by UV exclusion might be linked to the remarkable increase in rate of photosynthesis in sorghum varieties. The magnitude of the response was high in I-26 and I-27 as compared to CSV-23 and I-12 after exclusion of solar UV. All the varieties of sorghum had a negative cumulative stress response index (CSRI), the sensitivity of the sorghum varieties was in the following sequence I-12>CSV-23>I-26>I-27. Thus I-27 was the most sensitive and I-12 the least sensitive variety to present level of solar UV radiation. The differences in UV sensitivity identified among sorghum varieties might be useful in breeding programs for increased tolerance to UV-B radiation.