Growth enhancement of soybean (Glycine max) upon exclusion of UV-B and UV-B/A components of solar radiation: characterization of photosynthetic parameters in leaves.
Exclusion of UV (280-380 nm) radiation from the solar spectrum can be an important tool to assess the impact of ambient UV radiation on plant growth and performance of crop plants. The effect of exclusion of UV-B and UV-A from solar radiation on the growth and photosynthetic components in soybean (Glycine max) leaves were investigated. Exclusion of solar UV-B and UV-B/A radiation, enhanced the fresh weight, dry weight, leaf area as well as induced a dramatic increase in plant height, which reflected a net increase in biomass. Dry weight increase per unit leaf area was quite significant upon both UV-B and UV-B/A exclusion from the solar spectrum. However, no changes in chlorophyll a and b contents were observed by exclusion of solar UV radiation but the content of carotenoids was significantly (34-46%) lowered. Analysis of chlorophyll (Chl) fluorescence transient parameters of leaf segments suggested no change in the F v/F m value due to UV-B or UV-B/A exclusion. Only a small reduction in photo-oxidized signal I (P700+)/unit Chl was noted. Interestingly the total soluble protein content per unit leaf area increased by 18% in UV-B/A and 40% in UV-B excluded samples, suggesting a unique upregulation of biosynthesis and accumulation of biomass. Solar UV radiation thus seems to primarily affect the photomorphogenic regulatory system that leads to an enhanced growth of leaves and an enhanced rate of net photosynthesis in soybean, a crop plant of economic importance. The presence of ultra-violet components in sunlight seems to arrest carbon sequestration in plants.
Guruprasad
Kadur
K
School of Life Sciences, DAVV, Vigyan Bhawan, Khandwa Road, Indore, 452001, India.
Kadur
Guruprasad
G
Bhattacharjee
Swapan
S
Swapan
Bhattacharjee
B
Kataria
Sunita
S
Sunita
Kataria
K
Yadav
Sanjeev
S
Sanjeev
Yadav
Y
Tiwari
Arjun
A
Arjun
Tiwari
T
Baroniya
Sanjay
S
Sanjay
Baroniya
B
Rajiv
Abhinav
A
Abhinav
Rajiv
R
Mohanty
Prasanna
P
D018533:Biomass; D002734:Chlorophyll / Q000378:metabolism; D010788:Photosynthesis / Q000528:radiation effects*; D018515:Plant Leaves / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D013025:Glycine max / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D013472:Sunlight; D014466:Ultraviolet Rays
D002734:Chlorophyll