Online) An Open Access

Rajendiran, Vidya, Arulmozhi
2015 Online International Journal Available at   unpublished
The growth parameters studied in three varieties of green gram viz. CO-8, NVL-585 and VAMBAN-2 after in situ supplementary ultraviolet-B (UV-B) radiation (2 hours daily @ 12.2 kJ m-2 d-1 ; ambient = 10 kJ m-2 d-1) showed variations in the plant height, number of leaves, total leaf area, fresh weight, dry weight and relative growth rate during different stages of growth (15, 30, 45 and 60 DAS-days after sowing). Number of leaves was reduced by 33.33 % under UV-B stress in all varieties on 30 DAS
more » ... compared to controls, but the crops recovered quickly equalling controls at later stages, with only CO-8 showing a reduction (33.33 %) during harvest stage. UV-B reduced the total leaf area (15.32 to 67.33 %), specific leaf weight (SLW) (16.86 to 49.71 %), fresh weight of leaves (12.49 to 78.22 %) and dry weight (23.09 to72.74 %) at all stages of growth. UV-B exposures reduced root length (10.86 to 74.07 %) and shoot length (16.25 to 39.60 %). VAMBAN-2 had less S / R ratio (10.91 % on 15 DAS) under UV-B stress while CO-8 and NVL-585 recorded higher values (7.2 to 44.30 %) till 60 DAS over control. Fresh weight of roots increased with age in all treatments. But the biomass accumulation in root was inhibited by UV-B treatment by 13.29 to 69.87 % on 15 DAS, the maximum reduction being in CO-8. On 30, 45 and 60 DAS all the varieties of green gram did not show any recover as the reduction continued to reach 27.06 to 77.28 %. UV-B stress imposed a general decrease in fresh weight (11.27 to 78.22 %), root biomass (18.85 to 93.97 %) and plant dry weight (58.40 to 70.29 %). The relative growth rate (RGR) was enhanced in all UV-B irradiated plants as the values were significantly higher (66.66 %) over control. The performances of CO-8 and VAMBAN-2 varieties of green gram were very poor under UV-B exposure at all stages of growth.
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