2009

Now showing 1 - 4 of 4

Use of ethylene diurea (EDU) in assessing the impact of ozone on growth and productivity of five cultivars of Indian wheat (Triticum aestivum L.)
(2009) Shalini Singh; S.B. Agrawal
Increase in concentrations of tropospheric ozone (O3) is one of the main factors affecting world agriculture production. Tropical countries including India are at greater risk due to their meteorological conditions (high solar radiation and temperature) being conducive to the formation of O 3. The most effective anti-ozonant chemical is N-[2-(2-oxo-1- imidazolidinyl) ethyl]-N-phenylurea or ethylene diurea (EDU). Due to its specific characteristics, EDU has been used in the field as a phytomonitoring agent to assess crop losses due to O3. Field experiments were conducted on five local cultivars of wheat (Triticum aestivum L. cv HUW234, HUW468, HUW510, PBW343, and Sonalika) grown under natural field conditions in a suburban area of Varanasi, Uttar Pradesh, India during December 2006 to March 2007 to determine the impact of O3 on their growth and yield characteristics. Mean monthly O3 concentrations varied between 35.3 ppb and 54.2 ppb at the experimental site. EDU treatment positively affected various growth and yield parameters with difference between cultivars. EDU-treated plants showed increase in shoot and root length, leaf area, absolute growth rate, relative growth rate, and net primary productivity, indicating O3 induced suppression in growth. EDU treatment was highly significant in different cultivars for total biomass and test weight but not for harvest index. Yield per plant was higher by 25.6%, 24%, 20.4%, 8.6%, and 1.9% in EDU-treated cultivars HUW468, Sonalika, HUW510, HUW234, and PBW343, respectively, than non-EDU-treated ones. These results clearly indicate the sensitivity of all the wheat cultivars to ambient levels of O3 with cv HUW468 appearing to be most sensitive. The present study also supports the view that EDU has great potential in alleviating the unfavorable effects of O3 and can be effectively used as a monitoring tool to assess growth and yield losses in areas experiencing elevated concentrations of O3. © 2008 Springer Science+Business Media B.V.
Effects of supplemental ultraviolet-B and cadmium on growth, antioxidants and yield of Pisum sativum L.
(2009) S.B. Agrawal; Shweta Mishra
The impact of supplemental UV-B irradiation (sUV-B) and cadmium (Cd, 68 μmol kg-1 soil) singly and in combination was studied on growth, pigments, enzymatic and non-enzymatic antioxidants, lipid peroxidation (LPO), uptake and translocation of Cd and yield of pea plants under field condition. Compared to the control, both the stresses individually and in combination led to in reductions in growth, photosynthetic pigments, ascorbic acid, catalase (CAT) activity and yield, whereas a reverse trend was observed for flavonoids, thiols and proline contents, superoxide dismutase (SOD) and peroxidase (POD) activities, and LPO. The uptake and translocation of Cd increased in different plant parts with duration of its treatment and also when applied with sUV-B. Combined treatment of sUV-B and Cd inhibited the growth and various metabolic processes antagonistically except the CAT activity which showed additive response. Further, CAT activity may be used as a bioindicator parameter to evaluate the individual and interactive effects of both the stresses. © 2007 Elsevier Inc. All rights reserved.
Combined effects of Psoralens and ultraviolet-B on growth, pigmentation and biochemical parameters of Abelmoschus esculentus L.
(2009) Rima Kumari; Suruchi Singh; S.B. Agrawal
The effects of pre-treatment of Psoralens (furocoumarin compounds) and supplemental ultraviolet-B (sUV-B) were studied on plant growth, photosynthetic and non-photosynthetic pigments, protein, phenylalanine ammonia lyase (PAL) activity and antioxidative defense potential as well as their ultimate effects on biomass production in Abelmoschus esculentus L. (Okra) plants. Psoralens are capable of absorbing radiant energy and stimulating the pigmentation of human skin when photo-activated in presence of UV-A or UV-B making them beneficial in the treatment of vitilago. Pre-treatment of Psoralens against sUV-B (pUV-B), stimulates higher production of UV-B protective pigments (flavonoids and carotenoids) and helps in maintaining its biomass against UV-B stress. Antioxidative defense system in the test plant was activated by combined treatment of Psoralens and sUV-B as evidenced by the enhanced activity of enzymatic (ascorbate peroxidase-APX, superoxide dismutase-SOD, POX) and non-enzymatic (ascorbic acid and phenol) antioxidants. Individual treatments of Psoralens and sUV-B showed inhibitory effect on various morphological traits i.e. reduction in plant height, leaf area and ultimately on biomass production. Our results clearly indicated that adverse effect of sUV-B on biomass production was ameliorated by pre- treatment with Psoralens. © 2009 Elsevier Inc. All rights reserved.
Effects of supplemental ultraviolet-b radiation on growth and physiology of acorus calamus L. (sweet flag)
(2009) Rima Kumari; Suruchi Singh; S.B. Agrawal
Increased UV-B radiation due to depletion of stratospheric ozone has potentially harmful effects on plant growth and development. The present study uses a field experiment to examine the effect of long-term supplemental UVB radiation at two intensities ( + 1.8 and +3.6 kJ m-2 d-1 above ambient) on the growth and physiology of the medicinal plant Acorus calamus L. (sweet flag). Plant height and leaf area were inhibited in a dose-dependent manner, with greater inhibition at the higher dose. At the lower dose the net photosynthetic rate increased, with an increase in stomatal conductance and water use efficiency. Stimulation of physiological functions in plants under the lower dose resulted in increased biomass production. At the higher dose, total chlorophyll content showed no marked variation, whereas carotenoids and UV-B-screening pigment flavonoids increased significantly after treatment. Increased flavonoid content under lower exposure correlates well with higher activity of phenylalanine ammonia lyase, a key enzyme of flavonoid biosynthesis. This study clearly showed that the lower dose of supplemental UV-B promoted rhizome growth in A. calamus, perhaps due to improved photosynthesis. Plant defense was stronger under the lower dose. © Polish Academy of Sciences and Jaglellonian University.

2009

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