Browsing by Author "O.K. Garg"

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Effect of boron on the pollen vitality and yield of rice plants (Oryza sativa L. var. Jaya)
(Martinus Nijhoff, The Hague/Kluwer Academic Publishers, 1979) O.K. Garg; A.N. Sharma; G.R.S.S. Kona
Rice plants were grown in sand cultures with nutrient solution including boron at 0, 1, 2.5 and 5 ppm concentrations. In general, supply of boron improved the pollen vitality of rice flowers. It was stimulating up to 2.5 ppm concentration in the nutrient solution, beyond which (i.e., at 5 ppm) inhibitory effects appeared. The availability of boron also increased the yield of rice grains in the same order. Stimulating effects of boron may be linked with greater availability of sugars, increased enzymatic activity and respiration which favoured better growth of pollen. Inhibitory effects of stronger concentration of boron (5 ppm) may be related with physiological depression and injury to protoplasm itself. © 1979 Martinus Nijhoff.
Effect of iron and zinc fertilization on senescence in french bean (phaseolus vulgaris L.)
(1986) O.K. Garg; A. Hemantaranjan; C. Ramesh
In greenhouse experiments, applications of Fe and/or Zn in the form of ferrous sulphate and zinc sulphate induced increased chlorophyll ‘a’ and ‘b’ concentrations, indole-3-acetic acid, nitrate reductase activity, and dry matter yield of french bean (Phaseolus vulgaris L.) plants. Iron and Zn in combination were more effective in delaying the leaf senescence compared to controls. Chlorophyll destruction was more rapid at the post-flowering stage in control plants which led to early senescence and reduced photosynthetic duration. A rapid decline in nitrate reductase activity and indole-3-acetic acid concentration in control plants after the 50-day growth stage further induced senescence. Iron alone and in combination of Zn appeared to contribute to the inhibition of senescence in french bean plants. © 1986, Taylor & Francis Group, LLC. All rights reserved.
Effect of pre-sowing exposure of seeds to gamma-radiation on the drought resistance behaviour of barley plants (Hordeum vulgare L.)
(Martinus Nijhoff, The Hague/Kluwer Academic Publishers, 1972) O.K. Garg; B.C. Misra; B.P. Singh
With a view to examine the effect of pre-sowing exposure of seeds to gamma radiation (3000 r) on the drought resistance behaviour of barley plants (Hordeum vulgare L., Var. K12), a pot-culture experiment was conducted at a glasshouse attached to the Department of Plant Physiology. The plants were subjected to wilting treatments at tillering stage and were maintained so for ten days. Subsequently, observations on survival capacity, growth behaviour and physiological changes were made during the wilting period. The data obtained were subjected to statistical analysis. Reduction in soil moisture causes a set-back in the physiological status of barley plants and thereby inhibits the crop growth. Presowing exposure of seeds to gamma-radiation induced drought tolerance in barley plants. It not only improved the growth behaviour but also maintained an active metabolism in plants even under wilting condition. Although the investigation is of preliminary nature, but it certainly offers newer scope of research towards useful utilization of gamma radiation in relation to drought tolerance in crops. © 1972 Martinus Nijhoff.
Introduction of nitrogen-fixing nodules through iron and zinc fertilization in the nonnodule-forming french bean (phaseolus vulgaris l.)
(1986) A. Hemantaranjan; O.K. Garg
Nitrogen-fixing symbionts associated with the french bean (Phaseolus vulgaris L.) are absent in soils in the Varanasi, India area. Greenhouse experiments were conducted to study the effects of Fe (ferrous sulfate) and Zn (zinc sulfate) on nodulation and N2fixation in french beans. Inorganic treatments were added to the soil. No exogenous supplement of Rhizobium was added to the soil. Iron alone at a concentration of 5 or 10 mg kg-1soil or in combination with the same concentrations of Zn enhanced nodulation. At 5 mg Fe and Zn kg-1soil, maximum nodulation and leghaemoglobin were noted. Enhanced in vivo N2fixation was also noted when either Fe or Zn (alone or in combination) were added at concentrations of 5 or 10 mg kg-1soil. These experimentsshowed that Fe could create a condition conducive to the formation of N2fixing nodules in french bean. Synergistic effects of Zn in these processes could not be ruled out. © 1986, Taylor & Francis Group, LLC. All rights reserved.
Iron and zinc fertilization with reference to the grain quality of triticum aestivum l
(1988) A. Hemantaranjan; O.K. Garg
Iron + Zinc (applied to the soil as ferrous sulphate and zinc sulphate) were found to significantly increase the number ear heeds per tiller, length of ear heads, number of grains per ear, grain yield per plant and the weight 1000 grains in proportion to its concentration used both in pot and field experiments. ‘This was coupled with the increase in total carbohydrate, starch and crude protein contents of wheat grains. All these activities were found optimum at the identical concentration of Fe + Zn (@ 7.5 mg kg−1 soil). A further increase in the exogenous iron and zinc concentrations (up to 12.5 mg kg−1 soil) led to the sharp decline of all these activities near the control level. Yield characters were observed to be better supported in the field condition than in pot cultures. Since natural availability of iron and zinc in the soil are only 2–4 mg kg−1 soil and 0.60 mg kg−1 soil, respectively, it is apparently suggested that the threshold level of iron and zinc (@ 7.5 mg kg−1 soil) has a definite role in the synthesis of carbohydrates, starch and protein contents in the wheat grains. It is further suggested that normal metabolism might be reasonably hindered due to an increased uptakability of Fe and Zn at their higher concentrations (@ 10 mg kg−1 soil and 12.5 mg kg−1 soil, respectively). This causes a reduction in the synthesis of chlorophyll and indole-3-acetic acid, leading to an inhibition of photosynthesis at grain filling stage and ultimately reduced total carbohydrate, starch and protein contents of grains, which might be a good reason for the production of inferior quality of wheat grains. The positive role of the threshold concentration (@ 7.5 mg kg−1 soil) of exogenous iron and zinc in the growth and yield potentiality of wheat crop is, therefore, emphasized. © 1988, Taylor & Francis Group, LLC. All rights reserved.
Iron sources in relation to leaf senescence in french bean (phaseolus vUlgarisl.)
(1988) O.K. Garg; A. Hemantaranjan
Pot and field experiment were conducted to study the effects of three iron sources, viz., Fe-EDTA, Fe-EDDHA and FeSO4 on the yield of french bean (Phaseolus vulgaris L.). The natural available iron in the soil was 2–4 ppm. All the iron sources in general, induced a significant increase in chlorophyll ‘a and b’, and indole-3-acetic acid components of french bean when used at a concentration of 5 to 10 mg kg−1 soil. Remarkably, these favourable acquisitions were more prominent in the cases of Fe-EDDHA (@ 5 mg kg−1 soil) and Fe-EDTA (@ 5 mg kg−1 soil) treatments, while a double dose of FeSO4 (@ 10 mg kg−1 soil) was required to induce a parallel change in the characteristics noted above. A critical individual assessment of the effects of the first two iron sources obviate the fact that Fe-EDDHA is superior most in inducing a delayed senescence and the related characteristics of applied importance. These effects were significantly better over those induced by the corresponding concentrations of Fe-EDTA, possibly due to known higher stability constant of Fe-EDDHA as well as its better mobility in plants. While in the control (iron-untreated) plants chlorophyll destruction (quite simultaneously a decline in the IAA content) is more rapid at the post-flowering stage, leading to an early senescence, reduced photosynthetic duration and low yield, the iron-treated plants exhibited a delayed senescence exhibited a delayed senescence of leaves coupled with a significantly enhanced photosynthetic duration and yield. Apparently, therefore, soil iron enrichment is of considerable importance in the regulation of physiological factors leading to an increase in the yield of french bean plants. © 1988, Taylor & Francis Group, LLC. All rights reserved.
Physiological significance of ascorbic acid in relation to drought resistance in rice (Oryza sativa L.)
(Martinus Nijhoff, The Hague/Kluwer Academic Publishers, 1971) O.K. Garg; B.P. Singh
A pot-culture experiment was undertaken to assess the physiological significance of ascorbic acid in relation to drought resistance in two high-yielding varieties of rice - Taichung Native - 1 and I.R. 8. The soil-moisture stresses were maintained at 7-10 and 15-20 per cent moisture at field capacity. The wilting treatments were given only at tillering and shooting stages. Observations pertaining to survivality of rice plants and determinations of ascorbic acid, acorbigen and ascorbic acid utilization in fresh leaves were made. The two varieties of rice, i.e. Taichung Native-1 and I.R. 8 were not identical in their drought tolerance. Taichung Native-1 was more drought resistant which may be presumed in view of their differences in morphological make-up and demand for water at different stages of growth. The leaves of Taichung Native-1 showed greater contents of ascorbic acid and ascorbigen following increased rate of ascorbic acid utilization as compared to I.R. 8. These values were significantly reduced during shooting stage, a critical period to drought. This confirms the significance of ascorbic acid towards drought resistance in plants with special reference to rice. © 1971 Martinus Nijhoff.