MADRAS AGRICULTURAL JOURNAL

Morpho-Physiological Characters Influencing Groundnut (Arachis Hypogaea L.) Yield during Drought at Different Flowering Phases

Abstract

                                ABSTRACT A pot culture study was conducted in Tamil Nadu Agricultural University, Coimbatore, to assess the morpho-physiological characters of different groundnut genotypes viz., CO 7, Cogn 4, TMV 7 and TMVGn 13 to water stress at different flowering hases viz., Pre Flowering Drought (PFD) between 15- 30 DAS, Flowering Drought (FD) between 35-50 DAS and Post Flowering Drought (PFD) between 75-90 DAS by withholding irrigation and a control was also maintained with irrigation to field capacity for comparison. Observations on various morphological (Plant height and leaf area) and physiological aspects (Relative water content, SPAD chlorophyll Index and Photosynthetic rate) were studied during stress period and after stress recovery. Among the treatments, higher value of morphological and physiological parameters were observed under PFD after recovery and CO7 performed better followed by TMV 7, TMVGn 13, Cogn 4.

Key words : Groundnut, Morphological parameter, Physiological parameter, Pre-flowering drought, Yield.

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                               Investigations were made to identify, screen and characterize rice apoplastic fluid endophytic bacterial strains for osmotic stress tolerance and plant growth promoting activity. These bacterial strains were identified phylogentically as Bacillus subtilis TSAC5, Bacillus subtilis TSAA2, Bacillus sp. R2AA10, Bacillus cereus R2AA7, Bacillus marisflavi TSAC7, Cupriavidus alkaliphilus TSAC1, Delftia sp. TSAC2, Janibacter melonis R2AA1, Microbacterium oleivorans R2AA6, Kocuria rosea R2AA5, Pseudomonas aeruginosa NAAI3 and Sphingobium yanoikuyae R2AI1. Of these 12 strains, eight were obtained from drought tolerant rice varieties such as Anna R4 and IR DRT 64 and four from normal rice variety CO51. These endophytes exhibited varied level of osmotic stress tolerance created using different concentrations of PEG 6000 (-1.5, -3.0, -4.0, -4.5, -5.0 and -5.5 MPa) under in vitro conditions in liquid and solid medium. Among the 12 strains, Cupriavidus alkaliphilus TSAC1, Delftia sp. TSAC2, Bacillus marisflavi TSAC7, Janibacter melonis R2AA1, Kocuria rosea R2AA5, Pseudomonas aeruginosa NAAI3 and Sphingobium yanoikuyae R2AI1 showed moisture stress tolerance up to -5.5 MPa. Further increase in moisture stress of -6.0 MPa inhibited growth of 12 tested strains. These strains also exhibited Indole acetic acid (IAA), gibberellic acid (GA3) and extracellular polysaccharide (EPS) production and also showed ACC deaminase (ACCD) activity. Maximum extracellular proline production was found in Bacillus marisflavi TSAC7 under both normal and water stressed conditions. Higher IAA productivity was registered in Janibacter melonis R2AA1 followed by Cupriavidus alkaliphilus TSAC1 and Sphingobium yanoikuyae R2AI1 in the absence of PEG 6000. In the presence of PEG 6000 Delftia sp. TSAC2 recorded maximum IAA productivity. Bacillus subtilis TSAA2 showed greater ACC deaminase activity. EPS production was in the order of Pseudomonas aeruginosa NAAI3 followed by Sphingobium yanoikuyae R2AI1. Sphingobium yanoikuyae R2AI1 produced maximum quantity of GA3 both under normal and water stressed condition. None of the tested strains indicated insoluble phosphate, silicate and zinc solubilisation.


 

Key words : Rice apoplast, Moisture stress, PEG 6000, GA3, IAA, ACCD

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MADRAS AGRICULTURAL JOURNAL

Biosorption of Chromium (III) from Aqueous Solution by Water Hyacinth Biomass

Abstract

                                Release of heavy metals into the environment is a matter of global concern for the past few years and it should be removed from industrial waste waters before discharge for maintaining water quality standards. This study involved the use of water hyacinth biomass as biosorbent for removal of Cr(III) from aqueous solution. The biosorbent was characterized by FTIR, SEM with EDAX. Batch experiments were conducted to determine the sorption isotherms, effect of solution pH, adsorbate concentration, contact time, biosorbent dosage and size. The results confirmed that water hyacinth biomass can remove Cr(III) from aqueous solution. The maximum sorption occurs at pH =5.0, biosorbent size= 0.2mm, biosorbent dosage=2.0g 100ml-1 of adsorbate, adsorbate / solute concentration= 100 mg L-1 Cr(III) at 25ºC at 250 rpm after 24 hrs. The rate of adsorption was rapid and equilibrium attained at 24hrs. Langmuir, Freundlich and Temkin isotherm models were used to analyze the equilibrium adsorption data. Langmuir isotherm fitted the data well with R2 value of 0.999. Overall, the powdered water hyacinth biomass could be utilized as effective low cost adsorbent for the removal of Cr(III) from waste water.

Key words : Adsorption, Cr Removal, Release kinetics, Water hyacinth

Copyright @ 2019 Madras Agricultural Journal | Developed by Crystalpro All right reserved.

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