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Subject: Crop Physiology × Author: Faqiha, Ph. × End date: 2019 × Start date: 2018 × Type: Thesis ×
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    ThesisItemOpen Access
    PHYSIOLOGICAL BASIS OF ALUMINIUM TOLERANCE IN RICE (ORYZA SATIVA L.)
    (AAU, Jorhat, 2019-07) Faqiha, Ph.; Das, Ranjan
    The investigation was carried out to evaluate the performance of some rice (Oryza sativa L.) genotypes under different levels ofaluminium during November 2017 to December 2018 in the Stress Physiology Laboratory, Department of Crop Physiology, Assam Agricultural University, Jorhat-13. In first experiment, 149 rice genotypes collected from different North-Eastern States were screened for aluminium tolerancewith two different aluminium levels of 60 μM Al and 100 μM Al using Yoshida solution along with a control. Out of 149 genotypes, seven genotypes viz., Alubari Dhan, Dewri, Ayangleima, Marin Chatpi, Rene Nepung Aam, Rongabetguti and Rajamani were found to be promising in terms of Al tolerance and these were further evaluated in second experiment for mechanism of responses of Al. In the second experiment the screened rice genotypes were grown in potsin three different levels of Alviz.,100 μM Al (T1), 200 μM Al (T2), and 300 μM Al (T3) along with a control (T0) to study the mechanism of the morpho-physiological and biochemical traits contributing to rice growth and development under higher levels of aluminium. Results obtained during the investigation revealed that higher levels of Al significantly influenced on number of leaves, specific leaf weight, leaf area index, membrane stability index, total leaf chlorophyll content, in-vivo leaf nitrate reductase activity, SOD, root volume, root length, root dry weight, plant height and yield attributes in all the genotypes. However, among the seven genotypes Rajamani and Rene Nepung Aam showed less reduction in root length, photosynthetis rate and total chlorophyll. These two genotypes also showed the lowest per cent reduction in grain yield and yield attributesover control. This could be correlated with the increase in superoxide dismutase and proline content in the leaf with proportional decrement of MDA. The genotype Rajamani and Rene Nepung Aam accumulated less amount of aluminium in its root biomass as compared to other genotypes which indicates that this genotype has a better tolerance mechanism by excluding aluminium from the root system thereby contributing better growth and development. Considering the studied morpho-physiological, biochemical and yield related attributes, Rajamani and Rene Nepung Aam genotypes may be considered as the most promising genotypes among all seven genotypes under higher levels of Al in the present investigation.