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20171
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Subject: Biochemistry × Author: Narender Mohan × End date: 2019 × Start date: 2017 × Type: Thesis ×
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    ThesisItemOpen Access
    Biochemical and morpho-physiological changes in Indian mustard [Brassica juncea (L.) Czern & Coss.] under terminal heat stress
    (CCSHAU, 2017) Narender Mohan; Nisha Kumari
    The present investigations were undertaken to study the changes in oxidative stress, antioxidative enzymes, metabolites and yield & yield attributes in Brassica juncea after subjecting to terminal heat stress at prematurity stage. Two thermo-tolerant genotypes viz. RGN-368 and RH-1566 and two thermo-sensitive genotypes viz. RH-1134 and RH-0749 were sown on two different dates (13th October and 15th November). Hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage which are indicators of cell membrane damage increased under terminal heat stress in all the genotypes but increase was higher in sensitive genotypes. The activities of antioxidative enzymes viz. superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) increased under terminal heat stress showing that the antioxidant defence mechanism play major role in heat stress tolerance in Brassica juncea. Ascorbic acid, proline and carotenoids increased under heat stress depicting their role as osmoprotectants and free radical scavangers, respectively. Relative water content (RWC), osmotic potential (OP), chlorophyll content and crude oil content was observed and a remarkable decline was reported in these attributes under late sown condition. Yield attributes, such as main shoot length, number of primary and secondary branches, numberof siliqua on main shoot, seeds per siliqua, siliqua length, 1000 seed weight and seed yield per plant also showed a significant reduction under terminal heat stress.