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Subject: Botany × Author: Sajid Khan × Start date: 2006 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Response of jasmonic acid for alleviating cadmium (Cd) toxicity in Brassica spp. (Brassica napus, Brassica juncea)
    (CCS HAU, Hisar, 2022-07-22) Sajid Khan; Sridevi Tallapragada
    The present study entitled “Response of jasmonic acid for alleviating cadmium (Cd) toxicity in Brassica spp. (Brassica napus, Brassica juncea)”. was investigated in the screen house during the Rabi season of 2021. Before sowing, the desired levels of cadmium stress (Control, 14 mg/kg, 21 mg/kg) were maintained by saturating each pot. Jasmonic acid (5 μmol L-1, 10 μmol L-1, and 20 μmol L-1) was applied exogenously after 30 days after sowing (DAS) under stressed as well as non-stressed plants in both genotypes (RH 725 and HNS 0901). Sampling was done at 45 DAS. Seeds of Brassica spp. were grown in pots (three plants per pot) under screen house conditions on 15th October 2021. Growth parameters decreased with increasing levels of cadmium stress, whereas foliar application of jasmonic acid enhanced the growth of plants at sampling stages. Similarly, plant water relation, gaseous exchange studies, chlorophyll content (SPAD units) and oil content also showed declining trend from Control to 21 mg/kg of cadmium level in both genotypes. Per cent decrease was observed at 21 mg/kg of cadmium stress like in ψw (68.3%), ψs (52.2%), photosynthetic rate (30%), transpiration rate (25%) and stomatal conductance (29.2%) in RH 725 at 45 DAS, over their respective control. The values ranged from 31.66 to 24.47 and 81.27% to 60.95% of chlorophyll content (SPAD units) and RWC respectively, decreased at 21 mg/kg of cadmium stress in RH 725 at 45 DAS. In anatomical study it is observed that increase in cadmium level is responsible for decrease in stomatal frequency (23.9%, 30%) and stomatal index (25.9 9%, 29.01%) in RH 725 and HNS 0901 respectively at 21 mg/kg of cadmium stress. Foliar application of jasmonic acid is responsible for slightly increase in stomatal frequency and stomatal index at its maximum value (20 μmol L-1) in both genotypes at 45 DAS. Application of JA help in the alleviation of plant water status, exchange of gases and chlorophyll pigment irrespective of cadmium stress in both genotypes at 45 DAS. Reversibly, ash content and ECe show increase along different cadmium level. Seed yield decline significantly by decreasing yield attributing characters i.e., siliqua per plant, seed per siliqua, biological yield under cadmium stress. Reduction in seed yield was ranged from 4.55 to 3.14 in RH 725 and 4.16 to 2.58 in HNS 0901 at 21 mg/kg. Uptake of cadmium from soil increase along with increase in cadmium level 14 mg/kg to 21 mg/kg is 1144.50 μg/pot to 1450 μg/pot in RH 725 and 1025 μg/pot to 1224.8 μg/pot in HNS 0901. JA is showing an alleviating effect against cadmium uptake from soil and decrease cadmium uptake in plant. Conclusively, based on the above studies, it can be concluded that after foliar spray of JA, RH 725 performed better under cadmium stress by maintaining higher plant growth, water status, photosynthetic rate, seed yield, biological yield. JA treatments not only mitigate the negative effect of cadmium stress on plants, but also showed, a stimulating effect and 20 μmol L-1 JA was found more effective than 10 μmol L-1 at 45 DAS.