Physiological and biochemical basis of high temperature stress tolerance and its amelioration in bell pepper (Capsicum annuum L. var. grossum)
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Date
2020
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Punjab Agricultural University, Ludhiana
Abstract
The present investigation was carried out to evaluate the role of plant growth regulators viz.
Salicylic acid (SA) and 24-epibrassinolide (EBR) on the physiological and biochemical
parameters of bell pepper (Capsicum annuum L.). Two cultivars of bell pepper viz. hybrid
Indra and variety Royal Wonder were selected for the study along with Punjab Sindhuri (hot
pepper) used as a tolerant check for heat tolerance. Three concentration of each growth
regulator, SA (0.10 mM, 0.20 mM and 0.50 mM) and EBR (0.05 µM, 0.10 µM and 0.20 µM)
were applied in the form of foliar spray to both the cultivars at three growth stages, vegetative
bud stage (30 DAT), reproductive stage (60 DAT) and post-reproductive stage (90 DAT). All
the concentrations of PGRs were effective in imparting thermotolerance in terms of improved
growth parameters (plant height, plant spread and leaf area), membrane thermostability,
photosynthetic parameters (total chlorophyll content, carotenoid content and hill reaction
activity), levels of total soluble sugars, starch, proteins, proline, enhanced antioxidant system
(CAT, APX, POX, SOD and GR), fruit parameters (fruit length, fruit width, pericarp
thickness and fruit chlorophyll). Application of SA and EBR resulted in reduced lipid
peroxidation in leaf tissue and cellulase activity in pedicel of flowers, causing more retention
of flowers, increased pollen viability and fruit set percent even at high temperature ultimately
resulting in improved yield. Appearance of some new bands during SDS-PAGE of proteins in
treated plants pointed towards the foundation of HSPs which helped the plants to survive
under stressful conditions. Foliar spray of 0.10 µM EBR in hybrid Indra and 0.20 mM in
variety Royal Wonder done at reproductive stage (60 DAT) and vegetative bud stage (30
DAT), respectively, were most effective in ameliorating the effects of high temperature stress.
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Citation
Tejinder Preet (2020). Physiological and biochemical basis of high temperature stress tolerance and its amelioration in bell pepper (Capsicum annuum L. var. grossum) (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.