6-Benzylamino purine outperforms Kinetin and Thidiazuron in ameliorating flower longevity in Calendula officinalis L. by orchestrating physiological and biochemical responses

Mohammad Lateef Lone,Sumira Farooq,Shazia Parveen,Aehsan Ul Haq,Inayatullah Tahir

doi:10.1590/2447-536x.v27i2.2260

Abstract

Abstract In view of extending the relatively brief postharvest life of flowers by a range of technologies, the present study elucidates the implication of 6-benzylamino purine (BAP), kinetin (KN) and thidiazuron (TDZ) on postharvest performance and flower longevity of isolated flowers of Calendula officinalis. BAP and KN belong to adenine group cytokinins while as TDZ is a diphenyl urea compound having cytokinin like activity. The harvested flowers were supplemented with BAP, KN and TDZ at various concentrations viz., 25, 50, 75 and 100 µM at one day before anthesis (cup shaped) stage. The control was designated by a distinct set of flowers held in distilled water (DW). Our findings revealed substantial enhancement in flower longevity by application of various growth regulators as compared to the control. Vase solutions containing BAP and KN at 50 µM and TDZ at 75 µM (individually) were most effective in improving the longevity of cut Calendula flowers. Improvement in flower longevity was primarily associated with high membrane stability index (MSI), upregulated activities of various antioxidant enzymes viz., catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX), besides an attenuated lipoxygenase (LOX) activity in the petals. As compared to control, the treated flowers exhibited higher values of soluble proteins, total phenols and total sugars, besides lower α-amino acid content in the petal tissues. However, BAP outplayed TDZ and KN in improving the flower longevity of Calendula officinalis by maintaining higher physiological and biochemical stability in petals.

Highlights

Flowers offer an exclusive window to unveil the physiological, biochemical and molecular changes that occur in cells and tissues while progressing towards senescence
The petal tissue from the samples treated with the concentrations above and below of optimal concentrations (50 μM benzylamino purine (BAP) and KN) and (75μM TDZ) showed a significant decrease in all the parameters investigated except LOX activity and α-amino acids which showed a marked increase
The flower buds held in distilled water lasted for 5 days only, whereas application of growth regulators increased the longevity of cut Calendula flowers markedly

Summary

Introduction

Flowers offer an exclusive window to unveil the physiological, biochemical and molecular changes that occur in cells and tissues while progressing towards senescence. The key to extend the flower longevity is to understand the biological processes governing postharvest physiology, respiration, transpiration, hormonal imbalance and the activation of enzymes associated with petal discoloration (Wojciechowska et al, 2018). Cytokinins act as the front line anti-senescence hormones that improve the longevity in both the ethylene sensitive and insensitive cut flowers (van Doorn and Woltering, 2008; Ahmad and Tahir, 2016; Iqbal et al, 2017). Molecular studies report that cytokinins defer senescence through autoregulation of cytokinin biosynthesis through isopentenyl transferase gene using a promoter senescence-associated gene 12 (SAG12) In this regard, SAG12:IPT gene has been extensively evaluated in different species, and all of them evidenced delayed senescence (Xiao et al, 2017)

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Discussion

Conclusion