Physiological and biochemical changes in ‘Fuyu’ persimmon buds during dormancy

Gabriely Pinto Pereira,Aline José Maia,Flávio Zanette,Renato Vasconcelos Botelho,Felipe Francisco,Ruy Inacio Neiva De Carvalho,Luiz Antonio Biasi

doi:10.1590/0103-8478cr20200955

Abstract

ABSTRACT: This study identified physiological and biochemical changes in ‘Fuyu’ persimmon buds during dormancy. Branches were collected between March and August 2015. Dormancy was evaluated by biological testing of isolated node cuttings at 25 °C and a photoperiod of 16 h. The variables analyzed were water content; reducing sugar content; respiratory activity; activity of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POD) and polyphenol oxidase (PPO) enzymes; hydrogen peroxide content (H2O2) and lipid peroxidation. At the end of March 2015, the plants were already dormant, and the leaves and fruits present indicated a paradormancy effect. Induction of endodormancy may have occurred in June 2015, when chilling hours (CH) below 7.2 °C and higher CH below 12 °C began to accumulate, which coincided with the period in which there was a decrease in water content and respiratory activity, an increase in reducing sugars, a decrease in SOD, CAT, APX and PPO and an increase in H2O2. After an accumulation of 553 CH below 12 °C, the budburst capacity increased, and the buds presented increased water content, decreased reducing sugars content, increased respiratory activity, low activity in SOD, CAT, APX and POD and high levels of H2O2.

Highlights

Persimmon (Diospyros kaki L.) is a fruit tree of subtropical climates originating in China that presents bud dormancy in autumn and winter (GUAN et al, 2019)
Bud dormancy comprises the stages of paradormancy, in which budburst is inhibited by the influence of other plant structures on the bud; endodormancy, when endogenous bud factors inhibit budburst; and ecodormancy, in which unfavorable environmental factors limit budburst
The number of chilling hours below 7.2 °C that occurred until the last collection of branches, on August 04, was only 27 CH (Table 1); it was below the cold requirement for releasing dormancy of ‘Fuyu’ persimmon, which is 504 CH below 7.2 °C (FAQUIM et al, 2007)

Summary

Introduction

Persimmon (Diospyros kaki L.) is a fruit tree of subtropical climates originating in China that presents bud dormancy in autumn and winter (GUAN et al, 2019). Bud dormancy is an adaptive mechanism of plants that makes it possible to survive in adverse climatic conditions and it is based on the temporary suspension of visible growth; essential metabolic activities continue to occur (FALAVIGNA et al, 2019). Bud dormancy comprises the stages of paradormancy, in which budburst is inhibited by the influence of other plant structures on the bud; endodormancy, when endogenous bud factors inhibit budburst; and ecodormancy, in which unfavorable environmental factors limit budburst. The dynamics of dormancy involve external factors, such as temperature and photoperiod (FALAVIGNA et al, 2019), and internal factors, such as the balance of promoters and growth inhibitors (ZHENG et al, 2015), protein and carbohydrate metabolism (RADY & EL-YAZAL, 2013), water content (MARAFON et al, 2011; SCHMITZ et al, 2015), mitochondrial respiration and antioxidative metabolism (BEAUVIEUX et al, 2018)

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