Enzyme activity in the micropylar region of Melanoxylon brauna Schott seeds during germination under heat stress conditions

Marcone Moreira Santos,Eduardo Euclydes De Lima E Borges,Debora Kelli Rocha,Raquel Maria De Oliveira Pires,Glauciana Da Mata Ataíde

doi:10.1590/2317-1545v42229988

Abstract

Abstract: Recent studies indicate that global temperatures will rise substantially in the 21st century, leading to the extinction of several plant species, as plant metabolism and germination are greatly affected by temperature. Melanoxylon brauna, a tree species native to the Atlantic Forest that occurs from northeastern to southeastern Brazil, is one of the many species threatened by global warming. Despite the economic and ecological importance of M. brauna, studies investigating the influence of heat stress on seed germination and biochemical responses are still incipient. This study aimed to evaluate enzyme activity in the micropylar region of M. brauna seeds during germination under heat stress conditions. Endo-β-mannanase, α-galactosidase, polygalacturonase, pectin methylesterase, pectin lyase, total cellulase, 1,3-β-glucosidase, and 1,4-β-glucosidase activities were determined in micropyles of seeds imbibed for 24, 48 and 72 h at 25, 35 and 45 °C. Seed germination was highest at 25 °C. Endo-β-mannanase activity was not detected under any of the experimental conditions, but imbibition temperature had a significant effect on the activity of all other enzymes.

Highlights

Melanoxylon brauna Schott is a tree native to the Brazilian Atlantic Forest
Will the species be able to adapt to the effects of global warming? What can be done to prevent M. brauna and other vulnerable tree species from becoming extinct? To answer these questions, it is fundamental to increase the knowledge about the influence of temperature on the different physiological processes involved in seed germination
Considering the importance of M. brauna, the predictions of climate change, the influence of temperature on germination, and the lack of information about biochemical processes occurring in the micropylar region, this study aimed to assess the activity of endo-β-mannanase, α-Gal, PG, pectin methylesterase (PME), pectin lyase (PL), total cellulase, 1,3-β-glucosidase and 1,4-β-glucosidase in the micropylar endosperm of M. brauna seeds during germination under heat stress conditions

Summary

Introduction

Melanoxylon brauna Schott is a tree native to the Brazilian Atlantic Forest. It occurs mainly in the southeast and northeast regions of the country. Information on seed germination may contribute to the development of conservation strategies for M. brauna. Studies showed that global temperatures will rise by 1 to 5 °C over this century (PBMC, 2013). Will the species be able to adapt to the effects of global warming? What can be done to prevent M. brauna and other vulnerable tree species from becoming extinct? It is fundamental to increase the knowledge about the influence of temperature on the different physiological processes involved in seed germination Will the species be able to adapt to the effects of global warming? What can be done to prevent M. brauna and other vulnerable tree species from becoming extinct? To answer these questions, it is fundamental to increase the knowledge about the influence of temperature on the different physiological processes involved in seed germination

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Conclusion