Physiological Characteristics of Field Bean Seeds (Vicia faba var. minor) Subjected to 30 Years of Storage

Agnieszka I Piotrowicz-Cieślak,Dariusz J Michalczyk,Bogdan Smyk,Wiesław Podyma,Hanna Grajek,Magdalena Krupka,Katarzyna Głowacka

doi:10.3390/agriculture10110545

Abstract

Seed vigour and viability, synchronous fluorescence spectroscopy, and proteomic profiles were analysed in field bean (Vicia faba var. minor) (Vicia faba var. minor) seeds (two cultivars) subjected to dry storage at −14 °C or +20 °C for 30 years. The seeds stored at −14 °C retained very high germinability (91–98%) until the end of the experiments, while seeds from the same lots but stored at room temperature completely lost viability. The deterioration of seeds stored at +20 °C was also manifested by a vast (4- to 6-fold) increase in leachate electroconductivity, and the changes in synchronous spectra and proteomic profiles. To carry out detailed analyses of seed proteins, protein extracts were pre-purified and divided into albumin, vicilin, and legumin. Only one protein, superoxide dismutase, was more abundant in deteriorated seeds (of one cultivar) compared to the high vigour seeds. The results show that seed deterioration strongly and specifically affects the contents of some storage proteins. Moreover, the colour of seed coats changes gradually, and seeds stored at −14 °C were light brown, while those constantly exposed to +20 °C turned black. Synchronous fluorescence spectroscopy showed that this change of colour was caused by formation of oxidized and condensed phenols and that the phenol content in seed coats decreased parallel to seed deterioration.

Highlights

Provision and storage of crops are vital tasks of agriculture
The observation of increased fluorescence in methanol extracts from field bean (Vicia faba var. minor) seeds stored at +20 ◦ C, indicate that oxidized forms of phenols or condensed phenols can be formed in seed coats of such inadequately stored seeds
That the role of storage proteins is not limited to providing nutrients during germination, as they are important for preservation of seed vigour and viability, necessary to even start the germination process

Summary

Introduction

Provision and storage of crops are vital tasks of agriculture. Seed lots with particular economic value are stored in seed banks where they can be preserved for long periods [1]. Minor) seeds are considered valuable crops as they rank the seventh most important protein source among grain legumes, worldwide [2]. They are used as animal feed, rather than food for humans. The rate of seed ageing strongly depends on seed water content, in addition it is determined by the presence of microflora, seeds maturity, the relative humidity of ambient air, oxygen partial pressure, storage temperature, and other factors. Considering seed storability and its physiological/genetic determinants, seeds have been divided into three groups: orthodox, i.e., desiccation-tolerant, recalcitrant (damaged by desiccation and characterised by low storability), and intermediate (partially tolerant to desiccation but sensitive to low temperature) [3]. The orthodox seeds survive dehydration to a very low water content (5–10% dry mass) and their storability increases parallel to the decrease in Agriculture 2020, 10, 545; doi:10.3390/agriculture10110545 www.mdpi.com/journal/agriculture

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