Effects of seed moisture content, temperature, and storage period on various physiological and biochemical parameters of Lallemantia iberica Fisch. & C.A.Mey

Abstract

Alterations in physiological and biochemical parameters due to unfavorable storage conditions cause delayed germination, decreased germination rate, and even loss of viability of stored seeds. Therefore, these alterations constitute major problems for seed scientists, farmers, seed bank practitioners, and seed companies involved in seed production and storage. This research aimed to understand the mechanisms of seed ageing by the changing physiological and biochemical properties of Lallemantia iberica seeds. The seeds were stored with different moisture contents (5, 10, and 15%) at different temperatures (15 °C, 25 °C, 35 °C, and 45 °C) for 0, 30, 60, 90, and 120 days. Seed germinability was reduced from 100 to 0% by increasing seed moisture content, temperature, and storage period, while membrane integrity, as assayed by electrical conductivity (EC), K+/Na+ of the seed leachates, and malondialdehyde (MDA), was gradually compromised. Seed deterioration was characterized by exacerbation of membrane impairment, reduction of total soluble sugar, α-amylase and β-amylase activities as well as catalase (CAT) and ascorbate peroxidase (APX) activities. The results indicated a negative correlation of EC, K+/Na+, and MDA with germination indexes, vigor index, α-amylase and β-amylase activities, total soluble sugar, CAT, and APX levels. Generally, seed storage with 5% moisture content at 15 ℃ from 0 to 30 days had relatively high α-amylase and β-amylase activities, total soluble sugar, antioxidant enzyme activities, and low extents of membrane impairment. The results suggest that these storage conditions can be considered favorable for maintaining L. iberica seed quality; however, higher levels of the storage factors facilitate deterioration during storage.