Short-Term Liquid Nitrogen Storage of Maize, Common Bean and Soybean Seeds Modifies Their Biochemical Composition

Abstract

We studied the effects of liquid nitrogen storage of maize, common bean and soybean seeds on their germination, electrolyte leakage, levels of chlorophylls, phenolics, aldehydes, proteins and peroxidase activity. After storage for 28 days, seeds were retrieved from liquid nitrogen, some were set to germinate and others were analyzed biochemically. No phenotypic modifications were observed visually 5 days after beginning of germination, although percentage of seed germination was reduced by LN in maize and soybean. Moreover, numerous significant effects of seed cryopreservation were recorded at the biochemical status. In maize seeds, the most important and statistically significant modifications were observed in the increased levels of chlorophyll b and total chlorophyll pigments and in the decreased contents of free phenolics after 28 days of exposure to LN, compared to the control treatment. In common bean, relevant changes were observed in the increased electrolyte leakage and in the reduced levels of chlorophyll pigments (b, total) and free phenolics. In soybean, modifications were observed in the increased levels of chlorophyll pigments (a, b, total), malondialdehyde and electrolyte leakage, and in the decreased peroxidase activity. We have shown for the first time that immersion of maize, common bean and soybean seeds in liquid nitrogen modified the levels of different biochemicals.

Epigenetic and Genetic Integrity, Metabolic Stability, and Field Performance of Cryopreserved Plants

“…No significant differences in seed germinations were obtained between cryopreserved and non-cryopreserved (control) seeds in Phaseolus vulgaris [ 97 , 131 ], Solanum lycopersicum [ 132 ], and Zea mays [ 133 ]. However, reduced seed germinations were reported in the cryopreserved seeds of Zea mays and Glycine max [ 133 , 134 ]. In the study of cryopreservation of Solanum lycopersicum seeds, Zevallos et al [ 135 ] reported that cryopreservation increased the germination percentage of cryopreserved seeds at day 5 of germination, albeit with no significant differences at day 7.…”

“…More than 90% and 94% seedlings from the cryopreserved seeds of Oncidium flexuosum [ 92 ] and Hibiscus sabdariffa [ 137 ], respectively, survived after transfer to greenhouse conditions. The morphology of the seedlings developed from cryopreserved seeds were similar to those from the control in Phaseolus vulgaris [ 97 , 131 ], Solanum lycopersicum [ 135 ], Zea mays [ 134 ], Glycine max [ 134 ], and Hibiscus sabdariffa [ 137 ]. Seedling growth, measured by the fresh weight of roots, stem, and leaves, was markedly delayed in cryopreserved seeds of Zea mays [ 133 ].…”