Climate change affects seed aging? Initiation mechanism and consequences of loss of forest tree seed viability

Abstract

Key message Environmental stress resulting from rapid climate changes leads to the initiation of the seed aging process in mitochondria and peroxisomes. Seed storage methods limiting germinability loss are fundamental for forest future. Abstract Seed aging is a natural process. It decreases the seed germination rate, i.e. the process is essential for the plant’s life cycle. Aging involves a progressive accumulation of oxidative damage over time. One of the main plant responses to stress is an excessive production of reactive oxygen species (ROS), such as O 2 −• , H2O2 and •OH. If the concentration of ROS is too high, it causes damage of the structure of lipid membranes, proteins, carbohydrates, and DNA. Climate changes affect tree reproduction and may have long-term consequences in the form of reduced species dispersal and acquisition of new habitats. High temperatures accelerate the aging of seeds and decrease their viability. There is, therefore, an indisputable need to store forest reproductive material to maintain continuity of regeneration in farm forests. The quality of seeds subjected to long-term storage correlates negatively with ROS concentration, as ROS accumulation typically occurs in tissues experiencing oxidative stress. Therefore, to preserve forest genetic resources, it is particularly important to know the causes and sites of initiation of the aging process in seed cells, as well as to prevent the germination rate decrease by developing appropriate storage methods. The main organelles responsible for intracellular ROS production are mitochondria and peroxisomes. This article aims at verifying the causes of seed aging and determining its consequences for future forest regeneration due to climate changes. We review the literature on oxidative stress, as well as the sites where the tree seed aging process originates, such as mitochondria and peroxisomes.

Dynamic Changes in Membrane Lipid Metabolism and Antioxidant Defense During Soybean (Glycine max L. Merr.) Seed Aging

“…Mitochondria, peroxisomes, endoplasmic reticula, and plasma membrane NADPH oxidases are the primary sources of ROS (Sharma et al, 2012;Kijowska-Oberc et al, 2021). Despite their toxic effects, ROS are well-known second messengers in a variety of biological processes, including the alleviation of dormancy, enhanced rapid seed germination, and environmental stress tolerance (Bailly et al, 2008;You and Chan, 2015).…”

Physiological and biochemical responses of “mofumbo” seeds during storage

“…Germination speed index: evaluated in conjunction with germination, counting the emerged seedlings on a daily basis (Krzyzanowski et al, 2020).…”

“…Seedling dry mass: regular seedlings were placed in paper bags and moved to a forced ventilation oven at 65 °C for 72 h to determine the dry mass weight (Krzyzanowski et al, 2020). The dry material was weighed using a precision analytical balance (0.001 g) and the results expressed in seedlings.mg -¹. Quantification of neutral lipids: performed by the gravimetric method using hexane as solvent (Soxhlet, 1879).…”

“…Furthermore, this process can be verified by decreased germination, increased number of abnormal seedlings and reduced vigor of seeds and seedlings (Bilal and Abidi, 2015). In this regard, deterioration is considered an irreversible process, even under improved storage conditions (Kijowska-Oberc et al, 2021).…”

Can Forest Trees Cope with Climate Change?—Effects of DNA Methylation on Gene Expression and Adaptation to Environmental Change

“…To improve the ex-situ conservation of forest genetic resources using seed storage in gene banks, research on proper seed handling and identification of seed behavior during storage must continue persistently to further develop seed storage techniques (e.g., cryopreservation of seeds of forest tree species). Information regarding seed biology of forest tree species is limited [32,[46][47][48][49] and available resources are scattered, thus making it all the more important to expand knowledge in this area. This is even more important as there are studies also confirming the association of epigenetic processes with seed storage [38,50].…”