Effects Of Accelerated Aging And Simulated Drought And Salt Stress On The Viability Of Metasequoia Glyptostroboides Seeds

The propagation and population expansion of seed plants are mostly dependent on seeds.Seed vigor and germination characteristics not only determine the survival and reproduction of plants under natural conditions,but also play an important role in human biological protection,ecosystem management and farming,forestry and horticultural production.In this study,the seed of endangered plant,Metasequoia glyptostroboides Hu et Cheng,was studied by means of artificial accelerated aging treatment,determination of antioxidant enzyme activity and cell microscopic observation,and the mechanism of viability maintenance and loss was analyzed.The ability of germination and seedling formation under drought and salt stress was studied by simulating drought and salt stress.The main conclusions are as follows:1.Fresh mature M.glyptostroboides Hu et Cheng seeds have no dormancy,the average viability level is not high,and the final average germination rate is less than60% under each culture temperature.However,their germination adaptability to temperature is strong,and their germination temperature range(5 ~ 40°C)and the optimum germination temperature range(15 ~ 30°C)are wide,and germination is fast.Its germination characteristics are closely related to its distribution history and phylogenetic characteristics.2.The seed vigor maintenance ability of M.glyptostroboides Hu et Cheng is low.This is probably because the antioxidant enzyme system in Metasequoia seeds has low resistance to oxidative stress.Under accelerated aging conditions,lipid peroxidation occurs in cell membranes,which leads to electrolyte leakage,resulting in disorder of cell metabolism.In serious cases,the internal structure of cells gradually disintegrates and eventually the seed vitality is lost.3.Resistance of M.glyptostroboides Hu et Cheng seeds to drought and salt stress during germination is strong.As a fast-growing tree species with strong adaptability to temperature,the breeding of drought-resistant and salt-tolerant varieties is of great significance.