| Polysaccharides have a variety of physiological activity such as immune regulation,antioxidation,reducing blood fat blood glucose and inhibiting tumor,which has been widely used in functional food and medical care and other fields.Recently,polysaccharides as a kind of environmentally friendly creatures,have been widely used in agricultural production,regulation of plant growth and improving the quality of agricultural products.Fucoidan-containing sulfated polysaccharide(FSP)from seaweed can be developed as an efficient natural biological stimulant for green production of crops,fruits and vegetables because of its high yield,safety,non-toxicity and strong antioxidant activity.This paper systematically studied the antioxidant properties of FSP and their effects on Caenorhabditis elegans life activities and millet seed germination.The main research contents included: 1)the antioxidant properties in vitro were identified;2)the effects and molecular mechanism of FSP on resisting oxidative stress and prolonging lifespan in Caenorhabditis elegans were analyzed;3)the effect of FSP on improving salt stress resistance of millet(Setaria italica)was studied.The research will provide theoretical and technical support for the research and development of functional products and environment-friendly biological stimulants based on FSP.The main findings are as follows:1)Identification of antioxidant properties of FSP in vitro.The results showed that 0.1-0.5 mg·m L-1 FSP had certain scavenging ability on DPPH free radical and hydroxyl free radical,and the scavenging effect increased with the increase of concentration.The scavenging rates of DPPH free radical and hydroxyl free radical of 0.5 mg·m L-1 FSP were 41.81% and 30.13%,respectively,but lower than the control ascorbic acid at the same concentration.2)Effect of FSP on resisting oxidative stress and prolonging life in C.elegans was tested.The results showed that different doses of FSP(50,100,200 μg·m L-1)could improve the lifespan of C.elegans,enhance the antioxidant capacity in vivo and relieve the accumulation of age pigment.The effect of high dose FSP treatment group was particularly significant,which increased the lifespan by 48.42%;The activities of superoxide dismutase(SOD)and catalase(CAT)were increased by 82.75% and 74.95%,respectively;FSP regulated the aging of C.elegans by up-regulating the expression of daf-16,skn-1 and hsf-1 and down-regulating the expression of daf-2 in the insulin/IGF-1 signaling pathway.High dose of FSP significantly increased the average lifespan of C.elegans under oxidative stress(62.04%).Low dose FSP had the best alleviating effect on heat stress,and the average life span increased by 28.60% compared with the control group.3)To explore whether FSP can be used as an effective biological stimulant in crop production,the seeds of millet were treated with FSP and the germination of seeds under salt stress was determined.The results showed that 0-250 mmol·L-1 salt stress inhibited millet seed germination rate,germination potential,root length and shoot length.When salt concentration reached 150 mmol·L-1,germination rate and germination potential were significantly suppressed and reached only 23.33% and 36.67%.Soak seeds with 50,100 and200 mg·L-1 FSP could alleviate the inhibition effect of salt stress on seed germination,high dose FSP treatment is more effective.Compared with stress group,seed germination rate and germination potential in FSP treatment were increased by 15.00%,260.14%,root length and bud length were increased by 8.16%and 86.69%,respectively.In conclusion,FSP has physiological activities such as antioxidant,anti-aging and regulating body tolerance.FSP can be used as an anti-aging cofactor in the field of food and health care products,and can also be used as an environmentally friendly biological stimulant to promote crop seed germination and resist the ability of adverse stress. |
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