Research On Mechanism Of Vitamin E And Vitamin C Alleviating The Deficiency Of Macro-element In Plants

Nitrogen,phosphorus,and potassium are essential macro-element in plant growth and development.Although the total content of nitrogen,phosphorus and potassium in soil is high in China,its distribution is uneven and the utilization rate is low.The deficiency of macro-element has become one of the limiting factors for crop production in China.At present,fertilizer is mainly used to solve this problem,but the application of fertilizer may bring a series of problems,such as environmental pollution and increasing production costs.Plants produce reactive oxygen species under the deficiency of macro-element,Vitamin E and Vitamin C are lipid-soluble antioxidants and water-soluble antioxidants,respectively.However,the specific physiological mechanisms of Vitamin E and Vitamin C in alleviating the deficiency of macro-element are still rarely studied.Arabidopsis thaliana L.is a cruciferous plant with the characteristics of simple genome,short growth cycle and small volume.It is widely used in plant genetics and development research.In this study,wild-type(Col),Vitamin E-deficient mutants(ggr),and Vitamin C-deficient mutants(vtc1)were used as experimental materials.The mechanism of Vitamin E and Vitamin C alleviating the deficiency of macro-element in plant was studied by exogenous Vitamin E treatment and Vitamin C treatment.The main results were as follows:(1)The seedlings of Arabidopsis respond to the deficiency of macro-element by increasing Vitamin E and Vitamin C levels in the body.The deficiency of nitrogen,phosphorus and potassium could induce the increase of Vitamin E and Vitamin C content and the up-regulation of key enzyme genes(such as Geranylgeranyl reductase,GGR;Homogentisate phytyltransferases,HPT;GDP-D-mannose pyrophosphorylase,VTC1)in their synthesis pathways in the seedlings of Arabidopsis,among which the low phosphorus condition induced most significant.Exogenous application of 0.1 mmol/L Vitamin E and Vitamin C treatment both attenuated the up-regulation of gene expression induced by macro-element deficiency,that is,exogenous application of Vitamin E and Vitamin C can help plants adapt to the deficiency of macro-element.(2)Vitamin E enhanced the tolerance of Arabidopsis seedlings to the deficiency of macro-element.Under the deficiency of nitrogen,phosphorus and potassium,the growth of Arabidopsis seedlings was inhibited.The main symptoms were: the inhibition of root growth,the decrease of biomass,the decrease of chlorophyll content,and the increase of malondialdehyde content,among which the inhibition were most severely under low phosphorus conditions.Under the condition of nitrogen,phosphorus and potassium deficiency,compared with the wild type,the root length of the ggr mutant was shortened,and the content of malondialdehyde increased significantly under low phosphorus and potassium conditions,which were increased by 17.13 % and 29.85 %,respectively.The length of roots of vtc1 mutants were all shortened,and the content of malondialdehyde increased significantly,which were increased by 56.25 %,27.89 % and 1.49 times,respectively.The variation of root length in Arabidopsis treated with 0.1 mmol/L Vitamin E was significantly decreased,and the content of malondialde hyde was decreased by 19.12 % and 14.93 % under low phosphorus and low potassium conditions,respectively.Exogenous 0.1 mmol/L Vitamin C had no significant effect on alleviating the growth inhibition of Arabidopsis induced by lack of macro-element.(3)Vitamin E could delay the senescence of Arabidopsis under the deficiency of macro-element.The deficiency of nitrogen,phosphorus and potassium accelerated the senescence of Arabidopsis.Compared with normal conditions,the chlorophyll content in leaves and seeds of Arabidopsis 24 days after bolting decreased by 27.62 %,22.00 %,15.10 % and 26.57 %,18.28 %,11.76 %,respectively.Under the deficiency of nitrogen,phosphorus,and potassium,the chlorophyll content of leaves and seeds in the ggr mutant were significantly lower than that of wild type,which were decreased by 24.23 %,23.99 %,21.56 % and 36.42 %,31.88 %,30.14 %,respectively;the chlorophyll content of leaves and seeds in the vtc1 mutants were significantly lower than that of wild type,which were decreased by 10.93 %,14.19 %,18.12 %,and 17.07 %,16.58 %,15.89 %,respectively;the chlorophyll content of leaves and seeds in Arabidopsis treated with 5 mmol/L Vitamin E were significantly higher than that of wild type,which were increased by 22.84 %,21.33 %,17.19 % and 14.20 %,17.61 %,20.09 %,respectively.Spraying 5 mmol/L Vitamin C treatment had no significant effect on alleviating the senescence of Arabidopsis induced by the deficiency of macro-element.(4)Vitamin E and Vitamin C could attenuate the reduction in seed yield of Arabidopsis which caused by the deficiency of macro-element.The yield of Arabidopsis could be reduced by the deficiency of nitrogen,phosphorus and potassium.Compared with normal conditions,the seed yield per plant of wild type were decreased by 39.39 %,79.17 % and 72.73 %,respectively.Under the conditions of nitrogen,phosphorus,and potassium deficiency,the seed yield per plant of the ggr mutant was significantly lower than that of wild type,which were decreased by 66.25 %,59.09 %,and 58.33 %,respectively;the seed yield per plant of the vtc1 mutant was significantly lowe than that of wild type,which were decreased by 94.17 %,83.03 %,and 75 %,respectively;the seed yield of Arabidopsis treated with 5 mmol/L Vitamin E was significantly higher than that of wild type,which were increased by 95 %,30.9 % and 44.44 %,respectively;the seed yield of Arabidopsis treated with 5 mmol/L Vitamin C was significantly higher than that of wild type under nitrogen deficiency and potassium deficiency,which were increased by 76.25 % and 1.08 times,respectively.In conclusion,the deficiency of macro-element,Vitamin E and Vitamin C both result in impaired growth,increased senescence,and reduced seed yield per plant of Arabidopsis.Exogenous Vitamin E and Vitamin C are used to alleviate the deficiency of macro-element by enhancing the antioxidant capacity,delaying aging and increasing pod number.The relieving effect of Vitamin E is better than Vitamin C.