Study On The Physiological And Biochemical Response Of Oil-sunflower To Salt Stress Of Na~+ And Agronomic Character Manifestation

In order to define the adaptability range of salt tolerance and oil-sunflower mechanism, study the effects of salt stress on germination of seeds,main economic character, agronomical character,biological yield,and physiological and biochemical indexes of oil-sunflower.1.NaCl,NaHCO₃,NaHCO₃+NaCl and the temperature exert the stress and collaborated effect on the germination trend and germination rate of oil-sunflower: With the temperature increased,the seed germination trend and germination rate significantly increased,and with the increase of concentrations the seed germination trend and germination rate significantly dropped.The germination trend decreased by 86.1%, 75.0%and 33.3%compared with the contrast while the temperature was 15℃,25℃and 35℃.The germination trend and germination rate of oil-flower seed under the different temperature were harmed by the salt stress,while the order of the temperature was 15℃＞25℃＞35℃.The high temperature combined high salt concentrations increased the harm of the radicel length and fresh weight of cotyledon.The germination trend and germination rate of oil-flower seed were harmed under the salt stress,and the sequence of damage degree was NaCl＞NaHCO₃+NaCl＞NaHCO₃.The main reason of harm by salt stress on the germination of oil-sunflower seed was ion toxicity.Under salt environment,the suitable temperature can effectively increase the germination trend.Thus,the suitable sowing time can be chosed and alleviate the salt stress through shortening the germination time.2.The effects of the salt stress on different organs in different period:The salt stress significantly prolonged procreation period,the asexuality growing stage had more bigger effects on procreation course than on the sexual reproduction growing stage,and the salt stress had higher effect on the ground parts than on the under ground parts in adult period. With the increase of salt concentrations,plant height,leaf area,stem wide,branches diameters,and grain weight significantly decreased.When the salt concentrations exceeded 5.5g/kg,the ration of the root weight to the shoot weight and the activity of roots began to drop significantly,and ratio of living absorbance area to the total absorbance area of roots reduced.The high salt stress could change the sink-source relation,and more significantly affected the economical yield than the biomass yield.The high salt stress can also differently affected the dry matter at different growing stage,and the sequence of growing stage was filling>maturity>flowering>budding>seedling stage.When the soil salt content exceeded 6.0g/kg,the growth of oil-sunflower could be restrained seriously.3.The effect of NaCl+NaHCO₃ dealt with physiological and biochemical indexes under different salt range at different procreation:The cell membrane permeability in seedling stage was higher than that in squaring and flowering period,and when the salt concentrations exceed 6.0g/kg,the cell membrane permeability significantly increased.The SOD activity of leaf in oil-sunflower seedling was strong,reaching maximum at the salt concentration of 7.5 g/kg.The salt stress could influence the POD activity of root and leaf differently,and the POD activity of root peaked at the salt concentrations of 9.5g/kg,and the POD activity peaked at the salt concentrations of 11.5g/kg.The salt stress can differently affect the chlorophyll content of sprout at different growing stage,and the sequence of growing stage was seedling>budding>flowering period,and the chlorophyll content peaked at salt concentration of 6.5 g/kg.The salt stress can differently affect proline content at different growing stage,and the sequence of growing stage was budding>seedling>flowering.The proline content quickly increased from 100μg/g to 1000μg/g at the salt concentrations of 8.5g/kg in squaring period,which is ten times that of in seedling and flower period.In the salt content of 6.5g/kg,the MDA content was minimum in seedling period,then began to significantly increase;however,in squaring and flowering period,the MDA content was minimum at the content of 6.0g/kg,and then began to significantly increase.Based on a comprehensive analysis of the maximum value of cell membrane permeability,chlorophyll content,the corresponding minimum value of proline,and malonaldehyde content corresponding in different salinity zone,we can conclude that the most sensitive range soil salt content of oil-sunflower was about 6.5g/kg.4.Effects of salt stress on oil content and fatty acid of oil-sunflower:The salt stress significantly restrained the accumulation of seed and kernel;moreover,the influence to oil content of kernel was greater than did oil content of seed.With the increase of salt concentrations,the production of oleic acid was restrained,and linoleic acid was improved. The sequence of influence of soil salt content on fatty acid was:palmitic acid>oleic acid> linoleic acid> Itearic acid> linolenic acid.5.The effects of salt stress on the main physiological and biochemical of oil-sunflower:Cell membrane permeability significantly increased with the concentration of salt increasing,and the translucency function was so damaged as to make chlorophyll extravasated,the content of Na⁺ increased,K⁺ decreased,metabolic balance damaged,ion toxicity aggravated,and diversified secondary injuries induced,oil-sunflower self-restoration capability increased under salt stress,mainly because oil-flower contained oxygen free radical which could eliminate harmful substance during salt stress period so that the substance had a protective effect on the cells,and increased SOD and POD activity, especially in each stage.6.The crude ash content of plant and desalting efficiency of oil-sunflower:The content of Na⁺ in plant was 2～6 times than that of in the root systems and the difference enlarged with the increase of salt concentration,which showed that the loss of soil salt was mainly through oil-sunflower plant absorbed.The sequence of the ash content of oil-sunflower at different growing stage was seedling period＞budding＞flowering＞maturity＞filling period.When the soil salt concentration exceeded 6.0g/kg,the oil-sunflower growth could be significantly restricted,and the effect of desalting had no economical meaning.So if we want to obtain better desalting effects,we must ensure a certain number of biomass-yield on the ground part of oil-sunflower.