Study On The Relationship Between Components And Mechanical Properties Of Rice Stem

Rice stems plays an important role in supporting crop growth and nutrient transport.The main factors affecting the mechanical properties of rice stems are the cell wall composition,the degree of filling and the cross-sectional size of the stem.In this paper,a series of japonica rice brittle culm mutants'Wuyunjing7'and the new japonica rice brittle stem mutant 'kefujing7' with different growth performance at the growth stage obtained by heavy ion irradiation were used as research materials to study rice.The relationship between the cell wall composition,the degree of filling and the cross-sectional size of rice stems and the mechanical properties of stems provide a theoretical basis for the future breeding strategies and application of stems.The relevant research results are as follows:1.The results of cell wall component analysis showed that the ranges of the cellulose,hemicellulose and lignin of the series 'WuyunjingT brittle culm mutants were 16.99%?24.46%,19.40%?25.24%,and 3.51%?5.15%,respectively,the cellulose,hemicellulose and lignin contents of wild-type materials were 25.60%,15.68%and 3.95%,respectively.Compared with wild type,the brittle mutants mainly showed lower cellulose content and higher hemicellulose content.There was a significant positive correlation between cellulose content and bending strength and elastic modulus.The correlation coefficients were R3=0.9342 and R4=0.9413,respectively.The correlation between hemicellulose and lignin was not significant.2.There was a significant positive correlation between stem diameter,thickness and bending strength.The correlation coefficients were R1=0.8153 and R2=0.7080,respectively,but the correlation with stem bending strength was not significant;The bending strength of the same diameter of the adhesive materials prepared by different proportions was significantly positively correlated with the cellulose content(R6=0.9688),but it was significantly negatively correlated with the hemicellulose content(R7=-0.9688).3.The bending strength of mutant 'kefujing7' and wild type rice stems were decreased with the growth process,with the declines of 26.78%and 24.46%,respectively.Wind tunnel simulation experiments showed that both the mutants and the wild type rice at the milk-ripe stage had better lodging resistance.From the heading stage to the maturation stage stress-strain curve,it can be seen that the brittleness of the stems of the mutant material at the maturation stage is increased,showing the characteristics of brittle and easy to break.4.The water content of stems from heading stage to maturation stage showed a downward trend.The moisture content of mutants in mature stage was 7.29%higher than that of wild type,and the soluble sugar and starch decreased by 79.97%and 86.15%,respectively.It is suggested that the change of intercellular filling degree may be one of the mechanisms of stem brittleness in the mature stage 'kefujing7'.5.The research on the production and utilization of brittle mutant material showed that the yield traits also changed in addition to the stem becoming brittle and easy to break;the enzymatic efficiencies of mutant and wild type under acid pretreatment were 65.09%and 24.03%,respectively.Under alkaline pretreatment conditions,they were 73.81%and 34.00%,respectively,indicating that the brittle mutant has great value in the utilization and transformation of straw biomass.