Comparative Study On Organ Ecological Stoichiometry Characteristics Of Lycium Ruthenicum

According to eco-chemometrics theory,the ratio of bio-elements determines the key characteristics of organisms,and the difference of element composition of organisms is related to their main ecological functions.Chemometric characteristics of plant organs can link environmental impacts with organ functional characteristics,thus providing a method for exploring the intrinsic mechanism of environmental effects on plant organ functions.The growth rate hypothesis is one of the main theories of eco-chemometrics.It is a theory about the relationship between the growth rate of organisms and N:P in vivo.So far,there is no consistent conclusion about whether the chemometric characteristics of terrestrial plants conform to the growth rate hypothesis.The contents of C,N and P in stems,leaves and roots,stems,leaves and fruits of Lycium ruthenicum at different growth stages were measured under natural conditions.The changes of eco-stoichiometric characteristics of stems and leaves and the differences between organs were compared and analyzed.The relationship between organ function and stoichiometric characteristics of Lycium ruthenicum was discussed.The relationship between stem and leaf growth rate and stoichiometric characteristics was analyzed through field irrigation and fertilization experiments.The main results are as follows:(1)Under natural growth conditions,the relative growth rate of aboveground biomass of Lycium ruthenicum showed a change of first low,then high and then low,and reached the maximum at fruit expansion stage,which was significantly higher than other periods(P < 0.05).During the growth period of Lycium barbarum L.,C,N,P content and C: N were relatively stable,C: P and N: P decreased gradually,but there was no significant difference during the growth period;C content and C: N,C: P content in stems were significantly higher than those in leaves,and N: P was significantly lower than that in leaves.Leaf C content in vegetative growth period was significantly higher than that in reproductive growth period(P < 0.05).N and P content decreased first and then increased,while C: N,C: P and N: P increased first and then decreased.There was a significant positive correlation with leaf N content(P < 0.05),a significant negative correlation between leaf N content and P content(P < 0.01),a significant negative correlation between aboveground biomass relative growth rate and stem N content(P < 0.05),and a significant positive correlation with stem C: N content.There was no significant correlation with leaf N,P content and C: P,N: P,which was not consistent with the prediction of growth rate hypothesis.(2)The content of C was stem > fruit > big root > fine root > leaf,N was leaf > fine root > fruit > big root > stem,P was fruit > fine root > stem > big root,C: N was stem > big root > fruit > fine root > leaf,C: P was big root > stem > leaf,C: P was big root > stem > leaf > fruit > fine root,N: P was leaf > big root > fine root > fruit > stem,and the content of CNP was closely related to the main functions of organs.(3)Irrigation and fertilization significantly increased the growth of stem length,basal diameter and leaf length,leaf width and leaf dry weight of Lycium ruthenicum(P < 0.05),but the relative growth rates of stem length,basal diameter,leaf area and leaf dry weight were not significantly different from those of the control.The contents of C,N,P and C: N: P in stems and leaves after irrigation treatment were significantly higher than those of the control(P < 0.05),but the contents of C,N and C: N in stems and leaves were not significantly different from those of the control(P < 0.05);the contents of C,N and P in stems and leaves and C: N,N: P in stems and leaves after fertilization treatment were not significantly different from those of the control,but C: P in stems and leaves was significantly lower than that of the control(P < 0.05).C content and C:N,C:P content in stems were significantly higher than those in leaves(P < 0.05).There was no significant difference in N and P content between stems and leaves,while N:P content in stems was significantly lower than that in leaves(P < 0.05).Under the influence of irrigation and fertilization,the relative growth rate of stem and leaf had no significant correlation with N,P content and C:P,N:P,but the relative growth rate of basal diameter had a significant negative correlation with leaf N content(P<0.05)and a significant positive correlation with leaf C:P content(P<0.05),and also with the growth rate hypothesis predicted that "individual growth rate was negatively correlated with in vivo N:P,C:P,and in vivo N,P." The results of content positive correlation were inconsistent.