繁殖方式对杉木根系不同序级生物量、形态性状及碳氮含量的影响

[Objective]Understanding the effects of propagation methods on the biomass allocation and growth of different order roots of Chinese fir saplings is helpful to understand the differences in the early development level and growth strategies of individual roots of Chinese fir saplings due to propagation methods.[Method]Chinese fir saplings cultivated for 1 year by seed germination,tissue culture and rooted cutting were used as the research objects to determine and compare the differences in biomass,morphological traits and tissue carbon and nitrogen content of Chinese fir roots at different order levels,and analyze the internal relationships among the measurement indexes of root biomass at different order levels,so as to explore the differences in the influence of propagation methods on early root growth strategies of Chinese fir saplings.[Result](1)The root shoot ratio of Chinese fir saplings cultured by different propagation methods had a significant difference(P<0.05),and the results showed that rooted cutting>seed germination>tissue culture seedlings.According to the distribution of root biomass in the same sequence,the root biomass(0.68±0.13g)of the first grade of rooted cuttings was 4.31 times and 1.09 times that of the seed germination and tissue culture,respectively.The root biomass of tissue culture at grades 2-4 was significantly higher than that of seed germination and rooted cuttings,1.19±0.21g,1.63±0.19g and 1.82±0.27g,respectively.The biomass accumulation rate of tissue culture and rooted cuttings was faster.(2)With the increase of root order level,the average diameter,tissue density,C content and C/N of the roots of Chinese fir seed germination,tissue culture and rooted cuttings gradually increased,while the changes of specific surface area,specific root length and N content were opposite.(3)Chinese fir seed germination dominated 1-2 root extensions through 4-grade root growth,and their 4-grade root biomass and 1-2 grade root specific surface area were significantly larger than those of tissue culture and rooted cuttings.However,the functional level of different order roots of tissue culture and rooted cuttings was higher than that of seed germination,and the absorption and utilization of resources were enhanced mainly by increasing the root length of grade 1,and the root length of grade 1 was significantly greater than that of seed germination.(4)The N content of 1-2 roots of tissue culture and rooted cuttings was significantly higher than that of seed germination,but the N content of 3-4 roots was significantly lower than that of seed germination.The C content of 1-4 roots of tissue culture was significantly lower than that of seed germination and rooted cuttings.The C/N of grade 1 order roots of tissue culture and rooted cuttings was significantly lower than that of seed germination.(5)The root biomass of seed germination was related to grade 1 order roots tissue C,N,2-3 roots of the morphological traits,4 roots has significant relationship with both of them.The root biomass of tissue culture and rooted cuttings had significant relationship with morphological traits at 1-2 roots,and with morphological traits,tissue C and N at 3-4 roots,respectively.[Conclusion]There are differences in the early development level of Chinese fir saplings cultivated by different propagation methods,and the roots of seed germination have the growth strategy of exploring soil space resources.The root function of tissue culture is similar to that of rooted cuttings,showing a growth strategy to enhance the absorption and utilization efficiency of occupied space resources.Fully considering the influence of the root development level of Chinese fir on the growth of the whole plant,the quality of afforestation can be better improved by selecting saplings cultivated in suitable propagation methods for afforestation.