不同产地苦楝苗期生长节律研究

Melia azedarach is widely distributed in China and has a wide range of genetic variation. Inorder to study the growth characters of 1-year-old seedlings of M. azedarach from different seed sources,the growth characters of seedling height, ground diameter, compound leaf growth and biomassaccumulation of M. azedarach seedlings from 15 seed sources were observed, and the growth rhythm wasfitted by logistic equation. The results were as follows: (1) There were significant differences in seedlingheight, ground diameter, root biomass, stem biomass and compound leaf correlation between differenthabitats(P<0.05 or P<0.01). (2) The growth of seedling heights and ground diameters showed aslow-fast-slow growth pattern with type S. Compared with the emergence time of seedling height growthpeak, the emergence time of ground diameter growth peak was later. (3) The R2 of logistic fitting equationwas 0.976-0.994, which reached the highly significant correlation level, indicating that the growth rhythm of M. azedarach could be fitted by logistic equation. (4) According to theoretical calculation and practicalobservation, the duration of fast-growing stage of ground diameter was generally 20-30 d longer than that ofhigh-speed growth stage of seedling. The time of seedling heights and ground diameters enteringfast-growing stage and ending fast-growing stage in northern locality was earlier than that in southernlocality. The cumulative growth of seedling height and ground diameter in fast-growing stage was morethan 60% of the total growth.5All though traits were negatively correlated with latitude, seedling height,biomass of root and leaf area were positively correlated with longitude, the other traits were negativelycorrelated with longitude. In general, M. azadarach begongs to full-time growth type with significantdifferences in growth traits among seed sources. The growth was regulated by latitude and longitude,mainly by latitude .