苦楝不同种源苗期生长性状和生长节律研究

通过观测苦楝10个种源生长性状,分析苗高、地径和冠幅的生长节律,采用Logistic方程拟合其苗高、地径和冠幅生长过程。结果表明,拟合方程的决定系数为0.969~0.998,符合"S"型生长曲线;不同苦楝种源在苗高、地径和冠幅的物候期和生长参数上存在比较明显的差异,各种源前期生长量小于后期;不同种源速生期起始时间变动幅度为5—6月,最早与最晚时间在种源间相差20 d左右;速生期结束时间变动幅度为8—10月,最早与最晚时间在种源间相差50 d左右;速生期生长量占总生长量的比例均在58%以上,速生期生长量最大种源约为最小种源的2倍左右;地径和冠幅速生期起始时间相差不大,且均早于苗高;冠幅速生期结束最早,其次是苗高,最晚为地径;在速生期起始时间上,北方种源早于南方种源,在速生期结束时间上,北方种源晚于南方种源。

Growth Traits and Growth Rhythm of Melia azedarach Seedlings from Different Provenances

The growth traits of Melia azedarach seedlings from ten provenances were observed,and the growth rhythm of seedling height,ground diameters and crown width were analyzed by using the growth parameters simulated from the Logistic model.The results showed that the growth rhythm showed“Stype”curve.The determination coefficient varied from 0.969 to 0.998.There were significant differences in seedling height,basal diameter and canopy breadth among different provenances,the early growth was less than that in the later.The starting time of fast-growing period of different provenances changed from May to June,the earliest differed by 20 d from the latest one.The end time of fast-growing period changed in August to October there were about 50 d difference between the earliest and the longest prove-nance.In the fast-growing period,the growth accounted for the total growth in more than 58%.The provenance with the biggest growth amount in fast-growing period was about 2 times of the smallest provenance.There were no significant differences between ground diameters and crown width,and they started earlier than seedling height in the starting time of fast-growing period.The finish time of fast-growing period of crown width was earliest,and then was height and ground diameter.In general,the provenances from the northern were earlier than the ones from the southern in the start-ing time of fast-growing period,but were later in the ending time of fast-growing period.