Simulating growth model of different Magnolia officinalis provenances at seedling stage | 厚朴不同种源苗期生长模型的拟合

Chinese. 掌握厚朴不同种源苗期苗高、地径的生长规律及物候期参数和生长参数特征，为厚朴幼苗生产管理和优良种源筛选提供参考。对15个不同种源及2个种源区厚朴幼苗在苗期的生长状况进行连续观察，并用Logistic方程对其生长动态过程进行拟合，获得苗高、地径、物候期与生长特征参数。厚朴不同种源间苗高生长节律基本一致，速生期起止时间和持续时间存在较大差异，其中线性生长始期、线性生长末期和线性生长持续期最多分别相差21，22和18 d，线性生长量占总生长量的55%以上，该时期为幼苗生长的关键期；种源间幼苗地径的线性生长期、最大线性生长速率、线性生长速率均存在较大差异；苗高与线性生长始期、线性生长末期、最大线性生长速率、线性生长速率、线性生长量呈显著或极显著相关，地径与后三者及苗高呈极显著相关，线性生长始期和线性生长末期共同决定线性生长期和线性生长量。种源A区厚朴幼苗的苗高线性生长期比种源B区长15 d左右，种源A区厚朴幼苗的苗高和地径的最大线性生长速率、线性生长速率和线性生长量均高于种源B区。用Logistic方程可以拟合厚朴幼苗苗高和地径的生长动态，建议在幼苗线性生长期加强肥水管理，延长该生长期，促进线性生长量，提高线性生长量占总生长量的百分率。

English. The study was to know the growth pattern of seedling height, stem diameter, phenophase and growth parameters to lay a foundation of seedling cultivation management and provenance selection. Seedling height and stem diameter at ground level of 15 Magnolia officinalis provenances and 2 provenance areas at seedling stage were measured and simulated with S-shaped curves logistic equation. Seedling height, stem diameter, phenophase and growth parameters were abtained. The height growth rhythm among provenances were uniform. There were difference between early stage of linear growth and sustainable growth, such as early stage of linear growth, and final stage of linear growth. The longitudinal sustainable growthes were respectively 21, 22 and 18 d, with total growth more than 55% at the stage of linear growth, which was the critical stage of seedling cultivation management. At the same time, there existed difference among linear growth day, maximum growth rate, linear growth rate of stem diameter in different provenancs. Extremely significant or significant correlations were observed between seedling height and early stage of linear growth, final stage of linear growth, maximum growth rate, linear growth rate and total linear growth. Extremely significant correlations were also observed between stem diameter and the last three parameters, linear growth day and total linear growth were decided by early stage of linear growth and final stage of linear growth. Linear growth stage of seedling height from area A were 15 days more than that from area B. In the mean while, these index, such as maximum growth rate, linear growth rate and total linear growth of seedling height and stem diameter from area A, were all superior to those from area B. The logistic equation about seedling height and stem diameter were feasible in this study, and the strengthened management of water and fertilizer were suggested at seedling stage, in order to prolong the stage, to motivate total linear growth, and to raise the ratio of total linear growth.