Studies on Seed Development and Embryogenesis in Liriodendron chinense (Hemsl.) Sarg

Embryogenesis, seed formation and the relationship between pollination and seeding rate were investigated by means of artificial pollination, X-ray analysis, routine paraffin-embedded sectioning technique and fluorescence assay. Pollen germinated two hours after artificial pollination and the peak germination rate reached by six hours. The stigma vitality lasted about thirty hr. The pollen tube grew into the stigma canal through the secretion between the stigma hairs, then passed the style canal, obturator and nucellar cap and finally reached the embryo sac where porogamy was conducted. Two weeks after artificial pollination, ab initio cellular endosperm was formed first as a narrow tissue of two to three cells in thickness, but six weeks later it filled the entire embryo sac, along with the disappearance of the nucellus. The spherical or cordate-like embryo appeared during the seventh to the eighth week. The cotyledon was formed during the fourteenth to the sixteenth week. By the twenty-second weeks the seed became matured, containing abundant endosperm, the seeding rate of an individual plant with natural pollination was less than 1%; after artificial pollination, however the highest seeding rate of an individual fruit could reach 39%, the average rate of nine fruits being 17.7%.     

C-banding inLiriodendron tulipifera (Magnoliaceae): Some karyological and systematic implications

InLiriodendron tulipifera the Giemsa C-banding pattern differs remarkably from the distribution of condensed chromatin in prophase as revealed by conventional methods. The nature of proximal bands in metaphase chromosomes is interpreted to be different from the terminal ones. A comparison ofLiriodendron with some C-banded karyotypes of ± related taxa indicates a relatively high degree of karyomorphological differentiation in some woodyPolycarpicae. This has to be considered in karyosystematic comparisons.     

鹅掌楸人工林生长最优模型选择研究

选取鹅掌楸(Liriodendron chinense)标准木进行树干解析，采用Logistic、Webull、二次曲线等13个有代表性的数学模型对鹅掌楸胸径、树高和材积生长进行方程拟合。经筛选和验证，得出鹅掌楸胸径生长的最佳模型为：D= 75.6887{1-e–[(T+2.3354)/19.5656]^3.1489}；树高生长的最佳模型为：H=(55.5498+34.2298T1.9310)/(119.6386+T1.9310)；材积生长的最佳模型为：V=2.5736{1-e–[(T–2.2455)/16.3381]^3.8741}。这三个模型的决定系数均为0.9999，拟合精度分别为99.7258%、99.8827%、99.7930%，且平均偏差、平均绝对偏差、平均相对偏差、平均相对偏差绝对值较小。各林龄段的生长预测值和实测值比较，数据吻合度高，残差总体偏小，趋势线表现一致。各模型可用于指导预测福建省闽北地区鹅掌楸人工林中幼林的生长情况。