烟台海防林黑松种群胸径与种实性状关系

Relationships between diameter at breast height and cone/seed character of Pinus thunbergii population in Yantai coastal protection forest

为明确黑松海防林种群种子生产动态,以胸径作为年龄和个体大小的度量,对烟台黑松海防林种群胸径与种实性状的关系进行了研究。根据结实黑松的胸径大小及分布比例,将黑松海防林种群分为5个径级(3.5～6.5、6.5～9.5、9.5～12.5、12.5～15.5、15.5～19cm),并分别以5、8、11、14和17cm作为代表值,对各径级黑松种实性状进行多重比较及回归分析。结果表明:胸径大小对黑松种子生产有显著影响,随胸径增大,其生育力逐渐升高,达到17cm径级时开始略有下降;种子大小和百粒质量随胸径增大有下降趋势,种翅大小则有所上升,这是黑松种子生产中的一种权衡,种子减小的同时传播能力增强;各径级黑松均以可育种鳞数为预测球果产生种子数量和质量的最有效指标,但可育种鳞数并不能由球果的其他性状(如球果长、宽、干质量以及总鳞片数等)进行很好的预测,说明黑松种子生产为多因素控制过程。

To understand the seed production dynamics of Pinus thunbergii population in Yantal coastal protection forest, the relationships between the diameter at breast height （DBH） and cone/seed characters of the population were studied, with the DBH as the measurement of age and size. According to the DBH size and its distribution proportion, the population was divided into 5 diameter classes （3.5-6.5,6. 5-9.5, 9.5-12.5, 12.5-15.5, and 15.5-19 cm）, with 5, 8, 11, 14, and 17 cm as the measurement of each diameter class, respectively. Multiple comparison and regression analysis were conducted for the cone/seed character of each diameter class. The results showed that DBH had significant influence on the fecundity of P. thtmbergii. With increasing DBH, the fecundity increased first, but began to decrease when the DBH reached 17 cm. The seed size and 100-seed mass had a decreasing trend when the DBH increased, whereas the seed wing size was in adverse. This phenomenon might be a tradeoff in P. thunbergii seed production, i. e. , to decrease seed size and mass to increase seed dispersal abili- ty. For all DBH classes, the number of fertile scales was the most effective prediction variable of seed number and seed mass per cone, but could not better predict the other characters of cone, such as cone length, cone width, cone dry mass, and total number of scales, illustrating that the seed production of P. thunbergii was controlled by many factors.